Differences in Heart Failure-Related Cardiogenic Shock Between Ischemic and Non-Ischemic Cardiomyopathy

“I think the biggest thing is really just to recognize just how sick these patients are. For our study, the overall in-hospital mortality rate was 26.1%.”

Listen in Jason Feinman, MD, discusses a study utilizing data from the Critical Care Cardiology Trials Network (CCCTN) Registry. Dr. Feinman presented the study results at the 2023 American College of Cardiology Scientific Sessions/World Cardiology Congress in New Orleans.

Transcript

The transcript below has been lightly edited for clarity.

Welcome to Cath Lab Digest On Screen. I'm Managing Editor Rebecca Kapur. Today we're talking with Dr. Jason Feinman of The Mount Sinai Hospital about his presentation at the American College of Cardiology and World Congress of Cardiology meeting in New Orleans. Dr. Feinman and his group looked at differences in heart failure-related cardiogenic shock between ischemic and non-ischemic cardiomyopathy, using data from the Critical Care Cardiology Trials Network (CCCTN) Registry.

Thank you for joining us.

Dr. Jason Feinman:

It’s a pleasure to speak with Cath Lab Digest today. My name is Jason Feinman. I am one of the second year General cardiology fellows here at Mount Sinai Hospital, and the study that I'd like to talk about today is called “Differences in Heart Failure-Related Cardiogenic Shock Between Ischemic and Non-Ischemic Cardiomyopathy”, and these are data from the Critical Care Cardiology Trials Network (CCTN) Registry.

There was a lot of reasons that I wanted to do this study, and it was a pleasure to coordinate with the CCCTN, who coordinated out of the TIMI group and work alongside some of our faculty here at Mount Sinai. I have a particular interest in heart failure. I'm going to be applying for heart failure fellowship this year and hope to pursue that following my general cardiology training. And I really love the concept of and the field of cardiogenic shock.

We wanted to look a little bit more at this specific patient population, not just cardiogenic shock, but focusing specifically on heart failure-related cardiogenic shock. We know from data that have been published from CCCTN previously that the leading cause of cardiogenic shock admissions to contemporary cardiac ICUs is actually heart failure-related cardiogenic shock. A lot of research that comes out focuses on acute myocardial infarctions, but we know that heart failure, with its growing prevalence, is actually going to be the leading reason that patients for cardiogenic shock get admitted to the cardiac ICU. We wanted to tease out a little bit about the specific patient population and looked at that dichotomy, that division of heart failure into ischemic and non-ischemic cardiomyopathies.

We wanted to see what these patients look like and what their overall baseline characteristics are. Are there differences between the two groups? And then, when they get admitted for cardiogenic shock, what happens? What are their hemodynamic parameters, in terms of invasive hemodynamics? What types of treatments do they get in terms of inotropes, mechanical circulatory support, renal replacement therapies, mechanical ventilation? And overall, what are the outcomes? What's the in-hospital mortality for these patients? How many patients go on to advanced therapies like LVAD and transplantations? How many patients are discharged alive?

And try to tease out what some of the reasons for that might be. The study was done through the registry that's coordinated by the TIMI group. The CCCTN is a registry that encompasses cardiac ICUs across North America. We participate and give information to them, and then they were a fantastic group to work with. That helped with a lot of data analysis and teasing out some of the information that we did.

In total, these data were over four years. These were admissions to cardiac ICUs from 2017 to 2021, and there were 3,200 roughly admissions for cardiogenic shock during that time. We separated that into admissions for heart failure-related cardiogenic shock, acute myocardial infarction related cardiogenic shock, and then secondary causes, things like cardiac tamponade and ventricular arrhythmias. We excluded AMI-related cardiogenic shock as well as secondary reasons for cardiogenic shock, which left us with 1,844 patients admitted for heart failure-related cardiogenic shock. That was then subdivided into ischemic and non-ischemic cardiomyopathy. And that was done at the individual sites who adjudicated based upon the information that they had at hand. We were left with 692 patients with ischemic cardiomyopathy and 1,152 patients with non-ischemic cardiomyopathy, all admitted for heart failure-related cardiogenic shock.

When looking at some of the baseline characteristics for these patients, some of the things that we saw were not surprising. We know that patients with ischemic cardiomyopathy are going to have higher rates of some baseline comorbidities, things like hypertension, diabetes, and chronic kidney disease (CKD), and we saw that, certainly, in our group. Overall, the average age was around the low 60s. There were slightly older patients in the ischemic cardiomyopathy group, and they were more likely to be Caucasian and male. And then higher rates of, like I said, hypertension, diabetes, and CKD.

