Circulation November 17, 2020 Issue

This week’s episode features author Jaime Layland and Associate Editor Dharam Kumbhani as they discuss the ariticle "Colchicine in Patients with Acute Coronary Syndrome: The Australian COPS Randomized Clinical Trial."

TRANSCRIPT BELOW:

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 Dr. Greg Hundley, associate editor, director of the Pauley Heart Center, VCU Health, in Richmond, Virginia.

Dr. Carolyn Lam:

Greg, for our feature discussion we're talking about a very hot topic these days, the role of colchicine, this time in patients with acute coronary syndrome, with Australian data. I cannot wait to get to that, but I'm going to make you wait because I want to tell you about a whole lot of other really cool papers in today's issue.

Dr. Carolyn Lam:

First, have you ever wondered what is the association between risk factor control and cardiovascular disease risk in type 2 diabetes? Well, today's paper answers that. It's from Dr. Wright from University of Manchester and her colleagues who looked at a retrospective cohort using data from the English practices from Clinical Practice Research Datalink, or CPRD, and the Scottish Care Information diabetes dataset. They also linked to hospital and mortality data and identified more than 101,000 patients with type 2 diabetes in CPRD matched with almost 379,000 controls without diabetes and almost 331,000 patients with type 2 diabetes in the Scottish Care Information diabetes database between 2006 and 2015. The main exposure was a number of optimized risk factors, and these are: (1) Nonsmoker; (2) total cholesterol less than 4 mmol/L; (3) triglycerides less than or equal to 1.7 mmol/L; (4) HB A1c less than 7%; and (4) systolic blood pressure less than 140 or less than 130 mmHg of high risk.

Dr. Greg Hundley:

Carolyn, I am very curious. Lots of data here. What did they find?

Dr. Carolyn Lam:

So the key findings were:

Dr. Carolyn Lam:

First, even with optimally managed risk factors, people with type 2 diabetes still had a 21% higher risk for all cardiovascular disease events and non-fatal coronary heart disease, and a 31% higher risk of heart failure hospitalization compared to patients without diabetes.

Dr. Carolyn Lam:

2. Only 6% of people with type 2 diabetes had optimal risk factor controls, so a very low percent.

Dr. Carolyn Lam:

3. The association between the number of elevated risk factors and cardiovascular disease events and mortality was much stronger in patients with type 2 diabetes but without cardiorenal disease compared to those with established cardiorenal disease. People without cardiorenal disease were also younger and more likely to have suboptimal risk factor control and fewer prescriptions for risk-factor-modifying medication.

Dr. Carolyn Lam:

So take-home message: Greater use of guideline-driven care, clinical decision support, drug intervention, and self-management support should be encouraged for risk factor control, and people with type 2 diabetes and without cardiorenal disease may especially benefit greatly from cardiovascular disease risk factor intervention.

Dr. Greg Hundley:

Very nice, Carolyn.

Dr. Greg Hundley:

Well, my first study comes from Dr. Gregory Lewis from Mass General Hospital in Boston, Massachusetts. Carolyn, another quiz: Have you wondered about differences in metabolism in those who exercise versus those that do not?

Dr. Carolyn Lam:

Greg, I wonder about that all the time when I'm running out there.

Dr. Greg Hundley:

In this study, cardiopulmonary exercise testing, or CPET, and metabolite profiling was performed on Framingham heart study participants aged about 54 years with 63% of them being women with blood drawn at rest in 471 subjects and then again at peak exercise in 411.

Dr. Carolyn Lam:

Nice, and kudos for the majority women. So what were the results?

Dr. Greg Hundley:

The authors observed changes including reductions in metabolites implicated in insulin resistance and increases in metabolites associated with lipolysis, nitric oxide bioavailability, and adipose browning. Exercise-induced metabolite changes were variably related to the amount of exercise performed, peak workload, sex, and body mass index. There was attenuation of favorable exercise excursions in some metabolites in individuals with higher BMI and greater excursions in select cardioprotective metabolites in women despite less exercise being performed. Four metabolite signatures of exercise response patterns were analyzed in a separate cohort. The Framingham offspring study of 2,045 were about age 55 years and 51% were women, two of which were associated with overall mortality over a median follow-up at 23 years.

Dr. Greg Hundley:

So Carolyn, in conclusion, the authors found acute exercise elicits widespread changes in the circulating metabolome. These findings provide a detailed map of the metabolic response to acute exercise in humans and identify potential mechanisms responsible for the beneficial cardiometabolic effects of exercise that could be useful in future studies.

Dr. Carolyn Lam:

Beautiful. I'm going to keep exercising and I bet you will, too, Greg.

