Portal vein dynamics in biliary atresia.

A prospective sonographic investigation of portal vein caliber was done in 40 children with biliary atresia (n = 37) and biliary hypoplasia (n = 3) from 1 to 135 months old. The patients were divided into two groups according to hepatobiliary function (HBF). HBF was determined by serum bilirubin (greater than less than 1.5 mg/dL), serum albumin (greater than less than 3.5 g/dL), and bile bilirubin excretion (greater than less than 6 mg/d). There were 21 patients with "good" and 19 patients with "poor" HBF. The portal vein caliber, measured just proximal to its bifurcation, was 3 to 16 mm (median 7 mm), in the good HBF patients and 2 to 6 mm (median 4 mm) in the poor HBF group, the difference being statistically significant (P less than .01). Sequential studies of portal vein caliber were done in 30 patients. In the 15 patients with good HBF there was a progressive increase in portal vein caliber in nine, no change in six, and no patient had a decrease in caliber. Of the 15 patients with poor HBF, eight patients had a decrease in portal vein caliber, seven had no change, and no patient had an increase in caliber. The results indicate that patients with biliary atresia and poor HBF have an absolute and/or relative decrease in portal vein caliber and that the decrease may be progressive. Since portal vein anastomosis is essential to successful liver transplantation, referral must be done before portal vein shrinkage eliminates this option.