The mechanism of lysine-vasopressin hemostasis in bleeding esophageal varices.

The effect of vasopressin on the blood flow through experimentally induced esophageal varices and on the musculature of the lower end of the esophagus has been studied. The blood flow was measured by 85Kr injection into the portal vein and selective recording of the radioactivity of the blood flow through the varices. Simultaneous portography and recording of the portal and arterial blood pressure were performed. Following i.v. administration of vasopressin, there was seen a decrease in portal pressure and transient increase in arterial blood pressure. Simultaneously there was observed a decrease in blood flow through the varices, which were no longer visible at portography, while intra-esophageal pressure was increased. It is concluded that there is a dual mechanism of the effect of vasopressin on bleeding from esophageal varices. It reduces the portal pressure and it contracts the esophageal musculature with resultant compression of the afferent radicles to the submucosal esophageal varices.