Do Expanded Donor Criteria Impact Outcomes in Pediatric Heart Transplantation? A UNOS Registry Analysis

Abstract

Donor utilization rates continue to be low for pediatric heart transplantation (pHT) however efforts to expand the donor acceptance criteria have shown mixed results in single institution studies in pediatric and adult transplantation. We analyzed pHT UNOS data (2008-2018) to compare the recipient characteristics, donor characteristics and outcomes, based on donor ejection fraction of less than 50% (low EF) and or ischemic time of greater than 4 hours (prolonged IT). A total of 4345 pHT were performed of which 1309 (30.1%) were with prolonged IT and 122 (2.8%) in low EF. Additionally, 58 (1.3%) were performed with both low EF and prolonged IT (combined risk). Recipients of combined risk were more likely to be younger, have post-surgical congenital heart disease, be on ECMO or ventilator but less likely on VAD (all p < 0.01). Figure 1. There was no significant difference in donor characteristics such as mode of death, gender mismatch, race mismatch or inotrope use. Waitlist time was significantly lower for low EF (mean 39 days, range 15-109) or combined risk group (36 days, 15-80) compared to other groups (60 days, 23-125) (p=0.01). 1 year mortality was 8% in low risk group, 12% in prolonged IT, 14% in reduced EF and 28% in combined risk patients (p < 0.01). Additionally, 9% of low risk patients had episode of treated rejection, while 15% of prolonged IT, 5% of low EF and 15% in combined group had rejection (p<0.01).The KM survival analysis performed is shown in the figure 1. Lower EF donors performed similar to prolonged IT donor, but were uncommonly used. Acceptance of risk was common in recipients deemed higher risk for waitlist mortality and led to shorter wait times. However, episodes of treated rejection as well as 1 year mortality was higher with the higher risk transplants, specifically with combined risk donors. Caution should be used in accepting combined risk transplants and further analysis will help balance the waitlist mortality with post-transplant outcomes.