ECMO as a bridge to heart transplantation: Insights into stratification by heart failure etiology.

Background: Revisions to the heart allocation criteria in 2018 motivated an increased use of extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation. Studies have demonstrated inferior post-transplant outcomes in patients bridged with ECMO but do not account for underlying diagnosis. Our objective was to elucidate the differential impact of ECMO on outcomes by heart failure (HF) etiology. Methods: The United Network of Organ Sharing database was queried for adults who underwent isolated heart transplantation after October 2018. Patients were stratified by ECMO utilization at the time of transplantation and then by HF etiology. After baseline statistical comparisons, survival analysis relied on Kaplan-Meier estimates and Cox proportional models. Results: A total of 13,203 patients were included, of whom 761 (5.8%) were supported with ECMO. ECMO patients were younger (48 vs 54 years, Conclusions: Our findings illustrate that HF etiology is associated with differing outcomes when bridging with ECMO. ECMO patients with restrictive cardiomyopathy or CHD did not have increased mortality risk. With ECMO utilization increasing, these data are hypothesis-generating and serve as a basis for further studies.