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Circulation January 31, 2023 Issue Jan 31, 2023

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Please join Guest Host Maryjane Farr, authors Sarah Franklin and Stavros G. Drakos, as well as Associate Editor Hesham Sadek as they discuss the article "Distinct Transcriptomic and Proteomic Profile Specifies Heart Failure Patients With Potential of Myocardial Recovery on Mechanical Unloading and Circulatory Support." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your cohosts. I'm Dr. Carolyn Lam, associate editor from the National Heart Center in Duke National University of Singapore. Dr. Peder Myhre: And I'm Dr. Peder Myhre, social media editor from Akershus University Hospital and University of Oslo. Dr. Carolyn Lam: Peder, today's featured paper is very, very important in the heart failure world. It is such a deep dive into the transcriptomic and proteomic profile that specifies heart failure and the potential of myocardial recovery with mechanical unloading and circulatory support. Dr. Peder Myhre: Can't wait for that feature discussion today, Carolyn. Dr. Carolyn Lam: But you have to wait because I insist on telling you about yet another really important paper, of course in my favorite subject, heart failure with preserved ejection fraction or HFpEF. Now you know that exercise intolerance is a defining characteristic of HFpEF and a marked rise in pulmonary capillary wedge pressure during exertion is pethepneumonic for HFpEF and it's thought to be a key cause of the exercise intolerance. Now if that is true, acutely lowering the wedge pressure should improve exercise capacity, right? Well, don't assume this because to test this hypothesis, authors led by corresponding author Dr. Ben Levine from UT Southwestern evaluated peak exercise capacity with and without nitroglycerin, which was used to acutely lower pulmonary capillary wedge pressure during exercise in patients with HFpEF. Dr. Peder Myhre: Oh, that's so cool. What an amazing research question and Carolyn, you're the best to summarize this. Please tell us what did they find? Dr. Carolyn Lam: Well, they studied 30 patients with HFpEF and get this. They underwent two bouts of upright seated cycle exercise dosed with sublingual nitroglycerin or a placebo every 15 minutes in a single blind randomized crossover design. So really well done. Wedge pressure, VO2 and cardiac output were assessed at rest with 20 watts exercise and at peak exercise during both the placebo and nitroglycerin conditions and the principle finding of the study (singing) acutely lowering pulmonary capillary wedge pressure during upright exercise with nitroglycerin in HFpEF did not improve peak exercise performance. So peak VO2 was practically identical with a 1% difference despite a 17% drop in peak wedge pressure. Peak cardiac output and peak peripheral oxygen extraction were unchanged, again, despite the drop in peak wedge pressure suggesting that oxygen delivery and utilization were unaffected. Exercise performance variables including peak wattage, peak ventilation and peak RER were unchanged, suggesting that again, reductions in peak wedge were insufficient to improve exercise tolerance. All these results suggest acute reductions in wedge pressure are insufficient to improve exercise capacity and provide convincing evidence that a high wedge during exercise by itself is an epiphenomenon perhaps rather than a primary limiting factor for exercise performance in patients with HFpEF. Now of course this is incredibly interesting contrary to hypothesis and so please read the paper. The discussion is very rich. Dr. Peder Myhre: Oh wow, Carolyn. That is such a great paper. I can't wait to pick it up and read it from start to finish and now Carolyn, we're going to look into research within cardiovascular disease from COVID-19 and we have learned so much and so quickly about COVID-19 and its effects on the heart and we have really come a long way from the first case reports reported in the beginning of the pandemic and this paper, which comes to us from corresponding author Professor JP Greenwood, really adds important knowledge to this field. The COVID heart study was a prospective longitudinal multi-center observational cohort study of patients hospitalized with COVID-19 and at elevated serum troponin levels across 25 hospitals in the UK and these investigators aim to characterize myocardial injury, its association and sequela in convalescent patients following hospitalization with COVID-19 utilizing appropriately matched contemporary controls. Dr. Carolyn Lam: Ooh, important stuff. So what did they find? Dr. Peder Myhre: So these authors included in total 519 patients comprising 342 patients with COVID-19 and an elevated troponin, 64 patients with COVID-19 and a normal troponin and 113 age and comorbidity matched controls without COVID-19 and the frequency of any heart abnormality defined as left or right ventricular impairment, scar or pericardial disease was two full greater in patients with COVID positive and troponin positive, so 61% compared to the control groups and that is 36% for COVID positive and troponin negative and 31% for COVID negative and comorbidity positive and the myocardial injury pattern was different for these patients with COVID and an elevated troponin more likely than controls to have infarction and micro infarction. But there was no difference in non-ischemic scar and using the late MRI criteria, the prevalence of probable recent myocarditis was almost 7% for those with COVID and elevated troponin compared to only 2% for the controls without COVID-19 and myocardial scar is but not prior COVID-19 infection or troponin was an independent predictor of MACE. So Carolyn, these authors discussed their findings in light of previously reported studies and these authors identified a lower prevalence of probable recent myocarditis than previously described and a higher proportion of myocardial infarction and this newly described pattern of micro infarction following COVID-19 and Carolyn, there is a brilliant editorial really summarizing this by Dr. Stuber and Baggish entitled "Acute Myocardial Injury in the COVID Heart Study Emphasizing Scars While Reassuring Scarce." I really recommend everyone to pick this up and read the editorial as well. Dr. Carolyn Lam: Very clever title. Thank you. For the last original paper in today's issue, it focuses on the crosstalk between sterile metabolism and inflammatory pathways, which have been demonstrated to significantly impact the development of atherosclerosis. Authors today are featuring and focusing on 25 hydroxy cholesterol, which is produced as an oxidation product of cholesterol and belongs to a family of bioactive cholesterol derivatives produced by cells in response to fluctuating cholesterol levels and immune activation. So these authors with co-corresponding authors, Dr. Suárez and Fernández-Hernando from Yale University School of Medicine, they showed beautifully that first, 25 hydroxy cholesterol accumulates in human coronary atherosclerosis. Next, that 25 hydroxy cholesterol produced by macrophages accelerated atherosclerosis progression and promoted plaque instability by promoting the inflammatory response in macrophages and also via paracrine actions on smooth muscle cell migratory responses. Dr. Peder Myhre: Wow, that is so interesting, Carolyn. What are the therapeutic implications of these findings? Dr. Carolyn Lam: Yes, I'm glad you asked because it was summarizing a lot of work in those findings with the very important implications that inhibition of 25 hydroxy cholesterol production might therefore delay atherosclerosis progression and promote plaque stability. So this study actually opens a door to explore the role of 25 hydroxy cholesterol as a target to control inflammation and plaque stability in human atherosclerosis. Dr. Peder Myhre: Oh, that is so important. Thank you so much and there is more in this issue as well, Carolyn. We have another issue of Circulation Global Rounds and this time we're going to France in a paper written by Dr. Danchin and Bouleti. We also have an exchange of letters by Dr. Yang and Dr. Schultze regarding the article, "Deep Lipidomics in Human Plasma: Cardiometabolic Disease Risk and Effect of Dietary Fat Modulation" and an ECG Challenge by Drs. Manickavasagam, Dar and Jacob entitled "Syncope After Transcatheter Aortic Valve Implantation: Pace or Not." Dr. Carolyn Lam: Interesting. There's a Frontiers paper also by Dr. Dimopoulos on "Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus," a Research Letter by Dr. Kimenai on the impact of patient selection on performance of an early rule out pathway for myocardial infarction from research to the real world. Nice. Well let's carry on to that feature discussion on heart failure, transcriptomics and proteomic, shall we? Dr. Peder Myhre: Can't wait. Dr. Maryjane Farr: Welcome everybody to Circulation on the Run. We are so pleased to be talking with Dr. Stavros Drakos and Dr. Sarah Franklin from the University of Utah. My name is Maryjane Farr and I am the heart failure section chief at UT Southwestern and Digital Strategies editor for circulation. Myself and Hesham Sadek will be talking with them about their new paper and circulation called "Distinct Transcriptomic and Proteomic Profile Specifies Heart Failure Patients with Potential of Myocardial Recovery Upon Mechanical Unloading and Circulatory Support." Just briefly, Dr. Stavros Drakos is the director of cardiovascular research for the division of cardiology at Utah and co-director of the Heart Failure Mechanical Circulatory Support and Heart Transplant Program. Dr. Sarah Franklin is associate professor of medicine at the University of Utah whose lab has a specific expertise in the applications of proteomics to heart disease. Welcome, Stavros and Sarah. Dr. Sarah Franklin: Thank you. Dr. Stavros Drakos: Thank you. Thank you for having us. Dr. Maryjane Farr: This paper is exciting for clinicians. It's exciting for translational scientists. Hesham, why don't you start digging into this paper and tell us one or then the other of you tell us what this paper is about, what's the background and let's get into the science. Let's go there and then we'll pull back and look at some of the big picture stuff. Hesham. Hesham Sadek: Well, thank you. So I've been fascinated by the field of cardiac recovery for some time now and obviously Stavros is as an expert and one of the leaders of that field and what struck me about this is that we are starting to see some distinct molecular signature of patients that can experience recovery as opposed to patients undergoing the same procedures with the same profile that do not manifest evidence of myocardial recovery and specifically, the study was conducted very rigorously and the signature was very clear in that they saw primarily interest for someone like me who's interested in cardiac regeneration, a signature of cell cycle in the patients that experience recovery as well as ECM signature which could suggest reverse remodeling and also there's some evidence that ECM might impact cardiomyocyte and myocardial regeneration. So my interest in this for selfish reasons is primarily that this supports the hypothesis that perhaps there is a molecular signature of regeneration that occurs in patients that experience myocardial recovery with LVAD. Dr. Maryjane Farr: So Stavros, let's start with you. Give us the reason why to do this study. You mentioned some of the background. It'd be great to sort of talk for a moment about re-stage heart failure and then how it brought you to this study. Dr. Stavros Drakos: Thank you, Jane. So again, thank you for the opportunity to talk about the findings and the implications of this study. I like the way you are asking us to look a little bit at what led to this study and as you mentioned, the re-stage is a multi-center study that was performed in six US sites which showed in a reproducible fashion now given that we had single center studies from all over the world suggesting that, advanced heart failure is not an irreversible process that has to lead to end stage, an irreversible disease and what a re-stage demonstrated was that there is a subset of patients which if you select them based on clinical characteristics that we derived from other studies that were performed previously, you can achieve reverse remodeling, essentially a bad heart looking much better by every clinical, functional, structural characteristic in up to 50% of the selected patients. That's what re-stage showed. So having this finding now in a multicenter study, what made this study very timely was to be able to understand what drives this remarkable response. What are some of the mechanisms, as Hesham said, that we can if uncover take advantage of and expand this paradigm and enhance it and achieve reverse remodeling and recovery of even more patients and even go earlier in the disease process. So that's kind of how I would link the clinical findings that preceded this study with the motivation to perform the study and the implications of these findings for the ongoing translational and basic science research. Hesham Sadek: I'd like to ask a question here. So Stavros, do you think it's too early to sort of redefine the term reverse remodeling in this context to include perhaps some evidence of regeneration? Is there evidence of regeneration in this field or that's too premature to say? Dr. Stavros Drakos: I think the data are directing us towards the direction you just mentioned. I think that we can begin talking about it and planting the seed. We do have other evidence from work that you and others have performed indicating that this indeed is one of the mechanisms that drives this phenomenon and I think that the findings, especially in the cell cycle that we identified add to and contribute even more to that body of work that you and others have done. At this point, I will turn it to Sarah who can talk a little bit more about the findings related to the cell cycle that we identified in our study and I think that these may complete the answer to you, Hesham. Dr. Sarah Franklin: Yeah, I would love to comment. I think it's a really interesting phenomenon and really in these patient samples we were trying to understand molecularly what the difference is between individuals that respond positively to therapy and individuals that receive the same exact therapy and do not respond positively. So these are termed responders and non-responders and in our analysis we combined two platforms where we could molecularly interrogate what's different in these two tissues and try to see what is differentiating these populations. So what's consistent and reproducible different in responders and non-responders on a molecular level and in both the transcriptomic data and the phospho proteomic data, we saw clear patterns with cell cycle regulation and extracellular matrix or focal adhesion molecules and the interesting thing about cell cycle is cardiomyocytes have typically been thought to exit the cell cycle not long after birth and we see some interesting phenomenon either in humans or mice where we can have nuclei that have either multiple sets of chromosomes or multiple nuclei and there's some differences that have been observed in the nucleus with regards to disease, so hypertrophy, heart failure. So the molecules that we've identified, we saw a large difference in proteins involved in cell cycle regulation. Now the interesting thing is not all of those molecules are increasing or decreasing. We see a combination of molecules that are increasing or decreasing. But I think the other t…

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Circulation January 24, 2023 Issue Jan 23, 2023

