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

This study investigated the longitudinal changes in ventricular function and atrioventricular valve function to clarify the timing and the mechanisms of failing Fontan.

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.

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).

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.