Artificial Hearts: Past, Present and FutureMay 27, 2014
Dr. Miller: About 32 years ago, Barney Clark had the first artificial heart implanted here at the University of Utah. We're going to talk about how things have changed since then on The Scope Radio. This is Dr. Tom Miller.
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Dr. Miller: I'm here with Dr. Craig Selzman. He's an Associate Professor of Cardiothoracic Surgery in the Department of Surgery here at the University of Utah, and Craig is an expert in heart transplantation as well as ventricular assist devices, which are the new artificial hearts.
About 32 years ago, Barney Clark was the first man to undergo an artificial heart implantation, and that was here at the University of Utah. Now a lot has changed since then, I think. Dr. Selzman, can you talk to us about what's new with artificial hearts?
Dr. Selzman: Since that time, so much has happened. It's been in two or three areas, and it's just the technology.
Dr. Miller: That's got to have changed tremendously.
Dr. Selzman: It's huge.
Dr. Miller: I remember the pictures of Barney Clark. The pumps were huge. They had to wheel it around with Barney Clark. It was noisy. It was loud. It was terrible.
Dr. Selzman: It's a Zamboni machine. We still have one here in the hospital, if necessary, to clean the ice outside. But the deal now is that we have these pumps so small and they're very patient-friendly so that the patients can actually go home. They can do everything. They can play 18 holes of golf, walking. You name it; they can do it.
The one thing that is a little bit difficult is there's electricity going through this; they're not going for a swim any time soon, but that's even changing. We have pumps now that allow people to have artificial heart support that can actually go swimming with internal batteries and stuff. So it's been huge.
Dr. Miller: So are the pumps still external to the body, or are they within the body now?
Dr. Selzman: They're all within the body. We still have some that are used externally. Those are used for really the sickest of patients that we're really just trying to do whatever we can to save their lives. But in terms of folks that you want to actually go home and regain life, the thing about a lot of this field is that the chances of you having a long life with advanced heart failure is low. Probably the patients we're talking about, less than 10% are alive at two years.
Dr. Miller: I mean, that's as bad as many cancers.
Dr. Selzman: It's metastatic cancer. It's basically the same thing. I use an analogy a lot, and the one thing that the VADs have done in this artificial technology is that it's the therapy that is so much better than chemotherapy, meaning that you can put somebody on with an advanced cancer, and you might buy another two, three year, four months. We're talking about buying five to 10 years. And not only just years, but also quality years. These patients are back with their families. They're going back to work. They're living life. It's amazing.
Dr. Miller: Craig, does this mean that actually having a heart transplant may become obsolete?
Dr. Selzman: Ah, that's a great question, and it's one of the current debates within our community because the life expectancy, the one year survival rate for patients that are getting these machines is almost as good as getting a heart transplant. The problem with heart transplant: great therapy. There are just not enough of them.
For the last 25 years, we've done about 2,000-2,500 hearts a year in the United States, but there are probably 80- to 100,000 folks that need it today. So these pumps have really filled that gap. Early on, because the pump technology wasn't quite so good, you'd have complications. But now the complication rates are actually very manageable and the survival is quite good. One year survival is over 90% right now.
Dr. Miller: I remember in the Barney Clark days that that clots arising from the use of that type of pump were a real problem. That's pretty much eliminated now, is that right?
Dr. Selzman: Whenever you have blood that goes through a washing machine or a Kenmore or a Maytag, it's just not normal. And so we still are faced with this complex problem of hemostasis, thrombosis, and anti-coagulations. For the most part for these pumps, you will be taking some blood thinner medicines.
Dr. Miller: But the risk of having a clot is lower?
Dr. Selzman: It's much lower. I mean, it hearkens back to the old heart valve days where we used to have that had a ball that would go up and down, the old Bjork-Shiley valves and stuff. We don't use those any more, and so the whole field is new.
Dr. Miller: The whole technology.
Dr. Selzman: Yeah.
Dr. Miller: What does the future look like in terms of these devices? I mean, do you see these devices becoming smaller, like calculators becoming smaller and smaller?
Dr. Selzman: Yeah. I think there are two or three things that are going to really make a difference here, and you could actually trace back. If you look at the pacemaker defibrillator field, defibrillators used to be these big giant things that you used to put in the abdominal cavity, and now they're these little things below your collarbone.
So the same things happened in the VAD world. They're getting smaller and smaller, and because they're getting smaller and smaller, the complications are less and less, you're actually going to start putting these things in patients that are less sick to try to get them off this spiral of decline that happens with heart failure. So size definitely better, complication rate less. And then the main thing that's coming from an industrial standpoint is power. So just like you're trying to get batteries in that 747, or what was it, the 757, the lithium battery was the only bad thing.
Dr. Miller: Exactly.
Dr. Selzman: So they're starting to do the same thing with these VADs. And so a lot of the original DeBakey pump, believe it or not, was a collaboration with N.A.S.A. to help do these things.
Dr. Miller: Spinoff technology.
Dr. Selzman: Yeah, so there's a lot of cross collaboration there. The interesting thing I think really where the field is going, it's not so much about the pump because the pumps are getting better and better. But it's about the patient and the biology of the patient. And our goal is not to actually put the pump in to have them have it for the rest of their life or for them to get a transplant, but actually to get better so that we can remove the pump.
So how do we do that? Well, we're going to recondition the heart, probably use other biologic therapies to help us. So the main thing that I see the field going in the next five to 10 years is not so much about a pump, but about a patient that has a bad heart. How do you make that heart better with the assistance of a heart pump so that you can actually remove it so that patients can live long lives that way?
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