Feb 6, 2023
Please join author Petr Ostadal and Associate Editor Dharam Kumbhani as they discuss the article "Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock: Results of the ECMO-CS 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-hosts. 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 from Akershus University Hospital and University of Oslo in Norway. And today Carolyn will have such an interesting feature discussion. We are going to look into the use of ECMO to treat patients with cardiogenic shock, the results of the ECMO-CS randomized clinical trial. Isn't that interesting?
Dr. Carolyn Lam:
Awesome. Can't wait. But I suppose you're going to tell us about some papers in the issue first. I'm getting my coffee.
Dr. Peder Myhre:
Yeah, go ahead. Because first we're going to talk about a very interesting paper that relates to diabetes and the progression of coronary artery disease. So as you know, Carolyn, diabetes remains associated with an increased risk of cardiovascular morbidity and mortality. And although the absolute risk difference between patients with and without diabetes have declined over the past 20 years, we still don't know what is the diabetes associated differences in coronary plaque morphology and lipid content.
Dr. Carolyn Lam:
It's true. That's a very interesting question. And will you tell us more?
Dr. Peder Myhre:
Yeah. So the investigators in the prospect two study who enrolled patients exclusively from Denmark, Norway in Sweden who presented with biomarker positive MI and assessed both culprit lesions and untreated non-culprit lesions in these patients. And then they stratified the patients by diabetes status and examined with three vessel quantitative coronary angiography and near infrared spectroscopy and intravascular ultrasound imaging after successful percutaneous coronary intervention.
Dr. Carolyn Lam:
Okay, that's deep investigation. And what did they find?
Dr. Peder Myhre:
So diabetes was present in about 12% of patients and during a median or 3.7 year follow up, MACE occurred almost twice as free frequently in patients with versus without diabetes. And that was primarily due to an increased risk of MI related to culprit lesion stenosis and non-culprit relation related spontaneous MI. However, baseline prevalence of high-risk plaque characteristics was similar for patients with versus without diabetes, concerning culprit and the non-culprit lesions and in multi-variable models, diabetes was associated with MACE in lesions but not with prevalence of high-risk plaque characteristics. So Carolyn, the authors conclude that diabetes related plaque characteristics that might underlie the increased risk were not identified by multimodal imaging.
Dr. Carolyn Lam:
Oh, I just love studies like that so elegant with just a really, really intriguing results that make us ask more important questions. Love it. Thank you. Well, the next paper is also about myocardial infarction, but this time looking at the fibrotic remodeling after myocardial infarction because we know that MI induces a repair response that ultimately generates a stable fibrotic scar. And although the scar is important to prevent cardiac rupture, excessive pro-fibrotic response impairs optimal recovery because it promotes a development of non-contractual fibrotic areas. So would it be possible to regulate the expansion of cardiac fibroblast after MI through a paracrine action on the cardiac stromal cells? So the authors led by corresponding author Dr. Hulot from University of Paris performed a bioinformatic secretome analysis of cardiac stromal PW1 positive cells isolated from normal and post MI mouse hearts to identify novel secreted proteins.
And they found that first cardiac PW1 positive stromal cells responded to myocardial infarction by secreting factors that promoted the proliferation and activation of resident fibroblasts and one such factor growth differentiation factor three or GDF3 was highly upregulated in the ischemic hearts and promoted a high induction of fibroblast proliferation via interaction with TGF beta receptors and activation of SMAD1/5 and SMAD2/3 signaling cascades. The upregulation of GDF3 was detected in the plasma of mice and humans following MI and high levels of plasma GDF3 in the days following MI predicted adverse outcomes measured six months later including cardiac dilation and limited recovery of contractile function in humans.
Dr. Peder Myhre:
Oh, that's so interesting. We already know GDF15 were very well, but now we hear about GDF3 in predicting fibrotic remodeling post myocardial infarction. So Carolyn, what are the clinical implications of these findings?
