Risk factors of biliary cast syndrome among liver transplant recipients

Biliary cast syndrome (BCS) remains a significant concern that can lead to graft failure and mortality. Data on the etiology and outcomes are limited, particularly with regard to the differences in the risk of occurrence of BCS between living donor liver transplantation (LDLT) and deceased donor liver transplantation (DDLT). This study was aimed at identifying the risk factors for BCS and analyzing the impact of BCS on the long-term outcomes in recipients of liver transplantation. We retrospectively reviewed the data of 469 adults who underwent liver transplantation at the University of Tokyo between 2010 and 2023. The risk factors for BCS were analyzed by logistic regression analysis, and the survival outcomes were evaluated by the Kaplan-Meier method. Of the 469 liver transplant recipients included in this study, 31 (6.6%) developed BCS. DDLT was significantly more common in the BCS group (58.1% vs. 11.9%; p <0.01). Multivariate analysis identified DDLT [odds ratio (OR) 10.5; p <0.01], biliary stricture (OR 9.5; p <0.01), hepatic arterial complications (OR 5.0; p =0.04), and older donor age (OR 1.04; p =0.03) as significant risk factors for the development of BCS. No significant difference in the overall survival (OS) was observed between the BCS and non-BCS groups (81.5% vs. 85.6% at 5 y, p =0.79). DDLT was a significant risk factor for the development of BCS, independent of the presence of biliary stricture. When appropriately managed by endoscopic interventions, BCS did not affect the long-term graft or OS. These findings suggest that even in liver transplant recipients developing BCS, timely intervention can ensure favorable long-term outcomes.