CHICAGO – A third-generation, investigational left ventricular assist device performed at least as well as current devices on the market, and also showed signs of important benefits like reduced infections and bleeding during 6 months of follow-up as a bridge to heart transplant in 140 patients in a pivotal, multicenter study.
Dr. Keith D. Aaronson
Based on results from the ADVANCE (Evaluation of the HeartWare Ventricular Assist System for the Treatment of Advanced Heart Failure) study, HeartWare – the company developing the new device – said that it would seek marketing approval from the Food and Drug Administration for the HeartWare ventricular assist device (VAD) as a bridge to transplant before the year’s end. A small, continuous-flow pump, the HeartWare VAD is implanted in the pericardium with no need for a pocket. Experts who heard the new data cautioned that although the results so far look fine, the long-term durability and performance of the new VAD need assessment compared with the current standard, the HeartMate II.
"Implantation of the HeartWare VAD pump in the pericardial space was associated with a very high probability of success at 180 days," said Dr. Keith D. Aaronson at the annual scientific sessions of the American Heart Association. The 92% of patients who received the HeartWare VAD and were either alive with their device or had received a heart transplant during the 180 days after device placement was "the highest rate ever reported in any left VAD [LVAD] study," said Dr. Aaronson, medical director of the heart failure program at the University of Michigan in Ann Arbor.
"The survival and the success of the HeartWare VAD are excellent outcomes," Dr. Aaronson said. The question of which VAD works better – the HeartWare model or the HeartMate II – "comes down to the adverse event profile for the two devices. The only way to know for sure [which device is better] is to compare them head to head." A trial now underway compares the two VADs as destination therapy for patients who are unable to get a heart transplant, he noted.
Dr. Mariell L. Jessup
"The HeartMate II has been a good workhorse. People know how to use it and are comfortable with it. When the HeartWare device comes out, people will want to use it, and surgeons seem to like the idea of implanting the device directly in the heart. But [questions like] which is the best kind of VAD, where do you put it, and what’s the best way to anticoagulate patients [are] not clear. The HeartMate VAD advances one piece of the puzzle, but the upcoming trials that will compare the VADs head to head will give us a lot more answers," commented Dr. Mariell L. Jessup, professor of medicine and medical director of the heart and vascular center at the University of Pennsylvania in Philadelphia.
"This is the first successful completion of a bridge-to-transplant trial with a control" group of patients, noted Dr. Lynne Warner Stevenson, professor of medicine and director of the cardiomyopathy and heart failure program at Brigham and Women’s Hospital in Boston. "We all know that the bridge results are not the same as the destination results."
The HeartWare VAD arm of the study ran at 30 U.S. sites during August 2008–February 2010. The researchers screened 157 patients to find 140 who met the enrollment criteria, including having New York Heart Association class IV heart failure and being listed for a heart transplant. Surgeons ultimately placed the HeartWare VAD in 137 patients. The control arm included 499 U.S. patients who received a commercially available LVAD during the same period and were registered in the INTERMACS (Interagency Registry for Mechanical Assisted Circulatory Support) system. By the first half of 2009, 94% of these INTERMACS control patients received a HeartMate II as their LVAD, and throughout the 18 months of the study Dr. Aaronson estimated that all but 3%-4% of the control patients received a HeartMate II. The average age of the VAD recipients was 53 years, and about a quarter were women.
After 180 days, 63% of the HeartWare VAD recipients remained alive with their device in place, and 29% had received a heart transplant, 4% had their device switched for another VAD, and 4% had died. The overall 92% success rate in this group was comparable with a 90% overall success rate among the control patients in the INTERMACS registry. The similar rates in the two arms met the prespecified criteria for noninferiority of the new device. But the HeartWare VAD did not show statistically significant superiority to the control devices, either in an unadjusted analysis or after adjustment in a propensity analysis, Dr. Aaronson said.