Background: Recent data suggest that ABO blood group-incompatible donor hearts are immunologically well tolerated in infants undergoing transplantation.
Methods: Competing-risks methodology was used to assess outcomes after listing and the impact of a strategy to accept heart grafts from any blood group donor for infants less than 18 months of age.
Results: From 1992 to 2002, there were 91 listing episodes in 84 patients (including 20 fetuses; 50% were male and 63% had congenital heart disease). Beginning in 1995, a strategy to accept ABO-incompatible organs was adopted. Competing-risks analysis showed that after 20 months 60% underwent transplantation, 18% died, and less than 1% were still listed; the remaining 21% were de-listed because of a change of surgical strategy (9%), improved clinical condition (8%), and deterioration to ineligibility (4%). Risk factors for transplantation included only a strategy to accept ABO-incompatible organs (P <.001). Risk factors for death included failure to accept ABO-incompatible organs (P =.002) and Canadian listing status 3 (P =.085) or 4 (P <.001). Multivariable parametric models were used to create competing risk predictions for outcomes specific to status and ABO-incompatible strategy. Higher status resulted in greater mortality regardless of strategy, although for any status, more patients underwent transplantation and fewer died using a strategy to accept ABO-incompatible organs. Parametric modeling of time-related freedom from death or retransplantation demonstrated no significant difference at 4 years posttransplantation (P =.78) for ABO-incompatible (74%) versus ABO-compatible transplants (72%).
Conclusions: A strategy to accept ABO-incompatible donor hearts for infant transplantation significantly improves the likelihood of transplantation and reduces waiting list mortality while not adversely altering outcomes after transplantation.