Dr. Carolyn Lam:

So this next paper is a mechanistic study that revealed a special population of tissue regulatory T-cells in the heart with a unique phenotype and pro-repair function. So this comes from corresponding author Dr. Cheng from Tongji Medical College of Huazhong University of Science and Wuhan Hubei, China. He and his colleagues studied the dynamic accumulation of regulatory T-cells in the injured myocardium in mouse models of myocardial infarction, myocardial ischemia re-perfusion injury, or cardiac cryo injury, and using state-of-the-art methods such as bulk RNA sequencing, photo conversion, parabiosis, single-cell TCR sequencing, adoptive transfer, and functional assays.

Dr. Greg Hundley:

Carolyn, interesting. What did they find?

Dr. Carolyn Lam:

They showed that regulatory T-cells that accumulate in the injured myocardium after myocardial infarction or myocardial ischemia re-perfusion injuries had a distinct transcriptome which differs from lymphoid organ regulatory T-cells and other non-lymphoid tissue, and this represents a novel population of tissue regulatory T-cells in the heart. These heart regulatory T-cells were mainly thymus driven and recruited from the circulation showed active local proliferation with the IL-33/ST2 axis promoting their expansion. With the phenotype of promoting tissue repair, heart regulatory T-cells over-expressing spark contributed to elevated collagen content and enhanced maturation in infarct scars to prevent cardiac rupture and improve survival after myocardial infarction.

Dr. Carolyn Lam:

So in summary, this paper identified and characterized a phenotypically and functionally unique population of heart regulatory T-cells, which may lay the foundation to harness these cells for cardiac protection in myocardial infarction or other cardiac diseases.

Dr. Greg Hundley:

Wow, Carolyn. Very interesting.

Dr. Greg Hundley:

Well, my next paper comes from Dr. Michael Rubart from Indiana University School of Medicine, and as some background it's going to discuss calmodulin. So calmodulin mutations are associated with arrhythmia syndromes in humans. Exome sequencing previously identified a de novo mutation in CALM1 resulting in a P.N98S substitution in a patient with sinus bradycardia and stress-induced bidirectional ventricular ectopy. The objectives of the present study were to determine if mice carrying this N98S mutation knocked into CALM1 replicate the human arrhythmia phenotype and then to examine some of the arrhythmia mechanisms.

Dr. Carolyn Lam:

Okay. So what did they find?

Dr. Greg Hundley:

Carolyn, several techniques were used in this study. Mouse lines heterozygous for the CALM1 N98S allele generated using CRISPR and caspase 9 technology. Also, adult mutant mice and their wild-type litter mates underwent electrocardiographic monitoring. Ventricular D and re-polarization was assessed in isolated hearts using optical voltage mapping, and action potentials in wholesale currents as well as calcium influx were measured in single ventricular myocytes using patch-clamp techniques and fluorescence microscopy, respectively. Microelectrode techniques were employed for in situ membrane voltage monitoring of ventricular conduction fibers. Carolyn, it was really a comprehensive study.

Dr. Greg Hundley:

So what did the authors find? Heterozygosity for the CALM1 N9S mutation was causative of an arrhythmia syndrome characterized by sinus bradycardia, QRS widening, adrenergically mediated QTC interval prolongation, and bidirectional ventricular tachycardia. Second, beta adrenergically induced calcium influx L dysregulation contributed to the long QT phenotype. And finally third, they found that pause dependent early after depolarizations and tachycardia induced delayed after depolarizations originating in the His-Purkinje network and ventricular myocytes, respectively, constituted potential sources of arrhythmia in the CALM1 N98S positive hearts.

Dr. Carolyn Lam:

Wow. Sounds like a really comprehensive study. Thanks, Greg.

Dr. Carolyn Lam:

Let's talk about some other papers in this issue, shall we? There is a Perspective piece by Dr. Klassen on the COVID-19 pandemic, a massive threat for those living with cardiovascular disease among the poorest billion. There's an ECG challenge by Dr. Littman on a malignant electrocardiogram. Here's a hint: It's a pseudo-infarct pattern with important learnings. They're in an exchange of letters between Drs. Packard and Schwartz regarding the role of lipoprotein A and modification by alirocumab, a pre-specified analysis of ODYSSEY Outcomes randomized clinical trial.

Dr. Greg Hundley:

Oh thanks, Carolyn. I've got a couple other papers. Dr. Venkateswaran Subramanian has a Research Letter entitled Lysyl Oxidase Inhibition Ablates Sexual Dimorphism of Abdominal Aortic Aneurysm Formation in Mice. Professor Jan Cornell has another research letter entitled Colchicine Attenuates Inflammation Beyond the Inflammasome in Chronic Coronary Artery Disease. The LoDoCo2 proteomic substudy. And then finally, Dr. Sanjay Kaul from Cedars-Sinai Medical Center has a white paper reviewing the benefit/risk trade-offs in assessment of new drugs and devices.