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Please join author Subodh Verma and Guest Editor Christopher Granger as they discuss the article "Empagliflozin and Left Ventricular Remodeling in People Without Diabetes: Primary Results of the EMPA-HEART 2 CardioLink-7 Randomized Clinical Trial." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-host. I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore. Dr. Peder Myhre: And I'm Dr. Peder Myhre, social media editor and doctor at Akershus University Hospital at University of Oslo in Norway. Dr. Carolyn Lam: Peder, I am so excited to be discussing this issue. So many great articles and a feature discussion coming up on the SGLT2 inhibitor, empagliflozin. And do you think it's got effects on left ventricular remodeling in people without diabetes? Very interesting question. Dr. Peder Myhre: That is so interesting, Carolyn. I can't wait to hear this discussion. Dr. Carolyn Lam: Yep, I agree, but we got to wait till we discuss the other papers in today's issue. I want to go first. So we know that non-vitamin K oral anticoagulants, or NOACs, they've become the standard therapy for preventing stroke and ischemic thromboembolism in most patients with atrial fibrillation. But, what is the effectiveness and safety of NOACs in patients on dialysis? That is hemodialysis. The AXADIA-AFNET 8 study sought to test the hypothesis that apixaban would be non-inferior to vitamin K antagonists in these very patients undergoing hemodialysis. Dr. Peder Myhre: Oh wow. This is really a gap of knowledge that we've been waiting to hear more about. NOACs in patients with hemodialysis. Tell us about this trial, Carolyn. Dr. Carolyn Lam: Sure. So this is from corresponding author, Dr. Reinecke, and colleagues, from University of Munster in Germany. And it's an investigator initiated prospective randomized open-blinded outcome assessment of 97 patients with atrial fibrillation on chronic hemodialysis randomized to either apixaban 2.5 mg BID, or a vitamin K antagonist, aiming for an INR between 2 and 3. Over a median follow-up time of 429 days for apixaban, and 506 days for the vitamin K antagonist, the composite primary safety outcome of first, major bleeding, clinically relevant, non-major bleeding, or all cause death, occurred in 46% of patients on apixaban, and 51% of patients on the vitamin K antagonist. That would be a hazard ratio of 0.91, with a p for non-inferiority being 0.157. How about the primary efficacy outcome? While this was a composite of ischemic stroke, all cause death, myocardial infarction, or deep vein thrombosis, and/or pulmonary embolism, and that occurred in 21% of patients on apixaban and 31% of patients on the vitamin K antagonists. Again, no difference when there was testing. So, in summary, Peder, there were no differences in the safety or efficacy observed between apixaban and vitamin K antagonists in patients with atrial fibrillation on chronic hemodialysis. Of note, however, even receiving oral anticoagulations, these patients remain at very high risk of cardiovascular events. So these data really support the consideration of apixaban for prevention of cardiovascular complications in patients with atrial fibrillation on chronic hemodialysis, but larger studies are definitely needed. Dr. Peder Myhre: Oh wow, Carolyn, that is so clinically relevant. And the next paper is also a clinically relevant paper. And it comes to us from the SPRINT authors. And to remind you, the SPRINT study was a study of intensive systolic blood pressure lowering compared to standard blood pressure lowering. And the results demonstrated that there was a robust reduction in both heart failure endpoints and all cause mortality. And in this sub-study that comes to us from corresponding author Jarett Berry from University of Texas Tyler School of Medicine, these authors look at the mechanisms through which intensive blood pressure lowering reduces the risk of these endpoints. And given the important role of cardiac injury and neurohormonal activation in the pathways leading from hypertension to heart failure, and strong association that has been observed between hypertension and levels of cardiac troponin and NT-proBNP, the authors hypothesized that intensive systolic blood pressure lowering would decrease levels of high sensitivity cardiac troponin T and NT-proBNP. Dr. Carolyn Lam: Cool. That's interesting. So how did they do this, and what did they find? Dr. Peder Myhre: So, as expected, Carolyn, the authors found that increases in troponin and NT-proBNP from baseline to 1 year were associated with a higher risk of heart failure and death. And there were really no significant interaction by treatment assignment. But let's look at the changes in troponin. And these results showed that randomization to intensive blood pressure lowering versus standard blood pressure lowering resulted in a significant 3% increase in cardiac troponin T level over 1 year follow up, and a higher proportion of participants with more than 50% increase, and that's with an odds ratio of 1.47. And Carolyn, in contrast, NT-proBNP decreased by 10% in intensive blood pressure arm. And these patients had substantially lower probability of increasing more than 50% in NT-proBNP, with an odds ratio of 0.57 compared to the standard arm. And now, to the most interesting part of this analysis, Carolyn, the association of randomized treatment assignment on changes in troponin was completely attenuated after accounting for changes in eGFR during the follow up, whereas the association of treatment with NT-proBNP changes were completely attenuated after adjusting for changes in systolic blood pressure. So Carolyn, the authors highlight in their discussion the importance of non-cardiac factors influencing variation in cardiac biomarkers, and raise questions about the potential role of cardiac troponin T as a surrogate marker for heart failure or death in blood pressure lowering studies. Dr. Carolyn Lam: Wow, very interesting. Thanks, Peder. Can I tell you now about a preclinical study? Very interesting, because it shows that cardiac inflammation and hypertrophy are regulated by a heart-brain interaction. Dr. Peder Myhre: Wow, Carolyn, a heart-brain interaction. I'm excited to hear more about this. Please explain. Dr. Carolyn Lam: I'd love to, but first some background. Interleukin-1 beta, now that is a pro-inflammatory cytokine that causes cardiac hypertrophy and heart failure. I need to familiarize you with this, the nucleotide-binding domain leucine-rich containing family, pyrin domain-containing-3, NLRP3 for short, which is an inflammasome, which is a cytosolic multiprotein complex that mediates active interleukin-1 beta production. Okay? So you know these terms, and now I want to tell you about the study. This is an elegant series of experiments performed by co-corresponding authors, Dr. Higashikuni, from University of Tokyo, and Dr. Sata, from Tokushima University Graduate School of Medicine, and their colleagues. They first showed that genetic disruption of the NLRP3 inflammasome resulted in significant loss of interleukin-1 beta production, cardiac hypertrophy, and contractile function during pressure overload. Next, a bone marrow transplantation experiment revealed an essential role of NLRP3 inflammasome in cardiac non-immune cells in myocardial interleukin-1 beta production and the cardiac phenotype. It was extracellular ATP released from sympathetic nerve terminals that induced the hypertrophic changes of cardiac cells in an NLRP3 and interleukin-1 beta dependent manner in vitro. And finally, depletion of ATP release from sympathetic efferent nerves, or ablation of cardiac afferent nerves, or a lipophilic beta-blocker, all reduced cardiac extracellular ATP, and inhibited the NLRP3 inflammasome activation, the interleukin-1 beta production, and the adaptive cardiac hypertrophy during pressure overload. So all of this suggests that controlling the neuronal brain signals might have therapeutic potential for the treatment of hypertensive heart disease. Neat, huh? Dr. Peder Myhre: Oh, that is so interesting. The heart and brain interaction. And, Carolyn, we're going to stay in the field of preclinical science. And now we're going to talk about another field that is really interesting, and that is regeneration of cardiomyocytes. Because, Carolyn, developmental cardiac tissue holds remarkable capacity to regenerate after injury, and consists of regenerative mononuclear and deployed cardiomyocytes. Whether reprogramming metabolism promotes persistence of these regenerative mononuclear and deployed cardiomyocytes that enhance cardiac function in repair after injury is unknown. Therefore, these researcher, led by corresponding author, Mohsin Khan, from Temple University School of Medicine, investigated whether the RNA binding protein, LIN28a, which is a master regulator of cellular metabolism, plays a role in cardiac repair following injury. Dr. Carolyn Lam: Wow. That is always, always interesting, regeneration and repair following injury. So what did the authors find? Dr. Peder Myhre: Well, Carolyn, through a number of elegant experiments, the authors made the following key findings. For the first time, they documented a role for RNA binding protein LIN28A in regulating cardiomyocyte turnover in the postnatal and adult heart. And LIN28a overexpression promotes cardiomyocyte cell cycle activity during postnatal development and extends cardiac regenerative ability of the mammalian heart to postnatal day 7. And in the adult heart, the authors could demonstrate that LIN28a drives new myocyte formation, augmenting cardiac structure and function after myocardial injury. And Carolyn, I'm sure you're going to ask the clinical implications of this study. Dr. Carolyn Lam: Indeed. Dr. Peder Myhre: And that is that these results may suggest a novel translational role for LIN28a based strategy to replenish cardiomyocytes in the adult heart after injury. Dr. Carolyn Lam: Very nice, Peder. Thank you. Also in the issue is a Research Letter by Dr. Bick on interleukin-6 receptor polymorphism attenuates clonal hematopoiesis mediated coronary artery disease risk among many individuals in the UK Biobank. There's also Cardiology News by Tracy Hampton, where she highlights few really interesting things, like aging cardiomyocytes accumulate new genetic mutations that was published in Nature Aging, cytokines promote tissue repair after a heart attack in mice, and that was published in Science, and scientists identifying molecular alterations in a failing heart at a single cell resolution, which was published in Nature. Dr. Peder Myhre: And there are a couple of other papers also in this issue, Carolyn. And there's first, an exchange of letters by Drs. Halushka, Lu, and Mayr, regarding the article "Circulating MicroRNA-122-5p is Associated with a Lack of Improvement in Left Ventricular Function after TAVR and Regulates Viability of Cardiomyocytes Through Extracellular Vesicles." And finally, we have an "On My Mind" piece by doctors Monda and Limongelli entitled "An Integrated Sudden Cardiac Risk Prediction Model for Patients with Hypertrophic Cardiomyopathy." Dr. Carolyn Lam: Oh, nice. Nice full issue. Thank you, Peder. Let's go to our feature discussion now. Shall we? Dr. Peder Myhre: Let's go. Dr. Greg Hundley: Welcome listeners to this feature discussion on January 24th. And we have with us Dr. Subodh Verma, from St. Michael's University in Toronto, Canada. And a guest editor, Dr. Christopher Granger, from Duke University in Durham, North Carolina. Welcome gentlemen. Well, Subodh, we will start with you. Can you describe for us some of the background information that went into the preparation of your study, and what was the hypothesis that you wanted to address? Dr. Subodh Verma: First, my great pleasure to be here, and thank you very much for the opportunity to discuss this paper with your viewers. As you know, SGLT2 inhibitors have been truly transformative therapies. From a heart failure perspective, we know that they prevent incident heart failure in people with diabetes who have vascular disease or risk factors. They also have been shown to treat prevalent heart failure in people with heart failure and either a reduced, mildly reduced, or preserved ejection fraction independent of glycemic status. And really, these have been the basis of very strong recommendations to use these agents in the prevention of heart failure in people with diabetes, and also in the treatment of prevalent heart failure in people with and without diabetes. Now, the fact that these drugs have such broad effects in people with heart failure has led to a theory that maybe these drugs could be introduced earlier on in the natural history of heart failure in people who neither have diabetes nor have significant heart failure, the so-called sort of stage A or stage B patient. But there really have been no clinical trials evaluating this question. There've been a lot of translational randomized trials that have provided some mechanistic insights about LV remodeling in people with diabetes or in people with prevalent heart failure. And we hypothesized that maybe the first step to evaluate whether SGLT2 inhibitors may have favorable effects on cardiac remodeling in people without diabetes or without heart failure would be to conduct a randomized double-blind control trial looking at indices of left ventricular remodeling in a population that I've just described. Dr. Greg Hundley: Very nice, Subodh. So you've started us into your study design. Maybe describe that a little more fully, and then who was included in your study population? Dr. Subodh Verma: So EMPA-HEART 2 CardioLink was a multi-center double-blind placebo control randomized trial in which we studied the effects of empagliflozin, an SGLT2 inhibitor, at a dose of 10 mg per day versus placebo in people who did not have type 2 diabetes or significant heart failure. We included people who were adults between the age of 40 and 80 who met 1 of 2 entry criteria. Either they had to have one major criteria, which was an increase in left ventricular mass index by specific echo criteria or MRI criteria, or they could have increased LVH as identified by ECG or by intraventricular septal or posterior wall thickness. They could also get in if they had resistant hypertension, hypertension despite being on 3 antihypertensive agents, or the second strata was entry through 2 minor criteria, which included a history of myocardial infarction, a GFR between 30 or 60, or evidence of overweight or obesity. Dr. Greg Hundley: And how many subjects did you randomize? Dr. Subodh Verma: So we randomized, of the 318 that we screened, 169 were randomized to receive empagliflozin 10 mg or a placebo. Patients had a baseline cardiac MRI done, and then the exposure was 6 months. They had a follow-up MRI at the end of 6 months. And the primary outcome measure was a 6-month change in left ventricular mass index from baseline to 6 months between the two groups. Dr. Greg Hundley: Very nice. And so , Subodh, can you describe for us now, what did you find? What were your study results? Dr. Subodh Verma: So, first and foremost, what we found in terms of baseline characteristics was that we enrolled a population of people with a mean age of around 60 with a BMI of around 30 kg/m2, predominantly men, about 80% or so were men. These were patients who did not have significant heart failure. The NT-proBNP at baseline was around 50 pg/mL. The eGFR was around 80 mL/minute, and the vast majority of these patients actually had a history of hypertension. Of course, none of them had…

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Circulation January 17, 2023 Issue Jan 17, 2023

