Abstract 15779: A Comparison of Survival Outcomes in Ischemic Cardiomyopathy Following Heart Transplantation Under 2018 Allocation Criteria

Introduction/Background: The adult heart transplant allocation system was changed from a 3-tiered to a 6-tiered system in 2018, prioritizing unstable patients on temporary mechanical circulatory support and patients with non-ischemic cardiomyopathies on the waitlist.

Research Questions/Hypothesis: This study aims to compare post-heart transplantation survival rates and all-cause mortality of ischemic and non-ischemic cardiomyopathies in the United States before and after the implementation of the current 6-tiered heart allocation system.

Methods/Approach: The United Network for Organ Sharing registry was queried from 2011 to 2021 for all adults listed for isolated heart transplantation for the first time. The Kaplan-Meier method and Cox proportional hazards regression modeling were used to compare the post-transplantation outcomes between ischemic and non-ischemic cardiomyopathies.

Results: A total of 21,104 cases were included in the final analysis. The 1, 5, and 10-year survival rates of ischemic versus non-ischemic cardiomyopathies were 89.7% vs. 92.1%, 76.5% vs. 81.5%, and 48.5% vs. 62.4%, respectively (p<0.001). The risk of all-cause mortality was greater in patients with ischemic cardiomyopathy (Hazard Ratio: 1.368, 95% CI, 1.285 - 1.457, p<0.001). Post heart transplant survival rate has decreased by approximately 2% since 2018 compared to the era of the prior allocation system (p<0.001).

Conclusions: The gap between the survival rate of ischemic and nonischemic cardiomyopathies has not improved since 2011. The one-year survival rate has dropped by ~2% since 2018, partly due to the new heart allocation system prioritizing clinically unstable patients.