Impact of heart transplant allocation change on competing waitlist outcomes among listing strategies.

Abstract

In 2018, the United Network for Organ Sharing (UNOS) adopted a 6-tier system for heart allocation which shifted patterns in listing strategies. The effects of the change on waitlist survival and transplantation rates have yet to be substantiated by analysis of competing outcomes among various listing strategies. This study included all adult patients listed for first-time heart transplantation in UNOS between 10/17/15 and 6/12/20. Clinical characteristics were compared before and after allocation change among various listing strategies: no support, inotropes, intra-aortic balloon pump, durable left ventricular assist device (LVAD), temporary VAD, and extracorporeal membrane oxygenation. Fine-Gray proportional subhazard models were used to estimate the effect of allocation change on competing waitlist outcomes-transplantation, death, or removal from waitlist-among each strategy. During the study period, there were 17422 patients listed for heart transplantation. Among each listing strategy, clinical characteristics were similar before and after allocation change. Subhazard models demonstrated reduced risk for waitlist mortality (p<.001) among each strategy except temporary VAD and increased transplantation rates (p<.001) among each strategy except for durable LVAD. These results validate the association of the new allocation system on waitlist outcomes across listing strategies.