Recipient and Donor Characteristics - Impact on Outcome after Heart Transplantation

Abstract: Heart transplantation (HTx) is severely limited by a shortage of donors. This thesis aimed to investigate the effect of variables used to match donors to recipients in HTx. Methods: Data from the ISHLT registry was used to study: I: Identical versus compatible non-identical ABOmatching in 3,589 AB HTx recipients. II: Outcomes of 94 ABO-incompatible transplants were compared to an ABO-compatible group. III: Evaluation of the effect of sex and body size-matching with special reference to obese recipients. IV: Investigation of the association between donor and recipient age on early and late post-transplant mortality. Results: Study I: There was no difference in survival between identically and non-identically ABO matched transplants. Study II: The incidence of death or retransplantation was higher for ABO-incompatible recipients. After 2005, the rate ABO-incompatible HTx in adults increased, likely due to planned ABO-incompatibility. For these recipients, outcomes were similar to ABO-compatible recipients. Study III: Recipient-donor weight difference >30% predicted mortality in non-obese but not obese recipients. Sex mismatched transplants had impaired survival. There was no modification of the association between size matching and mortality risk by sex matching. Study IV: Recipient and donor age was associated with both early and late mortality. However, donor age influenced predominantly early mortality, while recipient age influenced predominantly long-term mortality. ABO-identical blood group matching has no survival benefit for AB recipients. ABO-incompatible heart tranplantation may be feasible in carefully selected adult patients. Current weight matching guidelines can likely be expanded for obese heart transplant recipients. Sex mismatch is a disadvantageous factor in heart transplantation, not only in the context of size mismatch. Donor age appears to have a larger impact on early mortality, likely due to a higher incidence of primary graft dysfunction. Recipient age appears to have a larger impact on late mortality likely due to effects of immunosenescence.