Rising Exception Requests in the Current Heart Allocation System

Despite the goal of the 2018 revision to the heart allocation policy to reduce reliance on exception requests through improved granularity in status criteria, there has been a dramatic rise in exception requests.

This study evaluated trends in exception use over the first 6 years of the updated policy, assessing associated clinical factors, temporal changes, and impact on waitlist outcomes.

This retrospective transplant registry analysis included all adult isolated heart transplant candidates from October 18, 2018, to September 30, 2024. Candidates were stratified by exception use, listing era, and region. Exception use was compared using Wilcoxon rank-sum and chi-squared tests, with multilevel logistic regression assessing independent associations. Trends over time and across UNOS (United Network for Organ Sharing) regions were evaluated, and a competing risks framework examined time to transplant and waitlist mortality.

Among 26,330 candidates, 38.6% used exception requests, with a statistically significant increase over time, particularly in higher priority statuses. Exception use was more common among Black, non-Hispanic candidates, and candidates with blood type O, and less likely for patients with blood type A (P < 0.001). Additionally, pretransplant isolated durable left ventricular assist devices were less common in candidates who requested exceptions (19.0% vs 31.6%; P < 0.001). Overall, 39.9% of exception candidates were listed at status 1 or 2 compared to 29% of nonexception candidates, and 69.2% of exception candidates were removed from the waitlist at status 1 or 2 compared with 37% of nonexception candidates.

The rising use of exceptions underscores ongoing limitations in allocation criteria, and disparities suggesting inequities in access to higher listing status. Policy refinements are needed to ensure a balance between medical urgency and equitable allocation.