Bidirectional cavopulmonary anastomosis (Glenn connection)

This illustration demonstrates the bidirectional cavopulmonary anastomosis ("Glenn" connection) in a patient with a history of a Blalock-Taussig shunt. The superior vena cava (SVC) has been transected, with the proximal end oversewn and the distal end sewn directly into the pulmonary artery. At the time of the Glenn, the prior Blalock-Taussig shunt is divided. This surgery allows for all SVC blood flow to drain directly to the pulmonary vascular bed; however, the inferior vena cava flow enters the systemic circulation through an atrial septal defect or patent tricuspid valve.