Comparison of Waitlist and Post-Transplant All-Cause Mortality in Patients with Hypertrophic Cardiomyopathy before and after the UNOS Allocation System Change

Abstract

PurposePatients with advanced hypertrophic cardiomyopathy (HCM) have high waitlist (WL) mortality. The United Network of Organ Sharing (UNOS) heart allocation system from 10/18/2018 provides greater emphasis and clarity for status exceptions for HCM patients. We analyzed the effect of allocation policy change on the WL and post-transplant outcomes in HCM patients.MethodsUNOS data from 06/1990 to 06/2020 was analyzed, HCM patients were divide into two cohorts: pre and post allocation change. WL status, selected baseline characteristics, waiting time, and WL mortality were summarized. Kaplan-Meier survival curves for all-cause mortality up to one year would also be examined.ResultsA total of 1,941 HCM patients were identified. Pre and post allocation change cohorts included 1,703 and 238 cases respectively. While the majority of pre-change patients were Status 2, most post-change patients were Adult Status 4 (Table 1). Post-change cohort had older recipient age, older donor age, longer ischemia time, and shorter waiting time but there were no significant differences in gender or IABP use (Table 2). The WL mortality was lower in the post-change group (33.6% vs 7.6%, p<0.0001). Additionally, there was no difference of Kaplan-Meier survival for all-cause mortality up to 1 year between the two groups (p=0.2671).ConclusionFor HCM patients awaiting heart transplant, the new UNOS allocation system decreased the WL mortality and waiting time. There was no significant difference in post-transplant survival in HCM patients with the new allocation system. Patients with advanced hypertrophic cardiomyopathy (HCM) have high waitlist (WL) mortality. The United Network of Organ Sharing (UNOS) heart allocation system from 10/18/2018 provides greater emphasis and clarity for status exceptions for HCM patients. We analyzed the effect of allocation policy change on the WL and post-transplant outcomes in HCM patients. UNOS data from 06/1990 to 06/2020 was analyzed, HCM patients were divide into two cohorts: pre and post allocation change. WL status, selected baseline characteristics, waiting time, and WL mortality were summarized. Kaplan-Meier survival curves for all-cause mortality up to one year would also be examined. A total of 1,941 HCM patients were identified. Pre and post allocation change cohorts included 1,703 and 238 cases respectively. While the majority of pre-change patients were Status 2, most post-change patients were Adult Status 4 (Table 1). Post-change cohort had older recipient age, older donor age, longer ischemia time, and shorter waiting time but there were no significant differences in gender or IABP use (Table 2). The WL mortality was lower in the post-change group (33.6% vs 7.6%, p<0.0001). Additionally, there was no difference of Kaplan-Meier survival for all-cause mortality up to 1 year between the two groups (p=0.2671). For HCM patients awaiting heart transplant, the new UNOS allocation system decreased the WL mortality and waiting time. There was no significant difference in post-transplant survival in HCM patients with the new allocation system.