Hemodynamic Changes of Azygos Venous Flow After Ligation of the Azygos Arch

The uppermost portion or arch of the azygos vein is frequently ligated and divided in thoracic surgery. The hemodynamic effects arising from this proce dure have not, however, been described previously. The authors assessed such effects by using transesophageal real-time two-dimensional Doppler echography (TE2DD). Nine patients, whose azygos arch had been ligated and divided in the course of surgery for lung cancer, were examined. The intervals between the prior operation and the examination with TE2DD ranged from one to fifty months. By use of a convex array transducer with a frequency of 7.5 MHz, the hemodynamics of both the azygos vein and the intercostal veins, which join the former, were assessed. The esophagopetal portion of the azygos vein could be visualized in color in 6 of 9 cases. In all these 6 cases, the flow direction of the azygos vein was reversed and directed caudally. Blood flow in both the azygos vein and the intercostal veins is normally pulsatile. After ligation, however, it had become constant in 3 of 5 cases analyzed by pulsed Doppler spectrum. The value of mean flow velocity in the azygos vein (9 ± 5 cm/sec) was significantly (p < 0.05) smaller than that of the control group (15 ±5 cm/sec).