Anomalous Systemic Venous Return

Abstract

Abnormal connections between the inferior vena cava, or right or left superior venae cavae to the right or left atrium may occur. A right-side anomaly (e.g., persistent left superior vena cava to the coronary sinus or azygos continuation of the inferior vena cava) may be of no consequence and require no treatment, although when other intracardiac anomalies require repair, the right-side abnormality may require an alteration in cardiopulmonary bypass cannulation techniques. When systemic veins connect to the left atrium, there is a right-to-left shunt with cyanosis, and repair is necessary. With a persistent left superior vena cava that connects directly to the left atrial roof (also known as unroofed coronary sinus), ligation of the structure obliterates the intracardiac shunt but is dangerous unless there is a normal innominate vein or large collateral connections in the head that allow unobstructed left head and neck flow into the heart. This left cava otherwise can be anastomosed directly to the right superior vena cava in certain circumstances or requires intracardiac tunneling to the right atrium.