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Circulation on the Run

May 4, 2020

Dr Carolyn Lam: Welcome to circulation on the run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.

Dr Greg Hundley: And I'm Greg Hundley, associate editor from the Pauley Heart Center at VCU health in Richmond, Virginia. Well Carolyn, our feature this week really examines long-term efficacy of drug eluting stents versus coronary artery bypass grafting in those patients with left main disease. Really looking at long-term extended follow up from the PRECOMBAT trial 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? And I'll start off. My first article is a basic science paper looking at catecholamine sensitive and ventricular tachycardia in ARVC. And it comes from Dr Long-Sheng Song from the University of Iowa Carver College of Medicine.

So, the study from Dr Song used protein mass spectrometry analyses and that identified integrin beta one is downregulated in those patients with arrhythmogenic right ventricular cardiomyopathy hearts without changes to calcium handling proteins as adult cardiomyocytes express only the beta-1 D isoform, they generated a cardiac specific beta-1 D knockout mouse model and perform functional imaging and biochemical analyses to determine the consequences from integrin beta-1 D loss of function in hearts in vivo and in vitro.

Dr Carolyn Lam: Nice, very elegant design. So what were the results Greg?

Dr Greg Hundley: Well Carolyn, the authors found that integrin beta- 1D deficiency and RyR2 serine 2030 hyper phosphorylation were detected by Western blotting in left ventricular tissues from patients with ARVC but not in patients with ischemic or hypertrophic cardiomyopathy. And in the mouse experiments, beta-1 D negative or knockout mice exhibited normal cardiac function and morphology, but presented with catacholamines sensitive polymorphic ventricular tachycardia consistent with increased RyR2 serine 2030 phosphorylation and apparent calcium handling in beta-1 D knockout cardiomyocytes.

So Carolyn, in conclusion, the authors found their data suggest that integrin beta-1D deficiency represents a novel mechanism underlying the increased risk of ventricular arrhythmias in patients with ARVC.

Dr Carolyn Lam: Okay. You told us about integrin beta-1 D and I'm going to tell you about apolipoprotein M. So Greg, what do you know about apolipoprotein M?

Dr Greg Hundley: Well, Carolyn, at seven o'clock the morning, I seem to have forgotten a little bit about that. Can you remind me what apolipoprotein M is?

Dr Carolyn Lam: Sure Greg, very happy to. So apolipoprotein M or apoM mediates the physical interaction between high density lipoprotein particles and sphingosine 1-phosphate and exerts an anti-inflammatory and cardio-protective effects in animal models. Now listen on, listen on. So authors, Dr Chirinos from Perelman Center for Advanced Medicine, University of Pennsylvania and Dr Javaheri from Washington University School of Medicine and co-authors hypothesized that reduced levels of apoM would be associated with worse outcomes in human heart failure.

Specifically, they tested the hypothesis that reduced circulating apoM would be associated with the risk of death, a composite of death, ventricular assist, device implantation or heart transplantation and a composite of death, heart failure related hospitalization among adults with heart failure and rolled in a large multicenter Penn heart failure study. They did stratified analysis in patients with heart failure with reduced and preserved ejection fraction and even replicated these findings in two independent cohorts, the Washington University heart failure registry and a subset of the TOPCAT trial. What they found was that reduced apoM plasma protein levels indeed were associated with adverse outcomes in heart failure including both HFpF and HFrF. The relationship between reduced apoM and outcomes and heart failure was particularly pronounced when concentrations of its binding partner sphingosine 1-phosphate were also reduced. ApoM protein levels were associated with inflammation in human heart failure and thus the conclusion being that apoM represents a risk marker in human heart failure.

Further studies are of course needed to assess whether it could be a therapeutic target as well.

Dr Greg Hundley: Very good. Carolyn. So more information for the world of heart failure isn't it. I'm going to sort of switch over to coronary artery disease and talk about low attenuation non-calcified plaques that are sometimes appreciated on cardiac computed tomography scans. And in this study, Dr Michelle Williams from the University of Edinburg evaluated the results from the multi-center SCOT-HEART trial or the Scottish computed tomography of the heart. So Carolyn, the future risk of myocardial infarction is commonly assessed using cardiovascular risk scores, coronary artery calcium score or coronary artery stenosis severity and the authors assessed in 1,769 patients about 56% men and the average age 58 years and they followed them up for a median of 4.7 years and looked at whether noncalcified low attenuation plaque burden on coronary CT angiography might be a better predictor of the future risk of myocardial infarction.

Dr Carolyn Lam: Interesting. So what did they find?

