ABO-identical blood group matching has no survival benefit for AB heart transplant recipients

Although identical blood group matching is preferred, it is uncertain if this results in improved survival and, if so, how large the survival benefits are. Earlier studies have yielded conflicting results and are mostly based on single-center cohorts with few long-term results. Recipients with blood group AB are of particular interest regarding nonidentical blood group matching because they may receive organs from all blood groups. We wanted to test the hypothesis that ABO-identical matching results in superior survival in recipients with blood group AB.

We used data from the International Society for Heart and Lung Transplantation registry to match a cohort of heart donors with transplant recipients with blood group AB. Cox regression analysis was used to assess the influence of blood group on outcome after heart transplantation. All-cause cumulative mortality during the study period was the primary end point.

The study material consisted of 3,589 adult patients with blood group AB who had received heart transplants, representing 18,085 patient-years. No significant difference in survival after identical, as opposed to compatible, ABO matching was found for recipients with blood group AB. In subgroup analysis, we found improved survival for younger recipients (< 55 years) with blood group AB who underwent transplantation with organs from donor blood group O rather than AB (p = 0.02).

We found no survival benefit for recipients with blood group AB transplanted with ABO-identical organs. In the subgroup of recipients younger than 55 years of age, our study suggests improved survival for recipients with blood group AB transplanted with an organ from a donor with blood group O.