The New UNOS Heart Allocation Changes Significantly Changed the Landscape of Heart Transplantation.

PURPOSE: October 2018 saw a change in the UNOS heart allocation which prioritized the sickest patients especially those of temporary devices. The main driver of the change was to reduce wait list mortality. We aim to examine whether the new allocation benefits come at a cost of reduced post-transplant survival.

METHODS: A retrospective UNOS database review of all heart transplants performed between April 2018 and April 2019 (n=3431). These patients divided according to their allocation status and whether they were done prior (n=2143) or after the allocation change (n=1288). Proportion of patients in each status and the rate of temporary device use were assessed. 6-month survival in each status was also analyzed.

RESULTS: The proportion of patient listed in the urgent status of 1, 2 or 3 was 77% which is a significant increase compared to the 69% for status 1A patients. We observed a significant reduction in Status 4 listing compared to status 1B 19% vs. 27%. ECMO use significantly increased from 1% in the old system to 5% in the new system with no differences in survival 76% vs. 79%. No significant changes in Impella utilization were observed however survival was reduced from 98% in the old system to 77% in the new p=0.006. IABP utilization significantly increased in the new allocation system from 8% to 23% utilization with no significant changes in survival.

CONCLUSION: Under the new allocation we have seen a significant rise in the ECMO and IABP utilization resulting in an increase in the proportion of status 1, 2 and 3 compared to status 1A group but was associated with a significant reduction in the status 4 patients (former status 1B). While this new allocation prioritizes a reduction in wait times and mortality, we have observed that this is associated with higher transplant mortality in status 1, 2, 3 and 4 patients. Finally, more time and data is required to determine if the new allocation results in reduced wait list mortality at the cost of lower post-transplant survival.