Increasing Donor-Recipient Weight Mismatch is Associated with Shorter Waitlist Duration and No Increased Morbidity or Mortality

Abstract

<h3>Purpose</h3> Infants awaiting pediatric heart transplantation (PHT) experience long waitlist duration and high mortality due to donor shortage. Using UNOS database, we explored if increasing donor-recipient weight ratio (DRWR) >2.0 (recommended cutoff) was associated with adverse outcomes. <h3>Methods</h3> Between 2007-20, 1392 infants received PHT. We divided cohort to 3 groups: A (DRWR ≤1.0,n=239,17%), B (DRWR 1.0-2.0,n=947,68%), C (DRWR >2.0,n=206,15%). Group characteristics and PHT outcomes were analyzed. <h3>Results</h3> DRWR ranged between 0.5-4.1. Underlying pathology (congenital vs. cardiomyopathy), gender, race, renal function, and mechanical circulatory support were comparable between groups. Group C patients were more likely to be ventilated, to receive ABO incompatible heart, and to have longer donor ischemic time. Waitlist duration was significantly shorter for Group C (33 vs. 50 days,p<0.1). Early outcomes for groups A,B,C were the following (respectively): operative death (6%,4%,3%,p=0.29), primary graft dysfunction (5%,3%,3%,p=0.30), renal failure (10%,7%,7%,p=0.42), stroke (3%,4%,1%,p=0.36). DRWR group was not associated with mortality in either congenital (OR=0.819,95%CI=0.523-1.282) or cardiomyopathy (OR=1.221,95%CI=0.780-1.912) patients and only pre-PHT ECMO was associated with mortality (OR=4.400,95%CI=2.761-7.010). Additionally, survival at 1 year (87%,87%,85%,p=0.80) and 5 years (76%,78%,77%,p=0.80) was comparable between the DRWR groups. <h3>Conclusion</h3> Infants who received PHT with DRWR >2.0 (up to 4.1) experienced shorter waitlist duration with no demonstrable increase in peritransplant complications, operative or late mortality. Historic practice to avoid DRWR>2.0 due to complications (e.g. hypertension-related stroke, graft dysfunction, death) is not currently supported in infants and stretching DRWR acceptance criteria would decrease PHT waitlist duration and potentially improve waitlist complications and mortality.