Effects of vasopressin on gastric mucosal blood flow in portal hypertension

In patients with portal hypertension, bleeding from the gastric mucosa is common, and is often treated with vasopressin (VP). VP reduces the portal pressure by contracting the arterioles of the abdominal organs. In normal rats, VP reduces the gastric mucosal blood flow (GMBF). However, it is not sure whether the reduction of the portal pressure by VP actually reduces the GMBF in patients with portal hypertension. Here, we studied the effects of VP on the GMBF of 24 patients with portal hypertension resulting from cirrhosis. The ICG15 test was done for 20 of the patients. We measured the GMBF of the antrum and body of the stomach using a laser Doppler flowmeter (Peliflux PF 2) connected with a gastrofiberscope without VP on one day and about 10 min after the start of administration of VP (0.4 U/min, i.v.) on another day. Unexpectedly, the GMBF was increased with VP in 14 of 22 patients at the antrum and in 19 of 24 patients at the body of the stomach. In the body of the stomach, there was correlation between the increase in the GMBF caused by VP and the results of the ICG15 test. A high ICG15 reflects high portal pressure, so this finding indicates that in high portal pressure, the GMBF is increased by VP, and in low portal pressure, the GMBF is decreased by VP.