pediatrics
Total Anomalous Pulmonary Venous Return (TAPVR)
Introduction
In total anomalous pulmonary venous return, the pulmonary veins drain to a confluence adjacent to the posterior wall of the left atrium but do not connect to the left atrium. Instead, the entire pulmonary venous return enters the systemic venous circulation through one or more persistent embryologic connections. Filling of the left heart structures and systemic blood flow is dependent on having an adequate atrial communication (stretched patent foramen ovale or actual atrial septal defect). If there is no obstruction to pulmonary venous return, cyanosis is mild, but pulmonary blood flow is markedly increased. Patients may be only mildly symptomatic or have significant heart failure symptoms. Severe obstruction of the pulmonary venous return may occur, resulting in severe neonatal cyanosis, pulmonary edema, and pulmonary hypertension. Diagnosis is by echocardiography. Surgical repair is required. (See also Overview of Congenital Cardiovascular Anomalies .) Total anomalous pulmonary venous return (TAPVR—see figure) accounts for 1 to 2% of congenital heart anomalies. The clinical manifestation depends on the connection between the pulmonary venous confluence and the right side of the circulation. The most common types include Return via an ascending left vertical vein that drains to the innominate vein or to the superior vena cava (supracardiac TAPVR) A descending vein that drains infradiaphragmatically to the portal circulation (infracardiac TAPVR) Connection of the pulmonary vein confluence to the coronary sinus (cardiac TAPVR) The infradiaphragmatic drainage type is invariably severely obstructed, leading to dramatic pulmonary edema and cyanosis unresponsive to supplemental oxygen that manifest shortly after birth. The other 2 types do not typically involve obstruction and lead to mild to moderate signs of Heart failure and mild cyanosis in the first month of life. The pulmonary veins do not connect to the left atrium; instead, the entire pulmonary venous return enters systemic venous circulation through various connections. Systemic blood flow depends on right-to-left atrial shunting. AO=aorta; IVC=inferior vena cava; LA=left atrium; LV=left ventricle; PA=pulmonary artery; PV=pulmonary veins; RA=right atrium; RV=right ventricle; SVC=superior vena cava. 