Indicator-dilution curves in systemic arteriovenous fistulas

Eight patients with systemic arteriovenous fistulas have been studied with special emphasis on systemic arterial and multiple right heart indicator-dilution curves with indocyanine green. Seven patients were studied preoperatively; 4 subjects were restudied after surgical intervention. One patient was catheterized only after surgical correction of the fistula. Five subjects were investigated before and during acute occlusion of the fistula. Cardiac output was determined by indocyanine green in all patients; the Fick principle was also employed in 4 patients to determine cardiac output. The cardiac index was elevated before surgery; occlusion of the fistula resulted in a decreased cardiac index. Surgical correction of the fistula also led to a fall in cardiac index. The indocyanine indicator-dilution curves were utilized to demonstrate and localize the left to right extracardiac shunts. After surgical correction, physiologic evidence of the shunt was no longer evident.