Hemodynamic effects of superior mesenteric arterial and intravenous vasopressin infusions in patients with portal hypertension.

Administration of vasopressin (0.4 units/minute) via the superior mesenteric artery (SMA) resulted in a mean 25% reduction in corrected hepatic venous wedge pressure (CHWP) in 9 stable non-bleeding patients with cirrhosis and portal hypertension. There was wide variation of response in individual patients with two of nine showing no decrease in CHWP to vasopressin. Selective intra-arterial infusion did not protect against the systemic effects of vasopressin and resulted in significant elevations in blood pressure (21%) and systemic vascular resistance (39%). A slight decrease in cardiac output (11%) was also observed. In 6 of these patients, vasopressin (0.4 units/minute) was also given intravenously. The resultant decreases in CHWP were similar to those observed with SMA administration.