Outcomes in Hypertrophic Cardiomyopathy before and after the UNOS Allocation System Change

Abstract

Purpose The UNOS allocation policy change in October 2018 was intended to prioritize and reduce waitlist (WL) mortality for the sickest patients, including patients with hypertrophic cardiomyopathy (HCM). A previous study demonstrated a trend towards increased mortality with decreased rates of heart transplantation (HT) in HCM patients after the policy change. This follow-up study seeks to delineate these outcomes with a larger cohort of patients. Methods 247 patients were identified in the UNOS registry with a diagnosis of HCM prior to undergoing HT in the 1 year periods immediately before (n = 127) and after (n = 120) the UNOS allocation policy change. Exclusion criteria included patients less than 18 years ago, lost to follow-up, or underwent multi-organ transplantation. Patient characteristics and demographics of the pre-policy vs. post-policy cohorts were compared using standard statistical methods. Comparison of survival was analyzed using multivariate Cox proportional hazards modeling. Results Baseline characteristics including age, gender and demographics as well as hemodynamic parameters were similar before and after the policy change. The percentage of patients on the waiting list (40.2% vs. 39.2%, p=0.99) and rates of heart transplantation/recovery (57% vs. 60%, p=0.26) 6 months after transplant listing for the pre-policy and post-policy cohorts were similar. There was a trend towards lower rate of death/deterioration 6 months after transplant listing in the post-policy cohort (3.2% vs. 0.8%, p=0.2). Conclusion Waiting list outcomes for HCM patients were similar before and following the policy change despite increased urgency in the revised system. There was a trend towards a lower rate of death/deterioration after listing post-policy change; however this was not statistically significant. Further study is warranted to understand the long-term implications of this policy change.