Functionally Single-Ventricle Complications After Fontan Palliation-A Narrative Review

Functionally single-ventricle (FSV) defects are complex congenital heart anomalies that require Fontan palliation, a surgical procedure redirecting systemic venous blood directly to the pulmonary arteries, bypassing the heart. Despite improvements in surgical techniques and perioperative care leading to enhanced survival rates, patients remain vulnerable to significant long-term complications, due to the unique Fontan circulation physiology. This circulation relies on low pulmonary vascular resistance and preserved single-ventricle function but predisposes patients to venous congestion and reduced cardiac output, resulting in multi-organ dysfunction. Key cardiovascular complications include systolic and diastolic dysfunction of the single ventricle, atrioventricular valve regurgitation, arrhythmias, pulmonary vascular disease, and thromboembolic events. Systemic complications encompass Fontan-associated liver disease (FALD), protein-losing enteropathy (PLE), plastic bronchitis (PB), renal impairment, and endocrine and psychosocial burdens. All the problems induce frequent hospitalizations, psychological challenges, and impaired educational and employment opportunities. Comprehensive management requires multidisciplinary approaches addressing the complex interplay of hemodynamic, organ-specific problems, and psychosocial factors inherent to Fontan physiology.