The value of Doppler ultrasound in cirrhosis and portal hypertension.

BACKGROUND: Cirrhosis and portal hypertension affect the flow profile of the liver vasculature. In these conditions Doppler ultrasound can provide important information on the hemodynamics of the portal venous system, the hepatic artery and the hepatic veins.
METHODS: The value of Doppler ultrasound in the assessment of the patient with cirrhosis and portal hypertension was determined by reviewing the literature.
RESULTS: Portal venous blood flow becomes reversed with advanced portal hypertension. Reversed flow is also demonstrated in patients with veno-occlusive disease and portosystemic shunts. Despite general agreement that portal flow velocity is decreased in cirrhotic patients, the absolute values of portal flow velocity in both healthy subjects and cirrhotic patients vary considerably. Errors in Doppler measurements, observer variability and collateral pathways contribute to these variations. Furthermore, portal blood flow is influenced by numerous factors such as changes in the body position, phase of respiration, timing of meals, exercise and cardiac output. Finally, portal flow may be unaltered due to a combination of high inflow from the splanchnic organs and increased resistance within the liver. High resistive index of the hepatic artery is seen in patients with end-stage liver disease, particularly in children with severe cirrhosis secondary to biliary atresia. However, hepatic artery flow remains normal in most patients. Abnormal hepatic vein flow profiles are seen in patients with cirrhosis, but dampening or flattening of the flow profile has a multifactorial origin (Budd-Chiari, metastases, ascites) and can be observed in healthy subjects.
CONCLUSIONS: Although many factors may affect the accuracy of volume flow and velocity measurements and the flow profile of the liver vasculature may change in different situations, Doppler ultrasound is useful in the assessment of the patient with cirrhosis and portal hypertension.