Use of color Doppler EUS in assessing azygos blood flow for patients with portal hypertension

Background: Azygos blood flow is an index of blood flow through gastroesophageal collateral vessels and varices in portal hypertension. Conventional measurement of azygos blood flow involves catheterization of the azygos vein. We studied the feasibility of assessing azygos blood flow with color Doppler endosonography and of monitoring the effects of vasoactive agents on azygos blood flow. Methods: Patients with portal hypertension were examined by means of linear array color Doppler endoscopic ultrasonography (EUS). Patients who had taken propranolol or nitrates in the 4 weeks before the day of measurement of azygos blood flow were excluded. After identification of the azygos vein and recording of baseline readings of mean arterial blood pressure, pulse rate, and azygos blood flow, patients were selected in a random manner to receive a bolus injection of 2 mg terlipressin, 250 mu g somatostatin, or saline solution (control). Azygos blood flow was measured 1, 5, and 10 minutes after injection (AzBF-1,AzBF-5, AzBF-10). Results: Six patients were recruited in each treatment group. Basal azygos blood flow showed a positive association with the Child-Pugh grade of cirrhosis (p < 0.005). After bolus injection of terlipressin and somatostatin, there was a marked decrease in AzBF-1 (24% and 37%), AzBF-5 (42% and 19%), and AzBF-10 (40% both) compared with baseline. The control group showed no significant change in azygos blood flow. Conclusions: Color Doppler EUS is useful in assessing azygos blood flow in portal hypertension and in monitoring the effects of vasoactive agents.