Survival on the Heart Transplant Waiting List: Impact of Continuous Flow Left Ventricular Assist Device as Bridge to Transplant

Abstract

Continued donor organ shortage and improved outcomes with current left ventricular assist device (LVAD) technology have increased the number of patients supported with bridge-to-transplantation (BTT) therapy. Using the United Network of Organ Sharing (UNOS) database, we assessed the impact on survival in patients supported with BTT while on the heart transplant waiting list. The UNOS database was queried from January 2005 to June 2012 to identify patients listed for heart transplantation as UNOS status 1A or 1B. Patients implanted with a pulsatile-flow device or an LVAD other than the HeartMate II (HM II; Thoratec Inc, Pleasanton, CA) were excluded. Patients were divided into LVAD and non-LVAD groups based on status at the time of listing. Patients were propensity matched (LVAD -non-LVAD = 1:2) for age, sex, weight, presence of diabetes, creatinine levels, mean pulmonary artery pressure, and UNOS status. Kaplan-Meier curves were analyzed for survival. A total of 8,688 patients were analyzed, with 1,504 (17%) in the LVAD group. Average age (52.6 ± 11.8 versus 51.3 ± 12.9 years; p = 0.0002) and weight (86.6 ± 18.6 versus 80.8 ± 18.2 kg; p < 0.0001) at time of listing were higher in the LVAD group. There were more men (79% versus 74%; p < 0.0001) and more patients with diabetes (30% versus 27%; p = 0.03) in the LVAD group. Of all patients, 6,943 patients (80%) underwent transplantation, 862 (10%) died, and 883 (10%) remained on the waiting list. After propensity matching, survival to transplantation was significantly better in the LVAD group than in the non-LVAD group at both 1 year (91% versus 77%) and 2 years (85% versus 68%). Patients supported with an HM II LVAD as BTT therapy were older with increased comorbidities; they demonstrated an improved survival while listed for heart transplantation. The use of LVADs as a BTT strategy can potentially improve patient survival while waiting for transplantation and allow better allocation of donor hearts.