ABO-Incompatible Heart Transplantation Remains Underutilized Despite Comparable Outcomes in Pediatric Heart Transplantation

<b>Background:</b> ABO-Incompatible (ABO-I) heart transplantation (HT) is a promising strategy to extend the hope of HT to many infants and children facing donor organ shortages and waitlist mortality. Despite increasing experience with ABO-I HT and comparable outcomes, universal adoption of this strategy has yet to be achieved. We aimed to provide a contemporary analysis of ABO-I HT with emphasis on the impact of the 2016 United Network for Organ Sharing policy change. <b>Methods:</b> This is a retrospective study of the Organ Procurement and Transplantation Network database examining patients listed for HT at ≤2 years of age in two eras: July 7, 2008, to July 7, 2016, and July 8, 2016, to July 8, 2024, to account for allocation policy changes. The primary outcome was posttransplant survival. Additional outcomes included waitlist mortality, center volume-survival relationship, and incidence of postoperative complications. <b>Results:</b> A total of 2,770 children underwent HT; 493 (18%) were ABO-I recipients. Frequency of ABO-I HT increased across the study period; there was no difference in waitlist mortality for ABO-I eligible candidates across eras (hazard ratio [HR] 0.70, confidence interval [CI 0.48-1.02, <i>P</i> = .07). No differences were observed in one- or five-year survival between ABO-I and ABO-compatible (ABO-C) cohorts. There was no difference in survival among ABO-I recipients between high-volume centers (HVCs) and non-HVCs (HR 0.87, CI 0.43-1.76, <i>P</i> = .70). <b>Conclusions:</b> ABO-Incompatible transplantation offers comparable posttransplant outcomes with ABO-C transplantation, regardless of center volume. The 2016 United Network for Organ Sharing policy has not impacted waitlist mortality for this population. These data provide support for universal adoption of ABO-I HT in appropriately selected patients as the standard of care for infants and children awaiting HT.