COMMENTARY

Understanding CV Hemodynamics Key in Heart Failure

Ileana L. Piña, MD, MPH; Daniel Burkoff, MD, PhD

Disclosures

January 12, 2017

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Ileana L. Piña, MD, MPH: Hello. I am Ileana Piña from Montefiore Medical Center and the Albert Einstein College of Medicine in the Bronx, New York, and this is my video blog. I am thrilled today to be at Transcatheter Cardiovascular Therapeutics (TCT) 2016 with my good friend, Dan Burkhoff, from the Cardiovascular Research Foundation (CRF) and Columbia University. He and I have been working together for quite a few years on the heart failure sessions at TCT on interventional cardiology and heart failure, devices, and heart failure. Dan is also very special because he is a biomedical engineer, and I am going to ask him some questions today about that. Dan, welcome and thank you for joining me.

Daniel Burkhoff, MD, PhD: Thank you so much, Ileana.

Research and Education Tool

Dr Piña: When I was studying for the heart failure boards, I watched a lecture that you had given in the board review about this incredible hemodynamic software that you developed, which I thought was a wonderful learning tool. Tell us a little bit about how you came up with that.

Dr Burkhoff: Yes, thank you for asking that particular question. I have been working on this for quite a long time. The initial modeling and development of this started in the early 1980s, when I was a graduate student. I worked in a lab for my PhD, where we studied the details of ventricular mechanics and vascular ventricular interactions. Being engineers, of course we did this in terms of mathematical equations, and we really got heavily into it. In the lab during this period of time, we developed models of the entire circulation that were very easy to put onto computers with a graphical interface that allows you to change parameters and see what happens in pressure-volume loops, and see what happens in time domain. You can look at atrial mechanics and ventricular mechanics.

Over the years, working by myself and with other people, including my colleague at Columbia, Marc Dickstein, we saw that there was potential for this not only in the research field but in the educational field as well. We developed an online program at Columbia, which became part of the core curricula for the medical school. As time went by, that dwindled because of changes in Internet languages, which I do not really understand.

Dr Piña: Yes, the curricula have changed in every medical school.

Dr Burkhoff: Curricula changes and whatnot. Now, what we have found was that there is a paucity of educational material available, let alone incorporated into medical school education. From talking to fellows on rounds or in their research, we have found that they did not have a clue about the details of hemodynamics, which is necessary, especially for research. But I think it also enhances clinical care.

About 4 or 5 years ago we developed it for the iPad. We believed that the iPad would really skyrocket and be a great forum for this. That was our initial platform, but now we are transitioning it to the Web so that it is available for anyone who has a computer, a laptop, or whatever. We are in the process of making that transition.

We have already started getting requests from medical schools to incorporate it [into the curricula]. We are giving a series of 13 fellows' lectures at Columbia. We are well into that now, and the feedback has been fabulous because they get nothing like it. The iPad app is used by several physicians during rounds and especially in the CCU to help teach principles of care of patients who are in heart failure on mechanical circulatory support. I should mention that the app and the program really have a lot of devices available that you can incorporate into the simulated patients. There is means of simulating individual patients.

Dr Piña: Decision-making, right at your fingertips?

Dr Burkhoff: That is one of the things that we are trying to push toward. Such a tool would require FDA clearance, and we are starting to talk to the FDA. They have a pathway for tools that do not implement healthcare but actually make suggestions or allow you to try different things before you implement them.

Dr Piña: What has happened with hemodynamics is very interesting because when I was a fellow, we were very heavy on hemodynamics in the cath lab and they were always testing us.

Dr Burkhoff: In the CCU, could you imagine taking care of a patient in cardiogenic shock without a right-heart cath?

Dr Piña: No. Yet we moved into this period where Swan-Ganzes were not exactly what everybody wanted to do. Then we did the ESCAPE trial.[1]There was a paper that talked about the complications of the Swan-Ganz.[2] I think in all my years I have seen one embolization from leaving the balloon up for too long. We did the ESCAPE trial and found it to be safe in the hands of people who knew what they were doing, but it never really picked up again. I always get asked by the fellows, "Do we really have to have a Swan?" Sometimes I say yes because it adds so much to the teaching.

