ECMO as a Bridge to Left Ventricular Assist Device or Heart Transplantation

Objectives: The purpose of this study was to compare outcomes between patients on extracorporeal membrane oxygenation (ECMO) bridged to left ventricular assist device (LVAD) versus heart transplantation (HT) using registry data. Background: Patients with heart failure supported with ECMO represent the highest priority in the new HT allocation system. For patients on ECMO, bridging to LVAD may be non-inferior compared with bridging to HT. Methods: Adult patients in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) from 2006 to 2017 and United Network for Organ Sharing (UNOS) database from 2006 to June 2019 requiring ECMO were included. Cause-specific hazard models were created and cumulative incidence functions were calculated with mortality, transplantation, and re-transplantation as competing events. Results: A total of 906 patients received ECMO as bridge to VAD (n = 587, 64.8%) or as bridge to HT (n = 319, 35.2%). Patients bridged directly to HT were younger (age 46.3 ± 15.4 years vs. 52.1 ± 13.2 years; p < 0.001) and more likely to be female (93 [29.2%] vs. 139 [23.7%]; p = 0.022). Patients bridged directly to HT were more likely to have a nonischemic cardiomyopathy, restrictive physiologies, and allograft failure; (p < 0.05 for all). ECMO use increased over time in both UNOS and INTERMACS. There was no significant difference in mortality between groups (Gray's p = 0.581). This remained true even when the analysis was restricted to transplant-listed or eligible patients as well as patients with dilated phenotypes (excluding patients with congenital heart disease, restrictive phenotypes, and allograft failure). Conclusions: There was no difference in mortality on pump support compared with posttransplant mortality among those bridged from ECMO to LVAD or HT.