Continuous Flow LVAD Shows Better Survival Rates Than Pulsatile LVAD

Treatment with a continuous-flow left ventricular assist device (LVAD) in patients with advanced heart failure significantly improved the probability of survival free from stroke and device failure at two years, compared with a pulsatile device, claims a new study.

Researchers at Duke University Medical Center (Durham, NC, USA), Johns Hopkins Hospital (Baltimore, MD, USA), and other institutions conducted a randomized trial that enrolled 200 patients at 38 U.S. medical centers between March 2005 and May 2007. All patients suffered from advanced heart failure, all had failed optimal medical therapy, and all were ineligible for transplantation. The patients were randomized in a 2:1 ratio to undergo implantation of a continuous-flow device (134 patients) or the currently approved pulsatile-flow device (66 patients). The primary endpoint was survival free from disabling stroke and device failure requiring reoperation at two years. Secondary endpoints included overall survival, adverse events, quality of life, and functional capacity.

The results showed that the primary composite endpoint was achieved in more patients with continuous-flow devices (46%) than with pulsatile-flow devices (11%), and that patients with continuous-flow devices had superior actuarial survival rates at two years (58% compared to 24%). Adverse events and device replacements were less frequent in patients with the continuous-flow device. In addition, only 10% of the patients who received the continuous flow LVAD needed surgery to repair or replace the pump, compared to 36% of patients with the pulsatile device. The quality of life and functional capacity improved significantly in both groups. The study was published ahead of print on November 17, 2009, in the New England Journal of Medicine (NEJM).

"The results of this trial will alter the manner in which we provide mechanical circulatory support. In the past, mechanical pumps delivered blood in a pulsatile manner; in other words, they beat like a human heart,” said study coauthor Joseph Rogers, M.D., medical director of the Duke heart failure program. "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.”

For the study, the researchers compared the HeartMate II continuous flow LVAD to the HeartMate XVE pulsatile flow LVAD, both manufactured by Thoratec (Pleasanton, CA, USA).

Related Links:
Duke University Medical Center
Johns Hopkins Hospital
Thoratec