Mid-Term Reassessment of Waitlist and Posttransplant Outcomes Under the 2018 Heart Allocation System: Improved All-Cause Survival

Abstract

Background: This study evaluates clinical trends and mid-term waitlist and posttransplant outcomes following the 2018 heart allocation policy change.

Methods: The United Network for Organ Sharing registry was queried to analyze adult waitlisted and transplanted patients undergoing isolated heart transplantation. Two analyses were conducted: (1) waitlist and (2) posttransplant outcomes. For the waitlist analysis, candidates were stratified into seasonally matched prepolicy (October 18, 2012-June 30, 2017) and postpolicy (October 18, 2018-June 30, 2023) groups, with a 1-year follow-up period. Waitlist outcomes included 1-year cumulative incidences of transplantation, delisting due to death/clinical deterioration, and all-cause survival from the initial waitlisting. For the posttransplant analysis, recipients were stratified into seasonally matched prepolicy (October 18, 2014-June 30, 2018) and postpolicy (October 18, 2018-June 30, 2020) groups, with a 4-year follow-up period. Posttransplant outcomes included 4-year survival. Propensity score-matching and multivariable Cox regression were used for risk adjustment.

Results: Under the 2018 allocation system, there was a continued shift toward the use of older donors, longer graft ischemic times, and shorter waitlist durations. In the waitlist analysis, 30 620 waitlisted candidates were analyzed, with 14 908 (48.7%) listed after the policy change. The postpolicy candidates had a higher 1-year cumulative incidence of transplantation (subhazard ratio, 2.06 [95% CI, 2.00-2.12]; P<0.001) and a lower 1-year cumulative incidence of delisting (subhazard ratio, 0.58 [95% CI, 0.53-0.63]; P<0.001) compared with the prepolicy candidates. In addition, the postpolicy candidates had significantly improved 1-year survival from initial waitlisting compared with the prepolicy candidates (90.0% versus 86.8%; P<0.001). In the posttransplant analysis, 13 712 recipients were analyzed, with 4597 (33.5%) transplanted following the policy change. The 4-year post-transplant survival was similar between the groups (83.3% versus 82.8%; P=0.593). Furthermore, the comparable 4-year post-transplant survival persisted in the propensity score-matched comparison and multivariable Cox regression.

Conclusions: Despite the changes in donor and recipient profiles following the 2018 allocation system change, this mid-term reassessment demonstrates its success in significantly improving waitlist survival, while maintaining comparable posttransplant survival.

Keywords: heart failure; heart transplantation; policy; survival; tissue and organ procurement.