Purpose: Portal hypertension in patients with biliary atresia (BA) is generally thought to result from portal vein (PV) narrowing secondary to hepatic fibrosis. To test the hypothesis, we morphometrically analyzed the PVs and hepatic arteries (HAs).
Methods: Morphometrical analyses of 25 BA and 26 non-BA liver biopsy specimens from patients treated from 2000 to 2014. The total specimen area, the fibrotic portal area, vessel diameter and medial thickness of the HAs were measured.
Results: The PV diameter in BA patients was significantly smaller than that in non-BA patients. In BA, the numbers of normal-sized PVs and capillaries were decreased and increased, respectively. The PV diameter was not significantly correlated with the degree of fibrosis. We newly found that medial hypertrophy and the HA diameter increased with the number of endothelial cells in BA. The PV diameter was not significantly correlated with the medial thickness and was positively correlated with the HA diameter in BA.
Conclusions: The narrowing of the PV is unlikely to occur secondarily to liver fibrosis. The medial hypertrophy of the HA is not correlated with the decrease in the PV blood flow. These findings seem to be unique to the primary vascular lesions of BA.
Keywords: Biliary atresia; Hepatic artery; Morphometrical analysis; Portal vein.