Clinical and Hemodynamic Outcomes After Transcatheter Fontan Fenestration Closure: A Single-Center Retrospective Cohort Study

Objective: To describe the indications, hemodynamic changes, and intermediate-term outcomes of transcatheter Fontan fenestration closure in a single-center retrospective cohort.
Method: This retrospective, single-center cohort study included all consecutive patients who underwent transcatheter closure of a surgically created Fontan fenestration between January 2015 and April 2025. Demographic, anatomical, echocardiographic, hemodynamic, procedural, and follow-up data were collected from medical records. The primary endpoint was the change in resting systemic arterial oxygen saturation. Secondary endpoints included changes in mean Fontan pressure, periprocedural complications, late Fontan-related morbidities, and the need for re-fenestration. Patients were also classified as undergoing early (≤24 months after Fontan completion) or late (>24 months after Fontan completion) fenestration closure.
Results: Sixteen patients (50% male) were included, and 75% had an extracardiac conduit Fontan. The median interval between Fontan completion and fenestration closure was 18.5 months, and 62.5% of the patients underwent early closure. Desaturation was the primary indication (87.5%), whereas suspected or documented systemic embolism accounted for 12.5% of cases. The baseline mean Fontan pressure was 12.0±3.0 mmHg, and systemic oxygen saturation was 82.7±10.0%. After closure, the mean Fontan pressure increased slightly to 12.9±3.0 mmHg (P = 0.056), whereas oxygen saturation improved to 95.4±3.5% (P < 0.001). During a median follow-up of 5.7 years, 93.8% of the patients remained free from major Fontan-related complications and the need for re-fenestration.
Conclusion: In carefully selected patients with a fenestrated Fontan circulation, transcatheter closure guided by balloon test occlusion was associated with a marked improvement in systemic oxygenation and only a small increase in mean Fontan pressure. Given the limited sample size and retrospective design, comparisons related to the timing of closure should be interpreted as exploratory, and closure decisions should be individualized based on clinical and hemodynamic assessments.

Keywords: Congenital heart disease, fenestration, Fontan operation, single ventricle, transcatheter closure.