A Pitfall in Azygos Vein Cannulation in Cirrhotic Patients: Mistaken Cannulation of the Mammary Vein

Azygos venous flow can be measured by a thermodilution catheter in patients with cirrhosis. This is a useful technique since azygos flow is thought to reflect the superior portosystemic collateral flow in these patients. The authors report 3 cases in which mistaken internal mammary vein cannulation mimicked azygos vein cannulation in the supine fluoroscopic view. A lateral fluroroscopic view con firmed internal mammary cannulation. They suggest that if the azygos arch is unpronounced or flow measurements are unexpectedly low in patients with portal hypertension due to cirrhosis, a lateral view be performed to rule out internal mammary vein cannulation.