Serial changes of systemic ventricular function and atrioventricular valve function in patients with failing Fontan

OBJECTIVES: This study investigated the longitudinal changes in ventricular function and atrioventricular valve function to clarify the timing and the mechanisms of failing Fontan. METHODS: Patients who underwent total cavopulmonary connection between 1994 and 2023 were reviewed, and longitudinal echocardiographic examinations of ventricular function and atrioventricular valve regurgitation were analysed. RESULTS: A total of 650 patients were included. The most frequent primary diagnosis was hypoplastic left heart syndrome in 175 patients. Dominant right ventricle was observed in 337 patients (51.8%). The median age at total cavopulmonary connection was 2.3 (1.8-3.3) years. Failing Fontan was observed in 78 patients (12%) during the median follow-up of 6.2 years. Among them, dominant right ventricle was observed in 51 patients (65.4%). Patients with protein-losing enteropathy or plastic bronchitis (n = 37) developed Fontan failure early (median 2.6 years post-total cavopulmonary connection). Still, patients maintained ventricular function (93.1% normal at 5 years) and atrioventricular valve competence (no case of moderate/severe regurgitation at 5 years) over time. Patients who developed failing Fontan associated with progression of heart failure (n = 41) had later onset (median 8.3 years post-total cavopulmonary connection) but indicated progressive ventricular dysfunction (68.3% normal at 5 years, 53.8% normal at 10 years) and atrioventricular valve regurgitation (12.3% moderate/severe at 5 years, 15.3% moderate/severe at 10 years). CONCLUSIONS: Patients with failing Fontan indicated different serial ventricular and atrioventricular valve function profiles. Ventricular function was preserved in failing Fontan patients with protein-losing enteropathy or plastic bronchitis, whereas progressive ventricular dysfunction was observed in failing Fontan patients with heart failure.