Dr Greg Hundley: Well, low attenuation plaque burden was the strongest predictor of myocardial infarction irrespective of cardiovascular risk score, coronary artery calcium score or coronary artery area stenosis. And patients with low attenuation plaque burden greater than 4% were nearly five times more likely to have subsequent myocardial infarction and the hazard ratio was 4.65 with a confidence interval of two to more than 10 and a half. So in conclusion, Carolyn in patients presenting with stable chest pain, low attenuation plaque burden is the strongest predictor of fatal or nonfatal myocardial infarction and these findings may add to classical risk predictors of myocardial infarction.

Dr Carolyn Lam: Wow. Important findings. Okay, let's go onto what else is in this week's journal issue. There's an online mind by Dr Jaffe. It's on the universal definition of myocardial infarction. It talks about both present and future considerations. There's an ECG challenge by Dr Arias and what's described as spontaneous wide QRS complex rhythm in a patient with wide QRS complex tachycardia.

Dr Greg Hundley: Very good, Carolyn. Well, I've got two other articles. Another on my mind piece from Professor Peter Nagele from the University of Chicago Medicine and it discusses a simplified proposal to redefine acute MI versus acute myocardial injury. Looking at that troponin question. And then finally Dr Fabian Hoffman from the Heart Center and University of Cologne has a research letter on providing new data regarding the evolution of pulmonary hypertension during severe sustained hypoxia.

Well Carolyn, how about we get onto that feature discussion looking at left main disease and whether we should place an intercoronary stent or undergo coronary artery bypass grafting.

Dr Carolyn Lam: Important question. Let's go, Greg.

Dr Greg Hundley: Welcome everyone to our feature discussion today that really pertains to interventional cardiology and we're very fortunate to have Duk-Woo Park from Asian Medical Center in Seoul, South Korea and our own associate editor, Dr Manos Brilakis from the Minneapolis Heart Institute. Well Duk-Woo, we'd like to get started with you and could you tell us a little bit about the background data and the hypothesis related to your research study?

Dr Duk-Woo Park: Our research, it was the 10-year report of the PRECOMBAT trial. If I'm going to first introduce the background over the last half of a century bypass surgery, it was a mainstream, the number one choice of on protecting the main disease. Yeah. Did you know unprotected left main disease, the one were very high risk of coronary artery disease and owing two and the supply, the large burden of myocardium. But the last two decades, 20 years. Their remarkable evolution in PCI field including development adaption of a drug eluting stent and the adaption of intravascular ultrasound as well as experience of intervention or catalyst expertise. So on the basis of such evolution, many interventional cardiologists think about that, a PCI with a drug eluting stent. Will it be non-inferior to a standard type A surgery? Sometime for single region PCI could be very nice alternative option for unprotected left main disease that the reason why we're going to start quick on the trial. This trial already done 15 years ago at the time. We designed this PRECOMBAT trial on the basis of that background.

Dr Greg Hundley: Very good. Well can you tell us a little bit about the study population of this trial and what was your study design?

Dr Duk-Woo Park: This is a open library trial design and we at first time we evaluated the noble unprotected left main disease and the for considerable for clinical and ethic eligibility, initially assessed by intervention or cardiologists as you as a cardiac surgeon and the reason why we try to pick up the post treatment eligible population and then at the screening initial re-screen the nearly 1,400 patient and then finally 600 of patient who was our individuation one arm is drug eluting stent, first-generation ciphers 10 versus another arm is convention or a coronary artery bypass stent grafting.

Dr Greg Hundley: What were you looking for your outcome measures and how long did you follow these patients?

Dr Duk-Woo Park: Initially and the BDN two year follow and are published in England, the journal of medicine nearly eight years ago. And then we did five year follow-up at the publish the JAG in five years ago and the this time is a, we did complete that 10 year follow up all the render mutation population and the median follow-up duration is nearly more than 11 years and we complete 10 year follow-up and the key outcome was PCI is a comparable apart from surgery for treatment of left main disease.

Dr Greg Hundley: And were there other outcomes that you were looking for?

Dr Duk-Woo Park: We evaluated several important clinical outcomes. We primary end the point we select competent outcome compass of all cause of mortality by myocardial infarction, stroke, or ischemia-driven target vessel revascularization. Secondary outcome was each component of a primary outcome all-cause mortality as you raise the harder clinical and the point like compost outcome like this am I sure. So finally we did not any statistical difference with the regard to primary composite outcome as well as a hard clinical compost outcome as death or stroke. Finally, we did not detect all-cause mortality. One exception or difference was a target vascularization as well as a repeat rebase collateralization was a much higher after PCI than after bypass surgery.

