Mid-term outcomes of classical hypoplastic left heart syndrome after Fontan procedure.

Objectives: To examine the outcomes of patients with classical hypoplastic left heart syndrome following extracardiac total cavopulmonary connection.

Methods: We retrospectively analysed 812 cases that underwent extracardiac total cavopulmonary connection at our hospital between 1994 and 2022. With a median follow-up of 10.1 years, we compared the survival rate, Fontan-related events, liver function, postoperative haemodynamics, freedom from reintervention and exercise tolerance in 109 patients with classical hypoplastic left heart syndrome (cH group), 205 patients with heterotaxy (Hx group) and 498 patients with other univentricular conditions (O group).

Results: The survival rates (97.2% at 10 and 20 years for the cH group) and freedom rates from all Fontan-related events (81.2% and 68.1%) were similar across groups. Liver enzyme variables did not significantly differ, and liver cirrhosis was not observed. Postoperative catheter examinations showed similar Fontan pressure, end-diastolic pressure, cardiac index and pulmonary vascular resistance across groups, with a lower pulmonary artery index in the cH group. The rates of freedom from reintervention at 10 and 20 years were lower in the cH group (80.5% and 55.7%). Maximal oxygen consumption during cardiopulmonary exercise testing declined faster in the cH group (-2.5% per year) than in the O group (-0.9% per year), with no difference with the Hx group (-2.4% per year).

Conclusions: The overall survival rate of patients with classical hypoplastic left heart syndrome after Fontan procedure was comparable to that of patients with other univentricular syndromes, showing good haemodynamics and lower mid-term comorbidities. However, lower pulmonary artery index, reduced freedom from reintervention and progressive decline in exercise tolerance are remaining concerns.