Bridge to Heart Transplant With Temporary Mechanical Circulatory Support: Trends and Outcomes in the 2018 Allocation Policy Era

The United Network for Organ Sharing (UNOS) 2018 heart allocation policy prioritizes patients receiving temporary mechanical circulatory support (tMCS) given the high waitlist mortality rate of this group. This study evaluates national trends and waitlist outcomes for patients receiving tMCS under the UNOS 2018 allocation policy. Adult patients waitlisted for isolated heart transplantation were included using the UNOS database. The prevalence of tMCS, 90 day waitlist mortality, 90 day incidence of transplantation, and posttransplant 1 year mortality were analyzed. A total of 27,343 patients were waitlisted during the study period (pre-policy change: 13,004 vs. post-policy change: 14,339). The prevalence of tMCS increased from 7.4% (n: 956) to 22.4% (n: 3,186) after the policy change (p < 0.001). The use of Impella increased proportionally among tMCS modalities. Patients on tMCS had lower adjusted odds of waitlist mortality (p < 0.001), higher adjusted incidence of transplantation (p < 0.001), and similar posttransplant mortality (p = 0.10) under the 2018 policy. Patients on extracorporeal membrane oxygenation (ECMO) support had the highest odds of 90 day waitlist mortality (p < 0.05) but also the highest incidence of transplantation in the post-policy change cohort (p < 0.05). In conclusion, the use of tMCS as bridge to heart transplantation increased threefolds and is associated with lower waitlist mortality and higher incidence of transplantation following the UNOS 2018 allocation policy change.