Successful Atrioventricular Valve Repair Modifies Clinical Outcomes in Single-Ventricle Patients: Multistate Model Analysis

BACKGROUND To evaluate the impact of atrioventricular valve regurgitation (AVVR) onset and atrioventricular valve repair (AVVrep) on survival in single ventricle (SV) patients using the multistate model and to analyze how successful AVVrep alters clinical course. METHODS We retrospectively reviewed all SV patients who underwent surgical palliations from 1998 to 2022, classified based on timing of AVVR onset, AVVrep, and bidirectional cavopulmonary shunt (BCPS). AVVrep was defined as successful if patients remained free from AVVR, death, or heart transplant (HTx) for at least one year post-repair. Clinical trajectories were analyzed using a multistate model incorporating time-dependent variables. Transplant-free survival was estimated using Kaplan-Meier and competing risk analyses. RESULTS Among 716 SV patients, 195 developed AVVR and 155 underwent AVVrep. Of these, 69 had a successful repair. Successful AVVrep significantly reduced risk of death/HTx (HR 0.1695%CI 0.07,0.40, p<0.001), achieving survival comparable to patients without AVVR(p=0.94). In patients with AVVR onset before BCPS, reduction in the risk of death/HTx could be achievable if those requiring AVVrep before BCPS reached BCPS(HR 0.180.05,0.65, p=0.009) and when AVVrep was performed at or after BCPS(HR0.240.11,0.53, p<0.001). Ventricular dysfunction, whether primary or secondary to AVVR, was strongly associated with inferior survival. CONCLUSIONS Successful AVVrep potentially reduces risk of death/HTx by 84% in SV patients with AVVR onset, particularly when performed at or after BCPS, resulting in comparable survival to those with no AVVR. Early AVVrep before BCPS confers high risk unless AVVrep is successful. Timing and success of AVVrep are critical determinants of long-term survival.