Impact of Left Ventricular Unloading on Outcome of Heart Transplant Bridging With Extracorporeal Membrane Oxygenation Support in New Allocation Policy.

Background: The new heart allocation policy places veno-arterial extracorporeal membrane oxygenation (VA-ECMO)-supported heart transplant (HT) candidates at the highest priority status. Despite increasing evidence supporting left ventricular (LV) unloading during VA-ECMO, the effect of LV unloading on transplant outcomes following bridging to HT with VA-ECMO remains unknown.

Methods And Results: From October 18, 2018 to March 21, 2023, 624 patients on VA-ECMO at the time of HT were identified in the United Network for Organ Sharing database and were divided into 2 groups: VA-ECMO alone (N=384) versus VA-ECMO with LV unloading (N=240). Subanalysis was performed in the LV unloading group: Impella (N=106) versus intra-aortic balloon pump (N=134). Recipient age was younger in the VA-ECMO alone group (48 versus 53 years, =0.018), as was donor age (VA-ECMO alone, 29 years versus LV unloading, 32 years, =0.041). One-year survival was comparable between groups (VA-ECMO alone, 88.0±1.8% versus LV unloading, 90.4±2.1%; =0.92). Multivariable Cox hazard model showed LV unloading was not associated with posttransplant mortality after HT (hazard ratio, 0.92; =0.70). Different LV unloading methods had similar 1-year survival (intra-aortic balloon pump, 89.2±3.0% versus Impella, 92.4±2.8%; =0.65). Posttransplant survival was comparable between different Impella versions (Impella 2.5, versus Impella CP, versus Impella 5.0, versus Impella 5.5).

Conclusions: Under the current allocation policy, LV unloading did not impact waitlist outcome and posttransplant survival in patients bridged to HT with VA-ECMO, nor did mode of LV unloading. This highlights the importance of a tailored approach in HT candidates on VA-ECMO, where routine LV unloading may not be universally necessary.