Taking a Closer Look at Distance: Does Increasing the Maximal Donor Distance Range Shorten Waitlist Times in Pediatric Heart Transplant Candidates?

Abstract

Data suggest that pediatric heart transplant (HT) centers can reduce waitlist time by expanding donor catchment via expanded parameters including the maximal donor weight range. Contrary to donor weight ranges, little is known about the effect of increasing the donor distance (DD) range. We sought to determine whether increasing the DD range can reduce waitlist time and how well actual DD predicts ischemic time (IT). All US children <18 years listed for HT at centers with ≥20 HT since 2007 were identified using OPTN data. Center variation in maximal DD range, defined as the median value of a center's maximal DD range, was analyzed and compared to actual DD. Pearson correlation was used to examine the correlation between actual DD and IT. Cox proportional hazards analysis was used to determine whether maximal DD range is associated with waitlist time. Among 4,240 children who met study criteria, the median age was 2 (IQR 0, 11) years, weight 12 (6, 35) kg, 53% had CHD. Centers varied considerably in their maximal DD range (1000-10,000 miles); median 1500 miles (Figure A). Overall, 86% of donors originated from ≤500 miles; 97% ≤1,000 miles (Figures A & B) with sharp drop-offs at 500 and 1000 miles (Figure B). After adjusting for patient factors, maximal DD range was associated with a shorter waitlist time. The correlation between actual DD and IT is fair (R=0.69) but explains only half (R2=0.49) of the variability in IT. Pediatric HT centers vary considerably in their maximal donor distance ranges, though most donors still fall within 500-1000 miles of recipients. Increasing the maximal DD range is associated with a shorter waitlist time. Actual DD explains only half of the variability in IT. Further research is needed to understand the optimal regional sharing distance for organ allocation and whether contemporary navigational software could better predict IT than the linear distance to the donor hospital.