Tricuspid Atresia and Fontan Circulation: Anatomy, Physiology, and Perioperative Considerations

Tricuspid atresia (TA) is a cyanotic congenital heart defect defined by agenesis of the tricuspid valve and resultant right ventricular hypoplasia, representing 1.4–2.9% of congenital heart disease. Survival depends on interatrial and interventricular shunts that permit systemic and pulmonary blood flow, with staged surgical palliation culminating in the Fontan procedure. While surgical advances have improved long-term outcomes, Fontan circulation remains a delicate physiology characterized by preload dependence, elevated pulmonary vascular resistance, chronic venous hypertension, and a prothrombotic state. These features predispose patients to arrhythmias, lymphatic complications, hepatic congestion, and progressive circulatory failure. For anesthesiologists, perioperative management of TA and Fontan patients is uniquely complex. Anesthetic considerations include meticulous preload optimization, modulation of systemic and pulmonary vascular resistance, and ventilatory strategies that minimize adverse effects on venous return. Additional challenges include the high risk of air embolism, individualized anticoagulation needs, and hemodynamic sensitivity to patient positioning. Preoperative evaluation with echocardiography and electrocardiography provides critical insight into anatomy and physiology, while intraoperative planning must emphasize goal-directed fluid management, careful agent selection, and tailored ventilation. Postoperatively, vigilant monitoring, effective pain control, and prevention of complications are essential. This review synthesizes classification systems, pathophysiology, and the evolution of surgical palliation, while emphasizing anesthetic principles for the perioperative care of patients with TA and Fontan circulation. As survival improves and the population of Fontan patients expands, a nuanced understanding of this physiology is essential for optimizing outcomes across cardiac and non-cardiac surgical settings.