Ultrasonic assessment of abdominal venous return. I. Effect of cardiac action and respiration on mean velocity pattern, cross-sectional area and flow in the inferior vena cava and portal vein.

Duplex scanning, i.e. combined real time ultrasonography and pulsed Doppler velocity measurement, of the inferior vena cava and portal vein was performed in 85 patients subjected to routine left and right heart catheterization. Mean blood velocity and volume blood flow in the inferior vena cava were found to be pulsatile, reflecting both cardiac action and respiration. Different flow patterns could be related to various heart conditions. The cross-sectional area of the inferior vena cava was also pulsatile, the normal variation with respiration being partial collapse during inspiration and maximum distension at end expiration. In the majority of patients, portal vein flow showed variation with respiration only, maximum flow occurring during expiration. The flow patterns found in the two veins were well in accordance with previous invasive findings in animals. It is concluded that duplex scanning is a useful tool in the assessment of abdominal venous return.