Nov. 13, 2001 Scientists supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health have demonstrated that despite several serious side effects, a type of implantable heart pump, called a left ventricular assist device (LVAD), can significantly extend and improve the lives of terminally ill patients with end stage heart failure (ESHF) who are not eligible for cardiac transplantation.
The study was presented today at the American Heart Association’s annual meeting in Anaheim, California. Due to the importance of the findings, the study was also published on the New England Journal of Medicine’s website in advance of the print publication on November 15, 2001.
“Heart failure affects an estimated 4.7 million Americans with 550,000 new cases diagnosed each year,” said Dr. Claude Lenfant, NHLBI director, “This compelling study shows that even with a high rate of complications a left ventricular assistance device can provide a significantly longer and better quality of life in extremely ill heart failure patients for whom a poor quality of life and death are certain.”
The study, Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH), was administered through a cooperative research grant agreement among Columbia University, NHLBI, and Thoratec Corporation, the Pleasanton, California company that manufactures and supplied the LVADs without cost to the trial. Additional funding for the routine costs of clinical care associated with the trial was made available by the Centers for Medicare and Medicaid Services and by the participating clinical centers.
The REMATCH study was conducted over 3 years from May 1998 through July 2001 in 20 cardiac transplant centers around the country. REMATCH involved 129 patients with chronic ESHF who had not responded to medical management of the disease and were ineligible for heart transplantation because of age or certain medical conditions. The patients enrolled in REMATCH were randomly assigned to one of two groups.
Sixty-eight patients whose average age was 68 years received the HeartMate, a vented electric (VE) LVAD. The HeartMate VE device is fully implantable and has wearable external components. It has a textured interior surface, which helps prevent blood clots and reduces the need for blood-thinning medication. The control group had 61 patients, average age 66 years. They received optimal medical management, which included angiotensin converting enzyme (ACE) inhibitors and monthly follow-up when out of the hospital.
As a group and regardless of age, the patients with the HeartMate had a 52 percent chance of surviving one year, compared to 25 percent of the patients in the control group. The 2-year survival rate was 23 percent for the HeartMate group versus 8 percent for the control group. Quality of life -- as measured by their emotional state, whether or not they were depressed, and their mobility -- was consistently higher in the VE LVAD patients at 12 months than in the control group.
Significant adverse events associated with the VE LVAD that frequently led to disability and death included infection, bleeding, and device malfunction. The probability of device infection within 3 months of implantation was 28 percent. After 2 years, the device failed 35 percent of the time, with 10 patients needing a replacement.
"This study is an initial step in demonstrating the feasibility of restoring or replacing heart function for extended periods of time," said Dr. John Watson, director of the Clinical and Molecular Medicine Program, Division of Heart and Vascular Diseases, NHLBI, and a study coauthor. Dr. Watson added that the REMATCH study is an outgrowth of the Artificial Heart Program mandated by Congress in the 1960s.
The HeartMate VE LVAD is the size of a compact disc player and is implanted in the upper part of the abdominal wall or in the peritoneal lining. The device has a tube entering the left ventricle, the heart’s main pumping chamber. Blood is drained from the left ventricle into the LVAD, which sends the blood to the aorta from where it travels to the body. A second tube extends outside the body and is attached to a battery pack, which is worn on a shoulder holster, and a beeper-sized control system, worn on a belt.
ESHF is a progressively debilitating disease that requires a complex array of treatment options. Annual direct and indirect health cost estimates range from $10 billion to $40 billion. The 5-year survival for all heart failure patients is approximately 50 percent. Although patients with mild to moderate heart failure have been shown to benefit from pharmacological advances, survival and quality of life for patients with ESHF remain limited.
Cardiac transplantation is the only treatment that provides substantial individual benefit to patients with severe heart failure but the small number of donor organs worldwide -- 2,733 in 1999 -- makes heart transplantation an unrealistic option for the more than 4,000 patients in the U.S. awaiting heart transplant.
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