UNOS listing status-related changes in mechanical circulatory support utilization and outcomes in adult congenital heart disease patients

Background: The aim of this study was to investigate the impact of the new United Network for Organ Sharing (UNOS) listing criteria on mechanical circulatory support (MCS) utilization and outcomes in adult congenital heart disease (ACHD) patients. Methods: We identified all ACHD and non-ACHD heart transplant candidates in the Scientific Registry of Transplant Recipients database listed during the 590 days prior to (historical cohort) or following (recent cohort) the UNOS allocation revision on October 18, 2018. Patients were grouped based on whether they received central temporary MCS (tMCS), peripheral tMCS, durable MCS, or no MCS. Results: A total of 535 ACHD (242 historical, 293 recent) and 12,188 non-ACHD (6,258 historical, 5,930 recent) patients were included in our study. For ACHD patients, we found no differences in the historical versus recent cohort in utilization of central tMCS (3.31% vs 3.07%, p = .88) or durable MCS (3.31% vs 3.41%, p = .95), whereas the rate of peripheral tMCS increased (2.07% historical vs 6.83% recent, p = .009). Across both cohorts, ACHD patients supported with peripheral tMCS had shorter time-to-transplant than non-supported patients (25.7 vs 121.7 days, p = .002). ACHD patients supported with central tMCS had greater rates of post-transplant mortality relative to other ACHD patients (40.0% vs 12.6%, p = .006), while those supported with durable or peripheral temporary MCS had no differences in waitlist or post-transplant mortality compared to non-supported ACHD patients. Conclusions: The 2018 UNOS allocation changes increased utilization of peripheral temporary MCS in ACHD patients, decreasing waitlist time without impact on post-transplant outcomes.