UM cardiac surgeons have put the first four VentrAssist heart pumps in U.S. patients.
The heart pumps 2,000 gallons of blood a day. I guess most of the time our hearts can handle that very well, but if somebody has a condition known as heart failure, their heart isn't pumping as well as it should. Is that true?
It's so true. In fact, congestive heart failure is the scourge of America, with more than 5 million cases every year in this country.
What is heart failure?
It's a failure of the heart muscle to squeeze effectively. So it's kind of a breakdown of the pump's pumping ability.
Why is that so common today?
It's common because we have lots of things that cause the heart to become diseased and swollen. The most prevalent would be heart artery blockages. If you have enough blockages and enough heart attacks, eventually the heart runs out of cylinders, if you wish, or power to make the blood go through. The other common cause is high blood pressure. Untreated, hypertension is a very big problem and causes the heart eventually to poop out.
Are there good medicines people can take for heart failure to increase the pumping ability of their heart?
You bet. The mainstay of heart medicines include medications that cause water to pass through our bodies, medications that dilate the blood vessels and make the heart more efficient in its contraction, and finally medications that just affect the muscle directly, make it kind of calm down and be more efficient.
And for most people those are effective?
These are the mainstay of therapy for most people, and they have made a huge difference.
Then there are people with severe heart failure who don't have a great prognosis so they will come to someone like you, a heart surgeon, for some other options, right?
Right. One of the things I spent a long time on is treating the hopelessly ill and patients with end stage heart disease, who really need something more than what medicine can give them. You can't take a pill usually when you get to me. Some patients, in spite of good care, end up with a swollen heart that does not respond to medication.
At this point there only two options -- a heart pump, which I will talk about in a minute, and a heart transplant, where you remove it and put a human donor heart in place. The problem with heart transplants is that there are too few donors available. The maximum number of heart transplants we’ve ever been able to do in this country in a year is around 2,000, and there may be 50,000 people every year who might qualify for heart transplants.
Do heart transplants work well if somebody is lucky enough to get a donated heart?
You bet. People would be amazed to know that a heart transplant is not meant to give patients just a few weeks of life -- it's really treatment. It's more than 50% of patients who are living seven to 10 years after a heart transplant, and my longest is living more than 20 years.
Because of the shortage of donated hearts, I know you are a pioneer in working on heart pumps (artificial hearts). Can you tell us a little bit about what's available today?
A lot has happened in the heart pump development. I used the first total artificial heart that was part of the Barney Clark story -- a very long time ago in my mind -- back in the early '80s. Since that time we developed the idea that again smaller is better, and again all of the cardiac surgical tools are getting smaller. We adopted a whole new class of pumps that run like a turbine engine and are working on them in our laboratories at the University of Maryland.
The Jarvik pump is inserted inside the pumping chamber of the heart.
One of these is called a Jarvik pump and it goes right inside the pumping chamber of the heart and contains a turbine and it runs continuously.
There are other types as well, one of the most interesting of which is the Ventracor [also called VentrAssist] pump. We had the privilege of putting the first four of these in patients now in the United States. It's a pump that runs continuously but the pump is designed a little differently in that it has no bearings and there is nothing that the spinning part touches. It just basically floats in the flowing blood and we think that means the pump will be more durable. It may last 25 years.
I know that heart pumps initially were designed just to bridge you over from severe heart failure until you can get a heart transplant. Are they now considered sort of the final definitive destination therapy, if you will?
Yes. The problem is these large numbers of patients who may not qualify for heart transplantation because they are older than 70 or have other conditions like very serious diabetes, which precludes them from doing well with heart transplantation. For this group of patient we offer them pumps in lieu of transplantation, and I think for a select group of patients it's a wonderful alternative. They can get back into their basic lifestyle and enjoy the end of their life.
How long do heart pumps last?
For the Jarvik pump, the longest is over five years in a patient, which is a long time if you suffered with heart disease and are 73 years old. If it can give you five years and leave you feeling healthy without needing to change your pump, that’s not bad.
Do people feel good and can they keep up a pretty good activity level when they have a heart pump inside of them?
If a patient has a smooth course, they can do anything they want.
Who is a good candidate for a heart pump?
Anybody with severe heart disease and heart failure who is failing all medications. For these people, we can put the pump in and worry about using it permanent or temporary later.
I know you are involved in a lot of research, for example, to develop very tiny Jarvik heart pumps for babies. How is that research coming along?
It's going very, very well. We hope to be able to provide children with this option just like adults with heart disease. Children get heart disease usually from congenital defects, and sometimes we don't have the right surgeries to take care of those defects. This would be a semi-permanent solution for those children.