Abstract 12426: Influence of Body Mass Index in Donor Recipient Size Mismatch in Pediatric Heart Transplantation

Abstract

Introduction: Body weight has been the traditional metric for matching donor and recipient size for pediatric heart transplantation (pHT). However, the impact of such mismatch is not well established. We hypothesized that mismatch in compound measures such as body mass index (BMI) or body surface area (BSA) rather than weight, may impact outcomes of pHT and therefore should be used for donor-recipient size matching. Methods: Analysis of the United Network for Organ Sharing database limited to pHT recipients was performed. Donor and recipient mismatch tertiles were created for weight, BMI, and BSA ratios. Differences in recipient characteristics between each tertile were studied using univariate analysis. Multivariable analysis was used to assess the impact of each mismatch on one-year survival. Kaplan Meier analysis was used to assess overall survival. Results: A total of 4,465 pHT patients were available and included in the analysis of which 43% had congenital heart disease (CHD). Overall, those with low donor-recipient ratio for BMI were more likely to be younger recipients, less likely to be Caucasian and be on ECMO (all p<0.01). In both CHD and non-CHD cohorts, multivariable regression analysis showed that use of ECMO (CHD OR 3.97; non-CHD OR 3.24), presence of liver dysfunction (CHD OR 1.10; non-CHD OR 1.11), and low donor to recipient BMI ratio (compared to normal) (CHD OR 1.70; non-CHD OR 2.28) were the only predictors of one-year mortality (all p <0.001). Low BMI ratio was also associated with worse long-term survival in non-CHD groups, but not in the CHD cohort. This finding probably reflects inferior overall outcomes in the CHD cohort. Weight and BSA ratio did not predict one year or long-term survival. Conclusions: Traditional matching practice using weight may be inadequate and use of BMI matching may provide improved donor-recipient matching. Use of low BMI donors compared to recipients may predict poor early and long-term survival and therefore should be avoided in pediatric heart transplantation. Further refinement of matching may be needed in specific recipient populations.