Higher Utilization of ECMO as a Bridge to OHT Has Not Led to Regional Variations

Abstract

<h3>Purpose</h3> Utilizing extracorporeal membrane oxygenation (ECMO) as a bridge to orthotopic heart transplantation (OHT) has become more common following the 2018 UNOS allocation policy change; however, potential regional disparities have not been studied. We sought to characterize regional differences in ECMO utilization, including support duration and outcomes. <h3>Methods</h3> The UNOS database was queried for adult patients who were bridged to OHT using veno-arterial ECMO between 1/1/2011 and 11/30/2020. The designated UNOS regions were consolidated into four standard categories: east, west, south and midwest. <h3>Results</h3> Among all OHT recipients, patients were more likely to be on ECMO at time of transplant following the UNOS allocation policy change regardless of region (p<0.001). In total, 316 ECMO-bridge to OHT patients were included: 96 (30.4%) from the east, 96 (30.4%) the south, 75 (23.7%) the midwest, and 49 (15.5%) the west. There were no significant differences in age (p=0.136), BMI (p=0.165), or immediate pre-transplant hemodynamics across regions. Those transplanted in the south (1.1 [0.8-1.7]) and midwest (1.0 [0.6-1.5]) had higher pre-transplant creatinine than those in the east (0.9 [0.7-1.4]) and west (0.9 [0.6-1.1]) (p=0.002). IABP use at the time of transplant was less common in the west (3, 6.1%) than in the south (17, 17.7%), east (22, 22.9%), and midwest (24, 32%) (p=0.005). ECMO support duration prior to OHT did not vary significantly across regions (south 5.0 [3-8], midwest 5.0 [3-9], east 6.0 [3.5-9.5], west 6.0 [3-11] days, p=0.196), nor did gender mismatch, donor-recipient weight ratio, or ischemic time (all p=ns). Survival was comparable across regions (p=0.719), both before (p=0.503) and after (p=0.820) the UNOS allocation policy change. <h3>Conclusion</h3> Across regions of the United States, ECMO-bridged OHT recipients exhibited no differences in patient characteristics or post-transplant outcomes, supporting the notion that the policy change has not resulted in significant regional variations in care.