Re-Exploration for Postoperative Bleeding in Heart Transplantation: Outcomes and Predictors From the Korean Organ Transplantation Registry

BACKGROUND AND OBJECTIVES: Postoperative bleeding requiring surgical re-exploration is a serious complication after cardiac surgery, yet its clinical impact in heart transplantation remains incompletely characterized. We assessed its clinical impact, predictors, and time-dependent risk profile. METHODS: We retrospectively analyzed 813 adult recipients in the Korean Organ Transplantation Registry (2014 to 2021). The primary outcome was all-cause mortality and the secondary outcome was infection-related mortality. Between-group effects were estimated using multivariable Cox proportional hazards and Fine-Gray subdistribution hazard models. Time dependence was examined with smoothing splines and a prespecified 3-month landmark analysis. Predictors of re-exploration were identified with multivariable logistic regression; discrimination was assessed by receiver operating characteristic analysis and the area under the curve (AUC), and the final model was presented as a nomogram. RESULTS: Sixty-two patients (7.6%) underwent re-exploration. Early mortality at 30 days, 90 days, and 1 year was higher in the re-exploration group. Re-exploration was associated with increased all-cause mortality (adjusted hazard ratio [HR], 2.11; 95% confidence interval [CI], 1.28-3.48) and infection-related mortality (adjusted subdistribution HR, 2.33; 95% CI, 1.06-5.14). The excess mortality risk was confined to the first 3 months, as shown by time-varying hazard and 3-month landmark analyses; thereafter the hazards were comparable. Cardiopulmonary bypass (CPB) time and preoperative renal replacement therapy independently predicted re-exploration. The prediction model showed acceptable discrimination (AUC=0.77) and was implemented as a nomogram. CONCLUSIONS: Re-exploration for postoperative bleeding markedly increases early mortality after heart transplantation. CPB time and renal replacement therapy may aid perioperative risk stratification and targeted prevention.