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Please join author Pieter Martens and Associate Editor Justin Grodin as they discuss the article "Decongestion With Acetazolamide in Acute Decompensated Heart Failure Across the Spectrum of Left Ventricular Ejection Fraction: A Prespecified Analysis From the ADVOR Trial." Dr. Greg Hundley: Welcome listeners to this January 17th issue of Circulation on the Run. And I am Dr. Greg Hundley, Director at the Pauley Heart Center at VCU Health in Richmond, Virginia. Dr. Peder Myhre: And I'm Dr. Peder Myhre from Akershus University Hospital and University of Oslo, in Norway. And today, Greg, we have such an exciting feature paper. It comes to us from the ADVOR trialists. And the ADVOR trial examined the effect of acetazolamide in acute decompensated heart failure. And in this paper we're going to discuss how that treatment effect was across the left ventricular ejection fraction, across the spectrum. Greg, what do you think? Dr. Greg Hundley: Oh, wow. Sounds very interesting. But we might have some other articles in the issue. How about we grab a cup of coffee and Peder maybe this week, I'll go first and we'll start with preclinical science. How about that? Dr. Peder Myhre: Let's do preclinical science, Greg. Dr. Greg Hundley: Well, Peder, this particular paper focuses on the relationship between cardiac fibroblasts and cardiomyocytes. Remember that myocytes sit on a lattice of network of fibroblasts. And when the myocytes die, the fibroblasts then proliferates, secrete collagen and form this thick scar. Now, if we're going to try to regenerate, how are we going to get myocytes to get back into that thick scar when there's really a complete absence? And so as adult cardiomyocytes have little regenerative capacity, resident cardiac fibroblasts synthesize extracellular matrix, post myocardial infarction to form fibrosis, leading to cardiac dysfunction and heart failure. And therapies that can regenerate the myocardium and reverse fibrosis in the setting of a chronic myocardial infarction are lacking. Now, these investigators led by Professor Masaki Ieda from University of Tsukuba, were going to evaluate this process. The overexpression of cardiac transcription factors, including Mef2c, Gata4, Tbx5, Han2, all combined as MGTH. They can directly reprogram cardiac fibroblasts into induced cardiomyocytes and improve cardiac function in and under the setting of an acute myocardial infarction. However, the ability of an in vivo cardiac reprogramming to repair chronic myocardial infarction with established scars, well, that is really undetermined. Dr. Peder Myhre: Oh, what a wonderful introduction, Greg. And the way you described to us how cardiomyocytes and fibroblasts interact was really fascinating. Thank you. And now let's hear what the authors found and don't forget the clinical implications. Dr. Greg Hundley: Thanks, Peder. So these authors developed a novel transgenic mouse system where cardiac reprogramming and fibroblasts lineage tracing could be regulated spatiotemporally with tamoxifen treatment to analyze in vivo cardiac reprogramming in the setting of chronic MI. Then with this new model, the authors found in vivo cardiac reprogramming generates new induced cardiomyocytes from resident cardiac fibroblasts that improves cardiac function and reduces fibrosis in chronic myocardial infarction in mice. Wow. And additionally, they found that overexpression of cardiac reprogramming factors converts profibrotic cardio fibroblasts to a quiescent state, and that reverses fibrosis in chronic myocardial infarction. And therefore, Peder, direct cardiac reprogramming may be a promising therapy for chronic ischemic cardiomyopathies and heart failure. Really exciting work, converting scar tissue to actual functional cardiomyocytes. Dr. Peder Myhre: That was such a fantastic summary, Greg, and a very interesting paper. And I'm now going to take us back to clinical science and epidemiology. Because Greg, we all know that social and psychosocial factors are associated with cardiovascular disease risk. But the relative contributions of these factors to racial and ethnic differences in cardiovascular health has not been quantified. So these authors, led by the corresponding author, Nilay Shah from Northwestern University Feinberg School of Medicine in Chicago, used data from NHANES to examine the contributions of individual level social and psychosocial factors to racial and ethnic differences in population cardiovascular health. And that was measured by something called the cardiovascular health score, CVH score, which ranges from zero to 14, and it counts for diet, smoking, physical activity, body mass index, blood pressure, cholesterol, and blood glucose. Dr. Greg Hundley: Wow, really interesting, Peder. So what did they find here? Dr. Peder Myhre: So Greg, among males, the mean cardiovascular health score was 7.5 in Hispanic, 8.7 in non-Hispanic Asian, 7.5 in non-Hispanic black, and 7.6 in non-Hispanic white adults. And the authors found that the education explained the largest component of cardiovascular health differences among males. And now what about females? In females, the mean score was 8.0 in Hispanic, 9.3 in non-Hispanic Asian, 7.4 in non-Hispanic black, and 8.0 in non-Hispanic white adults. And for women, education explained the largest competence of cardiovascular health difference in non-Hispanic black. And place of birth, and that is US born versus born outside the US, explained the largest component of cardiovascular health difference in Hispanic and non-Hispanic Asian females. So Greg, the authors conclude that education and place of birth conferred the largest statistical contributions to the racial and ethnic differences in cardiovascular health among US adults. Dr. Greg Hundley: Very nice, Peder. What a beautiful description and outline that so well highlighting the differences in men versus women. Well, now we're going to turn back to the world of preclinical science, listeners. And we will continue with the paper by Dr. Amit Khera from Verve Therapeutics. Now, Peder, VERVE-101, this is an investigational in vivo CRISPR base editing medicine designed to alter a single DNA base in the PCSK9 gene. And that permanently turns off hepatic protein production and thereby, durably lowers LDL cholesterol. In this study, the investigators tested the efficacy, durability, tolerability, and potential for germline editing of VERVE-101 in studies of non-human primates and also in a murine F1 progeny study. Dr. Peder Myhre: So more on PCSK9s, and this time CRISPR technology. Very exciting. Greg, what did they find? Dr. Greg Hundley: Right, Peder. So VERVE-101 was well tolerated in non-human primates and led to, listen to this, an 83% lower blood PCSK9 protein and 69% lowering of LDL-C with durable effects up to 476 days following the dosing. These results have supported initiation of a first inhuman clinical trial. That's what needs to come next in patients with heterozygous familial hypercholesterolemia and atherosclerotic cardiovascular disease. Wow. Dr. Peder Myhre: Even greater reductions from this therapy on PCSK9 than the previous PCSK9 inhibitor therapies. Wow. Okay, Greg, and now we go from one fascinating study to another. And this time we actually have the primary results from a large randomized clinical trial, Greg. Isn't that exciting? Dr. Greg Hundley: Yes. Dr. Peder Myhre: And this paper describes the primary results of a trial testing in Indobufen versus aspirin on top of clopidogrel in patients undergoing PCI with drug-eluting stent DES who did not have elevated troponin. So that is patients without mycardial infarction. And in fact, fact, this is the first large randomized control trial to explore the efficacy and safety of aspirin replacement on top of P2Y12 inhibitor in patients receiving PCI with death. And Greg, I suppose you like I wonder what Indobufen is, and I just learned that that is a reversible inhibitor of platelet Cox-1 activity and it has comparable biochemical and functional effects to dose of aspirin. And previous data indicate that Indobufen could lessen the unwanted side effects of aspirin and that includes allergy intolerance and most importantly, aspirin resistance, while it retains the antithrombotic efficacy. Dr. Greg Hundley: Wow, Peder. Really interesting and great explanation. Indobufen. So how did they design this trial and what were the primary results? Dr. Peder Myhre: So Greg, the investigators of this trial, called OPTION, led by corresponding authors, Drs. Ge, Quian, and Wu from Fudan University in Shanghai, randomized 4,551 patients from 103 center to either indobufen based DAPT or conventional, and that is aspirin based DAPT for 12 months after DES implementation. And the trial was open label and with a non-inferiority design, which is important to keep in mind. And the primary endpoint was a one year composite of cardiovascular death, non-fatal MI, ischemic stroke, definite or probable stent thrombosis or bleeding, defined as BARC criteria type 2, 3, or 5. And now Greg, the primary endpoint occurred in 101, that is 4.5% of patients in the indobufen based DAPT group compared to 140, that is 6.1% patients, in the conventional DAPT group. And that yields an absolute difference of 1.6%. And the P for non-inferiority was less than 0.01. And the hazard ratio was 0.73 with confidence intervals ranging from 0.56 to 0.94. And Greg, the occurrence of bleeding was particularly interesting and that was also lower in the indobufen based DAPT group compared to the conventional DAPT group. And that was 3.0% versus 4.0% with the hazard ratio of 0.63. And that was primarily driven by a decrease in BARC type two bleeding. So Greg, the authors conclude that in Chinese patients with negative cardiac troponin undergoing DES implementation, indobufen plus clopidogrel DAPT compared with aspirin plus clopidogrel DAPT significantly reduced the risk of one year net clinical outcomes, which was mainly driven by reduction in bleeding events without an increase in ischemic events. Dr. Greg Hundley: Very nice, Peder. So another reversible inhibitor of platelet COX-1 activity, indobufen. And seems to be very, have high utility in individuals of Chinese ethnicity and Asian race. Well, perhaps more to come on that particular drug. Peder, how about we dive into some of the other articles in the issue? And I'll go first. So first, there's a Frontiers article by Professor Beatty entitled "A New Era and Cardiac Rehabilitation Delivery: Research Gaps, Questions, Strategies and Priorities." And then there's a Research Letter by Professor Zuurbier entitled, "SGLT-2 inhibitor, Empagliflozin, reduces Infarct Size Independent of SGLT-2." Dr. Peder Myhre: And then Greg, we have a new ECG challenge by Drs. Haghighat, Goldschlager and Oesterle entitled, "AV Block or Something Else?" And then there is a Perspective piece by Dr. Patrick Lawler entitled, "Models for Evidence Generation During the COVID-19 Pandemic: New Opportunities for Clinical Trials in Cardiovascular Medicine." And Greg, there's definitely so much to learn from all the research that has been done through the pandemic. And finally, we have our own Molly Robbins giving us Highlights from the Circulation Family of Journals. And first, there is a paper describing the characteristics of postoperative heart block in patients undergoing congenital heart surgery described in Circulation: Arrhythmia Electrophysiology. Next, the impact of socioeconomic disadvantages on heart failure outcomes reported in Circulation: Heart Failure. Then there is social and physical barriers to healthy food explored in circulation, cardiovascular quality and outcomes. And then there is the association of culprit-plaque morphology with varying degrees of infarct, myocardial injury size reported in Circulation: Cardiovascular Imaging. And finally, the impact of optical coherence tomography on PCI decisions reported in circulation cardiovascular interventions. Dr. Greg Hundley: Fantastic, Peder. Well, how about we get off to that feature discussion? Dr. Peder Myhre: Let's go. Dr. Mercedes Carnethon: Well, thank you and welcome to this episode of the Circulation on the Run Podcast. I'm really excited today to host this show. My name is Mercedes Carnethon. I'm an associate editor at Circulation and Professor and Vice Chair of Preventive Medicine at the Northwestern University Feinberg School of Medicine. I'm really excited to learn from the lead author of a new study on decongestion with Acetazolamide and acute decompensated heart failure across the spectrum of LV ejection fraction. And I've got the lead author with me today, Pieter Martens, as well as my colleague and associate editor Justin Grodin, who handled the paper. So I'd love to start off with just welcoming you, Dr. Martens. Dr. Pieter Martens: Thank you for having me. It's a pleasure to be here today. Dr. Mercedes Carnethon: Yes. And thank you so much for submitting your important work to the journal, Circulation. I'd love to start to hear a little bit about what was your rationale for carrying out this trial and tell us a little bit about what you found. Dr. Pieter Martens: So the ADVOR trial was a double blind placebo controlled randomized trial, which was performed in Belgium. And it set out to assess the effect of acetazolamide in acute decompensated heart failure and this on top of standardized loop diuretic therapy and patients with heart failure. And the goal of the current analysis was to assess whether the treatment effect of acetazolamide in acute heart failure differs amongst patients with a different ejection fraction at baseline at randomization. So we looked specifically at patients with heart failure, reduced, mildly reduced and preserved ejection fraction to determine whether acetazolamide works equally well in those patients. Dr. Mercedes Carnethon: Well, thank you so much. Tell me a little more. What did you find? Did your findings surprise you? Dr. Pieter Martens: All patients that were randomized in the ADVOR trial, we registered a baseline left ventricular ejection fraction at baseline. And what we saw was at the multiple endpoints that we collected in the ADVOR trial, that randomization towards acetazolamide was associated with a pronounced and preserved treatment effect. And different endpoints that we looked at was a primary endpoint which was successful, which is an important endpoint, which we all strive towards in acute decompensated heart failure. And we saw that irrespective of what your baseline ejection fraction was, that randomization towards acetazolamide was associated with a higher odds ratio for having successful decongestion. And also looking at other endpoints which we find important in the treatment of patients with acute compensated heart failure, such as renal endpoints such as the diuresis, the amount of urine that they make, or the natruresis, the amount of sodium that they excrete, we again saw that randomization towards acetazolamide was associated with a higher treatment effect, so more diuresis, more natruresis, which was not effective, whether you had heart failure, reduced, mildly reduced or preserved eject fraction. We did see a slight increase in the creatinine, which was a little bit more pronounced in patients with heart failure with reduced ejection fraction. Dr. Mercedes Carnethon: Thank you so much for that excellent summary. I'm an epidemiologist, so I'm certainly aware that of the cardiovascular diseases and their changes over time, heart failure is one that is going up over time and affecting more of the population. So I know I really enjoyed hearing about an additional therapy that helps to improve quality of life and improve clinical outcomes in individuals who are e…

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Circulation January 10, 2023 Issue Jan 09, 2023

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Please join authors Loren Field and Sean Reuter, as well as Associate Editor Thomas Eschenhagen as they discuss the article "Cardiac Troponin I-Interacting Kinase Affects Cardiomyocyte S-Phase Activity But Not Cardiomyocyte Proliferation." Dr. Greg Hundley: Welcome listeners, to this January 10th issue of Circulation on the Run, and I am Dr. Greg Hundley, associate editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Dr. Peder Myhre: I am Dr. Peder Myhre from Akershus University Hospital and University of Oslo in Norway. Dr. Greg Hundley: Well, listeners, this week's feature discussion delves into the world of preclinical science and evaluates cardiac troponin I and its impact on S phase activity in cardiomyocytes, and does that relate to cardiomyocyte proliferation. But before we get to that, how about we grab a cup of coffee and Peder and I will work through some of the other articles in the issue. Peder, how about this week I go first? Dr. Peder Myhre: Go ahead, Greg. Dr. Greg Hundley: Right. So Peder, this first study evaluated whether the burden of positive coronary artery calcification on cardiovascular disease differed by multidimensional individual characteristics, and so the investigators led by Dr. Kosuke Inoue from Kyoto University sought to investigate the heterogeneity in the association between positive coronary artery calcium and incident cardiovascular disease. And so Peder, to examine this question, the authors implemented a cohort study design that included adults aged greater than 45 years, free of cardiovascular disease, from the Multi-Ethnic Study of Atherosclerosis, or MESA, and after propensity score matching in a one-to-one ratio, they applied a machine learning causal forest model to, first, evaluate the heterogeneity in the association between positive coronary artery calcium and incident cardiovascular disease and then, second, to predict the increase in cardiovascular disease risk at 10 years when the coronary artery calcium score was greater than zero, so versus is it zero at all at the individual level? Dr. Peder Myhre: Oh, Greg, that is so cool, so using machine learning for coronary artery calcium and risk prediction, I'm very excited. What did they find? Dr. Greg Hundley: Right, Peder, so the expected increases in cardiovascular disease risk when the coronary artery calcium score was greater than zero were heterogeneous across individuals. Moreover, nearly 70% of people with low atherosclerotic cardiovascular disease risk showed a large increase in cardiovascular disease risk when the coronary calcium score was greater than zero, highlighting the need for coronary artery calcium screening among such low-risk individuals. And Peder, future studies are really needed to assess whether targeting individuals for coronary artery calcium measurements based on not only the absolute ASCVD risk, but also the expected increase in CVD risk when a CAC score is greater than zero and whether that improves overall assessment of cardiovascular outcomes. Dr. Peder Myhre: Wow, that is so clinically relevant and very interesting. And we're actually going to stay clinically relevant with the next paper which is about anti-platelet therapy after PCI. And this paper describes the long-term results of the HOST-EXAM trial. To remind you, Greg, the HOST-EXAM trial was an investigator-initiated prospective, randomized, open label, multicenter trial done at 37 sites in Korea. They enrolled patients who had undergone PCI with DES and maintained dual anti-platelet therapy without any clinical event for a mean 12 months and then they were randomized one to-one to either clopidogrel, 75 milligrams once daily, or aspirin, 100 milligram once daily. The primary results of this trial was published in Lancet in 2021 and showed superiority of clopidogrel over aspirin in prevention of the composite of MACE and major bleeding during 24 months of followup. And then, through the current paper, this describes the results of the post trial extended followup of about five years. Dr. Greg Hundley: Very nice, Peder, so aspirin versus clopidogrel and looking at the maintenance of that monotherapy and cardiovascular outcomes. Wow, so what did they find? Dr. Peder Myhre: Yeah, Greg. They, in this extended followup study, had a total of 5.8 years median followup, and the primary endpoint occurred in 12.8% in the clopidogrel group versus 16.9% in the aspirin group, and that has a range of 0.74 with a 95% conference interval ranging from 0.63 to 0.86. So also the clopidogrel group had lower risk of the secondary thrombotic endpoint and the secondary bleeding endpoint while there was no significant difference in the incident on all caused death. So Greg, to conclude, these very interesting results from the primary analysis of the HOST-EXAM trial was consistent through the longer followup, and this support the use of clopidogrel over aspirin monotherapy from 12 months onwards after PCI. Dr. Greg Hundley: Very nice Peder, beautiful description and sounds like long-term clopidogrel use over aspirin was quite beneficial. Well, the next study comes to us from the world of preclinical science, and it is from the investigative group led by Dr. Yunzeng Zou from Shanghai Institute of Cardiovascular Diseases and the Zhongshan Hospital and Fudan University. Peder, the study pertains to diabetes. So diabetic heart dysfunction is a common complication of diabetes mellitus and cell death is a core event that leads to diabetic heart dysfunction. However, the time sequence of cell death pathways and the precise intervening time of particular cell death type remained largely unknown in diabetic hearts. And so, Peder, this study aimed to identify the particular cell death type that is responsible for diabetic heart dysfunction and propose a promising therapeutic strategy by intervening in this cell death pathway. Dr. Peder Myhre: Wow, Greg, that is really interesting. Heart dysfunction in diabetes is something that we really have to learn more about and I'm so excited to hear what these authors found, Greg. Dr. Greg Hundley: Right. So first, Peder, the authors identified necroptosis as the predominant cell death type at later stages in the diabetic heart. And then second, Peder, the CB2 receptor, and we'll call that CB2-R, recruits transcription factor Bach2 to repress necroptosis and protects against diabetic heart injury while hyperglycemia and MLKL in turn phosphorylates CB2-R to promote ubiquitous dependent degradation of CB2-R, thus forming a CB2-R centric feedback loop of necroptosis. And finally, Peder, cardiac CB2-R or Bach2 expression negatively correlates with both MLKL 10 expression and the extent of diabetic heart injuries in humans. And so the clinical implications of these findings, Peder, are that the CB2-R centric necrotic loop represents a promising target for the clinical treatment of diabetic heart injuries. Dr. Peder Myhre: So Greg, this paper that comes to us from corresponding author Amanda Paluch from University of Massachusetts Amherst, is a meta-analysis of eight prospective studies with device measured steps including more than 20,000 adults who were followed for CVD events. And the mean age of participants in this study was 63 years and 52% were women. And the participants were followed for a median of 6.2 years and 1,523 cardiovascular events occurred. So first, Greg, there was a significant difference in the association of steps per day in cardiovascular disease between older, that is greater or equal to 60 years, and younger, that is less than 60 years adults. So for older adults that has the ratio for cardiovascular disease using Q1 as reference was 0.80 for Q2, 0.62 for Q3, and 0.51 for Q4. And for younger adults that has ratio for cardiovascular disease using Q1 as reference was 0.79 for Q2, 0.90 for Q3, and 0.95 for Q4. And in the paper, Greg, there are some beautiful, restricted cubic lines that really illustrate the association between daily steps and the risk of cardiovascular disease among older adults and in younger adults. So the authors conclude that for older adults taking more daily steps is associated with a progressively lower risk of cardiovascular disease. And monitoring and promoting steps per day is a simple metric for clinician patient communication and population health to reduce the risk of cardiovascular disease. Dr. Greg Hundley: Well, Peder, we've got some other very interesting articles in this issue and how about we dive into that mail bag and discuss a few of those. So I'll go first. The first is a Perspective piece by Professor Powell-Wiley entitled "Centering Patient Voices through Community Engagement in Cardiovascular Research." A very important topic where can those in the community actually help us design meaningful outcomes for our research initiatives? And next Peder, there is a Research Letter from Professor Evans entitled "Increasing Mononuclear deployed Cardiomyocytes by Loss of E2F7/8, and does that fail to improve cardiac regeneration post myocardial infarction?" Dr. Peder Myhre: Thanks, Greg. We also have an ECG Challenge by Dr. Li entitled, "What Is The Truth Behind Abnormal ECG Changes?" And this is describing a very rare and interesting cause of ST segment elevation. I recommend everyone to read that case. We also have our own Nick Murphy who gives us the Highlights from the Circulation Family of Journals where he summarizes five papers from the Circulation subspecialty journals. First, the experience with a novel visually assisted ablation catheter is reported in circulation A and E. The impact of various exercise training approaches on skeletal muscle in heart failure with preserved the F is presented in circulation heart failure. Gaps in heart failure treatment over a decade are reported in circulation cardiovascular quality and outcomes, and the associations of machine learning approaches to plaque morphology from coronary CTA with ischemia are reported in circulation cardiovascular imaging. And finally, Greg, an observational study of left main PCI at sites with and without surgical backup is reported in circulation cardiovascular interventions. Let's go on to the feature paper today describing the cardiac troponin I interacting kinase and the impact on cardiomyocyte S phase activity. Dr. Greg Hundley: Great, let's go. Welcome listeners to this January 10th feature discussion. Very interesting today as we are going to delve into the world of preclinical science. And we have with us today Dr. Loren Field and Dr. Sean Reuter from University of Indiana in Indianapolis, Indiana. And our own associate editor, Dr. Thomas Eschenhagen from University Medical Center of Hamburg in Hamburg, Germany. Welcome gentlemen. Well, Loren, we're going to start with you. Can you describe for us some of the background information that went into the preparation of your study, and what was the hypothesis that you wanted to address? Dr. Loren Field: Sure. This study actually came about in a rather roundabout fashion. We were doing a study with Kai Wollert in Hanover, Germany, where we were looking at the impact of a CXCR4 antagonist, which is used to mobilize stem cells from the bone marrow. And we had sent our mice over to Kai's lab and we have a mouse model that allows us to track S phase activity in cardiac myocytes, so these are cells are starting to replicate. And Kai crossed them into a different genetic background. And when he sent the mice back to us to analyze the hearts, we observed that we saw things that we never saw before in our experiments here. His injury model was different than ours and now the mouse also had a genetic background, so we had to spend about a year to figure out if it was the injury model or the background. It turned out to be the genetic background, and the phenotype was these mice had about a 15-fold elevated level of cell cycle reentry. So then it became a relatively simple genetics game where we took the progenitor mice, made F1 animals, looked for the phenotype, did backcross animals, and basically identified the gene responsible for the phenotype. Dr. Greg Hundley: Very nice. And so in this study moving forward, what hypothesis did you want to address? Dr. Loren Field: Well, the main hypothesis was to figure out what the gene was and then secondarily to figure out the degree of cell cycle progression. When the cell is proliferating, the first task is to replicate its genome, which is S phase activity that's followed by the nuclei dividing and then finally by the cell itself becoming two cells. So our task was to identify, first, the gene and secondly, how far through the cell cycles the cells progressed. Dr. Greg Hundley: Very nice. And how did you construct your experiment? Dr. Loren Field: It was, again, very straightforward. It was simply setting up the appropriate genetic crosses to produce the animals. For the past 10, 15 years, we've been developing a computer assisted assay that allows us to identify the anatomical position of S phase positive cardiac myocytes in sections of the heart. And basically, we apply that program to the different genetic backgrounds and after that it's a ball of mapping studies, QTL mapping. Dr. Greg Hundley: So really mechanistic understanding. Well listeners, we're next going to turn to Sean, and Sean, can you describe for us your study results? Dr. Sean Reuter: Yes, as Loren stated, we saw a 15-fold increase in the S phase activity within the remote zone. Now we partition the heart in three different zones after injury, so the scar, the border zone, and then the remote zone or injury. And as Loren stated, we saw a 15-fold increase in the S phase activity, cell cycle activity, in the remote zone. And it's only because we have this system in hand that we can anatomically map the S phase activity within the heart that we were able to detect and also quantify this. And I think that's the reason we discovered this particular phenotype. But in addition to that, we performed RNA-seq or Exome sequencing and discovered that TNNI3K was the responsible gene for elevated S phase activity within the remote zone and border zone, but interestingly not in the scar. Dr. Greg Hundley: Very interesting, Sean, and so describe for us the importance of the TNNI3K and its relationship to this S phase. Dr. Sean Reuter: Sure. This particular gene was first discovered around 2000, and it's been studied for a while now, but the targets of this kinase specifically expressed in the heart, and it does get elevated after injury, but the actual targets are not well described or well known. It's believed that it phosphorylates some mild filament fibers and structural proteins, but the actual mechanism and the consequence of this is not known. So when we saw this in the remote zone, the elevated S phase, our current theory is that we believe that it's probably increasing oxidative stress that would basically further out from the at-risk zone or the border zone and then it now is in the remote zone. So we think it's just causing the heart, a pathological area of the heart, basically to expand. And so that's our current theory. Other groups have published on the oxidative stress in over expression of TNNI3K as well. Dr. Greg Hundley: Very nice. Well listeners, next we are going to turn to our associate editor, Thomas many articles come your way and come across your desk. What attracted you to this particular article, and how do we put its results really in the context of cardiac regeneration? Dr. Thomas Eschenhagen: Indeed, there were several arguments. It's a cool paper and the whole field is still very important. As probably most of you know, the field have a rough ride over the last 20 years, went up and down, lots of bad findings. And in the end it turns…

