Measurement of azygos venous blood flow in the evaluation of portal hypertension in patients with cirrhosis. Clinical and haemodynamic correlations in 100 patients.

Blood flow in the azygos vein, an index of blood flow through gastro-oesophageal collaterals, was measured by continuous thermal dilution in 100 patients with cirrhosis. Azygos blood flow was directly related to portal pressure (r = 0.54, P less than 0.001). Patients with portal hypertension had very high azygos blood flow (692 +/- 32 ml/min) in comparison with controls (n = 11, 174 +/- 29 ml/min). Patients with previous oesophageal bleeding had similar azygos blood flow as those without, but azygos blood flow was significantly greater in patients with massive or recurrent bleeding than in those with less severe haemorrhage, suggesting that the magnitude of collateral flow may influence the course of variceal bleeding. Patients with grade III varices had higher azygos blood flow than those with grades II or I. In addition, both oesophageal tamponade and vasopressin infusion, procedures of known value in variceal bleeding, markedly reduced azygos blood flow (-40% and -25%, respectively). Measurement of azygos blood flow allows evaluation of haemodynamic changes in the oesophageal collaterals of patients with portal hypertension, and provides useful information on the effect of therapeutic procedures aimed at arresting or preventing variceal haemorrhage.