High-Urgency Heart Transplantation and Outcome Trade-offs: Early Post-Transplant Infection and Mortality

AIMS: To evaluate differences in post-transplant outcomes by pre-transplant urgency status, focusing on early post-transplant infection and its contribution to mortality. METHODS: We retrospectively analyzed 801 adult heart transplant recipients enrolled in the Korea Organ Transplant Registry (April 2014-December 2021). Recipients were classified as Status 0 (highest urgency; n=287) and Status 1-3 (n=514). Outcomes included all-cause mortality, post-transplant infection, acute allograft rejection, and cardiac allograft vasculopathy up to 5 years. Mediation, landmark, and multivariable time-dependent Cox models assessed the impact and determinants of infection. RESULTS: During 5-year follow-up, 128 recipients (16.0%) died. Status 0 recipients had higher mortality than Status 1-3 recipients (28.0% vs. 13.5%; P <0.001). Infection was the leading cause of death and was more frequent in Status 0 recipients at 1 and 6 months, whereas rejection and cardiac allograft vasculopathy rates were similar between groups. Infection at 1, 6, and 12 months was strongly associated with mortality and mediated the association between urgency status and mortality, accounting for 47.4%, 34.9%, and 34.2% of total effect, respectively. After adjustment for pre- and post-transplant organ support, urgency status was no longer independently associated with infection risk, whereas prolonged mechanical ventilation (>24 hours) remained the strongest predictor. CONCLUSION: Status 0 heart transplant recipients had higher mortality and early post-transplant infection risk than Status 1-3 recipients. Early infection, largely associated with greater clinical severity and prolonged mechanical ventilation, may explain the excess mortality in this high-urgency group.