Abstract 13704: Early Trends in Cardiac Allograft Vasculopathy After Implementation of the New 2018 Donor Heart Allocation Protocol in the United States

Abstract

Introduction: The new donor heart allocation policy implemented in October 2018 prioritizes hemodynamically unstable patients with the greatest need for urgent transplantion. The impact of this policy change on the incidence of cardiac allograft vasculopathy (CAV) has not been described. Methods: We performed a retrospective analysis of adult (≥ 18 years) heart transplant recipients registered in the UNOS database between 10/18/2015 - 11/25/2019 to evaluate the effect of the new allocation system on angiographic CAV at 1 year. Recipients undergoing first-time single organ heart transplant with 1 year follow-up were stratified based on the old (10/18/2015 - 10/17/2018) or new (10/18/2018 - 11/25/2019) allocation system. Recipient and donor demographic and cardiovascular risk factors, wait-list factors, and transplant factors with a p-value < 0.10 in univariable analysis were included in multivariable logistic regression models to identify independent predictors of accelerated CAV. Results: Of 8,724 transplant recipients (mean age 54 ± 13 years, 73% male), 6,661 (76%) and 2,063 (24%) were listed in the old and new allocation systems, respectively. The old cohort consisted of 4,409 (66%) classified as Status 1A, while the new cohort consisted of 168 (8%) classified as Status 1 and 944 (46%) as Status 2. The incidence of accelerated CAV was 520 (7.8%) in the old allocation cohort compared with 130 (6.3%) in the new allocation cohort (p=0.02). In adjusted analyses, the new allocation system was significantly associated with a reduction in CAV (OR=0.72, 95% CI: 0.59-0.89, p=0.002; Table). This association persisted even after restricting the cohort to the highest acuity patients—Status 1A (old) and Status 1 or 2 (new) (OR=0.75, 95% CI: 0.57-0.99, p=0.04). Conclusions: The new donor heart allocation system is significantly associated with lower rates of accelerated angiographic CAV at 1 year, including among recipients requiring the most urgent transplants.