Show notes
This week, please join authors Marc Sabatine and Prakriti Gaba, as well as Associate Editor Amit Khera, as they discuss the article "Association Between Achieved Low-Density Lipoprotein Cholesterol Levels and Long-Term Cardiovascular and Safety Outcomes: An Analysis of FOURIER-OLE." Dr Greg Hundley: Welcome listeners, to this April 18th 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: And I'm Dr. Peder Myhre, Social Media Editor from Akershus University Hospital and University of Oslo. Dr Greg Hundley: Peder, today's feature discussion, very interesting. We're going to evaluate the association between what's achieved with LDL cholesterol lowering, and then also long-term cardiovascular and safety outcomes. But before we get to that, how about we grab a cup of coffee and discuss some of the other articles in the issue? Would you like to go first? Dr Peder Myhre: Yes, Greg. I would love to. And the first paper is from the World of Preclinical Science and it comes to us from corresponding author, Jan Magnus Aronsen from University of Oslo in Norway. And perhaps, as you know, Greg, cardiomyocyte contraction and relaxation depend on the activity of the sarcoplasmic reticulum CA+2 ATPase 2, abbreviated SERCA2, and lowered levels or reduced activity of SERCA2, as seen in chronic heart failure, weakens contractile force and delays relaxation and no available therapy involves direct manipulation of the SERCA2 activity. And Greg, phosphodiesterase 3A is proposed to be present in the SERCA2 interactome limit SERCA2 activity and disruption of phosphodiesterase 3A from SERCA2 might thus be a strategy to develop SERCA2 activators. And in this study, the authors investigated and mapped SERCA2 and phosphodiesterase 3A and assessed this in experiments assessing the binding between these two in cardiomyocytes and in vesicles. Dr Greg Hundley: Wow Peder, sounds very interesting. So what did they find and how about the clinical implications of the findings? Dr Peder Myhre: So Greg phosphodiesterase 3A bounded directly to SERCA2 in the cardiomyocyte. So that's the first finding. Second, they demonstrated that SERCA2 phosphodiesterase 3A disruption increased SERCA2 activity independently of the catalytic activity of phosphodiesterase 3A in both normal and failing cardiomyocytes. And third, SERCA2 activity by the optimized SERCA2 phosphodiesterase 3A disruptor peptide OPT F reduced mortality and improved contractility after aortic binding in mice. So the clinical implication is that direct targeting of phosphodiesterase 3A binding to SERCA2 could be a novel approach to increase SERCA2 activity and thus cardiac contractility in patients with heart failure. Dr Greg Hundley: Very nice Peder. What a great new finding in the world of preclinical science. Well my paper is going to delve into the world of clinical science and involves patients with stroke. So Peder in this study led by corresponding author, Dr. Dileep Yavagal from University of Miami Miller School of Medicine performed a survey in 75 countries through the Mission Thrombectomy 2020+ Global Network between November of 2020 and February of 2021 to determine the availability of mechanical thrombectomy for large vessel occlusion in patients with stroke. Now Peder, the primary endpoints were the current annual mechanical thrombectomy availability, the mechanical thrombectomy operator availability and the mechanical thrombectomy center availability. All of these availabilities were defined as the proportion of estimated large vessel occlusion for patients receiving mechanical thrombectomy in a given region annually. Dr Peder Myhre: Okay, Greg, so this is really an access question. So in essence, what is the availability of mechanical thrombectomy worldwide? So what did they find? Dr Greg Hundley: Right, great Peder. So what they found, the authors received 887 responses from 67 countries and low-income countries had 88% lower mechanical thrombectomy availability compared to high-income countries. The global mechanical thrombectomy operator availability was 16.5% of optimal, and the mechanical thrombectomy center availability was only 20.8% optimal. And with these results, the authors indicate that global cooperation and targeted region-specific public health interventions, including all stakeholders involved in stroke care delivery, are really needed to rapidly increase access to this brain-saving and disability-sparing treatment with mechanical thrombectomy really worldwide. Dr Peder Myhre: Oh wow. What a beautiful summary, Greg. Thank you so much. And we also have some other interesting papers in the mailbag today. We have an exchange of letters between Dr. Yang and Dr. O'Donoghue regarding the article "Long Term evolocumab in Patients with Established Atherosclerotic Cardiovascular Disease." Dr Greg Hundley: Great Peder, and also Professor Perera has a Frontiers article entitled "Unloading the Left Ventricle in Venoarterial ECMO in Who, When and How?" and then finally there's a Research Letter from Professor Verma entitled "Prevalence of Diabetes and Cardiovascular Risk in the Middle East and Africa: The Primary results of the PACT-MEA Study." Well Peder, how about we jump to