Miniature heart pumps, which until now have been viewed only as temporary bridge devices until a transplant becomes available, are an effective treatment on their own and could save some 27,000 lives annually, researchers said Monday.
Each year, about 100,000 Americans reach end-stage heart failure, where death is imminent. But only about 2,100 donor hearts become available. Making permanent implants available for large numbers of such patients would be a major breakthrough in the treatment of heart disease, the nation's largest cause of premature death.
Optimism about the potential of the pumps reflects the rapid improvements that designers of heart devices have made in recent years. The most attention recently has gone to the AbioMed artificial heart, which replaces a patient's diseased heart. But the new research focused on smaller pumps, known as left ventricular assist devices, that are designed to help the chamber of the heart that is responsible for pumping blood throughout the body.
The new research--the first trial specifically designed to study long-term use of the devices--showed that patients with the pumps had twice the survival rate after one year and three times the rate after two years of patients receiving drug treatment for their heart problems. Moreover, the patients using the devices experienced a greatly improved quality of life.
The devices were associated with an increased rate of side effects, such as strokes, bleeding and infections, but the overall benefits far outweighed the side effects, experts said.
"Even with a high rate of complications, a left ventricular assist device can provide a significantly longer and better quality of life in extremely ill heart-failure patients," said Dr. Claude Lenfant, director of the National Heart, Lung and Blood Institute.
For every 1,000 people reaching end-stage heart failure who received a left ventricle assist device, 270 lives could be saved, Dr. Eric A. Rose of Columbia University told a meeting of the American Heart Assn. in Anaheim. A report on the study is also in this week's New England Journal of Medicine and is available at http://www.nejm.com.
One potentially major block to the wider use of the assist devices is cost. Implanting one will cost the same as a heart transplant, about $160,000 per year, Rose said. Most of the potential patients are elderly, so much of that cost would be borne by Medicare, to the tune of $1 billion or more per year.
"But the survival benefit was very dramatic," Rose said. "If you saw comparable results for bone marrow transplants for breast cancer, there's no question" that Medicare would pay for it, he said. "I'm optimistic" they will cover it, he added. The cost per unit could also decline as the devices become more common.
One example of the dramatic improvement that the devices can make in a patient's life came at the heart meeting from Dr. O.H. Frazier of the Texas Heart Institute.
Frazier told of a British heart patient wearing an assist device, although not the one used in the new study. The patient was walking in London with a sack over his shoulder containing the batteries for his assist device when a purse snatcher came along and stole the pack. The device had made the patient so much healthier, Frazier said, that he was able to run down the crook and retrieve the batteries.
At least 3,000 patients have received left ventricle assist devices, in most cases to help them recover from heart surgery or to keep them alive long enough for a donor heart to become available. Using the devices in that manner is good for the patients involved but does little to ameliorate the overall shortage of hearts for transplant. If one patient is kept alive long enough to receive a donor heart, another patient will not receive one.
Moreover, many sick patients are not eligible for a transplant because of complications such as diabetes, lung disease, kidney damage and cancer. For those patients, more widespread use of the assist devices could provide new hope for long-term survival.
The new trial was conducted using a device called the HeartMate VE, produced by Thoratec Corp., located in the East Bay city of Pleasanton. The device is the size of a compact disc player and is implanted in the upper part of the abdominal wall or in the lining of the abdominal cavity. The device is attached to arteries outside the heart and boosts its pumping ability. It has a tube extending outside the body to the battery pack and control system.
Rose and his colleagues at 20 medical centers enrolled 129 patients with chronic heart failure who were ineligible for transplants. "The patients were much sicker than those who receive a transplant," Rose said. "The slightest form of exertion, such as tying a shoelace, resulted in shortness of breath."
The patients were randomly assigned to receive either the HeartMate or the best drug treatment available: 68 received the device, 61 medical treatment.