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Circulation January 3, 2023 Issue Jan 03, 2023

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This week, please join author Judith Hochman, Editorialist Steven Bradley, and Guest Host Mercedes Carnethon as they discuss the article " Survival After Invasive or Conservative Management of Stable Coronary Disease" and editorial "If the Fates Allow: The Zero-Sum Game of ISCHEMIA-EXTEND." Dr. Greg Hundley: Welcome everyone to our new year 2023, and we are here on this January 3rd edition of Circulation on the Run. I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Dr. Peder Myhre: I am Dr. Peder Myhre, Social Media Editor and doctor at the Akershus University Hospital and University of Oslo. Dr. Greg Hundley: Very nice. Well, welcome listeners and this week's feature, ah, very interesting. You know many times patients with stable coronary artery disease, we're seeing a lot in the literature about an invasive strategy versus a conservative strategy. But what happens long term for these patients? What's their prognosis? Well, more to come in the feature discussion. But first, how about we grab a cup of coffee and we discuss some of the other issues in this session. Peder, would you like to go first? Dr. Peder Myhre: Yes, Greg I would love to and the first paper today is very interesting and relates to one of the most important challenges globally, namely climate changes and extreme temperatures. And in this paper, which comes to us from corresponding author, Barrak Alahmad from Harvard Chan School of Public Health in the United States, together with a large international group of authors, investigated the associations between extreme temperatures and cardiovascular cause-specific mortality in 567 cities in 27 countries from 1979 to 2019. Dr. Greg Hundley: Wow Peder, that is a really large comprehensive study. So, how did they perform this analysis? What did they find? Dr. Peder Myhre: So Greg, the investigators collected city-specific daily ambient temperatures from weather stations and analyzed cause-specific cardiovascular mortality and excess deaths in association with extreme hot and extreme cold temperatures. And in total, the analysis included more than 32 million deaths from any cardiovascular cause, which were subdivided into deaths from ischemic heart disease, stroke, heart failure and arrhythmia and at extreme temperature percentiles. And that is defined as heat above the 99th percentile and as cold below the first percentile were associated with a high risk of dying from any cardiovascular cause, ischemic heart disease, stroke and heart failure as compared to the minimum mortality temperature, which is the temperature associated with least mortality. And Greg, across a range of extreme temperatures, hot days above the 97.5 percentile and cold days below the 2.5 percentile accounted for more than two and more than nine excess deaths for every thousand cardiovascular death respectively. And heart failure was associated with the highest excess death proportions from extreme hot and cold days. So Greg, it seems like extreme temperatures really impact the cardiovascular mortality across the globe. Dr. Greg Hundley: Yeah, beautiful description Peder. And I think what was really exciting about that particular article is you had results from 27 countries. Wow, so really quite a global study and very informative. Dr. Peder Myhre: Yes, indeed very impressive. Dr. Greg Hundley: Well, Peder my next study comes to us from the world of preclinical science. And Peder, these investigators led by Professor Jose Luis de la Pompa from CNIC, evaluated two structural cardiac diseases, left ventricular non-compaction and bicuspid aortic valve. And they wanted to determine if those two conditions were caused by a set of inherited heterozygous gene mutations affecting the notch ligand regulator, Mind bomb-1 and co-segregating genes. Dr. Peder Myhre: Okay Greg, so we are looking at mechanisms for non-compaction and bicuspid aortic valve. What did they find? Dr. Greg Hundley: Right Peder, so whole exome sequencing of the left ventricular non-compaction families identified heterozygous missense mutations in five genes co-segregating with E3 ubiquitin protein ligase-1 Mib-1 as well as left ventricular non-compaction. And corresponding mouse models showed that left ventricular non-compaction or bicuspid aortic valve in a notch-sensitized genetic background. Now, also gene profiling showed that increased cardiomyocyte proliferation and defective morphological and metabolic maturation in mouse hearts and human pluripotent stem cell cardiomyopathy. Biochemistry suggested a direct interaction between notch and some of the identified gene products. And so, these data Peder support a shared genetic basis for left ventricular non-compaction and bicuspid aortic valve with Mib-1 notch playing a crucial role. And thus, identification of heterozygous mutations leading to left ventricular non-compaction or bicuspid aortic valve may allow us to expand the genetic testing panel repertoire for better diagnosis and or risk stratification of both of these conditions, left ventricular non-compaction and bicuspid aortic valve. Dr. Peder Myhre: All right, that is really great and novel linking left ventricular non-compaction to bicuspid aortic valve, really great. And now Greg, we're going to go back to clinical science and we're going to talk about lipoprotein(a) or Lp(a). And as you know, elevated Lp(a) is a common risk factor for cardiovascular disease outcomes with unknown mechanisms. And the authors of this next paper coming to us from corresponding author Olli Raitakari from University of Turku in Finland, examined Lp(a)'s potential role in identifying youths who are at increased risk of developing adult atherosclerotic cardiovascular disease, ASCVD. And they did this by measuring Lp(a) in youths nine to 24 years old and linking that to a diagnosis of ASCVD as adults and also linking it to carotid intermediate thickness in the Young Finns Study. And in addition, these results were validated in the Bogalusa Heart Study. Dr. Greg Hundley: Oh, very nice Peder. So, what did they find? Dr. Peder Myhre: So Greg, those who have been exposed to high Lp(a) levels in youth and that was defined as greater than or equal to 30 milligrams per deciliter, had about two times greater risk of developing adult ASCVD compared to non-exposed individuals. In fact, all the following youth risk factors were independently associated with a higher risk. Lp(a), LD, cholesterol, body mass index and smoking all independently associated with ASCVD. And similar findings were made in the validation cohort who were participants with a high Lp(a) had 2.5 times greater risk of developing adult ASCVD compared to non-exposed individuals. And this also persisted in adjusted models. Now, what about the carotid intermediate thickness? In that analysis, there were no associations detected to youth Lp(a) levels in either of the cohorts. Dr. Greg Hundley: Very nice, Peder. So, great description of the utility of lipoprotein(a) measurements in the youth and for predicting future major cardiovascular events. Well, the next paper goes back to the world of preclinical science. And Peder, cardiac hypertrophy increases demands on protein folding, which causes an accumulation of misfolded proteins in the endoplasmic reticulum. Now, these misfolded proteins can be removed via the adaptive retro-translocation, poly-ubiquitylation and a proteasome mediated degradation process. The endoplasmic reticulum-associated degradation, ERAD, which altogether as a biological process and rate has not been studied in vivo. So, these investigators led by Dr. Christopher Glembotski from University of Arizona College of Medicine, investigated the role of ERAD in a pathophysiological model and they examined the function of the functional initiator of ERAD, VCP-interacting membrane protein and positing that the VCP-interacting membrane protein would be adaptive in pathological cardiac hypertrophy in mice. Dr. Peder Myhre: Thanks Greg. So, we're talking about degradation of the endoplasmatic reticulum and the association to hypertrophy. So, what did these investigators find, Greg? Dr. Greg Hundley: Right, Peder. So, this was really the first study to demonstrate that endoplasmic reticulum-associated protein degradation or ERAD is responsible for degrading and thus, regulating the levels of a cytosolic non-endoplasmic reticular protein. The results reported here describe a new mechanism mediating the pathological growth of the heart, such that in the healthy heart SGK-1 levels are low due to ERAD-mediated degradation. While in the setting of pathology, ERAD-mediated degradation of SGK-1 is disrupted, allowing the pro-growth kinase to accumulate and contribute to pathological cardiac hypertrophy. And so Peder, the clinical relevance of these findings is that the investigators found that a variety of proteins that constitute the ERAD machinery were decreased in both mouse and human heart failure samples while SGK-1 was increased, supporting the possibility that SGK-1 is a contributor to the disease phenotype. And this is notable and that these studies could lead to the development of new therapeutic approaches for managing pathological cardiac hypertrophy and heart failure that target the ERAD to restore efficient SGK-1 degradation. Dr. Peder Myhre: That was an excellent explanation of a very difficult topic. Thank you, Greg. Dr. Greg Hundley: Well, Peder how about we take a look and see what else is in the issue? And now I'll go first. Well, first there's an In Depth by Professor Ntsekhe entitled, "Cardiovascular Disease Among Persons Living with HIV: New Insights into Pathogenesis and Clinical Manifestations within the Global Context." And then, there's a Research Letter by Professor Verma entitled, "Empagliflozin in Black Patients Versus White Patients With Heart Failure: Analysis of EMPEROR results-Pooled." Dr. Peder Myhre: Great Greg and there is an On My Mind by Gabriel Steg entitled, "Do We Need Ischemia Testing to Monitor Asymptomatic Patients With Chronic Coronary Syndromes?" Very timely and interesting. And finally, there is an AHA Update from Michelle Albert, the President of the AHA entitled, "Tackling Adversity and Cardiovascular Health: It is About Time." Dr. Greg Hundley: All right. Well Peder, how about we get onto that feature discussion looking at survival after invasive or conservative management in stable coronary heart disease? Dr. Mercedes Carnethon: Thank you so much for joining us for this episode of Circulation on the Run. I'm Mercedes Carnethon, Professor and Vice Chair of Preventive Medicine at the Northwestern University, Feinberg School of Medicine. And I'm very excited today to have as a guest, Dr. Judith Hochman, who is going to be discussing the long-awaited findings from the ISCHEMIA-EXTEND trial that are looking at survival after invasive or conservative management of stable coronary disease. Really pleased to have you with us today, Judy to hear about these findings. Dr. Judith Hochman: It's a pleasure to be here. Dr. Mercedes Carnethon: Thank you. So, just to start off, can you tell us about this study? What motivated this long-term follow-up of this particular trial? Dr. Judith Hochman: Yeah, so as I think the viewers or the listeners will recall, we built on a wealth of data from COURAGE and BARI 2D, some of the landmark trials that looked at revascularization versus optimal medical therapy or guideline-directed medical therapy alone. We tested an invasive strategy versus a conservative strategy dating back already to 2012 is when we started. And we had a five component primary outcome, which included cardiovascular death, myocardial infarction or hospitalization for unstable angina, heart failure or resuscitated cardiac arrest. And at the end of 3.2 median years of follow-up, we saw no difference in the primary outcome in that the curves crossed with some excess risk upfront due to periprocedural MI and decreased risk of spontaneous MI long-term. But the net overall timeframe spent free of event was similar between the groups. So, we did observe improved quality of life for the invasive strategy, but in terms of clinical outcomes there was no difference. So, cardiovascular death at the end of that time period was no different between the groups, all-cause mortality was no different, non-cardiovascular death, there was actually an increase in the invasive group, which was somewhat of a mystery. We can get into that a little bit later because I think that becomes important. But 3.2 years meeting and follow-up is relatively short. So, everyone was very interested in what would the long-term outcomes be. So, we had another grant from the National Heart, Lung and Blood Institute to follow these patients long-term. And this is an interim report with seven years of follow-up, a median of 5.7 years. And the bottom line is that all-cause mortality was the same at seven years but for the first time, an invasive strategy resulted in lower cardiovascular mortality, which was very interesting and very exciting except that it was offset, exactly offset by the continued excess that we had previously observed in non-cardiovascular mortality. And that's basically the upshot of what we just reported and why we continue to follow patients and why we're going to continue to follow patients and have a final report in 2026. Dr. Mercedes Carnethon: This is really fantastic work. As you point out, the initial follow-up was fairly short and the findings were so critically important demonstrating that there were subtle differences between the two approaches but that overall, things appeared relatively similar. Did it surprise you? Oh, please correct me. Dr. Judith Hochman: I should point out that because there were less spontaneous MIs during follow-up and spontaneous MIs are associated with a heightened risk of subsequent death more so than the periprocedural MIs, we did hypothesize and we're very interested in longer term cardiovascular and all-cause mortality thinking that those reduced spontaneous MIs in the invasive group would be associated with reduced cardiovascular death and perhaps reduced mortality. As I did indicate, cardiovascular death mortality was reduced but all-cause mortality was the same with a hazard ratio of 1.0. Dr. Mercedes Carnethon: Well, nothing seems more clear than a hazard ratio of 1.0 with those very tight confidence limits so thank you so much. I'm really pleased that our editorialist, Dr. Steve Bradley was also able to join us today because to hear his thoughts about where this fits in the context of what we know can be really insightful. So, I'd really love to turn to you, Dr. Bradley. In your opinion, why was this study question so important and tell us a little bit about how you think the clinical field should use these findings. Dr. Steven Bradley: Absolutely and thanks for having me. I think there were some indication that perhaps the farther we follow the patients out from the original ISCHEMIA trial that we might start to see some evidence of benefit for revascularization. I think Dr. Hochman spoke about the evidence of more of these spontaneous myocardial infarctions that were happening in the non-revascularization arm of the study and an association with worse cardiovascular outcomes in patients that experience spontaneous events. And so, the thoughts might be that over time we would see the benefit of that. And certainly if you parse out cardiovascular versus non- cardiovascular outcomes, we do, we see lower rates of cardiovascular death in the patients who undergo revascularization but it's balanced out by non-cardiovascular death. And so, it becomes a zero sum game for a patient. They want to be alive, it doesn't mat…

