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A sea change in management of severe heart failure began two and a half years ago, in January 2010, when the Food and Drug Administration approved U.S. marketing of the HeartMate II continuous-flow, left ventricular assist device for destination therapy. Patients, cardiologists, and cardiothoracic surgeons at last had a reasonably durable, effective, and relatively safe alternative to heart transplant to offer patients at the end stage of deteriorating heart function.
The Heart Mate II quickly supplanted the prior-generation, pulsatile-flow devices, and 2010 also saw a 10-fold spike in the number of left ventricular assist devices (LVADs) placed in U.S. patients as destination therapy.
During the first half of 2011, 6-month survival among U.S. patients with a continuous-flow LVAD (which means the HeartMate II, the only continuous-flow device on the U.S. market) was 89%, and 12-month survival during 2010 was 81% (J. Heart Lung Transplant 2012;31:117-26, putting the continuous-flow LVAD in at least the same ballpark as heart transplant, which has a 5-year survival of about 80% and a median survival of about 10 years in U.S. patients.
Photo courtesy Thoratec Corporation
The HeartMate II LVAD changed the field for severe heart failure, but a unit with no drive line would be the Holy Grail.
But despite estimates that many thousands, if not tens of thousands, of Americans meet the clinical criteria to qualify for placement of an LVAD, the reality is that in the 30 months since the HeartMate II became available for routine destination therapy through mid-2012, only about 4,600 were placed in U.S. patients. In addition, just slightly more than a third of those patients, roughly 1,700, received their LVAD explicitly for destination therapy.
Even in 2012, a majority of patients who received an LVAD got their device with the understanding that it was as a bridge to transplant, an LVAD placed with temporary intent to help patients survive and improve clinically until their LVAD could be swapped out and replaced by a transplanted heart.
LVAD Numbers Up, but Still Low
If the availability of the HeartMate II for destination therapy in routine practice was a revolution for the management of many patients with New York Heart Association class IV heart failure – which is how many experts in this field view the device – it has so far been a revolution played out in slow motion. In large part that’s because the field started small, and stayed small until recently. At the end of 2008, fewer than 1,000 patients had ever received a ventricular assist device or a total artificial heart. Even though the number nearly doubled in 2009, by decade’s end the cumulative total still remained under 2,000.
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Despite the low numbers compared with the estimated need, many physicians and surgeons who specialize in advanced heart failure say they are satisfied with the pace at which continuous-flow LVADs have entered patients over the past 2 years. Though they acknowledge that the number of potential U.S. candidates for an LVAD undoubtedly is far larger than the nearly 4,600 who received one since early 2010, they note that the implantation rate grew in a steady and robust way during the past 30 months, as has the number of centers performing the surgery. With a better-than-50% year-over-year growth spurt in both 2010 and 2011, and with that pace continuing into the first months of 2012, the 140 U.S. centers that now place LVADs are on track to do nearly 3,000 this year (although only 42% were for destination therapy during January-March 2012).
"You probably don’t want it to increase too rapidly, because it is still high risk and expensive," said Dr. David E. Lanfear, a cardiologist specializing in advanced heart failure and transplantation at Henry Ford Hospital in Detroit. LVAD placements "have not reached the maximum number of patients who they could help, but you need to be cautious because it requires specialized expertise to do it properly. I wouldn’t expect that [during 2 years] it would immediately reach maximum use. It’s still in the growth phase. There are a lot of patients out there, so it will continue to grow; I’m not concerned that it’s not growing fast enough," he said in an interview.
An LVAD or a Heart Transplant?
Experts also note an important shift in attitude about the role for LVADs, a change that has brought them to the brink of replacing transplanted hearts as the default treatment for patients with end-stage heart failure.
Dr. Mark Slaughter
"The current outcomes with HeartMate II have already changed the field. We published a paper last year that showed there was no difference between LVADs and transplant in costs and outcomes at 1 year (Ann. Thorac. Surg. 2011;91:1330-4)," said Dr. Mark S. Slaughter, professor of surgery and chief of thoracic and cardiovascular surgery at the University of Louisville (Ky.). Between that and the competitive mortality benefit from LVADs "we need to rethink the role of transplant. In appropriately selected patients, we can achieve outstanding long-term results with limited adverse events."