A new, continuous flow heart pump, or left ventricular assist device (LVAD), delivered better two-year survival in advanced heart failure patients than the current pulsatile model, researchers reported in a late-breaking clinical trial presentation at the American Heart Association's Scientific Sessions 2009.
In the HeartMate II Destination Therapy Trial, researchers tested a new device that helped heart failure patients who weren't responding to optimal medical therapy and weren't eligible for a heart transplant. They found significant improvement in outcomes of patients who received the continuous flow LVAD (HeartMate II) compared to those who received a pulsatile flow LVAD (HeartMate XVE), the only FDA-approved device for treating such patients.
"The results of this trial will alter the manner in which we provide mechanical circulatory support," said Joseph G. Rogers, M.D., co-author of the study and medical director of the Duke Heart Failure Program at Duke University Medical Center in Durham, N.C. "In the past, mechanical pumps delivered blood in a pulsatile manner; in other words, they beat like a human heart.
"The newer pump is smaller, operates quietly and has demonstrated superior durability. Interestingly, it also pumps blood continuously, which reduces the systolic blood pressure. We believe that in the future there will be little need for pulsatile blood pumps."
The study included 200 end-stage heart failure patients implanted at 38 U.S. medical centers between March 2005 and May 2007. All patients had failed optimal medical therapy and were ineligible for a heart transplant.
The primary endpoint was survival free from disabling stroke and device failure requiring re-operation at two years. Secondary endpoints included overall survival, adverse events, quality of life and functional capacity
A greater proportion of continuous flow LVAD patients successfully reached the primary composite end-point compared to pulsatile flow (46 percent vs. 11 percent) -- a highly significant finding, researchers said.
At one-year follow-up, 68 percent of the continuous flow LVAD patients had survived compared to 55 percent in the pulsatile flow group. At two years, survival was 58 percent for the continuous flow device vs. 24 percent with the pulsatile device.