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Circulation December 27, 2022 Special Dec 26, 2022

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In this week's Circulation on the Run podcast, we turn the show over to Circulation's Social Media Editors Dr. Pishoy Gouda and Dr. Peder Myhre. They interview the 2022 recipients of the Joseph Loscalzo Award for Best Basic Science Article, and the 2022 recipients of the James T. Willerson Award for Best Clinical Article. Dr. Maryjane Farr: Welcome everybody to Circulation on the Run. My name is Maryjane Farr, and I'm the digital strategies editor at Circulation. Carolyn and Greg are on break this week. And as part of the Circulation tradition, we turn the stage over to two of our social media editors, Dr. Peder Myhre from Oslo and Dr. Pishoy Gouda from Edmonton. They're going to be interviewing the 2022 winners of the Loscalzo Award and the Willerson Award. Take it away, Peter and Pishoy. Dr. Peder Myhre: Today. Pishoy, we have a very exciting issue of Circulation on the Run. We are going- Dr. Pishoy Gouda: We certainly do. Dr. Peder Myhre: Yeah. We're going to discuss two amazing papers that are award-winning and we're going to talk to the first authors who really know these papers and conducted the amazing work that we're going to display here today. Dr. Pishoy Gouda: Yeah, I'm excited. Peter. And with us today, we'll start talking about the recipients of the Loscalzo Award. So I wanted to start off by introducing Dr. Leo and Dr. Suvorava, who are the very proud recipients of the Loscalzo Award for their paper entitled Red Blood Cell and Endothelial eNOS Independently Regulate Circulating Nitric Oxide Metabolites and Blood Pressure. So welcome Doctors Leo and Suvorava. How are you guys doing today? Dr. Francesca Leo: Hi, thank you for the introduction and pretty well, I'm currently in Italy for my winter Christmas holidays, but I'm really excited and happy to be here today with you. Dr. Pishoy Gouda: Excellent. Dr. Suvorava: Hello. I'm also very happy to be here today. Thank you for your invitation and for your congratulations. It's a privilege and honor for me to be a recipient of this Dr. Loscalzo Award. Thank you. Dr. Pishoy Gouda: Well, I just wanted to start off by taking another second here to congratulate you both on this award. We all know the sheer amount of work and dedications to get these projects going, so congratulations. And I'm going to start off with a really easy question for you guys. When you found out that you were a recipient of the Loscalzo Award, who is the first person that you told? Dr. Francesca Leo: As I mentioned, I'm Italian and as a good Italian I need to say that. Of course, the first people I told were my parents because we all know that Italian and parents are just one thing. So they were the first ones. And then all of course, my partner and friends came second, parents first, family first. Dr. Pishoy Gouda: Very good. What about yourself, Tatsiana? Dr. Tatsiana Suvorava: Hi. Yeah. I had to think back like seven years ago and I very good remember one day when I was really excited about the results, what we found, I was in the lab, I was developing a western blood to check the functional ability of our models and it showed that it was very successful that we couldn't knock out our protein of interest almost completely. And at that day exactly, we had a lab meeting. So I directly pulled this image on my USB stick and then showed it on the lab meeting. So actually these were my colleagues who first hear about this. Dr. Pishoy Gouda: That's awesome. That's lovely. Well, after I got married, sometimes my parents get bumped to the second phone call and they weren't very happy about that and they let me know very clearly. But let's switch gears a little bit and tell us a little bit about how you made the decision to pursue academics. It's such a daunting career and a daunting topic sometimes. And how did you get interested in research and how did you find yourself coming into this research project? Dr. Francesca Leo: If I can start first. Well, I decided to pursue an academical career at the beginning following my master thesis that I did at the University of Pisa here. And I've always wanted to go abroad and gain experience, get to know different realities apart from Italy. And I was actually really lucky that I got the opportunity to work in the laboratory Professor Cortese-Krott because that gave me the opportunity to grow a lot, both personally and professionally, of course. I learned new techniques and together with our great team, we managed to achieve many goals. In particular, this paper, I must say that was my last satisfaction before my doctoral exam. So I think the feeling that you get after any also small achievement is something that you can really, I cannot find it hard to explain to people that are not in research or not in science in general. Dr. Pishoy Gouda: No, I totally agree. When I get a new data set, I get so excited and my wife is telling me, what are you doing is I just got new data and I'm like a little child on Christmas day. She doesn't understand it, but she appreciates that some people like that. What about yourself? What about yourself? Dr. Tatsiana Suvorava: Yeah, well my decision to pursue academic career started with as probably for many researchers, started from intense fascination from one discovery. I was at the beginning of my bachelors' science studies and then the Nobel Prize was given for the discovery of nitric oxide as a signaling molecule in a cardiovascular system. And I was so fascinated that the gaseous molecule so simple has so lots of responsibility in the body. And since that time, that was always in the focus of my research and this is for me, a lifelong journey. I'm still on the way. Dr. Pishoy Gouda: That's amazing, Tatsiana. And that sort of sets us up nicely. And as you guys know, I'm a interventional cardiologist. Basic science is a little bit farther from my memory. So I'll start off by admitting that my basic science research is not where it should be. But with that in mind, I was wondering if you could just tell our listeners a little bit about your research and why this question is so important and explain it to you like you were lowly clinicians that don't really understand basic science. Dr. Francesca Leo: I always take over Tanya, but yes, I have less to say than you. I must admit. Dr. Tatsiana Suvorava: Okay so let's start. No problem. Dr. Pishoy Gouda: It's a team effort. It's a team effort. Dr. Tatsiana Suvorava: Its a team effort and yeah. Ok. Dr. Francesca Leo: It's been a really teamwork, I must say from the really, really, really beginning. So this paper was, as I said, the central focus of my doctoral thesis. I just take two small part of it, of course, in particular, what is really important on the paper, I think that is we use really new mice models that Tanya and my Professor Cortese-Krott really and highly characterized at the really beginning, so developed completely from new, and they are mice that are expressing or not eNOS this protein that is responsible for nitric oxide production in the endothelium or in red blood cells. So the importance of this research was to demonstrate the role or pivotal role of eNOS expressed in the red blood cells in the modulation of blood pressure as well as circulating nitric oxide metabolites. And we actually did it with this paper. And considering that cardiovascular disease are one of the major causes of death nowadays, this results can really have important clinical and therapeutical implications for future research and real life, let's say. Dr. Tatsiana Suvorava: Yeah, maybe I could add to Francesca. Dr. Francesca Leo: Sure, Dr. Tatsiana Suvorava: Yeah. Dr. Pishoy Gouda: Of course. Dr. Tatsiana Suvorava: I think our research was especially important because it's identified the existence of previously unrecognized and actually non-canonical pathway, how the red blood cells can regulate blood pressure. And it was so exciting about this. Dr. Pishoy Gouda: Right. So trying to find out if the red blood cell, nitric oxide synthase can actually regulate blood pressure. And this has obviously lots of clinical implications. So in practice, how did you guys set up your experiments? How did you try to test the significance of the Enos red blood cells effects? Dr. Francesca Leo: Just if I can add something, what was really important. So what is known is that Enos expressing the endothelium plays an important role in the modulation of blood pressure. What we actually found out is that the one in the red blood cells also is involved and played a role that seems to be independent from the one played from the eNOS expressed in the endothelium. For answering your question, I also, I need to say I'm not the right candidate because this is a huge project that started about 10 years ago. So I was really, I repeated and I will always repeat it, I was really lucky to take part to this project and to get the opportunity to take part to this journey because it was really a journey and it gave me the opportunity to work with very different people and get in touch with very different realities, academical realities. And I can say that this project started from my previous boss and Tanya that they had this idea and started this whole project together with, of course Tanya is the one that is involved since the really beginning. So she can definitely better answer to this question. Dr. Tatsiana Suvorava: Yeah, thank you, Francesca. It's a long way actually what we did, and actually I started this particular project on the level of postdoc and eNOS and hypertension have been already in a center of my research interest for several years. And in a previous project what I had, I also had a transgenic mice, which were generated by conventional genetic approach by micro injection of D N a. And at that time we observed a significant contribution of external endothelial component into the blood pressure regulated. However, at that time we were not able to identify the exact extracellular allocation of this component. There were several candidates which were suggested, and one of them there were red blood cells. And everyone was kind of skeptical about this because the level of eNOS protein in red blood cells is extremely low. And furthermore, there were a lot of doubts how eNOS activity can be exported from the red blood cells because it's red blood cells are full of heme, which is a scavenger of nitric oxide. Furthermore, actually it was not clear how they transported and how it is released this activity. But now if we think that red blood cells are the largest component contributor to overall cell number in the body, so maybe then we can more critically think and then think that the total amount of red blood cells maybe compensate for this very low eNOS protein expression. And actually because they have a high density and their shape is erase high, so they provide a very sufficient release of this inactivity from red blood cells. But this idea was doubted for many years, although there it was reported that eNOS is expressed in red blood cells in 2006 was a paper. Dr. Pishoy Gouda: Well that's very exciting. So what we really learned is that eNOS system in both red blood cells and endothelial cells contribute to blood pressure regulation. Now I might direct this to you, Francesca. Well what does that mean for the clinicians in our audience? Well, what does that mean for a hypertension patients? Dr. Francesca Leo: So for clinicians, so, I must say these findings may have really important pathophysiological implication in the understanding of the interrelationships between hematologic and cardiovascular disease and may reveal the really novel therapeutic approaches to improve tissue perfusion. Moreover, our data and models may also help in understanding how red blood cells eNOS signaling can really affect red blood cells function, the scavenging of nitric oxide, as Tanya had previously said, as well as the crosstalk between nitric oxide and the sulfides that are of highly present in the bloodstream and in the body as well as oxygen transport. And may also enable us to refine the criteria for blood banking transfusion and to also try to develop new strategies or therapies for many diseases and pathologies where red blood cells are involved. For example, coronary artery disease, chronic kidney disease that normally are pathologists that show a decrease in the expression of eNOS expressed in the red blood cells or hematologic disease hemoglobinopathies, which are normally characterized by a systemic decrease in nitric oxide bioavailability or one of the most common diseases, sickle cell disease. Cause of course the shape of red blood cells is definitely also responsible of their functioning. And it can also determine, of course, an impairment or more alteration in the release of nitric oxide in the body. Dr. Tatsiana Suvorava: Yeah, maybe I'll just add few words. So actually that's open as a perspective that impairment of red blood cells, eNOS may contribute to the pathogenesis of hypertension. So this is the most important thing I think here in clinician point of view. Dr. Pishoy Gouda: Yeah, absolutely. Lots of different ways that this research might be heading. And like you were saying earlier, Tatiana research is really a longitudinal process. You started this almost a decade ago and I'm sure that there's more projects and plans that you have with this for the future. What are you working on now? Dr. Tatsiana Suvorava: Well, I'm still in academia and I'm still doing academic career, actually. We continued our study and we also studied pathophysiological significance of red blood cells eNOS for cardio protection. For example, in regulation of coronary blood flow, myocardial performance in myocardial infarction, acute myocardial infarction in vivo. We recently published this and here we could also see involvement of red blood cells eNOS, which limit infarct size in acute myocardial infarction. In a pipeline is also a manuscript about red blood cells and endothelial cells eNOS in exercise induced cardio protection and of course the other focus would be the role of red blood cells eNOS in other disease conditions and a chronicle kidney disease for example. It will be also investigated. So we are full of plans, however, I changed department, but I'm still having eNOS in focus and hypertension as well. Dr. Pishoy Gouda: Well that's really exciting stuff and yes, I just wanted to congratulate you both again Dr. Leo and Suvorava and thank you for taking the time to share with us your very clear passion for this topic and I wish you guys both the best of luck. Congratulations again. Dr. Francesca Leo: Thank you so much. Dr. Tatsiana Suvorava: Thank you so much. Dr. Pishoy Gouda: Well congratulations again to our award recipients and Peter, why don't you tell us a little bit about what article we're going to be talking about next? Dr. Peder Myhre: Yes, thank you so much Pishoy. And first, I must say it was so much fun to listen to you guys discuss the paper. You can really feel the passion for the science coming through the microphone. And that was for me as a clinician as well. I learned a lot. And now we're going to actually take a step and move over back to clinical science and we are going to talk to the winners of the James T. Willerson Award. So welcome doctors, Jeanne du Fey and Dr. Alexandra Prepoudis. Dr. Jeanna du Fay de Lavallaz: Thank you very much for having us on the podcast. It's a pleasure to be here and we're also very happy to be able to discuss this paper with you. And of course we were extremely glad to receive this award, so we're excited about the discussion. Dr. Peder Myhre: And so for the listeners who are…

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Circulation December 20, 2022 Issue Dec 19, 2022

