Left ventricular assist devices (LVADs), or mechanical cardiac pumps, are among the newest treatment options for congestive heart failure, which occurs when the heart can no longer pump enough blood to the body's organs. Traditionally, doctors treat these patients with medications that strengthen the heart's pumping ability or, when symptoms are life-threatening, with heart transplantation. LVADs perform the mechanical work of the heart when medications fail. They're implanted in the abdomen and attached to the left ventricle and the main blood vessel carrying blood from the heart to the body. A tube connects the pump to an external controller and power supply that are worn outside the body.
"We wanted to assess the impact of the Novacor LVAD in the treatment of patients with end-stage heart failure, who were not candidates for transplantation," said Joseph G. Rogers, M.D., lead author of the study and associate professor of medicine and medical director of the Cardiac Transplant and Mechanical Circulatory Support Program at Duke University School of Medicine in Durham, N.C.
Researchers studied 55 patients with the worst possible heart failure symptoms, including shortness of breath and fluid buildup in the body, who required intravenous medications to stay alive. In the non-randomized study, 18 patients were given intravenous medications, while 37 received an LVAD. Patients at the start of the study had an average 14 percent ejection fraction (EF), the measure of heart contractility. Normal EF is between 55 percent and 60 percent.
The researchers studied the patients for the remainder of their lives. They found that those with end-stage heart failure who were treated with only medications had a remarkably poor prognosis.
"The average survival was three months in the medication therapy arm of the trial," Rogers said. "Patients with the LVAD had a significant improvement in survival. The LVAD reduced the risk of death by 50 percent at six and 12 months and extended the average life span from 3.1 months to more than 10 months."
"The pumps functioned well," Rogers said.
"At the time the abstract was written, we had nearly 30 cumulative years of support and there were two patients on the device for more than three years," he said. "No patient had catastrophic pump failure, defined as death, or the need for emergency pump replacement." Researchers said this study provides additional support for the notion that mechanical heart technologies can extend life. The findings also point out the real challenges that doctors and their heart failure patients face.
"We need to refine patient selection for these pumps and work to minimize the complications associated with mechanical heart technology," Rogers said. "Further, we need to continue to focus on new strategies for treating end-stage heart failure, which has a survival rate so low that it rivals any cancer."
WorldHeart funded the study.
Co-authors are Richard Pierson III, M.D., Ph.D.; Javed Butler, M.D.; Alan Gass, M.D.; Steven L. Lansman, M.D., Ph.D.; Peer M. Portner, Ph.D.; and Michael K. Pasque, M.D.
Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.