Biliary atresia is the most common cause of LTx in children. Although several causes have been hypothesized — including genetic, embryological, infectious, and immunological factors. The etiology of this infantile obstructive cholangiopathy remains unknown. An untreated extrahepatic obstruction of the bile ducts leads to progressive inflammatory destruction of the extrahepatic and intrahepatic bile duct system, to cholestasis and secondary liver damage with consecutive fibrosis, cirrhosis, and portal hypertension and subsequently to death.

The focal point of treatment is to restore bile flow to the intestine, which can be achieved with KPE. In most cases, this involves a bridging therapy to gain time for a later LTx, which is necessary in about 80% of cases. One of the major risks in managing this disease is the timing of diagnosis as delayed referral may lead to a late diagnosis which, in turn, may result in an urgent need for LTx. Abnormal prognostic parameters at the time of diagnosis indicate the progress of the disease and consequently, the consideration of adequate treatment.

The correlation of KPE timing and survival with the patient's own liver has been widely discussed in various literature and the cut-off has been reduced from 12 weeks to 30 days.  Bilirubin clearance after KPE also appears to have an influence on transplantation-free survival: children with normal bilirubin serum levels three to six months after KPE had significantly higher survival rates without LTx. In addition to bilirubin, Goda et al. found a clear correlation between AST and ALT levels and transplantation-free survival.

There are various theories in literature on the correlation between fibrosis at the time of KPE and the clinical course of the children with the disease. Certain studies showed no correlation exists between the two , while others showed a remarkable link between the degree of fibrosis and long-term outcome. In this study, fibrosis was measured using the Pico-Sirius Red Staining, which is a specific method for identifying collagen I, collagen II, and collagen III. It was used in renal fibrosis measurements and has shown informative correlations between function and histology. In the 1990s, this method was used by Moragas et al. to identify liver fibrosis in children who will undergo LTx. Another change in liver histology in children with BA is neoproliferation of the bile ducts, which can be measured through cytokeratin-7 staining, indicating an increased presence of neo-bile ducts as a reaction of the liver to cholestasis and as an indicator of liver damage.

In this study, we have thus investigated whether the histological findings at the time of KPE and LTx correlated with the clinical course measured by biochemical variables in order to be used as prognostic parameters. Therefore, we also used the pediatric end-stage liver disease score (PELD) as an objective tool to prioritize children waiting for LTx. A higher PELD score in children is associated with increased mortality before LTx.

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Regards
Alex John
Managing Editor
Neonatal and Pediatric Medicine