An overview of approved and investigational left ventricular assist devices

Randy Marcel, MD, and Dan M. Meyer, MD

According to the American Heart Association, 4,600,000 people have congestive heart failure, and 550,000 new cases of congestive heart failure are diagnosed each year (1). Pharmacological intervention is the main therapy for most of these patients, but many become refractory to medical therapy. If these patients are suitable candidates, they are placed on the waiting list for heart transplantation. Those who are not candidates for transplant or for whom an organ is not available in a timely fashion may require mechanical support for their failing hearts with a left ventricular assist device (LVAD). This device may be used as a "bridge to recovery" or, in patients where no recovery is expected, as a "bridge to transplant" (2, 3).

The first experimental bridging devices were used at the Texas Heart Institute in 1968, 1978, and 1981 (4). However, all of the patients receiving the devices died while awaiting a donor heart for transplantation. The first successful bridge to transplant occurred in 1985 at the Texas Heart Institute (5). More recently, data from the REMATCH trial (for which Baylor University Medical Center was one of 20 US sites) indicated that LVAD treatment is a plausible alternative to medical therapy for patients who are not candidates for heart transplantation (6). This group of patients is beginning to receive LVADs as "destination therapy," with no intention of transplantation or removal of the device. LVAD destination therapy has now been approved by the US Food and Drug Administration (FDA) and the Centers for Medicare and Medicaid Services (6).

The cost of LVAD implantation is considerable but less than the cost of maintaining a status I candidate for heart transplant for 42 days, the median waiting time in 2001 (1). About 90% of patients fitted with an LVAD can be discharged from the hospital, and about 75% survive to undergo transplantation (7). Many studies suggest that patients with LVADs do better at transplant than those without such devices. The contention is that patients with LVADs demonstrate physiologic improvements that lead to better survival (8).