Dr. Carolyn Lam:
Exactly, Peder, in fact you said it. So the detection of high circulating GDF3 in plasma may serve as a novel biomarker of adverse fibrotic remodeling in heart tissue. That's one. And next the measurement of GDF3 plasma levels in the early post MI phase may allow for the identification of patients within an increased risk of severe myocardial fibrosis and heart failure and therefore could guide specific disease management.
Dr. Peder Myhre:
Thank you. That was an excellent summary of the paper, Carolyn. And now I'm going to look into a paper that relates to the important issue of arteriosclerosis following heart transplantation because as you know, transplant arteriosclerosis characterized by concentric and diffuse narrowing of vastly lumen is a major complication in long-term survivors of heart transplant patients. And increased lymph flow from donor heart to host lymph nodes has been reported to play a role in transplant arteriosclerosis. But how lymphangiogenesis affects this process is unknown. The authors of this paper, which comes to us from corresponding author Sue from Sejong University, transplanted vascular allografts between various combinations of mice including mice with severe combined immune deficiency and studied the lymphatic vessels within the grafted arteries.
Dr. Carolyn Lam:
Wow, that is really cool. Studying lymphatics and lymphangiogenesis in atherosclerosis. Interesting. What did they find, and what are the clinical implications?
Dr. Peder Myhre:
So Carolyn, lymphangiogenesis within allograft vessels began at the anastomotic sites and extended from preexisting lymphatic vessels in the host. Tertiary lymphatic organs were identified in transplanted arteries at the anastomotic site and lymphatic vessels expressing CCL21 were associated with these immune structures. Fibroblasts in the vascular allografts released VEGFC, which stimulated lymphangiogenesis into the grafts and inhibition of VEGFC signaling inhibited lymphangiogenesis, neointima formation and adventitial fibrosis of vascular allografts. And these studies identified VEGFC released from fibroblasts as signal stimulating lymphangiogenesis extending from the host into the vascular allografts. So, Carolyn, the authors conclude that the formation of lymphatic vessels play a key role in the immune response to vascular transplantation and inhibition of lymphangiogenesis may be a novel approach to prevent transplant atherosclerosis.
Dr. Carolyn Lam:
Wow, that is super interesting. Thanks, Peder. While also in this issue, there's an exchange of letters between Drs. Tanaka and Schulze regarding SGLT2 inhibitor treatment in acute decompensated heart failure. Why do we initiate it early? There's also a really nice On My Mind paper by Dr. Schiattarella on Cardiometabolic HFpEF. Is it the NASH of the heart?
Dr. Peder Myhre:
Oh, that's interesting. We also have some cardiology news by our own Bridget Kuehn entitled “No Benefit Seen for Nighttime Dosing Over Morning Dosing for Antihypertensive Medications.” And this is a summary of the time trial, which was presented at European Society of Cardiology Congress in 2022. And finally, Carolyn, we have a Research Letter entitled “Stepwise Generation of Human-Induced Pluripotent Stem Cell Derived Cardiac Parasites to Model Coronary Microvascular Dysfunction” by Dr. Joseph Wu from Stanford University School of Medicine.
Dr. Carolyn Lam:
While cool, Peder. But now I'm so excited to hear about the ECMO-CS randomized trial. Let's go.
Dr. Greg Hundley:
Welcome listeners to this February 7th feature discussion and we have with us today Dr. Petr Ostadal from Na Homolce Hospital in Prague in the Czech Republic and our own associate editor, Dr. Dharam Kumbhani from UT Southwestern in Dallas, Texas. Welcome, gentlemen. Well, Petr, we'll start with you. Can you describe for us some of the background information that really led you to perform this study, and what was the hypothesis that you wanted to address?
Dr. Petr Ostadal:
According to the current guidelines from the management for the management of cariogenic shock, it should be considered administration of inotropes and vasopressor for hemodynamic stabilization, or it may be considered administration of inotropes and vasopressors and it should be considered the use of short-term mechanical circulatory support. And the aim of the ECMO-CS trial was to compare early conservative therapy with inotropes and vasopressors and immediate implementation of ECMO in patients with the rapidly deteriorating or severe cardiogenic shock. The hypothesis of the ECMO-CS trial was that immediate implantation of ECMO in patients with cardiogenic shock and critical hemodynamic condition will be associated with improved outcomes.
