Outcome after portoenterostomy in biliary atresia: pivotal role of degree of liver fibrosis and intensity of stellate cell activation.

OBJECTIVES: Biliary atresia (BA), a congenital idiopathic obliterative cholangiopathy, rapidly leads to liver cirrhosis and liver failure if untreated. A timely Kasai portoenterostomy (KP) variably alters this natural history. We evaluated liver fibrogenesis by the intensity of alpha-smooth-muscle actin (SMA) expression, which is a marker for hepatic stellate cell activation. We hypothesized that liver fibrogenesis as determined by intensity of alpha-SMA is already progressing at the time of KP, is related to age and degree of fibrosis at KP, and predicts outcome after KP.

METHODS: BA patients at KP (n = 22, age 22-84 days, median 59) had wedge liver biopsies assessed by quantitative morphometry of immunohistochemistry for alpha-SMA expression. Fibrosis was scored by blinded pathologists. Outcome, reflected by conjugated bilirubin concentration 3 months after KP (CBili3m), survival of the native liver, need for liver transplant, or death, were assessed for 2 to 10 years after KP.

RESULTS: At KP, age, fibrosis score, and alpha-SMA expression were significantly correlated. Moderate-severe fibrosis and intense alpha-SMA expression was observed in 15 of 22 (68%) patients. Severe fibrosis and high alpha-SMA expression were significantly associated with CBili3m greater than 2 g/dL and unfavorable liver survival (>90% of these ultimately underwent liver transplantation or died). Conversely, those with mild fibrosis and low alpha-SMA expression had normal CBili3m and favorable liver survival.

CONCLUSION: Intense liver fibrogenesis is already established in many cases of BA at the time of KP. Fibrosis scores and intensity of alpha-SMA expression may be predictors of outcome after KP and may indicate those patients who might benefit from trials of potential antifibrotic agents early in the course of BA.