Transcatheter Fontan Fenestration Closure: Sustained Improvements in Oxygen Saturation with Minimal Morbidity and Mortality.

Fontan fenestration decreases central venous pressure and preserves cardiac output while decreasing systemic oxygen saturation. Transcatheter fenestration closure increases oxygen saturation, though the persistence of this increase and the long-term incidence of adverse outcomes such as death and heart transplant remain unknown. We describe immediate and long-term clinical and adverse outcomes following fenestration closure. Catheterization, echocardiogram, and clinic reports were reviewed following transcatheter Fontan fenestration closure. Data were reported as n (%) and median (IQR). Continuous variables were compared using Wilcoxon ranked sum test. 51 patients had fenestration closure 0.9 (0.7-1.5) years following extracardiac Fontan operation. Most (84%) were closed with Amplatzer Septal Occluders. Systemic O2 saturation immediately increased from 87 (83-89) to 95 (94-97)%, P < 0.05. Cardiac index decreased from 4 (3-5) to 2.9 (2.6-3.5) L/min/m2. Fontan pressure and pulmonary vascular resistance were not significantly changed. Clinical follow-up duration for all patients was 7.3 (range 1.3-16) years. Oxygen saturation at last follow-up was 94.5 (92-97)% and did not decrease over time (P < 0.05). One patient (2%) developed protein losing enteropathy, 1 (2%) had heart transplant, and 1 (2%) patient died 9.4 years following fenestration closure. No patient required fenestration re-creation following closure. Transcatheter Fontan fenestration closure leads to sustained increases in systemic oxygen saturation and a low incidence of adverse outcomes such as death and transplant. Further study comparing fenestration closure to non-closure and longer follow-up duration are required to determine if there is a survival benefit to fenestration closure.