Intraoperative Evaluation of Surgical Systemic-to-Pulmonary Artery Shunts

At the time of operation it is difficult to ascertain the patency, inadequacy, or excessiveness of surgical systemic-to-pulmonary artery shunts performed for various types of cyanotic heart disease. An intraoperative test based on the decrease in mean aortic pressure upon opening the newly created shunt was made in 36 patients undergoing operation for creation of a subclavian-to-pulmonary artery or aorta-to-pulmonary artery anastomosis. The subsequent postoperative course of these patients was compared to the percentage of decrease in mean aortic pressure. A failure of the pressure to fall always indicated an occluded shunt (3 patients), a pressure drop of less than 9% always indicated an inadequate shunt for sustained palliation (4 patients), a pressure drop greater than 20% could indicate an excessively large shunt (1 of 3 patients), and a pressure drop between 9 and 20% usually indicated an adequate shunt for sustained palliation (29 of 32 patients). The exceptions are noted and discussed. This intraoperative test accurately predicts occluded, patent, or excessive shunts so that immediate revision may be undertaken.