Dr Greg Hundley: So overall, in this more lengthy follow up of 10 years. The primary outcomes were similar between the two interventional arms, but there was a difference in target vessel revascularization. With that being more frequent after PCI as compared to bypass, were there any other subgroups that tended to have distinctions or discrepancies between your primary outcome?

Dr Duk-Woo Park: As the sensitive to analysis, in circulation we supply the subgroup analysis or more, we did not find any differential treatment. IPEC according to subgroup in age group, diabetes and clean-cut presentation or in environmental coronary embolism shock versus application. We didn't find any interaction effect, just the except the extent of disease vessel, left or main. We the three best three digit bypass surgery was better than PCI. However we did not do any P value. Adjust them on. So interpretation is should it be cautious.

Dr Greg Hundley: Well you know as an interventional cardiologist, what new information does this bring and how do you interpret the results of this study relative to other studies that have been published in the past?

Dr Emmanouil Brilakis:  I think this is a very timely study, especially since about a year ago we did have the five-year outcomes from two other similar trials, the Excel file and the Nobel trial which say randomized patients with unprotected left main disease to either PCI or bypass. And actually those studies had some differences which are also relevant to the present study. So for example, Excel overall the outcomes were similar. There was a higher all-cause mortality in the PCI where normal had better outcomes in terms of death, MIT VR, but there was no difference in mortality. So I think the natural question that comes up from the studies was whether mortality is different with PCI versus coronary bypass and you know the PRECOMBAT, the 10 years. It's really suiting in that respect because it doesn't show any difference in the overall mortality. So I think this comes very timely and the answers a lot of questions. Of course there's limitations with the sample size and the number of patients treated, but I think although it's a very timely result.

Dr Greg Hundley: Maybe I'll start first with you, Manos and then I'll circle back to you. Duk-Woo. Manos what do you see is the next important study to perform in this field?

Dr Emmanouil Brilakis:  I think the natural question here is these outcomes which are similar but use first generation drug eluting stents, which we no longer use. He did use high proportion of five which is an excellent feature in, again congratulate Duk-Woo and the other co-investigators for doing such a high rate of follow-up. But we now know that the techniques, for example, for bifurcations, maybe the DK crush or double DK crush might be a better technique to do. So in my mind, the next question would be if who use the current, a much improved the drug eluting stent and state of the art bifurcation techniques. For example, DK crush where the double-kiss crush bifurcation would, the outcomes have been different and perhaps PCI will be similar, even better than bypass in long-term outcomes. So for me this next study will be state of the art techniques, state of the art materials and long-term for follow-up as in frequently.

Dr Greg Hundley: Duk-Woo. How about from your perspective?

Dr Duk-Woo Park: You know, a future perspective is a very difficult to expect. Our trial is the longest to follow-up trial. We have the nation are insurance support and we nearly a hundred percent pop picked up fighters status, but I think most of them interventional cardiologists as well as a cardiac surgeon. One true additional longest follow-up Excel and Noble trial. The reason why we didn't do additional random trial using additional second generation drug eluting stent. We already do exit trial approximately 2000 and noble trial and more than thousand patients we already do and the two trial a complete five-year follow and most of the trial is as well as the clinician want to extend the follow-up of Excel and Noble trial but I don't know how much that extended of a follow-up would be possible.

Dr Duk-Woo Park: The next step as you know the intervention or cardiac surgeon still debate about the long-term mortality issue after release of exited five-year-old research and the data peak issue, European association cardiac thoracic group. We did draw the endorsement of a guideline so I think an additional stem we require the individual patient level data analysis involving, Excel, Nobel, Syntech and PRECOMBAT trial would be required to provide the more definite compelling evidence for mortality difference as well as the have the end point and including or so some end point to repeat revascularization. We do allow individual patient data analysis. That would be next. The short step, next the long step, we definitely require extended follow-up, Excel and Noble trial.

Dr Greg Hundley: Very good. Well listeners, this has been another very informative feature discussion where we've compared PCI and coronary artery bypass grafting in those with left main disease. And now from this PRECOMBAT trial, 10 years of follow up showing very similar outcomes related to death, myocardial infarction and stroke in the two randomized arms. We want to thank Dr Duk-Woo Park and Dr Manos Brilakis for presenting this information and as we move forward, their insights as to next studies with newer technologies and different examinations of stents. More long-term follow-up from ongoing trials and then individualized patient assessments.

Listeners, we hope you have a great week and hope everyone is staying safe in this COVID crisis. Take care.

This program is copyright of the American Heart Association 2020.