Landscape of Heart Transplantation Following Changes in UNOS Donor Allocation Policy

Purpose The new donor heart allocation policy in United States, which prioritizes the most urgent patients on the waitlist, may affect post-transplant care and outcomes. The objective of this study was to analyze national transplantation outcomes and the use of temporary mechanical circulatory support before and after the implementation of the new allocation system. Methods A retrospective review of the UNOS registry of all heart transplants performed between April 2018 and April 2019 (n=3431) was performed. Patients were divided according to their allocation status and whether they underwent transplantation prior to the allocation change (n=2143) or after (n=1288). Results The proportion of patients listed in the urgent status of 1,2 or 3 (77%) was significantly higher than status 1A (69%), while the proportion of patients in status 4 listing (19%) was significantly lower than status 1B (27%). The use of ECMO significantly increased from 1% prior to the change in allocation to 5% after the implementation of the new allocation system, with no differences in survival (76% vs. 79%, respectively). No significant changes in the use of temporary microaxial support devices (Impella) were observed. Survival was reduced from 98% prior to the change in allocation to 77% in the new allocation schema (p=0.006). IABP utilization significantly increased in the new allocation system (8% to 23%), with no significant changes in survival. Conclusion The utilization of ECMO and IABP in United States increased under the new donor allocation system, and was associated with high proportion of patients classified as status 1,2 and 3 compared to status 1A. While the new allocation prioritizes reduction in waitlist time and mortality, we observed higher post-transplant mortality in status 1, 2, 3 and 4 patients. Thus, lower mortality on the waitlist may be annulled by higher post-transplant mortality.