Advancements in Heart Failure Treatment: How the Left Ventricular Assist Device Has Evolved

Podcast Transcript

Announcer:

Welcome to Love Your Heart, brought to you by Cleveland Clinic's Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute. These podcasts will help you learn more about your heart, thoracic and vascular systems, ways to stay healthy and information about diseases and treatment options. Enjoy.

Michael Zhen-Yu Tong, MD:

Good morning. My name is Michael Tong. I am the surgical director of heart transplantation and MCS at the Cleveland Clinic, and today I will be talking about long-term outcomes with durable mechanical circulatory support. So long-term support for patients with chronic heart failure. This is really about the mechanical circulatory support with HeartMate III and with heart transplantation.

So the first human heart transplant was done in South Africa by Christian Barnard. This was in 1967. However, most of the research was done in the United States. So Shumway and Lower did most of the studies and experiments and developed a technique for the heart transplantation and they were at Stanford. So the story with Shumway was that he wanted to be back in academic medicine. He didn't want to go to private practice. So the only job that he could get at the time was to work the graveyard shift in the dialysis unit. So that was the only job he can find at the time. So he took that job, but what that job afforded him was a lot of free time. So that's when he developed the techniques for transplantation and as we know it today, so every lemon can be turned into lemonade.

So what you may have heard about the first heart transplantation was in 1967, but what you may not have known was that the first heart transplant at the Cleveland Clinic was just one year after in 1968.

So what you realize about the Cleveland Clinic that was different was the emphasis was never on the individual. It was always on the team. So you look at this is in The Plain Dealer, this was the team of everybody that took care of that first transplant patient and the emphasis was always on the team. And it is that emphasis that still rings true today.

So the transplants in the first few decades were not all that successful. They died because of rejection. They died because of infection. And it wasn't until cyclosporine became available in the late seventies that transplants finally became a viable long-term treatment option. And cyclosporine allowed for us to be able to selectively immune suppress these patients, but not to the degree that they were going to get infections or not to the degree where they were going to get bad infections. And it was only after cyclosporine became available that you saw a dramatic increase in the number of heart transplantation in the 80s. And in the nineties, the number of transplantation did drop in the United States and around the world.

But in recent years, it has come up. We do about 4,000 to 4,500 transplants in the United States. However, that number was never going to be enough to support all the patients who need advanced treatment that have end-stage heart failure. And the solution has always been mechanical hearts and the development of a mechanical device that can support these patients long-term. So the first mechanical device that was used was a total artificial heart. But what you may not realize is that a lot of that research that went into the development of that came from the Cleveland Clinic.

So Willem [Kolff], he was the father of artificial organs. He developed the first dialysis machine and most of that work was done here at the Cleveland Clinic. And he had a center for artificial organs. And a lot of that research that went into the development of the first total artificial heart was done at the Cleveland Clinic.

So the first device that became nationally recognized and FDA approved was the HeartMate XVE, or what we call the HeartMate I in some places. And it's a very large device. It was a pulsatile device. It had two plates that moved and then pumped the blood through the patient. And however, that device did work. It was a big bulky device. It had a driveline that comes out that's attached to batteries, but it did show efficacy. So in their trial, it randomized patients to get the LVAD, the HeartMate XVE, or medical management. And if you look at what happened to the patients that just got medical management, at one year, only one out of four patients were alive. And at two years, only 8% of the patients were still alive. So when you have advanced heart failure, it was worse than any cancers you can imagine. It's worse than breast cancer. It's worse than colon cancer, it's worse than lung cancer. And when you had an LVAD, that first generation LVAD, your survival more than doubled.

However long-term, because of how bulky these devices were and because of all the moving parts and all the complexity, these devices unfortunately just were not that durable. Very few of these patients survived more than two years. So over time, what the field realizes, we cannot have these big bulky devices. We need simpler devices with less moving parts and less complexity. Less moving parts will ensure that you're going to have a more durable system. And that's where the HeartMate II came in. The HeartMate II had only one moving piece. It only had a single rotor that spun inside the housing. And as it spun, it sucked blood from the left ventricle injected into the aorta.

That device really became the bread and butter heart failure device that we knew for the last 15 to 20 years. There's been over 10,000 patients that's been treated with the HeartMate II. And it was really in the golden era of mechanical circulatory support. The downfall of the HeartMate II was the fact that it still had two bearings. So these two ruby bearings on which the device, the rotor spun, and that ruby bearing did create some heat, even though the blood as it comes in was able to dissipate some of that heat has really led the industry to develop the HeartMate III and the centrifugal pump. And the HeartMate III really has been a revolutionary pump.

It's a centrifugal pump. It is completely levitated by magnets. And as those magnets suspend the rotor in the air, it'll spin the rotor. And because of that, there is no moving parts. There is no parts of friction, I mean. So there is no friction at all. And the blood will just continuously get pumped with no friction. And because of no friction, you have no hemolysis. And this has been a design that has really brought mechanical circulatory support to the modern era and allows to achieve the results that we achieve today. You have a driveline that comes out, it's attached to a computer, and that computer is attached to batteries. It's an efficient system. So patients do need to change the batteries, but they just change it twice a day and at night when they're asleep, they connect it to the wall. So everything is suspended by magnets and which is the great design.

So in conclusion, LVADs have seen a significant improvement in survival in the last 20 years to the point where LVAD survival now is equivalent to that of heart transplant. I have patients who have had LVADs now that are on the transplant list, and they come back and they tell me, "I feel perfectly great with my LVAD. I'm no longer interested in having another surgery. I want to be taken off the transplant list." It's not the majority, however, there's a lot of patients that do want to just live with their LVADs. And with that, I want to thank you.

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