Effects of Kasai procedure on liver pathology

Objective To explore the effects of Kasai procedure on liver pathology. Methods During December 2013 to April 2014, explanted livers from 12 consecutive children undergoing transplantation for biliary atresia (BA) were examined with a standardized protocol. The specimens were divided into Kasai and non-Kasai groups (n=6 each). Masson and CK19 immunohistochemical staining were used to detect liver fibrosis degree and bile duct reaction. Hepatic morphology and imaging data were used to explore the correlations with liver parameters. In Kasai group, 2 cases had better prognosis and their ages were 7 and 11 years respectively and the remainder from 7 to 17 months. Non-Kasai group had an age range of 5 to 8 months. The liver specimens were divided into two parts in Kasai group: hypertrophic and atrophic areas. The former contained liver Ⅳ and Ⅷ segments while the later liver Ⅱ segment. Large central nodules were found in two cases with better prognosis. On the contrary, there were severe bile congestion and even cirrhosis in non-Kasai group. Results The liver Ⅳ and Ⅱ segment specimens were collected and the values of liver fibrosis and bile duct reaction evaluated. In Kasai group, liver fibrosis and bile duct reaction were (6.43±1.90)%, (0.61±0.45)% in liver Ⅱ segment versus (9.62±3.58)%, (1.39±0.73)% in liver Ⅳ segment. For non-Kasai group, (7.30±2.53)%, (2.84±1.37)% in liver Ⅱ segment versus (8.42±2.84)%, (3.08±0.46)% in liver Ⅳ segment. No significant inter-group differences existed in liver fibrosis or bile duct reaction (P>0.05). Significant differences existed between liver fibrosis and bile duct reaction in Kasai group (liver Ⅱ segment: P=0.014; liver Ⅳ segment: P=0.048). Furthermore there was a linear equation between liver volume and liver fibrosis degree in liver Ⅳ segment of Kasai group: y=-0.448x+ 1.237, r2=0.665 (y represented liver fibrosis of liver Ⅳ segment, x value of liver volume with 10 logs base). And pre-transplantation computed tomography (CT) showed some inter-group differences. Conclusions In patients with BA, liver morphology changes after Kasai procedure. It may be due to an imbalance of bile drainage by different segments so that comprehensive anatomy area should be expanded during Kasai procedure. There is no inevitable correlation between liver morphology and histopathology after Kasai procedure. Key words: Biliary atresia; Liver transplantation; Liver cirrhosis