Bidirectional Glenn procedure

The bidirectional Glenn shunt or hemi-Fontan procedure is one of several surgical techniques used to temporarily improve cardiac function in patients with severe structural heart disease which feature single ventricular physiology. Patients with certain severe valvular or ventricular anomalies (e.g. hypoplastic left heart syndrome or single ventricle, etc.), have an abnormal cardiopulmonary circuit in which a single ventricle functionally serves as the driver of both systemic and pulmonary circulations. Typically, the bidirectional Glenn shunt is the second in a series of three staged surgeries to reconstruct a single ventricle heart, in situations where corrective bi-ventricular surgery or cardiac transplantation are not feasible.

The bidirectional Glenn shunt procedure involves rerouting circulation such that the superior vena cava (SVC) drains into the right pulmonary artery. This results in deoxygenated blood returning from the head and upper body directly routed to the pulmonary arteries for oxygenation by the lungs, to some extent reducing the ventricular workload. Since the blood passing from the SVC into the pulmonary arterial system flows bidirectionally to both right and left lungs, it is called a bi-directional Glenn procedure.

The Glenn procedure was introduced in 1958 by William Glenn and modifications to the procedure were published by Dr. Azzolina in 1973.[1][2] The original description by Dr. Glenn allowed communication only between the right pulmonary artery and the SVC, whereas the modified technique had the SVC connecting at or before the bifurcation between the right and left pulmonary arteries.