Results presented Tuesday at the Orlando, Fla., meeting of the American Heart Association showed that a new type of device doubled the two-year survival of heart failure patients. The key to the improvement was the development of a smaller, quieter, more reliable pump that is less likely to break down and need to be replaced, an outcome that requires the patient to undergo a second major surgery. The pumps are called left ventricular assist devices, or LVADs. They are not meant to replace the entire heart, only to assist in the pumping action of the left ventricle, which pushes blood out the aorta to the body. Researchers originally thought that LVADs had to mimic the action of the heart, pushing out blood in a series of pulses that were timed to coincide with pulses from the heart itself. That required complex machinery to produce the pulses and sophisticated electronics to synchronize them with the heart. Such devices had a high propensity to fail. But more recently, researchers have concluded that a simple, continuously operating pump can work just as well, if not better. Such pumps typically have only one moving part -- the impeller -- and don't need to be synchronized with the heart, so their reliability is much greater. They are also much smaller, typically only about one-seventh the size of older models. The findings presented Tuesday were of one such device, manufactured by Thoratec Corp. of Pleasanton, Calif., and called the HeartMate II. The device is currently approved by the Food and Drug Administration only as a temporary bridge to a transplant. 'We had a sense that these smaller devices were going to have better long-term outcomes, and this trial proves it,' said Dr. Alfred A. Bove, president of the American College of Cardiology, who was not involved in the research, in an e-mailed statement. 'These devices have come a long way in five years. I expect that technology will continue to move things forward and they will be even better five years from now.' The need is great. An estimated 150,000 Americans have advanced heart failure that could be treated with a heart transplant, but there are only about 2,100 donors available in a given year. The big issue in the future may be not the availability of the devices but the financial strain that they will put on the health care system. The Thoratec pump costs about $80,000 and the surgery to implant it an additional $45,000. With thousands of patients needing the device, costs could mount quickly. In the new trial, headed by researchers from Duke University Medical Center and the University of Louisville, researchers at 38 centers in the United States enrolled 200 heart failure patients between ages 26 and 81. All had failed medical therapy for their condition and were considered too sick to be candidates for a transplant. About two-thirds of the patients received the HeartMate II, and the rest received an older version that pumps in pulses. The team reported in Orlando and in an article published online in the New England Journal of Medicine that patients receiving the new pump lived longer and had a higher quality of life than those receiving the older one. One year after the original surgery, 68 percent of those with the new pump were still alive, compared with 55 percent of those who received the older pump. But at two years, the results were much more dramatic: 58 percent of those who received the HeartMate II were still alive, compared with 24 percent of those receiving the older pump. Similar patients receiving only medical therapy typically survive about six months, and fewer than 10 percent survive two years. (Begin optional trim) One reason for the better survival rate is the reliability of the new device. About one-third of the older pumps failed during the experiment and had to be replaced, compared with 10 percent of the new ones. In addition to survival, the devices also improved quality of life. The patients with the continuous-flow LVADs could walk twice as far as those with a pulsatile-flow device, the authors found. The Thoratec device is not the only one attempting to capture this market. A similar device developed by Heartware International Inc. of Australia has been shown to keep as many as 80 percent of patients alive for two years in smaller clinical trials. In an editorial accompanying the new report, by Dr. James C. Ang of University Hospitals Case Medical Center in Cleveland said, 'The first priority would be to make sure patients and physicians are aware that ventricular assist therapy is available, effective and safe for well-selected patients. 'Second, we should not delay referral until surgical morbidity and mortality become prohibitive. ... The optimal time for referral is most likely before the development of major complications from heart failure.' (End optional trim) The study was funded by Thoratec. 