Improved mortality and rehabilitation of transplant candidates treated with a long-term implantable left ventricular assist system

Abstract

Objective: This nonrandomized study using concurrent controls was performed to determine whether the HeartMate implantable pneumatic (IP) left ventricular assist system (LVAS) could provide sufficient hemodynamic support to allow rehabilitation of severely debilitated transplant candidates and to evaluate whether such support reduced mortality before and after transplantation.

Methods: Outcomes of 75 LVAS patients were compared with outcomes of 33 control patients (not treated with an LVAS) at 17 centers in the United States. All patients were transplant candidates who met the following hemodynamic criteria: pulmonary capillary wedge pressure > or = 20 mm Hg with a systolic blood pressure < or = 80 mm Hg or a cardiac index < or = 2.0 L/minute/m2. In addition, none of the patients met predetermined exclusion criteria.

Results: More LVAS patients than control patients survived to transplantation: 53 (71%) versus 12 (36%) (p = 0.001); and more LVAS patients were alive at 1 year: 48 (91%) versus 8 (67%) (p = 0.0001). The time to transplantation was longer in the group supported with the LVAS (average, 76 days; range, < 1-344 days) than in the control group (average, 12 days; range, 1-72 days). In the LVAS group, the average pump index (2.77 L/minute/m2) throughout support was 50% greater than the corresponding cardiac index (1.86 L/minute/m2) at implantation (p = 0.0001). In addition, 58% of LVAS patients with renal dysfunction survived, compared with 16% of the control patients (p < 0.001).

Conclusions: The LVAS provided adequate hemodynamic support and was effective in rehabilitating patients based on improved renal, hepatic, and physical capacity assessments over time. In the LVAS group, pretransplant mortality decreased by 55%, and the probability of surviving 1 year after transplant was significantly greater than in the control group (90% vs. 67%, p = 0.03). Thus, the HeartMate IP LVAS proved safe and effective as a bridge to transplant and decreased the risk of death for patients waiting for transplantation.