Exception Status Listing in the New Adult Heart Allocation System: A New Solution to an Old Problem?

Background: One of the goals of the revised 6-tiered US adult heart allocation policy was to improve risk stratification of patients to lower exception status utilization for transplant listing. We sought to define the characteristics and outcomes of waitlisted patients using exception status and to examine region- and center-level differences in utilization of exception status in the new heart allocation system.

Methods: This retrospective cohort analysis of the United Network for Organ Sharing database included adult waitlisted patients for heart transplant between October 18, 2018, and June 30, 2020, in the United States, stratified by use of exception status versus standard criteria.

Results: Out of 6351 patients, 1907 (30.0%) were waitlisted under exception status. Patients using exception status were more likely to have a nonischemic cause of heart failure, blood type O, United Network for Organ Sharing status 2 at listing and were less likely to have a durable left ventricular assist device at listing. Exception status utilization varied significantly between and within United Network for Organ Sharing regions. Listing by exception criteria was associated with a significantly higher incidence of heart transplantation compared with listing by standard criteria (hazard ratio, 1.25 [1.15-1.38], <0.001), without increased risk of death or delisting for worsening clinical status (hazard ratio, 0.83 [0.65-1.05], =0.12) after multivariable adjustment.

Conclusions: The status tiers of the new heart allocation system may not fully capture medical urgency and complexity of waitlisted patients as assessed by transplant physicians and review committees and may limit the ability to develop a heart allocation score.