TAPVR

Total anomalous pulmonary venous return (TAPVR) is a congenital heart defect in which all four pulmonary veins do not connect to the left atrium. Instead, the pulmonary venous blood drains into the right atrium or into systemic venous structures through anomalous pathways. Because the venous return is right-sided, an atrial septal defect is typically present to allow mixing of oxygenated and deoxygenated blood and enable systemic circulation.

TAPVR is usually categorized by the site of drainage: supracardiac (the most common form, draining via a vertical vein to the brachiocephalic vein or superior vena cava), cardiac (to the coronary sinus or right atrium), infracardiac or infradiaphragmatic (draining to portal or hepatic veins or the inferior vena cava), and mixed forms. Obstruction can occur along the anomalous pathways, most notably in infracardiac and some supracardiac forms, leading to severe pulmonary venous congestion and rapid deterioration.

Clinical presentation ranges from mild cyanosis in nonobstructed cases to severe, life-threatening distress in obstructed TAPVR. Neonates with obstruction may develop tachypnea, poor oxygenation, pulmonary edema, and metabolic acidosis and require urgent stabilization and surgical repair.

Diagnosis is primarily by echocardiography. Chest radiography may show a characteristic snowman sign in supracardiac TAPVR. CT or MRI can delineate anatomy preoperatively. Treatment involves surgical correction to reestablish drainage of the pulmonary veins to the left atrium and closure or redirection of any associated septal defects. Long-term outcomes are favorable for nonobstructed TAPVR, but both obstructed TAPVR and postoperative pulmonary vein stenosis carry higher risks and may require reintervention. TAPVR accounts for a small fraction of congenital heart disease and is frequently associated with other anomalies.