Defining the causes for Fontan circulatory failure in total cavopulmonary connection patients.

Objectives: This study aims to identify causes of failure in Fontan patients with a total cavopulmonary connection.

Methods: We conducted a comprehensive review of all patients who underwent a total cavopulmonary connection procedure at our centre between 1988 and 2023, aiming to identify and analyze the factors contributing to Fontan failure (defined as mortality, heart transplantation, Fontan takedown, protein-losing enteropathy, plastic bronchitis, or New York Heart Association Functional Classification class III or IV).

Results: The study included 217 patients (median age at time of Fontan completion 3.7 years) with a median follow-up of 12.7 years (IQR, 7.2; 17.7). Systolic ventricular function decreased significantly over time in patients with right ventricular dominant morphology (P = 0.002), while systolic ventricular function remained stable in patients with left ventricular dominant morphology. Fontan failure occurred in 24 patients, with estimated freedom from Fontan failure rates of 97.7% (95% CI, 95-99) at 1 year, 93.9% (95% CI, 89-97) at 15 years and 77.2% (95% CI, 65-86) at 20 years follow-up. Systolic ventricular dysfunction was the most common cause of failure (29%), followed by atrioventricular valve regurgitation (16.7%), a high pulmonary vascular resistance (16.7%), restrictive pathophysiology (16.7%) and obstruction (12.5%). Patients with right ventricular dominance developed most often systolic ventricular dysfunction, while patients with left ventricular dominant morphology developed most often restrictive pathophysiology or a high pulmonary vascular resistance.

Conclusions: Approximately 10% of patients experienced Fontan failure within 15 years postoperatively. Patients with right ventricular dominance experienced progressive decline due to systolic dysfunction, while those with left ventricular dominance exhibited failure due to restrictive pathophysiology or high pulmonary vascular resistance.