Dr. Greg Hundley:
Very nice. Can you describe for us this study population and then also what study design did you use to address your hypothesis?
Dr. Petr Ostadal:
We try to select patients who can really profit from the early ECMO implantation, and we define two categories of patients. First category where the patients with rapidly deteriorating cardiogenic shock corresponding to current sky stage D or E. This patient should have evidence of left ventricle pump failure as left ventricle ejection fraction below 35% or ejection fraction 35 to 55 in case of severe mitral regurgitation or aortic stenosis. And this patient also should require a repeated both of vasopressors to maintain mean arterial pressure about 50 millimeters of mercury. The second category where the patients with severe cardiogenic shock corresponding to current sky stage D and this patient should have the criterion of a hemodynamic conditions which was cardiac index less than 2.2 or systemic blood pressure below 100 millimeters of mercury in both situation with higher doses of inotropes and vasopressors. And in case of a low systolic blood pressure, also the evidence of left ventricle pump failure based on ejection fractional below 35 or ejection fraction 35 to 55 in case of severe mitral regurgitation of aortic stenosis.
The second criteria for the metabolic criteria, that was the evidence of tissue hypoperfusion and this was defined as a higher lactate above three millimeters per litter or low ScvO2 below 50%. And the third criterion was exclusion of hypovolemia, and this was based on central venous pressure or pulmonary artery wedge pressure. So this was the major inclusion criteria in the ECMO trial. The study population was not defined based on theology of cardiogenic shock, but just on severity of cardiogenic shock.
Dr. Greg Hundley:
Very nice. And so your design, did you have a one-to-one randomization, or how did that work? And then also how many subjects did you include in this important trial?
Dr. Petr Ostadal:
The patients were randomized in one-to-one ratio to immediate implementation of ECMO or to early conservative therapy. But it is important to point out that in the early conservative therapy downstream use of ECMO was allowed in case of further hemodynamic worsening defined as increase of what lactate by three millimeters per litter. We enrolled 122 patients, 61 were randomized to early ECMO and 61 to early conservative strategy. Five patients were excluded due to absence of informed consent and finally 58 patients were analyzed in the early ECMO or immediate ECMO arm and 59 patients were analyzed in the early conservative arm.
Dr. Greg Hundley:
Sounds great Petr. And then tell us and describe your study results.
Dr. Petr Ostadal:
The primary endpoint was composite of death from any cause, resuscitated circulatory RS and implementation of another mechanical circulatory support including ECMO in the early conservative arm at 30 days. And there was no difference in the primary endpoint with P 0.2221 and has a ratio of 0.72 with a 95% confidence in interval 0.46 to 1.12. There was also no difference in the incidence of death from any cause. 50% in the immediate ECMO arm and 28%, 47.5% in the early conservative arm. There was no difference in the incidence of resuscitated circulatory arrest, 10.3 in the immediate ECMO arm and 13.6 in the early conservative arm. Less patient required another mechanical circulatory support in the early ECMO arm through 17.2 in comparison with 42.4% in the early conservative arm and downstream ECMO was used in 39% of patients in the early conservative arm.
Dr. Greg Hundley:
Very nice. So similar results both immediately and then 30 days later for both arms. And I think that last point that you make is very interesting. 39% of the individuals randomized to the conservative arm went on to receive VA-ECMO. Well, listeners next, we're going to turn to one of our associate editors and Dharam, you have many papers that you see. How do we put the results that Petr has just described really in the context of management of shock and results that have been published previously?
