Extrahepatic Cholestasis Increases Liver Stiffness (Fibroscan®) Irrespective of Fibrosis

Aims: Transient elastography [Fibroscan (FS)] is a novel non-invasive tool to assess liver fibrosis/cirrhosis. However, it remains to be determined if other liver diseases such as extrahepatic cholestasis interfere with fibrosis assessment since liver stiffness is indirectly measured by the propagation velocity of an ultrasound wave within the liver.

Methods and Results: In this study we measured liver stiffness immediately before ERCP and 3 to 12 days after successful biliary drainage in patients with extrahepatic cholestasis due to benign or malignant bile duct obstruction. Initially elevated liver stiffness decreased in 13 of 15 patients after intervention, in 10 of them markedly. In 3 patients, liver stiffness was elevated to a degree that suggested advanced liver cirrhosis (mean 15.2 kPa). Successful drainage led to a drop of bilirubin by 2.8 to 9.8mg/dL while liver stiffness almost normalized (mean 7.1 kPa). In all patients with successful biliary drainage, the decrease of liver stiffness highly correlated with decreasing bilirubin (Spearman’ rho=0.67, P<0.05) with a mean decrease of liver stiffness of 1.2±0.56 kPa per 1g/dl bilirubin. Two patients, in whom liver stiffness did not decrease despite successful biliary drainage, had advanced liver cirrhosis and multiple liver metastases, respectively. The relationship between bile duct obstruction and liver stiffness was reproduced in an animal model of bile duct ligation in landrace pigs where liver stiffness increased from 4.6 kPa to 8.8 kPa during 120 min of bile duct ligation and decreased to 6.1 kPa within 30 min after decompression.

Conclusion: Extrahepatic cholestasis increases liver stiffness irrespective of fibrosis. Once extrahepatic cholestasis is excluded e.g. by liver imaging and laboratory parameters, transient elastography is a valuable tool to assess liver fibrosis in chronic liver diseases.