Risk stratification and transplant benefit in children listed for heart transplant in the United States

Abstract

Background-The sickest children among those listed for heart transplant (HT) are also at higher risk of post-transplant mortality. We hypothesized that transplant benefit, defined as percentage reduction in risk of 1-year mortality on receiving HT, increases with higher risk of wait-list mortality. Methods and Results-We analyzed all children aged <18 years listed for first HT in the United States between July 2004 and December 2010. We developed a model for 90-day wait-list mortality (or removal because of deterioration) and stratified listed children into deciles based on their risk of wait-list mortality. Listed children were followed up for 1 year to assess cumulative 1-year wait-list mortality among the 10 risk groups. We developed a model for 1-year post-transplant mortality to estimate the risk of post-transplant mortality for children in each risk group. Of 2979 listed children, 15% reached the wait-list end point within 90 days and 18% within 1 year. Of 2034 HT recipients, 6.8% died within 90 days and 10.8% within 1 year. The risk of 90-day wait-list mortality increased progressively from 2.4% to 51.6% from the first to the tenth risk decile. Transplant benefit increased progressively across the wait-list risk groups (P<0.001 for trend). However, transplant benefit for children in the top 5% of risk (7.4%) was lower than that for children in the 91st to 95th percentile of risk (10.3%). Conclusions-Sicker children on the wait-list benefit more from HT unless the post-transplant mortality is predicted to be very high. Whether consideration of transplant benefit in allocation policy can improve overall survival among listed children requires further analysis. © 2013 American Heart Association, Inc.