Portal vein hypoplasia is present in patients with biliary atresia at the time of diagnosis.

Background: In patients with biliary atresia (BA), severe portal hypertension (HTN) develops even with successful bile flow restoration, suggesting an intrinsic factor driving portal HTN independent from bile obstruction. We hypothesize that patients with BA have abnormal portal vein (PV) development, leading to PV hypoplasia.

Methods: In this observational cohort study, we enrolled patients who were referred to a tertiary center from 2017 to 2021 to rule out BA. Newborns who underwent computed tomography angiogram as a clinical routine before intraoperative cholangiogram, and laparoscopic Kasai hepatoportoenterostomy. The diameter of the PV and hepatic artery (HA) were compared to the degree of liver fibrosis in the wedge biopsies. The jaundice clearance, native liver survival, and clinical portal hypertensive events, including ascites development and intestinal bleeding, were assessed.

Results: 47 newborns with cholestasis were included in the cohort; 35 were diagnosed with BA. The patients with BA had a smaller median PV diameter (4.3 vs. 5.1 mm; p < 0.001) and larger median HA diameter (1.4 vs. 1.2 mm; p < 0.05) compared to the patients with other forms of cholestasis. The median PV and HA diameter did not correlate with the degree of liver fibrosis. Among 35 patients with BA, 29 patients (82.9%) achieved jaundice clearance, and 23 patients (65.7%) were alive with their native liver at two years of age. Seven patients (20%) developed intestinal bleeding, and seven patients (20%) developed ascites, with one overlapping patient.

Conclusion: PV hypoplasia is present in patients with BA independent of liver fibrosis at the time of diagnosis.