Medical Center is First on East Coast to Use the New Rotary Blood Pump
Cardiac surgeons at the University of Maryland Medical Center have implanted an experimental Jarvik 2000 heart pump to save the life of a 63-year-old man with heart failure who is awaiting a heart transplant. The University of Maryland is the first medical center on the East Coast and the third in the nation to implant the Jarvik 2000 device, which is a quiet, battery-powered flow pump about the size of a thumb.
The pump was implanted on September 6, 2002, in Woodrow Snelson, from Burtonsville, MD. If he continues to do well, he may be the first person in the U.S. to go home with the Jarvik 2000.
The Jarvik 2000 is the smallest and simplest left ventricular assist device (LVAD) available-so small it fits directly inside the heart's left chamber (ventricle). In contrast to other heart pumps, the Jarvik's size would enable it to be used in small adults and children. It was designed to function reliably for as long as a decade, and to reduce the risk of blood clotting and infection. Those are problems associated with larger pulsatile pumps, which beat to create a pulsing blood flow similar to a natural heart.
"This device, if it proves to work well, could change the whole paradigm of how we treat end stage heart disease," says Bartley P. Griffith, M.D., chief of Cardiac Surgery at the University of Maryland Medical Center and professor and head of the Division of Cardiac Surgery at the University of Maryland School of Medicine. "We may not have to wait for patients to end up in intensive care with end stage heart disease. We may, in fact, select a device like this much as we select a pacemaker-off the shelf, before the patient is critically ill," says Dr. Griffith, who led the team that implanted the pump.
Dr. Bartley Griffith led the University of Maryland Medical Center team in implanting the Jarvik 2000 heart pump in Mr. Woodrow Snelson.
Dr. Griffith has a long association with Robert K. Jarvik, M.D., inventor of the Jarvik 2000. That relationship goes back to the mid-1980's, when Dr. Griffith implanted the Jarvik 7, an early mechanical heart, in the seventh patient ever to receive that device.
The Jarvik 2000 pump is designed to complement the heart's own function, not to entirely replace it. Inside the pump is a blade, or impeller, that spins on an axis between 8,000 and 12,000 RPM, drawing oxygenated blood from the lungs into the heart's left ventricle. The blood is then pushed through a Dacron graft to the descending thoracic aorta. The patient can boost the speed of the pump to increase blood flow during exercise or slow it down at rest by adjusting a small controller box. The battery pack, which powers the device, is connected to the pump by a wire that comes out of the abdomen, and is worn at the waist on a belt or carried in a small shoulder bag.
Mr. Snelson, the first patient implanted with the device at the University of Maryland, had a major heart attack in 1989 and underwent coronary artery bypass surgery. He was well for more than a decade, but about a year ago, the first symptoms of heart failure began to appear.
He says his condition had deteriorated so much prior to the surgery that even the mildest exertion caused shortness of breath and exhaustion. "I was spiraling downhill rapidly before the surgery," says Mr. Snelson. Now, as he exercises by walking in the hospital, he says breathlessness is not a problem.
Mr. Snelson received the experimental device as part of a feasibility study that will include 50 patients around the U.S. The Food and Drug Administration (FDA) required previous patients with the Jarvik 2000 to remain hospitalized until a donor heart became available, but the FDA has now modified that restriction to permit patients to be discharged to their homes, something Mr. Snelson says he looks forward to.
In congestive heart failure, the heart's pumping ability is impaired. According to Stephen S. Gottlieb, M.D., a cardiologist who heads the Heart Failure Service at the University of Maryland Medical Center, 70 percent of heart failure cases in the United States are caused by coronary artery disease, which can lead to a heart attack.
"If you have a major heart attack, part of your heart muscle dies. The rest of the heart has to work harder but usually cannot compensate," says Dr. Gottlieb, who is also a professor of medicine at the University of Maryland School of Medicine. "Most people don't notice symptoms until their lungs become congested with fluid, causing shortness of breath."
The American Heart Association says nearly five million Americans are living with heart failure. About 550,000 new cases are diagnosed each year. Smoking, being overweight, a high fat diet and lack of exercise all contribute to heart failure. High blood pressure, abnormal heart valves and heart muscle disease are some of the conditions that may cause heart failure.
Cardiologists have a number of medications that can treat mild to moderate heart failure effectively. For example, ACE inhibitors and vasodilators expand blood vessels to make it easier for the heart to function, beta blockers improve how the heart's left ventricle works, digitalis increases the heart's pumping action and diuretics help the body eliminate excess salt and water. Until now, with the development of increasingly reliable mechanical hearts and assist devices, transplantation may have been the only option for severe heart failure.
Preliminary studies suggest heart pumps may actually reverse the course of heart failure. Dr. Jarvik says expanded studies should begin in the United States during 2003 that will test his device as a lifetime treatment rather than a temporary measure until a new heart becomes available. In Europe, the Jarvik 2000 has been implanted in 15 patients for long term use. Ten of them have been discharged home and many have returned to work.
"The most important thing we've learned is that the device really can provide stable support long term. We have had no mechanical failures, and our infection rates are very low. We've shown that patients can lead a very high quality of life," says Dr. Jarvik.
A surgeon holds the Jarvik 2000 heart pump prior to its implantation at the University of Maryland Medical Center.
Jarvik Heart, Inc., and the Texas Heart Institute in Houston have been developing the new pump for almost 15 years. The Texas Heart Institute has implanted the device in 27 patients, and two patients have received the device at the Cleveland Clinic. Dr. Jarvik assisted the University of Maryland Medical Center team in the operating room during Mr. Snelson's procedure.
Heart pump implantation is one of the comprehensive cardiac services of the Heart Center at the University of Maryland Medical Center, where ten patients have received heart transplants so far this year. The Heart Center has implanted several different heart pumps in patients to keep them alive until they are able to have a heart transplant.
The pump implant team for Mr. Snelson's surgery at the University of Maryland Medical Center also included Jamie Brown, M.D., heart transplant surgeon and associate professor of surgery at the University of Maryland School of Medicine, Richard N. Pierson, M.D., clinical director of heart and lung transplantation and Timothy B. Gilbert, M.D., director of cardio-thoracic anesthesiology and associate professor of anesthesiology and medicine.
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