Dr. Dharam Kumbhani:
Yeah, Greg, thank you. And Petr, thank you for this important paper and again, I'm really honored to be here on behalf of Circulation on the Run. So again, want to congratulate the authors for really an important study. I think in terms of context, what is really interesting is the use of ECMO, particularly VA-ECMO for patients with shock has really skyrocketed. And it is interesting that this expansion has occurred in the absence despite, I guess high quality clinical trials, this trial certainly fills an important void. Although it is a small patient population, it is randomized, it is a largest randomized trial to date on this important population. And so I think most of the studies that have been done so far have been done using observational data sets which have sort of inherent limitations. So I certainly want to congratulate you on trying to study this very challenging population because in sort of that acute setting, it's frequently very hard to get patients randomized.
So just broadly in that context, I think at the same time this study does sort of pose some important questions and sort of perhaps leads, just given the limitations of the sample size does sort of leave a few unanswered questions. So one question I have is, Petr, in addition to the 40% crossover rate is obviously important as Greg pointed out. The other thing is it appears that the use of other mechanical support during the conduct of this trial was also close to 40%, about 42%. So pretty much everybody in the conservative arm ended up with some kind of mechanical support. Now, at least in the last few years, a concept that has gained a lot of traction is a concept of a shock team where a number of providers with particular expertise from different disciplines would get together and sort of decide next steps was a shock team sort of part of the decision-making, especially for the conservative arm.
Dr. Petr Ostadal:
Thank you for this question. The situation is maybe a little bit more simple in the Czech Republic here, the cardiologist are responsible for the acute cardiac care, usually competent and experience not only for the diagnosis and examinations and monitoring of patients in cardiogenic shock, but also experience in insertion and management of the mechanical circulatory support. So here this attending cardiologist competent to manage this patient from different sites from the manage not only the conservative therapy but also the mechanical circulatory support therapy in these patients. So in this respect, this is more simple situation in the Czech Republic.
Dr. Dharam Kumbhani:
I just had a very quick question about, and I don't know if you want to include this, but Petr, I was curious, were patients with cardiac arrest, I know you mentioned sky shocks in were patients with cardiac arrest on the field or in the hospital included?
Dr. Petr Ostadal:
Thank you for this excellent question. And in comparison, with other trials comparing the or focusing on patients with cardiogenic shock in the ECMO-CS trials, cardiac arrest survivors were excluded. And the reason was that the brain damage, which is the major cause of death in these patients cannot be influenced by ECMO insertion. And second, in majority of patients after cardiac arrest, if there is a presence of shock, there is frequently combined shock with important peripheral component. And again, it cannot be assumed that this peripheral component can be reversed by ECMO implantation. So in the ECMO-CS trial, the cardiac arrest survivors were excluded from that enrollment.
Dr. Greg Hundley:
Well, thank you so much Petr. Petr, what do you think is the next study to be performed really in this area of research?
Dr. Petr Ostadal:
I think that we are happy because several other clinical trials focusing on the mechanical circulatory support in patients with cardiogenic shock underway. And there are other trials focused on ECMO and trials a bit focused on combination of ECMO with balloon pump and trials focused on Impella. So I think in the very close time we will be able to see the results of these current running trials1.
Dr. Greg Hundley:
And Dharam, do you have anything to add?
Dr. Dharam Kumbhani:
No, I agree completely with Petr. I think this is a very exciting field. I know there's a lot of interest in doing well conducted clinical trials in this space. And so certainly, I think the future is bright for investigation in this field.
Dr. Greg Hundley:
Very nice. Well, listeners, we want to thank Dr. Petr Ostadal from Prague in the Czech Republic and our own associate editor, Dr. Dharam Kumbhani from Dallas, Texas for bringing us this study highlighting that immediate implementation of VA-ECMO in patients with rapidly deteriorating, or severe cardiogenic shock did not improve clinical outcomes compared to an early conservative strategy that permitted downstream use of VA-ECMO in the case when the patient's hemodynamic status worsened.
Well, on behalf of Carolyn, and Peder, and myself, we want to wish you a great week and we will catch you next week on the run. This program is copyright of the American Heart Association 2023. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.