Imaging description

A full-term neonate was noted to be cyanotic and rapidly developed severe respiratory distress requiring endotracheal intubation. A chest radiograph (Fig. 31.1a) showed a diffuse pulmonary edema pattern, but a normal sized cardiac silhouette. Echocardiography demonstrated a large atrial septal defect (ASD) and absence of pulmonary veins entering the left atrium; however, it could not identify the drainage pattern of the pulmonary veins. CT angiography of the chest on the same day showed all pulmonary veins converging into a confluence posterior to the left atrium and draining below the diaphragm (Fig. 31.1b, c), consistent with infracardiac total anomalous pulmonary venous return (TAPVR) with obstruction. Prenatal ultrasound examinations had been reported as within normal limits.

Importance

TAPVR or total anomalous pulmonary venous connection is a rare congenital cardiovascular malformation (2–3% of all congenital cardiovascular anomalies) in which all four pulmonary veins drain into systemic veins or the right atrium with or without pulmonary venous obstruction. More severe obstruction tends to correlate with both earlier clinical presentation and increased severity of symptoms. TAPVR is classified based on the location of pulmonary venous drainage. In all types, the pulmonary veins tend to form a primary confluence, usually behind the left atrium, which then drains ultimately to a systemic vein and the right atrium. Approximately one-third of TAPVR patients have other complex cardiovascular anomalies including asplenia and pulmonary atresia (Fig. 31.2). All types of TAPVR have shunting through the lungs back to the right side of the heart, and require a right to left shunt for survival. An ASD and/or patent foramen ovale (PFO) are essential to allow for the return of blood to the systemic side.