Show notes

This week, please join author Mads Liisberg and Guest Host Mercedes Carnethon as they discuss the article "Clinical Characteristics, Incidences, and Mortality Rates for Type A and B Aortic Dissections: A Nationwide Danish Population-Based Cohort Study from 1996 to 2016." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-host. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke, National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, Associate Editor, Director of the Poly Heart Center at VCU Health in Richmond, Virginia. Dr. Carolyn Lam: Greg, today's feature paper is about aortic dissections and it's the first nationwide population based study investigating the clinical characteristic, incidents, and mortality based on validated diagnosis of aortic dissection in a national patient registry. You want to hear more? Well, you have to just keep listening. Let's go on though first to discuss the other really important papers in today's issue, shall we? Dr. Greg Hundley: Absolutely. Dr. Carolyn Lam: You know what, Greg? I'm going to start while you grab a coffee. I want to talk about high sensitivity cardiac troponins and how they have allowed the use of strategies in the emergency department, for example, to rapidly rule out acute MI within one to three hours and potentially facilitate early discharge of low-risk patients. Now, the ability to rapidly rule out MI of course depends on the turnaround time of these high sensitivity cardiac troponin results from the central laboratory, which is often delayed due to specimen transport and handling and all these things. So, point-of-care assays can reduce this turnaround time by even 40 minutes, and early studies have actually used frozen plasma bio banks to assess these point-of-care assays... But no study has evaluated these point-of-care assays with fresh whole blood to safely rule out MI in the emergency department. That is until today's paper. So in today's study led by corresponding other Doctor Fred Apple from Hennepin Medical Center in Minneapolis, Minnesota and his team, they aimed to derive and validate an optimal high sensitivity cardiac troponin threshold concentration using whole blood point-of-care troponin eye assay on a single sample at presentation in the emergency department to identify patients at low risk of index MI for potential early discharge. Dr. Greg Hundley: Fascinating study Carolyn. So point-of-care testing, high sensitivity troponin from whole blood in the ED. So what did they find? Dr. Carolyn Lam: Among consecutive emergency department patients from two prospective observational studies with suspected acute coronary syndrome, a point-of-care, whole blood, high sensitivity cardiac troponin eye assay, the Atellica VTli provided a sensitivity of 98.9% and a negative predictive value of 99.5% for ruling out MI. A single measurement using a cutoff of less than four nanograms per liter for whole blood was successful in rapidly identifying patients at low risk of MI cardiac and all cause death and unplanned revascularization at 30 days. Dr. Greg Hundley: Very nice Carolyn, and could be quite practical. So Carolyn, my next paper comes to us from the world of preclinical science and it pertains to cardiac regeneration. So cardiac regeneration after injury is limited by the low proliferative capacity of adult mammalian cardiomyocytes. However, certain animals readily regenerate lost myocardium via process involving dedifferentiation, which unlocks their proliferative capacities. So inspired by this concept, these investigators led by Professor Patrick Hsieh from Academic Sinica, generated mice with inducible cardiomyocyte specific expression of the Yamanaka factors enabling adult cardiomyocyte reprogramming and dedifferentiation in vivo. Dr. Carolyn Lam: Wow. So what did they find, Greg? Dr. Greg Hundley: Right, Carolyn. So two days following induction, adult cardiomyocytes presented with a dedifferentiated phenotype, an increase proliferation in vivo. Microarray analysis revealed that the up-regulation of ketogenesis was central to this process. Now adenovirus driven HMGCS2 over-expression induced ketogenesis in adult cardiomyocytes and recapitulated cardiomyocyte dedifferentiation and proliferation observed during partial reprogramming. This same phenomenon was found to occur after myocardial infarction, specifically in the border zone tissue. And HMGCS2 knockout mice showed impaired cardiac function and response to injury, and so in summary, Carolyn, these data demonstrated the importance of HMGCS2 induced ketogenesis as a means to regulate metabolic response to cardiomyocyte injury, thus allowing cell dedifferentiation and proliferation as a regenerative response. Dr. Carolyn Lam: Wow, that's so cool. From cell regeneration to autoimmunity in this next paper. Now autoimmunity is increasingly recognized as a key contributing factor in heart muscle diseases. However, the functional features of cardiac autoimmunity in humans remain undefined due to the challenge of studying immune responses in situ. Now, these authors previously described a subset of c-Met expressing memory T lymphocytes, which preferentially migrate to cardiac tissue in mice and humans. In today's study, these authors led by co-corresponding authors, Dr. Federica Marielli-Berg and Saidi Mohidden from William Harvey Research Institute, Barts and the London Faculty of Medicine and Dentistry, and Queen Mary University of London, and their colleagues performed in-depth phenotyping of peripheral blood T cells in groups of patients with inflammatory and non-inflammatory cardiomyopathies, patients with non-cardiac autoimmunity and healthy controls... And they found that c-Met positive T cells were selectively increased in the circulation and in the myocardium of patients with inflammatory cardiomyopathies. The phenotype and function of c-Met positive T-cells were distinct from c-Met negative T cells, including preferential proliferation to cardiac myosin and co-production of multiple cytokines. Further, circulating c-Met positive T cell subpopulations in different heart muscle diseases identified distinct and overlapping mechanisms of heart inflammation. Furthermore, validation studies in experimental autoimmune myocarditis showed that elevations of auto-antigens specific c-Met positive T cells in peripheral blood, marked the loss of immune tolerance to the heart. Importantly, disease development could be halted by pharmacologic c-Met inhibition indicating a positive role for these c-Met positive T cells. Dr. Greg Hundley: All right, Carolyn, as you always ask me. So what's the take home message here? Dr. Carolyn Lam: This study demonstrates that the detection of circulating c-Met positive T cells may have utility in the diagnosis and monitoring of adaptive cardiac inflammation and additionally defined new targets for therapeutic intervention when cardiac autoimmunity causes or contributes to progressive cardiac injury... And this is discussed in an editorial by doctors at Abplanalp, Merten, and Dimmeler. Dr. Greg Hundley: Very nice, Carolyn. Wow. More fantastic preclinical science. Well, in the mail of the bag today, there is a Research Letter by Professor Burr entitled "Cannabis Inhalation Acutely Reduces Muscle Sympathetic Nerve Activity in Humans." Dr. Carolyn Lam: There's an ECG Challenge by Dr. Reddy entitled "Shortness of Breath and Near Syncope During Exertion In a Child, When Patient Worry Syndrome." There's also a Perspective by Dr. Weitz on what is the future of Factor 11 inhibitors. Dr. Greg Hundley: Well Carolyn, I'm looking forward to learning more about aortic dissections and that large Danish population-based study. Wow. Dr. Carolyn Lam: That's great. Let's go Greg. Dr. Mercedes Carnethon: Well, welcome to this episode of Circulation on the Run. My name is Mercedes Carnethon, an Associate Editor of Circulation, and Professor and Vice Chair of Preventive Medicine at Northwestern University. I'm really excited today to be here with the senior author of a really exciting paper that we're featuring on clinical characteristics, incidences and mortality rates for aortic dissections type A and B, a nationwide Danish population-based cohort study, and we have with us today Mads Liisberg. So welcome today. Dr. Mads Liisberg: Thank you. Dr. Mercedes Carnethon: So thank you so much for joining us and really thank you for sharing your important research with Circulation. This topic is so critically important, particularly given the high mortality rates associated with aortic dissections. Can you tell us a little bit about the work that you and your co-authors did in this important space? Dr. Mads Liisberg: Yes. Well actually the work originated when I started my PhD thesis and we got a registry data dump from the Danish medical registries and we found that almost none of our patients in the registry were registered with a specific aortic dissection code. So we did a validation study on the same time period from 1999 to 2006 where we went through all these medical records to ensure that we had the right aortic dissection TC 10 codes on population. Then we went a bit further and looked at the clinical characteristics of this patient, 'cause that's one of the really major things about Danish medical registries in our country, is that we have access to not only every patient's specific in hospital contacts, but also their medicine abuse, their drug use based on a TC code. So we can go really deep into each and everyone's drug history. When we did this study, we wanted to find out if the incidence rates during this timeframe had changed, which we find that it did, but also looking at mortality rates because, as you said, it's really high risk disease to be diagnosed with. So that's more the rationale for this study. Dr. Mercedes Carnethon: Thank you so much for sharing that. Certainly we know that the mortality rates from this are very high. I note that you report some changes over time between 1996 and 2016 in the incidents of these types of aortic dissections. So what did you find about the patterns of change in type A aortic dissections? Dr. Mads Liisberg: We found that it almost doubled from the beginning of our time period to the last, and the question is why is this? 'Cause that's one of the thing that the data doesn't reveal. We are only able to see that the incidence actually rises, but is it because that they are underdiagnosed in the beginning? Or is it because that we are better diagnosing in the end of the study that really are progressed? Dr. Mercedes Carnethon: That's a good question. I noted that when you studied the correlates of aortic dissection, you identified a number of characteristics and what stood out to me was the finding about the strong association of hypertension. I'm less aware of patterns of hypertension in the Danish population. Do you think that the changes in the prevalence of hypertension in the population contributed at all to these findings? Dr. Mads Liisberg: Well, most certainly, 'cause when you look at the prevalence of hypertension throughout any person's lifespan, the older they get the more likely they are to suffer from hypertension, and the Danish population has aged quite a lot in recent years. So I think that's one of the main reasons we find this, and also that most of our arctic dissection patients are actually quite old, which would correlate with hypertension as well. Dr. Mercedes Carnethon: One thing I really like, and you pointed this out, is really the richness of the data that you have in your health system, and I wonder, just going even a little deeper on the hypertension question, given that it is the most common medical diagnosis worldwide, were you able to study characteristics of hypertension that would be more strongly associated with aortic dissection? So for example, duration of hypertension, severity, prevalence of hypertension control? Dr. Mads Liisberg: That's actually a funny question 'cause the last study of my thesis, which hasn't been published yet or even submitted for that fact, examines the correlation between use and the risk of arctic dissection. On a very specific level, the way that hypertension is treated mostly in Denmark is with your general practitioner. So the way that we examine in studies like these, is that we look at prescription drug use. So if we find that an individual has a TC codes corresponding with anti-hypertensive drugs, then we are able to code them as hypertensive patients. Dr. Mercedes Carnethon: Okay, thank you for that. I always... I'm an epidemiologist myself, so I really love to see great population science studies and this registry is large, you have long-term follow up and you've got a great deal of data, but those people who feel as though it's obviously not appropriate to make causal conclusions around epidemiology and that perhaps epidemiologic findings shouldn't be driving clinical decision-making. In response to that, I think I would pose the question to you, which is how do you see clinicians and providers using this information from your observational study? Dr. Mads Liisberg: I think that's rather difficult. One of the findings that we present is to pose it over mortality for type B dissections when we exclude the 30-day mortality, but then we show that type A dissections have almost a corresponding mortality rate compared to a hypertensive cohort... And this finding is difficult to draw any clinical conclusions from, but there's actually a Danish randomized controlled trial just starting up in the next year. I think it's called the Sunday trial, where they will include all uncomplicated type B dissections and randomize them for treatment or no treatment, and the issue here is that you'll probably be over-treating some patients and under-treating others, but this discussion with the uncomplicated type B dissection has been ongoing for so many years. So it's difficult for me to just give one golden answer. Dr. Mercedes Carnethon: Certainly, and I appreciate the caution as we certainly don't want to overstep our findings. You did make a recommendation in the conclusion that it might be beneficial to treat type B aortic dissections more aggressively. Is this what you're alluding to, based on the other study that you're referencing? Dr. Mads Liisberg: Yes, yes, definitely. We see some clinicians being more cautious treating type B dissections with a TIVA or a surgery. So it's a difficult thing when they're uncomplicated, why treat them? But they can't be or become complicated quite easily and fast and then it's a difficult thing, because should you have treated them earlier? Or do you need to treat them now in their acute phase? Or wait for a chronic phase? It's a really good question. Dr. Mercedes Carnethon: No, I appreciate that and what I really love are the types of research studies that leave you with many more questions and next steps, and so I would like to really sort of bring us to a close with the big picture question, which is what do you see as the next steps in this line of research, given really what we all agree on is a very significant clinical problem. Dr. Mads Liisberg: We would really like to expand our database with even more clinical data as of now and include any image diagnostics for our cohort. So we're might be able to see any trends in our modulation before the dissection occurs. If any of our patients have any diagnostics done prior to being diagnosed. Dr. Mercedes Carnethon: I really want to thank y…

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Circulation December 13, 2022 Issue Dec 12, 2022

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This week, please join author Trisha Singh as she discusses her article "Manganese-Enhanced Magnetic Resonance Imaging in Takotsubo Syndrome." Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass for the journal and its editors. We're your co-hosts. I'm Dr. Carolyn Nam, Associate Editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, Associate Editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Carolyn, very interesting feature discussion this week. Many times we hear in magnetic resonance imaging the use of gadolinium contrast. And remember, gadolinium is an extracellular agent. And when we apply it in the heart, we look for infarcts, or areas of the heart that are perhaps dead, or scarred over. This week's feature discusses manganese as a contrast agent and it is an intracellular contrast agent. And very interestingly, it identifies calcium handling, so it's a marker of viability. And these authors are going to apply manganese as well as gadolinium in trying to understand mechanisms behind Takotsubo cardiomyopathy. But before we get to that, how about we grab a cup of coffee and jump into some of the other articles in the issue? Dr. Carolyn Lam: Oh, I'd love to tell you about the other articles. But just have to first say, I loved your description of the feature paper. It's right up your alley and I can't wait to learn more. But my first paper today I want to talk about pulse field ablation. Now, what is that? Pulse field ablation, or PFA, is a unique and novel technique to treat atrial fibrillation. It has a unique safety profile largely related to its preferentially for myocardial tissue ablation. And thus, sparing the esophagus and thus, deemed to have a unique safety profile. Now, a pentaspline catheter was the first such PFA system studied for AF ablation. And in the initial trials the catheter was used for pulmonary vein isolation and left atrial posterior wall ablation. However, following its regulatory approval in Europe, in clinical practice, physicians have ablated both these locations and expanded lesions that could be in closer proximity to the coronary arteries. Now, this is an unstudied important issue since preclinical and maybe some clinical data have raised the potential for coronary arterial spasm. Hence, the investigators led by Dr. Vivek Reddy from Icahn School of Medicine at Mount Sinai and colleagues studied the vasal spastic potential of PFA lesion sets, both remote from and adjacent to coronary arteries. Dr. Greg Hundley: Wow, Carolyn, this is a really interesting question. So what did they find? Dr. Carolyn Lam: In this retrospective analysis of a series of 25 patients undergoing PFA for atrial fibrillation in whom coronary angiography was performed pre, during and post ablation, they found that during pulmonary vein isolation and left atrial posterior wall ablation, coronary spasm did not occur. However, cavotricuspid isthmus ablation provoked severe subtotal vasospasm in five out of five consecutive patients. And this was relieved by in coronary nitroglycerin. ST elevation was not observed. No patient had severe spasm if first pretreated with parenteral nitroglycerin, either intracoronary or intravenous. And so in summary, coronary vasospasm was not provoked during PFA at locations remote from the coronary arteries. But when the energy is delivered adjacent to a coronary artery, like in cavotricuspid isthmus ablation, PFA did provoke subclinical vasospasm. And the phenomenon was attenuated by nitroglycerine administered either post hoc to treat spasm or as prophylaxis. And this is discussed in accompanying editorial, I like it, "Coronary Vasospasm in PFA Primum Non Nocere" by Drs. Estes and Sundeep and Saba. Dr. Greg Hundley: Very nice Carolyn. Very important research in this area using that particular methodology. Well Carolyn, my next study comes to us again from preclinical science. And Carolyn, this study evaluated mechanisms responsible for pulmonary hypertension. So as background, pulmonary hypertension is associated with increased expression of VEGFA and it's receptor VEGFR-2. But whether and how activation of VEGFA signal participates in the pathogenesis of pulmonary hypertension, that's unclear. And so these authors led by Dr. Yangxin Chen from Sun Yat-Sen Memorial Hospital and Sun Yat-Sen University evaluated VEGFA, VEGFR-2 signal activation and VEGFR-2 Y949 dependent vascular leak in lung samples from patients with pulmonary hypertension as well as in mice exposed to hypoxia. Dr. Carolyn Lam: Another one of those excellent translational pieces, isn't it Greg? So what did they find? Dr. Greg Hundley: Right Carolyn. So these authors found that pulmonary hypertension led to excessive pulmonary vascular leak in both patients and hypoxic mice. And this was owing to over activated VEGFA and VEGFR-2 Y949 signaling axis. Abolishing VEGFR-2 Y949 signaling via a specific point mutation was sufficient to prevent pulmonary vascular permeability and inhibit macrophage infiltration and Rac1 activation in smooth muscle cells under hypoxia exposure. This, in turn, led to alleviation of pulmonary hypertension manifestations including muscularization of distal pulmonary arterials, elevation of right ventricular systolic pressure and right ventricular hypertrophy. And so Carolyn, in summary, these results suggest that VEGFA, VEGFR-2 Y949 dependent vascular permeability is an important determinant in the pathogenesis of pulmonary hypertension and might serve as an attractive therapeutic target pathway for this disease. Dr. Carolyn Lam: Aw, thanks Greg for explaining that so well. The next paper talks about transcatheter aortic valve replacement of TAVR, recognizing that it is a well established treatment now for high and intermediate risk patients with severe symptomatic aortic stenosis. However, the question asked here is what makes some, but not all patients improve their left ventricular ejection fraction following TAVR associated after load reduction? Now, hypothesizing that circulating microRNAs may play a role here, the authors led by corresponding authors, Dr. Hosen and Jansen from University of Bonn and their colleagues profiled the differential expression of microRNAs in circulating extracellular vesicles in patients after TAVR. And in particular, the novel role of circulating microRNA 1225p in cardiomyocytes. Dr. Greg Hundley: Oh wow. So Carolyn, important study. So what did they find? Dr. Carolyn Lam: Well, first aortic stenosis increases circulating microRNA 1225p, which correlated with a lack of improvement of the EF in patients after TAVR. Extracellular vesicles harbored microRNA 1225p and facilitated its startling into the cardiomyocytes. Vesicular shuttling of this particular microRNA was regulated by a direct interaction with a multifunctional RNA binding protein called heterogeneous nuclear ribonucleoprotein U in a sequence specific manner. Extracellular vesicles containing the specific microRNA post transcriptionally repressed BCL2 an anti-apoptotic gene, which is central to cell viability and apoptosis. So in summary, Greg, an increase in extracellular vesicle microRNA 1225p in patients with aortic stenosis represents a novel mechanism for the deterioration of cardiac function in patients following TAVR. And pharmacological manipulation of this axis may improve ejection fraction and cardiac function in patients with aortic stenosis by improving the viability of cardiomyocytes, which opens the door to a potential therapeutic approach in patients with limited EF improvement following TAVR. Dr. Greg Hundley: Oh Carolyn, beautiful, beautiful description of that wonderful preclinical science. Well, let's reach into the mail bag and see what else is in the issue. And first, there's a research letter by Professor van Raalte entitled "Kidney Hemodynamic Effects of Angiotensin Receptor Blockades Sodium Glucose Co-transporter 2 Inhibition Alone and in Their Combination: A Crossover Randomized Trial in People with Type 2 Diabetes." And Carolyn, there's also an In Depth piece from Dr. Marx entitled "GLP1 Receptor Agonist for the Reduction of Atherosclerotic Cardiovascular Risk in Patients with Type 2 Diabetes." Dr. Carolyn Lam: Very, very nice papers, those two. There's also an exchange of letters between Drs. Hou and Sedej regarding the article, "Fine Tuning Cardiac Insulin Like Growth Factor 1 Receptor Signaling to Promote Health and Longevity." As well as a Perspective by Dr. Eagle, "Comments on the 2022 Aortic Guidelines: Seeking More Precision in Aortic Care." Now, let's go onto the feature discussion of all things MRI, shall we? Dr. Greg Hundley: You bet. More on manganese. Welcome listeners to this very interesting feature discussion on December 13th. And we have with us Dr. Trisha Singh from the University of Edinburgh in Edinburgh, Scotland. Welcome, Trisha. This is a fascinating study incorporating manganese cardiovascular magnetic resonance to study some of the mechanistic underpinnings of hypokinesis left ventricular hypokinesis in patients with Takotsubo syndrome. So maybe just describe for us some of the background information that went into the preparation of your study, and what was the hypothesis that you wanted to address? Dr. Trisha Singh: Yes, of course. So we know with patients with Takotsubo syndrome, it predominantly affects middle aged women, patients present with a degree of left ventricular dysfunction, which is transient. And, unfortunately, it can be quite difficult to diagnose because it can phenotypically present very similar to an acute coronary syndrome. We know from previous studies that these patients do have ongoing symptoms despite normalization of their LV function. And actually their outcomes are not as benign as previously thought. In terms of manganese enhanced MRI imaging, we at Edinburgh University have imaged patients with other cardiac conditions such as hypertrophic cardiomyopathy, and dilated cardiomyopathy. And have established that it can be used as a surrogate marker of myocardial calcium uptake and handling. So we were very interested to see whether or not patients with acute Takotsubo syndrome have got a myocardial calcium dysfunction and more importantly whether or not this translates into long-term dysfunction and perhaps could explain their symptoms and worse prognosis in long-term. Dr. Greg Hundley: Trisha, manganese MRI. Now, we hear about gadolinium MRI, how is manganese different? You mentioned it's a nice marker for calcium handling. Is this widely used clinically? What kind of contrast does it provide? Dr. Trisha Singh: So manganese was actually one of the first contrast agents to be used with magnetic resonance imaging. It kind of came about in the 1970s and 1980s. And previous animal models have looked at how it is essentially an intracellular contrast agent. And what I mean by that is manganese is a calcium analog and therefore, in cells where they are viable and there's intact cell function, they will be taken up through a voltage gated calcium channels. So, for example, in the heart. So the theory is that manganese, when you've got normal viability, manganese is taken up into the myocardium via voltage gate calcium channels. And several studies have shown that if you then have disease myocardium, these tissues do not take up the manganese as normal tissue would. And the main difference between manganese and gadolinium is they are both paramagnetic, which is why they're helpful and useful in MRI. But gadolinium, as a compound, is too big and it cannot cross an intact cell membrane and therefore, gadolinium is more extracellular. And as, we know, accumulates in tissues where there is increased edema, or water content. So gadolinium, for all intents and purposes, is incredibly useful contrast agent, certainly what we use predominantly at the moment in clinical practice, but it is extracellular. So the theory behind manganese is that it is an intracellular contrast agent as opposed to gadolinium. And where gadolinium accumulates in disease tissue, manganese accumulates in viable tissue. So they behave almost kind of in contrast to each other. And currently, manganese is not used in clinical practice. I think the only clinical compound contrast agent utilizing manganese was mangafodipir, otherwise known as Teslascan, which I believe came off the market in 2012 and that was predominantly used for imaging liver metastasis. Dr. Greg Hundley: Well Trisha, thank you for clarifying for us the difference between manganese, the intracellular contrast agent, and gadolinium, the extracellular contrast agent, that's so widely used clinically. Well, with that description, can you describe for us now, your study population and your study design? Dr. Trisha Singh: Perfect. So the study population was we aimed to recruit 20 patients with acute Takotsubo syndrome. The diagnosis of Takotsubo syndrome was based on a clinical diagnosis, so all our patients underwent a baseline echocardiography and invasive coronary angiography. Now, for us, the coronary angiography was quite important because we wanted to ensure we ruled out anyone with an acute myocardial infarction, which can often be tricky in this cohort of patients. So after recruiting 20 patients during the acute phase of Takotsubo, they all underwent a baseline gadolinium enhanced MRI scan followed by a manganese enhanced MRI scan. And these were done at least 48 hours a part. And then about three months roughly after the acute index, they were all invited to participate in a second manganese enhanced MRI scan. Dr. Greg Hundley: Very good. So two exams separated longitudinally over time. What were your study results? Dr. Trisha Singh: Our results demonstrated that during the acute phase as one would expect, patients had a degree of left ventricular dysfunction. The majority of our patients had afibrillar Takotsubo, so had afibrillar ballooning with preservation of the basal segments. With this, we also noted that in the areas that were affected by Takotsubo, so kind of the mid ventricular wall and the apex that all patients had significantly elevated native T1 and associated T2 as well. And as we expected there was reduced uptake of manganese and therefore kind of reduced calcium uptake in the myocardium in the area affected by Takotsubo syndrome. Interesting, what we also noticed was that all these patients had significantly elevated LV mass, which has been described in previous Takotsubo papers, certainly by Professor Dawson. And when you measured the left ventricular wall thickness, the LV wall thickness is elevated in the affected and actually not even in the non-affected areas, which I suspect explains why in the acute phase people almost doubles up which kind I guess fit with kind of acute myocardial edema and intense water content. And then, three months later when these patients returned for their follow-up scan, a lot of the acute changes had resolved. So native T2 values had improved and gone back to baseline. Native T1 and post contrast T1 values had remained elevated compared to the control population. And what we found was that manganese uptake, though it had improved, it still remained abnormal and reduced compared to the control population, which is a finding that we weren't expecting to find. Dr. Greg Hundley: Very interesting. So acutely we've got extracellular water there, elevation of myocardial T2, and also impaired manganese uptake. So intracellular abnormalities with calcium handling. Then later, so three months later, we have restoration of myocardial T2 so the extra water content is absent, but we have impaired manganese uptake i…

