Eighty interposition mesocaval shunts, using a knitted Dacron large diameter prosthesis, have been performed during the past five and one-half years. Patients were evaluated from the standpoint of protection from recurrent esophageal hemorrhage, shunt patency, encephalopathy and cumulative survival analysis. In a selected group of patients, hemodynamic measurements were also obtained in the pre, intra, and postoperative periods. These included measurements of wedged hepatic vein pressure, superior mesentric venous blood flow, and residual superior mesenteric, hepatic sinusoidal and inferior vena cava pressures following the shunt procedure. Additionally, direct shunt flow measurements utilizing a square wave of electromagnetic flowmeter were also performed. Results indicate that the shunt patency is 95%; adequate decompression of the portal system was accomplished; recurrent variceal hemorrhage did not occur if the shunt remained patent; the incidence of encephalopathy was low (11%); and the operative mortality for the entire series was 9%. Continued perfusion of the liver was documented in 44% of patients and appears to be a function of the residual total portal resistance largely controlled by inferior vena caval pressure at the level of graft replacement. Life survivhat the interposition mesocaval shunt appears to be an effective technique for the control of variceal hemorrhage, has important hemodynamic advantages and can be applied to most patients for the control of variceal hemorrhage due to portal hypertension.