SNOWMASS, COLO. — The Food and Drug Administration's recent approval of Thoratec Corp.'s HeartMate II left ventricular assist device as destination therapy—that is, as an alternative to heart transplantation—is a landmark development heralding a long-awaited era of lifetime mechanical circulatory support in patients with terminal heart failure, experts said at a conference sponsored by the American College of Cardiology.
“This represents a significant step forward and now becomes a realistic option in the treatment of patients with advanced heart failure,” said Dr. Clyde W. Yancy, the president of the American Heart Association, at the conference.
“When I went to the Cleveland Clinic in 1978, we believed that we were just about ready to have an effective mechanical cardiac replacement. And, honestly, one of the most disappointing parts of my career is that for a long time we really didn't make much progress in that area. Basically, the devices just weren't good enough. The pumps fell apart. There was a high incidence of stroke, bleeding, and infection. It made for very poor quality of life,” observed Dr. Bruce Lytle, professor and chairman of the department of cardiothoracic surgery at the Cleveland Clinic Foundation.
The HeartMate II has not solved all those problems, but it does represent a great improvement over earlier-generation devices. “Mechanical replacement really does now appear to be on the cusp of being able to offer real benefit to at least some patients with severe heart failure,” Dr. Lytle said.
Dr. Yancy explained that the technologic break-through that has finally brought destination therapy to the fore is the development of small, reliable, totally implantable left ventricular assist devices (LVADs) featuring continuous-flow rotary pumps.
The HeartMate II is the prototype. It earned FDA approval as destination therapy on the strength of a 200-patient, multicenter, randomized trial in which it was compared with its predecessor, the HeartMate XVE, which uses a pulsatile-flow pump.
The primary study end point—survival at 2 years free of disabling stroke or reoperation to replace or repair the pump—was achieved in 46% of HeartMate II recipients and 11% of those who got the pulsatile-flow device. Two-year actuarial survival was 58% in the HeartMate II group, compared with 24% on the pulsatile-flow device (N. Engl. J. Med. 2009;361:2241-51. Two-year survival in medically managed patients with similarly advanced heart failure is typically less than 10%, noted Dr. Yancy, medical director of the Baylor Heart and Vascular Institute and chief of cardiothoracic transplantation at Baylor University Medical Center, Dallas.
Dr. Michael B. Fowler cautioned that outcomes with the HeartMate II are not nearly as good as with heart transplantation, which has a 1-year survival of roughly 85% and a 10-year survival of 50%. But heart transplantation is available to only 2,000 patients per year because of the very limited donor organ supply.
It is clear from observational registry data that LVADs need to be implanted relatively early in the course of end-stage heart failure to achieve the best long-term survival. In one large registry, older age, shock, and right-heart failure as reflected in ascites or increased bilirubin at device implantation were significant predictors of shortened survival (J. Heart Lung Transplant. 2009;28:44-50), said Dr. Fowler, professor of medicine and director of the heart failure program at Stanford (Calif.) University. He noted that the HeartMate II has not solved the problem of device-associated thromboembolism: The rate of disabling stroke in the randomized trial was 11% in the HeartMate II arm and 12% with the pulsatile-flow LVAD.
Disclosures: Dr. Yancy and Dr. Lytle indicated they have no relevant financial interests. Dr. Fowler disclosed that he serves as a consultant to Medtronic, AstraZeneca, GlaxoSmithKline, Merck, and Scios.
The HeartMate II is 'a realistic option in the treatment of patients with advanced heart failure.'
Source DR. LYTLE
'Outcomes with the HeartMate II are not nearly as good as with heart transplantation.'
Source DR. FOWLER