Abstract 12472: Impact of Left Ventricular Unloading on Outcome of Heart Transplant Bridging With Extracorporeal Membrane Oxygenation Support

Abstract

Introduction: The new heart allocation policy prioritizes veno-arterial extracorporeal membrane oxygenation (ECMO) supported candidates at the highest status. Evidence suggests that left ventricular (LV) unloading during ECMO is beneficial by reducing the LV end-diastolic pressure and increasing support. The impact of LV unloading on outcomes following bridging to heart transplant (HT) with ECMO is uncertain. Methods: Under the new policy (Oct 18, 2018 to Jun 30, 2022), 596 patients on ECMO at the time of HT were identified in United Network for Organ Sharing database and divided into two groups: ECMO alone (N=387) vs. ECMO with LV unloading (N=209). Sub-analysis was performed in LV unloading group: Impella (N=73) vs. intra-aortic balloon pump (IABP) (N=136). Results: The median duration on the waitlist was 5 days for both groups. The ECMO alone group had younger recipients (ECMO alone, 48 vs. LV unloading, 53 years, P=0.018) and younger donors (ECMO alone, 29 vs. LV unloading, 32 years, P=0.041). Other characteristics were similar. In LV unloading group, recipient characteristics were comparable between Impella and IABP patients. Kaplan-Meier survival analysis showed comparable 1-year survival rates between the groups (ECMO alone, 88.1±1.8% vs. LV unloading, 89.8±2.3%, P=0.96, Figure 1A). Multivariable Cox hazard model revealed no association between LV unloading and post-HT mortality (hazard ratio, 0.95, 95% confidence interval, 0.59, 1.54, P=0.80). In the different LV unloading methods, 1-year survival was similar: Impella, 90.6±3.7% vs. IABP, 88.9±2.9%, P=0.65, (Figure 1B). There was a trend toward a higher stroke rate with Impella (12%) compared to IABP (5.2%) (P=0.061). Conclusions: LV unloading did not impact survival in patients bridging to HT with ECMO under the new allocation policy, regardless of the specific mode of LV unloading. Individualized approaches are crucial for patients on ECMO undergoing HT, as LV unloading might not always be necessary.