Impact of the 2018 UNOS Heart Allocation Policy Change on Post-Transplant Outcomes: Intermediate Term Analysis

Abstract

<h3>Purpose</h3> The 2018 UNOS heart allocation policy intended to prioritize recipients of highest acuity in addition to broader geographic sharing. As such, 6 tiers were developed from 3 to try and account for this heterogeneous population. We sought to assess the impact of this change on post-transplant outcomes in the highest urgency statuses (Status 1-3 vs prior Status 1A). <h3>Methods</h3> 7710 patients were identified in the UNOS registry that were either prior status 1A (n=3764) or status 1-3 in the current system (n=3946) during a 2-year period immediately prior and following the policy change. Comparisons between cohorts were assessed using standard statistical methods, survival analysis was censored at 1-year using the Kaplan-Meier method, and multivariate Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time & HLA mismatch) were performed. <h3>Results</h3> Waitlist times were significantly shorter following the policy change for the status 1-3 group (21.0 vs 54.5 days, p<0.001). With the current policy, recipients were less likely to be female (24.1% vs 29.1%, p<0.001). Additionally, recipients were more likely to have longer ischemic times (p<0.001), to be supported with intraaortic ballon pumps (IABP) (p<0.001) as well as elevated pulmonary arterial pressures (p<0.001). Notably, recipients were less likely to be supported with an LVAD (35.8% vs 42.7%, p<0.001). There was no difference in survival (p=0.144). Unadjusted analysis demonstrated HR 1.13 (CI 0.96-1.32) and following adjustment HR 1.03 (CI 0.87-1.23). <h3>Conclusion</h3> The new UNOS heart allocation policy change did not adversely affect post-transplant outcomes in this intermediate term analysis. In the highest acuity statuses, waitlist time decreased. However, further study is warranted to better understand implications and perhaps unintended consequences for gender as well as change in therapeutic strategies (increased IABPs, less VADs).