Impact of the New UNOS Heart Transplant Allocation System on Waitlist and Early Post-Transplant Mortality among Adults with Congenital Heart Disease

Purpose Adults with congenital heart disease (ACHD) are more likely to die or be delisted while awaiting heart transplant, less likely to receive a heart transplant and more likely to die in the early (30-day) post-transplant period compared to non-ACHD patients. On October 18, 2018; the UNOS heart allocation system was redesigned providing unique listing status for ACHD patients. The impact of this change on outcomes is unstudied. Methods Using the Scientific Registry of Transplant Recipients we compared ACHD patients listed for the first-time for heart transplant from 2 eras of equal duration (new era: October 18, 2018 to June 2, 2020 and prior era: March 3, 2017 to October 17, 2020). Patients with transplants occurring in the new era who were initially listed in the prior era were excluded. We compared baseline characteristics, Kaplan Meier curves and log-rank tests to assess differences in early post-transplant mortality and the composite of waitlist mortality or delisting due to clinical worsening among those with CHD between both eras. Results Out of 535 ACHD patients listed, 293 were in the new era (4.7% of total listings) and 242 were in the prior era (3.7%). Age, sex, racial distribution, renal function, hemodynamics and need for ECMO were identical between the two groups. 163 (56%) ACHD patients in the new era versus 150 (62%) in the prior era were transplanted; 11 (3.8%) versus 15 (6.2%) died on the waitlist; 32 (11%) versus 35 (14%) were delisted and 15 (9.2%) versus 19 (12.7%) died within 30 days of transplant respectively. In the new era, ACHD patients were significantly less likely to experience waitlist mortality or delisting due to clinical worsening but had similar early post-transplant mortality compared to the prior era. Conclusion The new UNOS heart transplant allocation system improved waitlist outcomes among ACHD patients listed for heart transplant.