Occluded Fenestration is Associated with Improved Long-Term Outcomes in Patients Undergoing the Fenestrated Fontan Operation.

Objective: The modified Fontan operation, a palliative approach for single ventricular circulation patients, often incorporates a fenestration to facilitate postoperative management. Postoperative fenestration closure is sometimes performed to mitigate potential risks such as low oxygen saturation. However, the benefits and potential risks of this procedure remain under investigation.

Methods: A retrospective propensity score matching study was conducted at the National Taiwan University Children's Hospital. It included all patients who underwent their first-ever fenestrated modified Fontan procedure between February 1998 and July 2020. The primary objective was to assess the incidence of death, Fontan takedown, and heart transplantation. Major adverse cardiovascular events (MACEs) were considered as a secondary outcome.

Results: The study comprised 173 patients (male/female 100/73), median operation age of 4.6 years, and a median follow-up of 10.4 years (interquartile range 6.2, 14.0 years) post-operation. At the latest follow-up, fenestration was occluded in 74 (42.8%) patients, with 29 undergoing transcatheter closure and 45 experiencing spontaneous occlusion. After propensity score matching, patients with occluded fenestration demonstrated significantly better event-free survival (15-year survival 95.3% vs. 78.6%, P = 0.047), although the intention-to-treat fenestration closure group showed similar outcomes compared to the natural course group. High recent NT-proBNP and Fontan pressure emerged as critical risk factors for worse event-free survival and MACEs. The cut-off points of NT-proBNP and Fontan pressure were 467.7 pg/mL and 18 mmHg, respectively.

Conclusions: Patients with occluded fenestration exhibit superior event-free survival. Fenestration closure presents as a feasible strategy to enhance oxygen saturation without elevating Fontan pressure.