Risk Stratification for Patients Bridged to Heart Transplantation on Venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO) Support.

Abstract

The 2018 heart allocation policy led to increased use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as a bridge to heart transplantation (HT). Despite known poorer outcomes with ECMO bridging, no established risk stratification tool exists to guide candidate selection. This study analyzed risk factors for 1-year mortality following VA-ECMO bridged to HT to provide a risk stratification guide for decision-making. The UNOS registry was used to identify all adults bridged to HT with VA-ECMO from January 2000 to June 2024. Recipient and donor characteristics were analyzed. Univariable and multivariable cox regression analyses were performed to identify recipient and donor variables associated with increased 1-year post-HT mortality. Kaplan-Meier analysis was used to compare survival stratified by the number of risk factors. Among 1,235 VA-ECMO-bridged HT patients, unadjusted survival at 30-days, 90-days, 1-year, and 5-years was 93.09%, 89.28%, 84.29%, 72.71%, respectively. Risk factors for increased 1-year mortality included age >61 years (p=0.024), creatinine ≥ 1.4 (p<0.001), ventilator-dependence prior to HT (p<0.001), total bilirubin >3.4 (p<0.001), ischemic cardiomyopathy (p=0.006), and patients undergoing re-transplantation (p<0.001). Donor variables associated with increased risk of 1-year mortality were female-to-male donor-recipient sex mismatch (p=0.003) and ischemic times >3.9 hours (0.035). One-year survival in patients with 0, 1, 2, and ≥ 3 risk factors were 95.36%, 91.12%, 86.10%, and 60.95%, respectively. Patients bridged to transplant with VA-ECMO face elevated post-transplant mortality. Identifying key risk factors enables more informed patient selection. Patients with ≥2 risk factors had <87% 1-year survival, warranting cautious consideration for transplant.