In terms of the way that these patients were treated when they got to the hospital, that's where things start to get interesting. So patients with ischemic cardiomyopathy and those with non-ischemic cardiomyopathy did not have significant differences in rates of inotrope infusions, didn't have significant differences in rates of mechanical circulatory support, and no differences in the rate of renal replacement therapy, despite patients with ischemic cardiomyopathy having higher rates of baseline CKD. Patients with ischemic cardiomyopathy were more likely to require mechanical ventilation during their hospitalizations.

For those patients who did end up having invasive hemodynamic monitoring, there were higher rates of biventricular and right ventricular dysfunction in the non-ischemic cardiomyopathy group compared to left ventricular dysfunction, which seemed to predominate with our ischemic cardiomyopathy patients. Patients with non-ischemic cardiomyopathy, interestingly enough, actually had slightly lower cardiac indices than patients with ischemic cardiomyopathy when looking at cardiac output and cardiac index. But I think the most interesting thing that we found was the end result: what happens to these patients, what are their outcomes during hospitalization?

One important thing that we wanted to do is control for some of these differences, so we did an adjusted odds ratio for in-hospital mortality, and we adjusted for things like age, sex, CKD, diabetes, Sequential Organ Failure Assessment (SOFA) score, so the severity of shock when patients were admitted to the hospital as well as preceding cardiac arrest.

We did see that patients with ischemic cardiomyopathy had higher rates of preceding cardiac arrest compared to non-ischemic cardiomyopathy. We knew that this was going to be something that we would have to adjust for in our analysis. But even after adjustment for all those things, ischemic cardiomyopathy had a 1.54 higher odds ratio for in-hospital mortality compared to non-ischemic cardiomyopathy. This seemed to be consistent across some of our pre-specified subgroups like age, sex, preceding cardiac arrest, as well as the ideology and time course of heart failure being de novo versus chronic heart failure.

One interesting thing that we did see was that patients with non-ischemic cardiomyopathy were more likely to go onto heart transplant compared to ischemic cardiomyopathy, but the rates of durable left ventricular assist device were not statistically different between the two groups. That gets us to the understanding as to why do we see these differences? Why do we see that patients with ischemic cardiomyopathy are more likely to have higher rates of in-hospital mortality, even after adjustment compared to non-ischemic? And why do patients with non-ischemic have higher rates of going on to heart transplant compared to ischemic patients?

Obviously this is a bit difficult to tease out in a registry analysis. Some possible suggestions are that patients with ischemic cardiomyopathy, because of their higher rates of comorbidities, may have been deemed to be less likely to benefit from heart transplantation, and maybe were less likely to have been listed, and that might be one of the reasons that we see the increase in heart transplants for the non-ischemics compared to the ischemics. It's also possible that patients with ischemic cardiomyopathy may just be more sensitive to hemodynamic changes.

They may end up in what we call a so-called ischemic spiral, where they become more hypotensive, they can't handle that decrease in coronary perfusion because of their ischemic disease that worsens cardiac output further, and then they unfortunately go down to the spiral that leads to in-hospital mortality. I think this was a fascinating topic to look at, something that I'm certainly very passionate about, something that I love exploring more. Be on the lookout for the full manuscript to be published, and I would be happy to answer any questions at any time.

Can you describe the multidisciplinary care provided to these patients at Mount Sinai?

Dr. Jason Feinman:

At our institution, all of our care in the CICU is always multidisciplinary. Our teams are made up of intensivists. When we have cardiogenic shock patients, heart failure is always involved. Oftentimes interventional, especially, and always, if there's mechanical circulatory support, depending on their arrhythmic burden, electrophysiology (EP) may be involved as well, as well as some of our other cardiovascular and non-cardiovascular specialties that we have here. All of our care in the CICU is coordinated, and we know that cardiogenic shock teams that we have here at Mount Sinai, certainly patients where cardiogenic shock teams are present, tend to do better and have that coordination there. It is certainly something at our institution that we emphasize.

How has this study affected the physicians at your institution who are treating these patients?

Dr. Jason Feinman:

I think the biggest thing is really just to recognize just how sick these patients are. For our study, the overall in-hospital mortality rate was 26.1%. That was overall. For ischemics, it was 32.5%, for non-ischemics it was 22.3%, which means that unfortunately about three out of every 10 patients who get admitted for heart failure-related cardiogenic shock are unfortunately not going to survive that hospitalization. I think what this is telling us is that we have to keep a really close eye on these patients and maybe have to try to tease out which patient unfortunately may not have a good outcome. In terms of the management, I don't know that it'll necessarily change our management decisions. I think that those are certainly going to still be made with the information that we have at hand in terms of hemodynamic parameters, laboratory results, and how these patients are doing clinically. But I think this really just emphasizes just how sick this patient population is.