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Circulation December 6, 2022 Issue Dec 05, 2022

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This week, please join author Sean Pokorney and Associate Editor Shinya Goto as they discuss the article "Apixaban for Patients With Atrial Fibrillation on Hemodialysis: A Multicenter Randomized Controlled Trial." Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and Backstage Pass of the journal and its editors. We're your cohost. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore. Dr Greg Hundley: And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Carolyn, this week's feature, very interesting topic. In patients that have end stage renal disease that require dialysis, questions emerged should we anticoagulate them to prevent stroke, but of course, there's a risk of excess bleeding. Well, this feature discussion today is a study comparing apixaban and warfarin for anticoagulation in exactly this patient population. But before we get to those results, how about we grab a cup of coffee and go through some of the other articles in the issue? Would you like to go first? Dr Carolyn Lam: Absolutely, Greg. So my first paper is a pre-specified analysis of the Paradise MI trial and knowing you'll likely ask me what that was about, Greg, at least to summarize for everyone, the Paradise MI trial compared sacubitril/valsartan with ramipril and its effect on reducing heart failure events after an MI in more than 5,600 patients with an acute myocardial infarction complicated by LV systolic dysfunction, pulmonary congestion, or both. Now in today's paper, what Dr. Mehran and colleagues found was that among patients with a recent AMI and LV systolic dysfunction, heart failure are both, sacubitril/valsartan decreased the risk of coronary related events by 14% as compared with ramipril over a median follow-up of 22 months. The reduction in coronary events occurred with a favorable safety profile. Dr Greg Hundley: Wow, Carolyn, very interesting. Another indication perhaps for sacubitril/valsartan, especially relative to ACE inhibitors. So what does this mean for us clinically? Dr Carolyn Lam: Well, the results really cause us to consider if in addition to antiplatelets and lipid lowering therapies, sacubitril/valsartan may be explored as a potential agent to mitigate the residual risk in survivors of AMI. Of course, dedicated studies are necessary to confirm this finding and elucidate its mechanism. Dr Greg Hundley: Oh, very nice, Carolyn. Well, my first paper comes to us from the World of Preclinical Science and Carolyn, this study evaluated the scavenger receptors stabilin-1 and stabilin-2, proteins that are preferentially expressed by liver sinusoidal endothelial cells. Now, they mediate the clearance of circulating plasma molecules controlling distant organ homeostasis. And studies suggest that stabilin-1 and stabilin-2 may impact atherosclerosis. So in this study, the investigative team led by Professor Cyrill Géraud from the University Medical Center and Medical Faculty in Mannheim, Heidelberg comprehensively studied how targeting stabilin-1 and stabilin-2 affects atherosclerosis. Dr Carolyn Lam: Huh. All right, nicely explained. And so what did they find, Greg? Dr Greg Hundley: Right, Carolyn. So inhibition of evolutionary conserved class H scavenger receptors, stabilin-1 and stabilin-2, reduced aortic plaque burden in preclinical models and athero protection was mediated likely through down regulation on transcriptional factor ERG1 in monocytes by multifaceted plasma protein changes. And then finally, Carolyn transforming growth factor beta induced periostin, reelin, and they are novel ligands of stabilin-1 and stabilin-2 and are implicated in the development of atherosclerosis. Dr Carolyn Lam: Okay. Wow. Could you give us a take home message, please Greg? Dr Greg Hundley: Right. Carolyn, I knew you had asked me this. So here we go. Monoclonal, anti-stabilin-1 and anti-stabilin-2 antibodies provide a novel approach for the future treatment of atherosclerosis. And in the future, perhaps the plasma proteome composition may serve as a predictive factor, biomarker or surrogate parameter for cardiovascular disease in patients. Dr Carolyn Lam: Wow. Thanks Greg. My next paper is a true story of discovery. Now I could ask you what you know about the condition hypertension with brachydactyly type E... Greg, I love that expression. I wouldn't be able to answer that too. So let me tell you the story. So hypertension with brachydactyly type E is an autosomal dominant Mendelian disease resembling essential hypertension. Untreated patients die of stroke by the age of 50 years. Now, these authors had previously demonstrated a gain of function phosphodiesterase 3A gene mutations that caused the condition by increasing peripheral vascular resistance. They studied a large family with the condition earlier and were puzzled that cardiac hypertrophy and heart failure did not occur despite the decades of hypertension. And so they hypothesized that in the heart, this phosphodiesterase 3A or PDE3A mutations could be protective. Isn't that neat? And so corresponding authors, Doctors Bader, Klussmann, Bähring and Hübner, all from the Max Delbruck Center for Molecular Medicine in Berlin, Germany. So they studied new patients as well as CRISPR-Cas9 engineered rat models of this condition of hypertension with brachydactyly type E. And they comprehensively phenotyped all of them with the human induced pluripotent stem cells carrying these PDE3A mutations as well. So analyzing all of this from cells to new patients to CRISPR-Cas9 models. Dr Greg Hundley: Wow, Carolyn, what an interesting story. So what did they find? Dr Carolyn Lam: So while in vascular smooth muscle, the PDE3A mutations caused hypertension, in the hearts, they conferred protection against hypertension-induced cardiac damage, hypertrophy and heart failure. The mechanism involved long-term adaptations of mRNA and protein expression as well as calcium cycling. Non-selective PDE3A inhibition was a final short term option in heart failure treatment to increase cardiac cyclic AMP and improve contractility. So the data argued that mimicking the effect of PDE3A mutations in the heart rather than non-selective PDE3 inhibition was cardioprotective in the long term. And these findings could indeed facilitate the search for new treatments to prevent hypertension-induced cardiac damage. This is discussed in a really lovely editorial by Dr. Chiong, Houslay, and Lavandero. Dr Greg Hundley: Very nice, Carolyn. Wow. What another... we have such great articles from the World of Preclinical Science. Beautiful description as well. Well, we have some other articles in the issue, particularly from the Mailbag. And we have a Research Letter from Professor Thiagarajan entitled "Yield of Cardiac MRI in a pre-participation cohort of Young Asian males with T-Wave inversion." Dr Carolyn Lam: Interesting. There's an exchange of letters between Dr. Xu and Huang regarding the article associations of dietary cholesterol, serum cholesterol and egg consumption with overall and cause-specific mortality with a systematic review and updated meta-analysis. There is a Perspective piece by Dr. Marcus on Smart watch detected atrial fibrillation, the value in positive predictive value. Isn't that interesting? And now onto that very, very important question of anticoagulation in patients with kidney disease. Can't wait. Let's go, shall we? Dr Greg Hundley: You bet. Carolyn. Welcome listeners to our December 6th feature discussion. And we have with us today Dr. Sean Pokorney from Duke University in Durham, North Carolina, and our associate editor, Dr. Shinya Goto from Tokai University in Isehara, Japan. Welcome gentlemen. Well, Sean, we're going to start with you. Can you describe for us some of the background information that went into the preparation of your study and what was the hypothesis that you wanted to address? Dr. Sean Pokorney: Yeah, absolutely. Thanks for having me to discuss the renal AF trial. And so I would say that the background information to the study was that we know that atrial fibrillation is an incredibly common condition in patients with chronic kidney disease. And the decision of anticoagulation in patients with end-stage kidney disease, on hemodialysis is really quite complex because these patients are at high risk for stroke and they're at high risk for bleeding. There are concerns with warfarin around calcific uremic arteriolopathy or calciphylaxis and there have been some data including from the original Aristotle trial that apixaban was even more favorable in terms of bleeding reduction relative to warfarin in patients with more advanced chronic kidney disease. Although patients with creatinine clearance less than 25 were excluded from Aristotle and really all patients with endstage kidney disease on hemodialysis have been excluded from all trials of atrial fibrillation in the past. And so we really wanted to evaluate the safety of apixaban versus warfarin in patients with end-stage kidney disease, on hemodialysis. And the hypothesis was that apixaban was going to be non-inferior to warfarin with respect to safety in terms of major or clinically relevant, non-major bleeding in these patients with atrial fibrillation and end stage kidney disease on hemodialysis. Dr Greg Hundley: Thanks so much, Sean. And you've mentioned the renal AF trial. So could you describe for us, for your, I guess, substudy, what was the study population? Who did you include and describe for us also your study design? Dr. Sean Pokorney: Yeah, absolutely. So the trial included patients who had end-stage kidney disease, and/or on hemodialysis, as well as having concomitant atrial fibrillation. And the patients had to have a CHA-VASc score greater than equal to two. All of the patients had to be on hemodialysis for at least three months. So these were chronic hemodialysis patients. And the study design was an open label randomized trial that was 1:1 randomization between apixaban and warfarin with blinded outcome evaluation. And again, the primary endpoint of the study was major or clinically relevant non-major bleeding based on ISTH definitions. And there were secondary endpoints looking at stroke, systemic embolism, death, medication adherence, and I think a really important sub-study looking at PK data. And the goal was to have 50 patients where we included PK data that was going to more represent what chronic apixaban dosing data would look like in these patients with end-stage kidney disease on hemodialysis. And originally the goal of the trial was to include over 700 patients. Originally we were trying to include 762 patients based on our initial power calculations to achieve true non-inferiority. Unfortunately, the trial enrollment was low and so the trial was ultimately stopped prematurely at 154 patients, although we were able to include the original targeted 50 patients in the PK substudy. The dosing that we used in the renal AF trial was 5 mg of apixaban twice daily unless patients had a second dose-reduction criteria in addition to chronic kidney disease. So the fact that they had end-stage kidney disease and were on hemodialysis counted as one dose reduction criteria and patients that were under 60 kilograms or less were 80 years of age or older, who had then a second dose-reduction criteria were treated with the 2.5 mg twice daily dosage. And this was important to note because this is different than the dosage that was used in the AXADIA-AFNET trial. Dr Greg Hundley: Very nice. And so Sean, what did you find? Dr. Sean Pokorney: Yeah. So again, a lot of this data is really exploratory because of the limited sample size, we weren't really able to definitively conclude anything about the major or clinically relevant non-major bleeding rates. I would say that some of the key findings that we saw was that there were high rates of major or clinically relevant non-major bleeding in both arms of the trial and one year bleeding event rates were 25% in the warfarin arm and 31% in the apixaban arm. And again, there was no statistically significant difference, although again, this is really exploratory. I would say that some of the other interesting findings that we saw was that there were very low rates of ischemic and hemorrhagic stroke in this patient population. Again, there were 82 patients randomized to apixaban, 72 patients randomized to warfarin. And there was a difference in the randomization because of the stratification by site that was performed with the randomization. And so within the 82 patients that were randomized to apixaban, the patients, there was one ischemic stroke and one hemorrhagic stroke. There were no hemorrhagic strokes in the warfarin population and two ischemic strokes. Another key finding was the high rates of mortality in this patient population. So 26% of the apixaban patients experienced a mortality event, 18% in the warfarin arm. So again, the mortality rates in these patient populations were extremely high. I would also emphasize some of the data from the PK analysis. So we looked at the PK analysis in two different ways. For the patients that were treated with the 5 mg dose of apixaban, the PK data showed that there was consistent overlap in the steady state concentration at one month compared to patients in the Aristotle trial that had really mild to moderate, moderate to severe and severe chronic kidney disease. And so there was a consistent overlap in those steady state concentrations between the end-stage kidney disease population on hemodialysis and the chronic kidney disease population who benefited from a apixaban in the Aristotle trial. Similarly, in the 2.5 mg apixaban dose, the patient who had a second dose reduction criteria in addition to chronic kidney disease, those patients had consistent steady state concentrations of apixaban relative to patients with mild to severe chronic kidney disease. Dr Greg Hundley: Very nice. Well thank you so much, Sean. And listeners, now we're going to turn to our associate editor, Dr. Shinya Goto. Shinya, can you, sort of, highlight for us some of the interesting findings that you see from these study results that Sean just presented? Dr. Shinya Goto: Thank you, Greg. Thank you, Sean for your wonderful summary of your study. We had a great discussion with an editor for this paper. As Sean pointed out, this is a kind of underpowered trial or just terminated early, hypothesis was not tested in the trial. But this population of patient clearly needs a real-world clinical trial, patient with atrial fibrillation, end-stage kidney disease, on hemodialysis; things a clinician could do. In some country, nephology society defined warfarin contraindicated in this population. As Sean pointed out, whether the development of this trial include this high-risk population patient. So we had a discussion whether the underpowered trial provided something or nothing may be better than something just provided here. Our consensus finally reached was, this limited trial still provide something like, you have to make a decision to use the anticoagulation. I mean, that the apixaban might be still used due to the PK data. That is the kind of interesting point of this trial. Dr Greg Hundley: Very nice Shinya. Well, Sean, turning back to you and Shinya with that nice lead in really, Sean, what do you think is the next study that needs to be performed in this sphere of research? Dr. Sean Pokorney: Yeah, absolutely. I think this is a challenging patient population to study. And again, our trial, the renal AF trial stopped early. Unfortunately, the AXADIA-AFNET 8 study also stopped early, which was also looking at apixaban versus warfarin outside the US and Europe. And so again, it is a challe…