that feature discussion? Dr Peder Myhre: Can't wait. Dr Greg Hundley: Welcome listeners to this feature discussion on April 18th and we have with us today Prakriti Gaba and Marc Sabatine from Brigham and Women's Hospital and our own associate editor, Dr. Amit Khera. Welcome everyone. Well Marc, we'll start with you. Can you describe for us some of the background information that really helps constitute the preparation of your study and what was the hypothesis that you wanted to address? Dr. Marc Sabatine: Yeah, thanks Greg and thanks for having us. So we've seen in a variety of epidemiologic cohorts the association between LDL cholesterol and the risk of adverse cardiovascular events like in Framingham Heart Study and UK Biobank. But in those cohorts, in these industrial societies, we don't have the benefit of lots of data in individuals with very low levels of LDL cholesterol and so we had the opportunity with the FOURIER study that was the randomized comparison of evolocumab PCSK9 inhibitor versus placebo to get patients down to extremely low levels of LDL cholesterol and evolocumab. We were able to get individuals down to about 30 mg/dL. And so in addition to all the studies we've done showing the comparison of evolocumab to placebo, we also then had the chance to use FOURIER, and as you'll hear from PK, FOURIER-OLE, the open-label extension, as a cohort to then examine patients' new baseline, if you will, their new achieved LDL cholesterol and then it's association not only with cardiovascular events but safety events. And so the hypothesis is that there would be a relationship with the lower the LDL cholesterol, the lower the risk of cardiovascular events and we wanted to explore how far down that went. And then the second one for safety would be that there wouldn't be any association between low levels of LDL cholesterol and a variety of safety outcomes that rightly or wrongly people have ascribed to low levels of LDL cholesterol. Dr Greg Hundley: Thanks so much, Marc. Well listeners, now we're going to turn to PK, the first author, on this very interesting paper and PK, Marc mentioned to us the FOURIER-OLE study. Maybe describe for us here your study design and then what specifically was your study population? Dr. Prakriti Gaba (PK): Yeah, definitely. Thanks so much for the introduction. So the study population included 27,564 patients with stable atherosclerotic cardiovascular disease and LDL cholesterol levels that were greater than or equal to 70 mg/dL or non-HDL cholesterol greater than or equal to a 100 mg/dL on statin therapy. The patients who then went on to the FOURIER-OLE or the open-label extension part of the trial consisted of about 6,635 patients. And so in this study we essentially evaluated the combination of those populations in 2 separate analyses. We then categorized patients according to 6 pre-specified bins based on their achieved LDL cholesterol levels at designated time points and those ranged from LDL levels of less than 20 mg/dL all the way up to 100 mg/dL. And then we looked at their baseline characteristics and evaluated the cardiovascular and safety outcomes that Dr. Sabatine mentioned earlier. Dr Greg Hundley: Very nice PK. Well we've got a great listening audience today and they're anxious to hear your study results, so can you share those with us please? Dr. Prakriti Gaba (PK): Definitely. So over the course of more than 77,000 patient years of follow-up, we found that there was a monotonic relationship between achieving lower LDL cholesterol levels down to very low levels of less than 20 mg/dL and a lower annualized risk of the primary efficacy endpoint, which was a composite of 5 individual endpoints. We also found that there was a similar relationship observed between lower LDL achieved, LDL cholesterol levels and a lower annualized risk of the secondary efficacy endpoint, and then when we looked at safety, there were actually no clear monotonic trends between lower achieved LDL levels and the risk of any of the 8 adverse events and these included things like serious adverse events, hemorrhagic stroke or muscle related events. Dr Greg Hundley: Very nice PK and I'm sure our listeners are wanting to know, did you find any discrepancy in your results based on either age or gender? Dr. Prakriti Gaba (PK): That's an excellent question, and we did look at age and gender throughout. I think across the board the results were pretty consistent, but additional subanalyses will further address this question. Dr Greg Hundley: Very good. Well listeners now we're going to turn to one of our associate editors, Dr. Amit Khera, who has helped move this article through the process of evaluation with the editorial team. Amit, you have many papers come across your desk, what attracted you to this paper and then how do we put this study's results really in the context of other studies that have sought to dramatically lower LDL cholesterol? Dr. Amit Khera: Well first thanks a lot Greg for allowing me to participate today. I want to congratulate Drs. Gaba and Sabatine on a fantastic paper and the minute I saw it, and you know can tell when you've done this for a while what's a great paper, and this one