Extracorporeal membrane oxygenation bridge to heart transplant: Trends following the allocation change

Background: This study compared outcomes of patients bridged with extracorporeal membrane oxygenation (ECMO) to orthotopic heart transplantation (OHT) following the recent heart allocation policy change.

Methods: The United Network of Organ Sharing Registry (UNOS) database was queried to examine OHT patients between 2010 and 2020 that were bridged with ECMO. Waitlist outcomes and 1-year posttransplant survival were compared between patients waitlisted and/or transplanted before and after the heart allocation policy change. Secondary outcomes included posttransplant stroke, renal failure, and 1-year rejection.

Results: A total of 285 waitlisted patients were included, 173 (60.7%) waitlisted under the old policy and 112 (39.3%) under the new policy. New policy patients were more likely to receive OHT (82.2% vs. 40.6%), and less likely to be removed from the waitlist due to death or clinical deterioration (15.0% vs. 41.3%; both p < .001). A total of 165 patients bridged from ECMO to OHT were analyzed, 72 (43.6%) transplanted during the old policy and 93 (56.3%) under the new. Median waitlist time was reduced under the new policy (4 days [interquartile range {IQR}: 2-6] vs. 47 days [IQR: 10-228]). Postoperative renal failure was higher in the new policy group (23% vs. 6%; p = .002), but rates of stroke and 1-year acute rejection were equivalent. One-year survival was lower the new policy but was not significant (79.8% vs. 90.3%; p = .3917).

Conclusions: The UNOS heart allocation policy change has resulted in decreased waitlist times and higher likelihood of transplant in patients supported with ECMO. Posttransplant 1-year survival has remained comparable although absolute rates are lower.