Heart Transplant Waitlist Outcomes by Center Volume in the Post-2018 Allocation Change Era
H. L. T.. Elwell1, A. Sparks2, F. Y.. Chen2, G. S.. Couper2, M. Kawabori3 1Tufts University School of Medicine, Boston, Massachusetts 2Tufts Medical Center, Boston, Massachusetts 3Tufts Medical Center, Brookline, Massachusetts
MD/PhD Candidate Tufts University School of Medicine Boston, Massachusetts, United States
Disclosure(s):
Hannah L. T. Elwell, BS: No financial relationships to disclose
Purpose: In 2018, the United Network for Organ Sharing (UNOS) implemented a new allocation system to improve heart transplant (HTx) waitlist outcomes. Under the old system, higher volume centers had better survival to HTx and survival after HTx. The present study explored waitlist outcomes by center volume under the new system. Methods: The UNOS registry was used to perform retrospective analyses of adults (>18 years old) listed for the first time for primary HTx from January 1, 2019 to January 1, 2022. Dual organ transplant candidates were excluded. Transplant centers were assessed as low ( < 10 HTx/year), medium (10-30 HTx/year), and high (>30 HTx/year) volume as has been established by previous stratification schemes, and waitlist outcomes stratified by the 3 groups were compared. Chi-squared tests and Kruskal-Wallis tests were performed on preoperative recipient candidate demographics and waitlist outcome variables as appropriate. Post-HTx 180-day survival was evaluated by log-rank Kaplan-Meier survival analysis. Results: Of the 11,300 candidates included in our study, 7,786 (68.9%) underwent HTx, 1,116 (9.9%) were delisted due to death or deterioration prior to receiving HTx, and 417 (3.7%) were removed from the waitlist due to recovery prior to HTx. Center volume status was found to be correlated with waitlist outcome. High volume centers had higher rates of survival to HTx (74.3% vs 54.1% for low volume centers and 66.7% for medium volume centers; p < 0.001) and lower rates of removal due to death or deterioration (8.9% vs. 13.1% for low volume centers and 10.2% for medium volume centers; p < 0.001) (Table 1). Although prior reports showed an advantage in post-HTx survival by high volume centers in the pre-change era, our study found no significant difference in post-HTx 180-day survival likelihood across Htx center volumes under the new allocation system (93.6% for high volume centers vs. 91.6% for low volume centers and 92.3% for medium volume centers; p = 0.146) (Figure 1). Conclusion: Under the new allocation system, higher volume centers have superior waitlist outcomes. However, HTx center volume is no longer associated with post-HTx 180-day survival. Further research should examine the factors underlying waitlist outcome differences to target approaches toward further improving outcomes in lower-volume centers.
Identify the source of the funding for this research project: N/A