The modified US heart allocation system improves transplant rates and decreases status upgrade utilization for patients with hypertrophic cardiomyopathy.

Background: On October 18, 2018, the US heart allocation policy was restructured to improve transplant waitlist outcomes. Previously, hypertrophic cardiomyopathy (HCM) patients experienced significant waitlist mortality and functional decline, often requiring status exemptions to be transplanted. This study aims to examine changes in waitlist mortality and transplant rates of HCM patients in the new system.

Methods: Retrospective analysis was performed of the United Network for Organ Sharing Transplant Database for all isolated adult single-organ first-time heart transplant patients with HCM listed between October 17, 2013 and September 4, 2020. Patients were divided by listing date into eras based on allocation system. Era 1 spanned October 17, 2013 to October 17th, 2018 and Era 2 spanned October 18th, 2018 to September 4, 2020.

Results: During the study period, 436 and 212 HCM patients were listed in Eras 1 and 2, respectively. Across eras, no differences in gender, ethnicity, BMI or functional status were noted (p>0.05). LVAD utilization remained low (Era 1: 3.7% vs Era 2: 3.3%, p = 0.297). Status upgrades decreased from 49.1% to 31.6% across eras (p = 0.001). There was no statistically significant difference in waitlist mortality across eras (p = 0.332). Transplant rates were improved in Era 2 (p = 0.005). Waitlist time among transplanted patients decreased in Era 2 from 97.1 to 63.9 days (p<0.001). There was no difference in one-year survival post-transplant (p = 0.602).

Conclusions: The new allocation system has significantly increased transplant rates, shortened waitlist times, and decreased status upgrade utilization for HCM patients. Moreover, waitlist mortality remained unchanged in the new system.