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Circulation November 29, 2022 Issue Nov 28, 2022

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This week, please author Gemma Figtree and Associate Editor Nicholas Mills as they discuss the Frontiers article "Noninvasive Plaque Imaging to Accelerate Coronary Artery Disease Drug Development." Dr. Greg Hundley: Welcome listeners to this November 29th, 2022 issue of Circulation On the Run. I am one of your hosts, Dr. Greg Hundley, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Dr. Peder Myhre: I am Dr. Peder Myhre from Akershus University Hospital and University of Oslo in Norway. Dr. Greg Hundley: Well, Peder this week's feature discussion very interesting. It is a state of the art review and it involves noninvasive plaque imaging and really how we might assess plaques to evaluate whether coronary artery disease is accelerating. Very important information by a large group of clinician scientists that will develop programs that, maybe, can be used in therapeutic drug development. Dr. Peder Myhre: That's so interesting, Greg. Dr. Greg Hundley: Right. A great group of individuals all put together, but before we get to that interesting feature discussion how about we grab a cup of coffee and start with some of the other articles in the issue? How about this week I go first? Dr. Peder Myhre: Go ahead Greg. Dr. Greg Hundley: Peder, these authors led by Marianna Fontana from University College London Medical School sought to characterize changes in the clinical phenotype of 1,967 patients with a diagnosis of transthyretin cardiac amyloidosis over the last 20 years enrolled and participating in the National Amyloidosis Center from 2002 to 2021. Dr. Peder Myhre: Oh yes, Greg, please. This cardiac amyloidosis we have to learn more about it. Please, tell me what did they find. Dr. Greg Hundley: Right, Peder. First, there's been a substantial increase in the number of patients diagnosed with transthyretin amyloid in recent years. This is associated with greater proportions of patients referred following cardiovascular magnetic resonance imaging and bone scintigraphy scans. Second, transthyretin amyloid patients are often now being diagnosed much earlier in their disease process, as evidenced by a shorter duration of symptoms prior to diagnosis, milder stages of disease, and more favorable structural and functional echocardiographic changes at the time of diagnosis. Then, finally, mortality in these transthyretin amyloids patients has improved substantially in recent times aside from any potential benefits from disease modifying treatment or participation in clinical trials. Dr. Peder Myhre: Wow. Greg, over the course of 20 years we have seen some differences in the diagnosis or cardiac ATTR amyloidosis, so what would you say are the take home messages from this paper, Greg? Dr. Greg Hundley: Right, Peder. Transthyretin amyloid is now often diagnosed earlier in the disease process with improved prognosis. I think, more data needed to guide decisions on in whom and when to initiate treatment and then which treatments should be used at each stage of the disease. Peder, along with this article there's an excellent editorial by Doctors Patel and Maurer entitled "The Future for Patients with Transthyretin Cardiac Amyloid is, It's Looking Brighter." Dr. Peder Myhre: Okay. Greg, I'm going to continue in the field of clinical research and this paper actually describes a new ablation technique for ventricular tachycardia. Isn't that exciting? Dr. Greg Hundley: Absolutely. Dr. Peder Myhre: The paper comes to us from corresponding author Miguel Valderrabano from Houston Methodist Hospital in Texas and is entitled "Substrate Ablation by Multi-vein, Multi-balloon Coronary Venous Ethanol for Refractory Ventricular Tachycardia and Structural Heart Disease." Ablation of ventricular tachycardia, VT, in the setting of structural heart disease often requires extensive substrate elimination, which is not always achievable by endocardial radiofrequency ablation and epicardial ablation is not always feasible. The left ventricle venous circulation allows vascular access to reach intramural substrates of VT in the context of myocardial infarction or non-ischemic scar, where radiofrequency ablation has limited success. Greg, in this study the authors enroll patients with ablation refractory VT and used phonography and epicardial mapping to perform a double balloon venous ethanol ablation. That is, by blocking flow with one balloon and injecting ethnol via this second balloon. Dr. Greg Hundley: Peder, what a beautiful description and very interesting strategy to address this situation. What did they find? Dr. Peder Myhre: Greg, after the venous ethanol ablation vein maps and epicardial maps showed elimination of abnormal electrograms of the VT substrate an intracardiac echocardiography demonstrated increased intramural echodensity at the target lesions of the 3D maps and at one year of follow up VT recurrence occurred in seven patients, which translates into a success rate of 84%. The authors conclude that multi-balloon multi-vein intramural ablation by venous ethanol ablation can provide effective substrate ablation in patients with ablation refractory VT in the setting of structural heart disease over a broad range of left ventricular locations. Dr. Greg Hundley: Very nice, Peder. What a beautiful description. Excellent. Well, this next paper Peder comes to us from the world of preclinical science and these authors led by Professor Christine Sideman from the Harvard Medical School evaluated alpha-kinase 3. Now, alpha-kinase three is a muscle specific protein in which loss of function variants cause cardiomyopathy with distinctive clinical manifestations in both children and adults. At presence the muscular functions of alpha-kinase 3 remain poorly understood, so to address this dilemma these investigators explored the punitive kinase activity of alpha-kinase 3 and the consequences of damaging variants using isogenic human induced pluripotent stem cell derived cardiomyocytes. Mice and human patient tissues. Dr. Peder Myhre: Okay, Greg. This sounds like impressive basic science work, so what did the authors find. Dr. Greg Hundley: Right, Peder. Damaging variance in alpha-kinase 3 encoding an abundant muscle specific protein caused both neonatal and adult onset cardiomyopathies and led to both ventricular dilation and hypertrophy. Now, although alpha-kinase three contain an alpha kinase domain the team showed that it lacks catalytic activity and is really a pseudo kinase. Then finally, Peder, alpha-kinase 3 localizes to both the nuclear envelope of cardiomyocytes and the M-band of the sarcomere where it regulates the expression and localization of myomesins, myomesin 1 and myomesin 2, and additional M-band proteins important for sarcomere protein turnover. Dr. Peder Myhre: That is a beautiful summary, Greg. Since you did so well at summarizing this difficult topic, I'm not going to ask you what a clinical implications, but rather to take home messages here. Dr. Greg Hundley: Very nice. Glad you asked Peder. First, alpha-kinase 3 cardiomyopathy may cause impaired contractility and ventricular dilation due to miss localization and dysregulation of myomesin proteins which are critical for force buffering in cardiomyocytes. Next, alpha-kinase 3 cardiomyopathy may cause hypertrophy due to dysregulation of key M-band proteins, which are important for sarcomere protein turnover. Then finally, therapeutic strategies to restore cardiomyocyte force buffering functions and sarcomere protein turnover may ameliorate disease phenotypes in patients with alpha-kinase three cardiomyopathy. Dr. Peder Myhre: Thank you Greg. The next paper is also from the field of preclinical science and it is about the Hippo-YAP signaling pathway which maintains sinal atrial node homeostasis. It comes to us from the corresponding author Jun Wang from the University of Texas Health Science Center at Houston. Greg, this paper is not about hippos, but it is about the Hippo signaling pathway, which is known to control organ size and growth in animals and humans. These authors sought to investigate this pathway in relation to the sinal atrial node, i.e. The sinus node. As you know Greg, the sinal atrial node functions as the pacemaker of the heart initiating rhythmic heartbeats. Despite its importance the sinal atrial node is one of the most poorly understood cardiac entities, because of its small size and complex composition and function. To uncover the function of Hippo signaling in sinal atrial node the authors use knockout mice and a series of physiological and molecular experiments including telemetry, electrocardiogram recording, echochoreography, calcium imaging, immunostaining, ANA scope, quantitative real time PCR, and western blotting. Dr. Greg Hundley: Wow, Peder, that sounds like quite an extensive series of experiments. What did they find? Dr. Peder Myhre: Deletion of essential Hippo kinases caused increased fibroblast proliferation and fibrosis in the sinal atrial node. They also found evidence suggesting that Hippo signaling regulates calcium hemostasis in pacemaker cells and that may be partially mediated by the regulation of genes and coding key calcium handling proteins such as RYR2. Finally, the demonstrated that deletion of Hippo effectors in the sin atrial node can rescue the defect previously described. Greg, the take home messages is that Hippo signaling was found to be an important regulator of the sinal atrial node homeostasis and that this provide insights applicable to the treatment of patients with sinus node dysfunction. Dr. Greg Hundley: Ah, beautifully done Peder. Beautifully done. We've got some other articles in this issue. Let me tell you about a Research Letter. It's from Professor Nazer entitled "Targeted Screening for Transthyretin Amyloid Cardiomyopathy in Patients with Atrial Fibrillation." Then Tracy Hampton has a whole series of cardiology news highlighting first that primary cilia are critical for exercise induced muscle hypertrophy. This is from the proceedings of the National Academy of Sciences. Next, there's a discussion of whole body reperfusion techniques to restore function in pig organs after death, that comes to us from nature. Then lastly, there's a final article scientists identify diverse pathogenic gene variants that lead to heart failure from the journal science. Dr. Peder Myhre: Thank you, Greg. Finally, there is one Perspective piece by Dr. Rajiv Agarwal from Indiana University School of Medicine entitled "Hydrochlorothiazide versus Chlorthalidone: What is the difference?" Now, let's move on to the feature discussion that I know you are very excited about, Greg, to learn more about the non-invasive plaque imaging in our frontiers of medicine. Dr. Greg Hundley: You bet. Well listeners, welcome to this feature discussion today on November 29th and we have with us Dr. Gemma Figtree from Sydney, Australia and our own associate editor, Dr. Nick Mills from Edinburgh, Scotland. Welcome to you both. Listeners, this is a really interesting feature discussion. It's one of our Frontiers articles that combines where we are in the past, but also where we want to move in the future and a very nice comprehensive review with many articles. Gemma, can you describe for us the genesis really of this article and what you've been working on? Dr. Gemma Figtree: Thanks so much, Greg. Look, I think it's very exciting times at the moment and it's a really important time for all of our community to actually get together in this space. We are driven by trying to make a more efficient process for drug discovery and translation to occur and to basically move into humans in the space of coronary artery disease. We've actually known, obviously, for a long time that the underlying process driving heart attack, but we've not been able to image and treat the actual underlying disease. What this article focuses on is how we actually merge top current technology with policy and approval of drugs. We are very excited about the team of over 20 different institutes around the world trying to work on the best measures of corona artery disease as the disease itself. Dr. Greg Hundley: Very nice. Now, help us understand different techniques and why is this a frontier? Dr. Gemma Figtree: Look, I think it's a mixture of the fact that, obviously, we're getting great advances in noninvasive imaging techniques that allow us to actually measure plaque burden, but also plaque characteristics. In the case of drug translation this is an absolutely fundamental piece. You can transform a clinical trial where you can look at the underlying pathology and be able to enrich trials or be able to look at the effect of trials of a new drug in humans. It's really important to acknowledge the fact that humans are really the only animal on the planet that get corona artery disease itself. To be able to translate some of the exciting new drugs that target the plaque itself and work synergistically with some of our agents on cholesterol, and blood pressure, et cetera, we really need to have these measures of coronary artery disease itself. It's a combination of the technology, but also how we apply it to a clinical trial and then how do we work with our regulatory authorities and policy advisors around getting this into humans. We really aiming to try to accelerate the development of drugs that can try to tackle our greatest burden of cardiovascular disease around the world. Dr. Greg Hundley: I'm hearing cardiovascular disease, I also heard in their imaging and lots of different modalities, and then I heard regulatory bodies. Are you thinking maybe we need standards? Dr. Gemma Figtree: That's exactly right. I think, importantly, whilst there's a lot of exciting technology and a lot of us are pursuing potentially different avenues of this we also need to be able to coordinate and develop a simple and harmonized approach that's able to be applied across the world in an equitable fashion. Whilst we, obviously, have developing exciting new toys we have to make sure that a measure that we want to work with regulatory authorities is able to be applied in all of our countries around the world to make sure that the drug development is applied in an equitable fashion. Dr. Greg Hundley: Very nice. Well listeners, next we're going to turn to our associate editor, Dr. Nick Mills. Nick, you evaluate many manuscripts. What attracted you to this particular paper? Also, help us put it in the context of why you think it's a new frontier that is emerging or needs to emerge in cardiovascular disease. Dr. Nick Mills: Yeah, thanks Greg. Three things, the expertise of this group, the focus and novelty of the topic, and the fact that it's a really timely issue Gemma just outlined. Gemma a phenomenal job bringing together people from all over the world to tackle this area that includes imaging expertise, drug development expertise, industry that gives it a very balanced and diverse range of views and marks it out from other reviews that focus on particular imaging modality. Novelty's really important, but timeliness as well. We've seen in the last five years major breakthroughs in the treatment of diabetes and heart failure. But, drug development of coronary heart disease is stalling. I cannot remember the last time I went to a really exciting late breaking trial on a new development for coronary heart disease that has changed the outcomes for patients. We do need to rethink. Gemma's absolutely right, that requires us to work with regulators to stimulate industry involvement in drug discovery, and delivery, and testing. This is occurring at a time where we've got more fabulous imaging modalities then we've ever had before. Critically, they're no…

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