certainly is and we work closely with them to try to make it better and enhance the analyses and as a group, I think we achieved that. I was fortunate to write an accompanying editorial that you'll see. So I got to take a pretty deep dive in this paper and I want to just talk about sort of what's important here, why is this important, and I think as Dr. Gaba mentioned, there's two sides to this. There's the efficacy side where you talk about LDL lowering and getting to very low levels. Now mind you, they got to, what I call, ultra low levels, even explored for a down to a median of 7 mg/dL, so really, really low. And first I think what our listeners need to know when we look at guidelines, these numbers of 70 or 55, these are completely arbitrary and they're based on what was observed in clinical trials, what was achieved in high intensity versus moderate intensity statins in IMPROVE-IT. There's no biology behind that, and I think what this study does is reminds us there is no biology behind how low we need to go. This group previously published their shorter-term data approximately 2 years with this construct of lower is better and I think that's fine, but people worry, particularly on the safety side about extension, and we'll get to that in a minute, so where this fits is it gives us even more reassurance that lower is better, reminds us there's no biologic basis of that even down to very low levels. And so what does that mean? I think that comes back to guidelines. We have some discrepancy between European, ACC, Multisociety Guidelines that are around 55 and so from a guideline perspective, I think we'll see a little bit more enthusiasm about lower cut points or lower thresholds. And from a clinical standpoint, as a clinician it reminds me that when I see someone that's very high risk, there's no magic to achieving a number that if the risk is high, we need to be quite intensive and get their LDL down as low as possible and as safely as possible. I do want to also acknowledge, there's not, to your point about context, the IMPROVE-IT study also showed very low levels show additional efficacy and there's also a lot of other data, genetics and ecologic data supporting this. So this is... we look at Bayesian analysis that this is consistent that we're seeing across different platforms. I do want to talk about safety too, Greg. That's really important because honestly this is when it comes to patient level, the safety part of it. We as clinicians may have comfort with very low levels, but the safety is important. I also want to, just from a steady design, this is post-hoc, so those that achieve very low levels are different. You can see that in their table 1, but these investigators did lots of things. They did pretty extensive multi-variable analysis, they looked at time-dependent LDLs, they looked at it multiple different ways, but as mentioned, there really did not seem to be a safety signal. And this is where time matters. Safety in two years, interesting, but safety 5 to 8 years really offers us much more reassurance. So I think that's where this really comes in about that safety piece with the extended analysis. So again, I think from a guideline perspective, from a clinical perspective, there's so many implications from this paper and I really hope people take the time to take a deep dive and also put it in context, like you said, to the other literature where this is not standalone, but it's corroborating what we're seeing. Dr Greg Hundley: Very nice, amit. Marc, I want to come back to you, just two quick questions thinking about the preparation of your study. One, did you sample cognition? One thing we hear about frequently in dramatic lowering of LDL cholesterol are questions around cognition, particularly in the elderly? Dr. Marc Sabatine: Yeah, it's a great question Greg. So first of all, in the FOURIER study itself, there was an embedded study called EBBINGHAUS that Bob Giugliano from our group led that actually did formal neurocognitive testing in individuals using basically a iPad-like test. We also collected the usual neurocognitive adverse events as part of safety collecting. So 2 ways, the general asking about any adverse events and then the specific neurocognitive testing. We had previously reported out the results of EBBINGHAUS that there wasn't any relationship between evolocumab and the low LDL cholesterol and the risk of any neurocognitive AEs. We just were able to recently do this OLE analysis over time for the major adverse cardiovascular events and for the general safety events including cognition, so all that looked good. As PK indicated, we're now digging into the EBBINGHAUS formal neurocognitive testing, which was also extended out. So stay tuned for those results. Dr Greg Hundley: Very nice. And then eligibility, maybe just walk us through that really quickly. Patients that are going to be randomized to this form of therapy, were they already on high-dose statins? Who exactly did we randomize in this trial? Dr. Marc Sabatine: Yeah, so at the get-go, as PK indicated, these are patients with atherosclerotic cardiovascular disease, so they had a prior…
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