Endoscopic Doppler ultrasound for measurement of azygos blood flow - Validation against thermodilution and assessment of pharmacological effects of terlipressin in portal hypertension

Background: Endoscopic ultrasound (EUS) is a new modality allowing real-tim e flow measurements by means of the Doppler technique. The aim of the study was to evaluate azygos blood flow measurements by endoscopic ultrasound. M ethods: Measurements of azygos blood flow by EUS and by the thermodilution technique were compared in 20 patients with portal hypertension. The abilit y of EUS flowmetry to detect changes in the azygos and portal venous flow a fter an intravenous dose of 2 mg of terlipressin was evaluated in 13 of the patients in a double-blind, randomized, placebo-controlled, cross-over des ign. Results: The EUS Doppler and thermodilution measurements correlated si gnificantly (R = 0.81, P < 0.001). The azygos blood how was found to be 14% higher by the EUS method than by thermodilution. The coefficient of variat ion of the EUS Doppler measurements of the azygos blood flow was 14.8%. Aft er administration of terlipressin, the azygos blood flow, as measured by EU S Doppler, decreased significantly by 23% from 915 to 704 ml/min (P = 0.014 ) and the portal venous flow decreased by 28% from 1170 to 789 ml/min (P = 0.03). No effects of placebo were detected. Conclusions: These results show that EUS measurement of the azygos blood flow correlate strongly to the me asurements by the thermodilution technique, and EUS is moreover well tolera ted by the patients. The method is applicable for monitoring pharmacologica l effects on the superior porto-systemic collateral circulation and portal venous flow in patients with portal hypertension.