Dr. Greg Hundley:

Well, Carolyn, how about we get on to that feature discussion and learn more about colchicine and acute coronary syndromes.

Dr. Carolyn Lam:

Yeah. Let's go, Greg. Today's feature discussion is all about colchicine, that commonly used treatment for gout that has recently emerged as a novel therapeutic option in cardiovascular medicine. I am so pleased to have with us the corresponding author of today's paper, Dr. Jamie Layland from Monash University, as well as our associate editor, Dharam Kumbhani, from UT Southwestern to discuss this very important trial data from Australia. Jamie, could you start us off by telling us all about this Australian COPS trial?

Dr. Jamie Layland:

We performed the Australian COPS trial back in 2015, and it finished recruiting in 2018. Essentially the trial was a trial to look at the safety and efficacy of colchicine being used in acute coronary syndromes, and this was prior to the release of important trial COLCOT. So essentially we randomized patients who presented to the hospital with an acute coronary syndrome to receive colchicine twice daily for one month followed by colchicine once a day for 11 months, and we followed these patients up for a minimum of 12 months. This was performed across 17 sites across Australia, and we looked at a composite endpoint of total death, acute coronary syndromes, unplanned urgent revascularization, and stroke.

Dr. Carolyn Lam:

Nice. So Jamie, could I first clarify that this was an investigator-led trial, I'll bet, and man, first of all, applause for doing this. I can only imagine how much work this took and maybe then tell us about the results.

Dr. Jamie Layland:

Yeah. So this was an investigator-initiated trial through a network of academic investigators across Australia on limited research funding, so through philanthropic and institutional support. So it was a huge effort over a number of years, and I'm very thankful to the support of Circulation and Dharam in supporting the paper, which I think was a great success.

Dr. Jamie Layland:

So the results of this trial were a surprise to us all, but essentially this was a negative trial in the sense that colchicine did not improve the primary outcome, so there was no improvement in the rate of the COLCOT outcome. And interestingly, there was an increase in total mortality, in particular non-cardiovascular deaths were higher at five compared to the placebo at one. That was over a 12-month follow-up period.

Dr. Carolyn Lam:

Interesting. So Jamie, I'm going to ask the question that's on everyone's mind then: What's the difference between your trial and COLCOT?

Dr. Jamie Layland:

That's a great question. Obviously, COLCOT was a much larger trial. COLCOT was an international trial of over 4,000 patients. Similar patient demographics, similar patient subgroup of acute coronary syndromes. However, importantly, COPS was a trial of inpatient initiation of colchicine. So patients when they had their STEMI, or non-STEMI most commonly, they were given colchicine usually within 72 hours of their index hospitalization and sometimes sooner, and this was given prior to discharge. With COLCOT, the median time of administration of colchicine was around 14 days, so slightly different groupings there. However, in COLCOT you were allowed to administer colchicine as an inpatient. You can see obviously from the European side of cardiology the impressive data when colchicine was given earlier in COLCOT how this translated to improved outcomes. So clearly, there is a potential benefit there for early administration of colchicine when you look at these two trials.

Dr. Jamie Layland:

But we administered colchicine acutely when patients presented in their index hospitalization. We also importantly used a different dosing schedule to COLCOT. So COLCOT was 0.5 mg daily and we used 0.5 twice daily. This was for the first 30 days, and this was based on early data from the group from western Australia who showed that when colchicine was given to patients at a BD dosing in those patients who were already on aspirin and high-potency statins, there was a significant reduction in hsCRP, obviously a commonly used marker of inflammation at four weeks, and also based on data showing that there was a heightened inflammatory response in the early days following an acute coronary syndrome. So we felt that using this twice-daily dose would be advantageous and potentially helpful for our patients. So they're the two main differences between the studies.

Dr. Carolyn Lam:

Thanks for explaining that so clearly. Dharam, could I have your thoughts? This was, of course, discussed heavily, right, by the editors. Could you give us a sneak peek of what else was discussed?

Dr. Dharam Kumbhani:

The trial is very important, although it is smaller perhaps in sample size and kind of done with less resources than COLCOT. I do think this adds to the body of literature on colchicine for secondary prevention of CAD. And one of the interesting things is that we see we also have the LoDoCo2 trial, which was a slightly different population, Jamie, which was the chronic coronary artery disease patients, but also still looking at secondary prevention. What is really striking to me is that a very similar signal in non-CV death was noted in that trial as well. Again, it was not seen in COLCOT and LoDoCo1, but it was very interesting that a similar finding was there. So I do think this is something that the field will need to investigate more and really try to understand is this just noise and by chance alone, or is this something that that's a real signal for.

Dr. Carolyn Lam:

Jamie, what are your thoughts about that and in LoDoCo differences with your trial?