The beauty of your system in that you can adjust the afterload or the preload and see what it does to the pressure-volume curve. What have you done at TCT with this?

Clinical Case Simulation

Dr Burkhoff: We had a full-day course. It was largely invitation-only. We targeted people who we knew are interventional cardiologists interested in mechanical circulatory support, where these kinds of concepts are really critical. We had a 7-hour course yesterday with five faculty (myself and several practicing clinicians) who recognize that understanding the hemodynamics really comes into clinical practice.

One of the premises of the course was to start with the basics—we spent 2 hours on what is preload and what is afterload.

Dr Piña: What is normal? Fellows cannot tell you what is normal.

Dr Burkhoff: We then had a couple of sessions on oxygen consumption, really getting into details of what determines myocardial oxygen consumption, which is so critical in the setting of myocardial infarction (MI). What determines coronary blood flow? What are the complicated interactions and regulation of this by the autonomous nervous system? Then we really launched into clinical scenarios, using the app.

Dr Piña: You had examples of clinical cases?

Dr Burkhoff: We had clinical cases that were submitted by clinicians that we then modeled, and we showed what happens in the simulation and correlated that with what happens in reality. We had cases of high-risk percutaneous coronary intervention during mechanical support, cardiogenic shock where we compared balloon pump with a transvalvular pump (like an Impella device), to extracorporeal membrane oxygenation (ECMO). By the way, I think the physiology of ECMO is the least well understood or least well appreciated physiology.

Dr Piña: Yet its use is growing and getting better. The surgeons are getting so much better at ECMO.

Dr Burkhoff: They are, but there is still a lot to learn about ECMO and the need to unload the ventricle while you are on ECMO, etc. We also had a case of isolated right-heart failure, and the most interesting cases were of biventricular failure where you have patients coming in with high central venous pressures, high wedges, and low cardiac output. How do you deal with this?

How do you manage when you have multiple devices like this? When you are a pilot of a plane, you test these things in a simulator first. Imagine that you are a clinician who presents a patient with a complicated physiology. This allows you to test this strategy and that strategy and see what happens before actually implementing it.

Dr Piña: My favorite scenario in the unit is the fellows who will see the cardiac index being low, and the first thing they reach for is the inotrope. I always ask, "What is the systemic vascular resistance? What is the pulmonary vascular resistance?" All of a sudden, when it is usually 1900 or 2000 dyne-sec/cm5/m2, I will say, why not try another approach? That would be a perfect case for your software to look at what to do.

Dr Burkhoff: The software would simulate that patient with its PVR, with its SVR. Then you could see that if you give a pulmonary vasodilator for more on the left side than the right side, what the difference would be.

Dr Piña: Through the years, you and I have been working together at TCT. I think when we started heart failure, some people said, "At TCT? Heart failure?" Do you think it is still as valuable as it was when we started?

Dr Burkhoff: Yes, I really do. This is an interventional cardiology meeting, and I have always been impressed that the interventional cardiologists, the key opinion leaders who are really leading the field, are interested in every aspect of treating the heart. They see the patients in follow-up who have heart failure. They are very good now at treating acute MIs, but as we all know, that has led to an explosion of heart failure.

Dr Piña: I want to thank you for coming here. I think the audience will thoroughly enjoy hearing about the software. If they want to know more about it, where do they go?

Dr Burkhoff: They can just contact me at CRF, DBURKHOFF@CRF.org. There is also a website that is called PVLoops.com.

Dr Piña: PVLoops—I love it. I love the PV Loop. You are going to figure out heart failure with preserved ejection fraction (HFpEF) for us. I know you are. Thank you for letting me chat with you. I know you were a little hesitant, but I appreciate it.

Dr Burkhoff: It has also been an extreme pleasure to work with you over almost 15 years on these programs at TCT. Thank you.

Dr Piña: Thank you. I want to thank my audience for joining us today. I hope you have found this instructive in telling you what we need to do about hemodynamics. If you are an educator, please talk to your fellows about hemodynamics. It is really critical to understand this, even to know how to approach a patient, especially patients in our coronary care units. Once again, this is Ileana Piña, signing off. Have a great day.

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