Mechanical Atrioventricular Valve Replacement During and After the Single-Ventricle Palliation.

Abstract

Mechanical atrioventricular valve (AVV) replacement in single-ventricle patients carries significant risks with limited outcome data. We evaluated outcomes and identified risk factors for mortality after mechanical AVV replacement during staged Fontan palliation. We retrospectively reviewed 22 patients who underwent mechanical AVV replacement from 1997 to 2022 after completing at least stage I palliation. Patients were stratified by early postoperative ventricular function (normal vs impaired) and timing of AVV replacement (primary vs post-AVV repair). The primary outcome was transplant-free survival. Median age at valve replacement was 1.7 years (interquartile range, 0.5-8.0 years). Hypoplastic left heart syndrome was the most common diagnosis (n = 10), and the Norwood procedure was the most frequent stage I palliation (n = 13). AVV replacement was performed before or at Fontan completion in 14 patients and after in 8 patients. A previous AVV repair was performed in 11 patients. Intraoperatively, 8 patients converted to AVV replacement after attempted AVV repair. There were 4 in-hospital deaths (18.2%). Transplant-free survival at 1 year was 55.6%. Postoperative reduced ventricular function (hazard ratio, 4.890; P = .018) and longer cardiopulmonary bypass time (hazard ratio, 1.013; P = .033) were risk factors for death. Patients with preserved ventricular function showed significantly better survival than those with impaired function (mild, moderate, or severe) (100% vs 25.7% at 1 year, P < .001). Approximately 1 in 10 single-ventricle patients undergoing AVV surgery required mechanical AVV replacement. Outcomes depend on the preserved ventricular function and the results of valve repair before AVV replacement.