Dr. Jamie Layland:

Good question, and a very important topic that obviously is currently under discussion amongst the colchicine community. As I said, it was a surprising result. We weren't anticipating this non-CV death signal, but as Dharam said when LoDoCo2 came out, a fantastic trial again, but this signal of non-CV death. I don't know whether it's merely just a noise as you say or whether it's a significant finding, but clearly we need to do more research in this field to understand the mechanism and whether this is a real signal or not. It seems a little bit discordant with previously published work. So if you look at the literature in patients with gout from across the world, there's no real signal of increased non-CV death in those patients. However, with patients with acute coronary syndrome as we are administering the colchicine on a daily basis and then commonly this isn't used for gout, so that is a slight difference. But certainly, there was no signal in the non-CV literature to support the findings that we had and the signal in LoDoCo2.

Dr. Jamie Layland:

The other thing to note is in a cohort of five non-CV deaths, three out of those five patients were actually not taking colchicine at the time of their death. They stopped the drug prematurely. So I think we just need to take a step back and really await the results. Obviously, we've got two-year and five-year data coming out from the COPS trial which will be interesting to look at, but also the Clear Synergy trial from the McMaster team, that would be a very important trial providing more data on this potential signal. But reassuringly, and I feel more reassured knowing the COLCOT data, which is a slightly similar cohort to ours, showing that there was no trend towards increased non-CV deaths. So I think it's something that we have to be aware of and there will be lots of metro-analysis I'm sure being published in the coming months looking at this specifically. But yeah, I think we shouldn't cast any aspersions on colchicine yet. I think that's too early, but I do think we need more data.

Dr. Carolyn Lam:

Thanks, Jamie. Speaking of looking deeper in your data and looking at those who died and were they taking the medication and so on, you did some other post-hoc analysis, right? And maybe you could just describe briefly, for example, the 400-day followup.

Dr. Jamie Layland:

Yes. So the interesting thing with our data, and I had mentioned this before, is that we had limited resources, so we really wanted to do this trial, and obviously competitive funding is tricky at the best of times, but we were really committed to doing this trial and we had a group of investigators who were all committed to doing this trial. But for this to work, we had a single research nurse and a fellow performing the follow-up. So at times, there was a little lag between the timing of the follow-up. So we ended up getting follow-up which was slightly prolonged over the 12-month window. On average, it was around 400 days. When we looked at the 400-day data, we saw that there was an increasing separation of the biomarkers after 365 days.

Dr. Jamie Layland:

The results, this was obviously not the primary outcome, this was a sensitivity analysis, but there was a suggestion or a significance out to 400 days with an improvement with colchicine. However, this is the primary composite outcome, so revascularization, acute coronary syndrome, stroke, and total death notwithstanding this positive outcome, there was still this trend to high rate of mortality, so that has to be taken into consideration. But there was a suggestion that the longer the duration of colchicine was given for, it culminated into these lights affect. And we see from CT data that colchicine actually has some plaque-modulating effects and reduces high-risk or low-attenuation plaque. So you could hypothesize that as the majority of the benefits seen in colchicine in LoDoCo2, in COLCOT, and in COPS was the reductions in urgent revascularization, stroke, and acute coronary syndromes.

Dr. Jamie Layland:

So perhaps there is this effect that colchicine is having on plaque stabilization so we're seeing less longer-term events, but this is just hypothesis generated and we need more data to support that. But it is a very interesting finding nonetheless.

Dr. Carolyn Lam:

Thank you. Dharam, could I hand you the last word on where you think this field is going or where you think it should go?

Dr. Dharam Kumbhani:

I think Jamie put it really nicely. I think he outlined the study nicely with its strengths and its limitations, and I think this is obviously a debate between perhaps the colchicine believers and the ones that are still perhaps trying to understand a little bit more about its true role, because as was mentioned I think there's really a benefit in ischemia-driven revasc. I think we've seen that in almost all the colchicine trials. There is no reduction in mortality, and as we saw in the COPS data maybe it goes the other way. So I think from a pathophysiological standpoint it makes sense. I think there's good translational data to suggest that it would be beneficial in this patient population, but I think that's the beauty of having clinical trials and the ones that are done by different investigators and perhaps in different settings, because they help us answer the truth. And whether colchicine becomes a stable part of our armamentarium for secondary prevention of CAD going forward, I think the jury is still out and as was mentioned I think Clear Synergy would probably be very helpful in hopefully tying all this together.

Dr. Dharam Kumbhani:

So again, I want to congratulate Jamie and his team for really providing us with a very interesting trial done in a very pragmatic setting, and I think the field is very thankful to them for providing us with this information.

Dr. Carolyn Lam:

Thank you, audience, for joining us today. You've been listening to Circulation on the Run. Don't forget to join me and Greg again next week.

Dr. Greg Hundley:

This program is copyright the American Heart Association 2020.