Enhancing prognostic insights in biliary atresia: implications of the iBALF score

Biliary atresia (BA) is one of the most challenging pediatric liver diseases, characterized by intra- and extra-hepatic biliary obstruction in infancy, leading to rapid progression of liver fibrosis, cholestatic cirrhosis, portal hypertension, and ultimately liver failure. Therefore, timely diagnosis and surgical intervention are crucial. The incidence of BA varies by region and ethnicity. Globally, the incidence of BA is approximately 1 in 10,000 to 20,000 live births. In Asian countries like Japan and China, the incidence is higher, about 1 in 8,000 to 12,000 live births. The standard treatment for BA is the Kasai portoenterostomy (KPE), aimed at draining bile from the liver to delay or avoid the need for liver transplantation (LTx). However, not all patients achieve good outcomes after the Kasai procedure. A key challenge in BA treatment is the difficulty in determining which patients will have poor outcomes after the Kasai procedure and may be better suited for direct LTx to avoid unnecessary surgery. Studies have reported that older age at the time of Kasai surgery, portal fibrosis, recurrent cholangitis, and cytomegalovirus (CMV) infection are all factors that contribute to poor outcomes after the Kasai procedure (1-3). Hideyuki Sasaki and colleagues conducted a retrospective study on 2,649 cases of patients aged between 31 and 90 days who underwent KPE. The results indicated that there are significant differences in jaundice clearance rates and native liver survival rates after KPE based on different anatomical types of BA (4). Nyholm et al. investigated the expression of fibroblast growth factor 19 (FGF19) in BA patients, finding that elevated serum FGF19 at the time of Kasai surgery predicted a lower long-term survival rate of the native liver, and was associated with unsuccessful portoenterostomy and elevated serum bile acids (5). Table 1 lists representative research findings that explain the survival of the native liver after the Kasai procedure for BA, as well as influencing factors. Clinical practitioners have long sought a quantifiable indicator to determine which pediatric patients are not suitable for portoenterostomy and should instead opt for LTx.

We are pleased to see the study by Tomita et al., titled “Predicting cirrhosis and poor outcomes of bile drainage surgery for biliary atresia: a multicentric observational study in Japan” (11), which addresses this urgent clinical need and provides a solution. The authors conducted a retrospective analysis of 380 BA patients who underwent bile drainage surgery between 2015 and 2019 across 60 centers in Japan, aiming to predict the outcomes of bile drainage surgery based on the Infant Biliary Atresia Liver Fibrosis (iBALF) score.

The iBALF score is calculated using a logarithmic formula based on serum total bilirubin levels, platelet count, and age in days. The formula is: {iBALF score = 8 + 1.185 × Loge [TB (mg/dL)] − 1.882 × Loge [platelet count (10⁹/L)] + 1.093 × Loge [age (days)]}.The score shows a strong correlation with different stages of liver fibrosis. As early as 2015, Tomita et al. applied the iBALF score to evaluate the degree of liver fibrosis and the survival rate of the native liver in infants under one year old with BA (12).

This multicenter study found that the preoperative iBALF score plays a critical role in predicting the outcomes of bile drainage surgery and identifying patients who require direct LTx.

A key finding of the study is that an iBALF score greater than 5.27 is a strong indicator of poor outcomes following bile drainage surgery. Among the 380 patients, 18 had an iBALF score above this threshold, and only two of these patients survived with their native liver by age one. Furthermore, patients with an iBALF score exceeding 5.27 had significantly higher mortality rates and required earlier rescure LTx. The native liver survival rate at age one was significantly different between patients with iBALF scores above and below 5.27, underscoring the score’s value as a predictor of surgical success.

These findings have important implications for the treatment of BA. Traditionally, bile drainage surgery is the first-line treatment for all BA patients, with LTx considered only after the failure of this procedure. However, Tomita et al.’s study suggests that early LTx may offer better outcomes for patients with high iBALF scores, avoiding the complications of failed bile drainage surgery and the risks associated with waiting for a liver transplant. Identifying these high-risk patients before surgery could lead to earlier, more personalized treatment decisions, improving overall survival rates in children with BA.

Nevertheless, this study has some limitations. It is a retrospective analysis, and despite the large sample size, prospective studies and validation in populations outside Japan are needed. Additionally, while the iBALF score performs well in identifying high-risk patients, other factors should be considered in clinical decision-making, such as the availability of donor organs, the risk of death while waiting for transplantation, the presence of splenic anomalies (which may affect platelet count and iBALF scores), and the patient’s overall clinical condition. In infants, the scarcity of donor organs and the technical challenges of transplantation complicate the timing of surgery. For patients unable to receive a transplant in a short period, attempting bile drainage surgery first may allow the child to delay LTx until after age one, improving overall survival rates. Dor Yoeli et al. conducted a retrospective analysis of data from 3,438 children with BA in the SRTR/OPTN database. The results showed that for patients who experienced early failure (within the first year of life) after KPE, there was no statistically significant difference in recipient and graft survival when comparing rescue LTx with primary LTx (13).

In any case, Tomita et al.’s study demonstrates that the iBALF score is a useful tool for predicting poor outcomes in bile drainage surgery for BA, providing strong support for optimizing clinical decision-making and enabling children with BA to achieve better treatment outcomes and long-term survival.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, HepatoBiliary Surgery and Nutrition. The article did not undergo external peer review.

Conflicts of Interest: The author has completed the ICMJE uniform disclosure form (available at https://hbsn.amegroups.com/article/view/10.21037/hbsn-24-528/coif). The author has no conflicts of interest to declare.

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