Radiological classification of non-anastomotic biliary strictures after liver transplantation

OBJECTIVES: Due to donor liver shortage, donation after circulatory death (DCD) livers are increasingly used for liver transplantation (LT). However, non-anastomotic biliary strictures (NAS) are more often observed after DCD LT, which can cause serious morbidity. To provide early adequate NAS-treatment, reliable NAS classification is pivotal. Therefore, the current study determined the clinical applicability of two radiological NAS-classification systems, namely the system of Croome and the Groningen system. MATERIALS AND METHODS: Patients included in the dual hypothermic oxygenated perfusion (DHOPE)-DCD trial (NCT02584283) who underwent LT between January 2016 and July 2019, and in whom per-protocol biliary imaging studies 6 months post-LT were available, were included in the study. NAS severity according to both scoring systems was scored by two independent radiologists, and the correlation for each system with clinical outcomes was made. RESULTS: In total, 133 patients were included. In our study population, both systems showed good correlation with clinical outcomes, as the highest rates of NAS-related cholangitis and biliary interventions were observed in patients with diffuse necrosis or multifocal progressive disease according to the Croome classification, and likewise in the moderate and severe NAS subgroups in the Groningen classification. Worst 5-year graft and patient survival rates were observed in the case of diffuse necrosis (77% and 80%) or severe NAS (81% and 67%). CONCLUSION: Both the radiological NAS classification system of Croome and the Groningen NAS classification system correlate well with clinical outcomes. As the Groningen NAS classification system does not necessitate follow-up imaging, it may be the preferred radiological NAS classification system. KEY POINTS: Question Given the potential severity of non-anastomotic biliary strictures after liver transplantation, there is a critical need for adequate radiological classification systems with strong clinical correlations. Findings Both radiological non-anastomotic biliary strictures classification systems of Croome et al and the Groningen system correlated well with clinical outcomes, but no follow-up imaging is needed in the Groningen system. Clinical relevance The Groningen non-anastomotic biliary strictures classification system is easy-to-use, serves as treatment guidance, and provides important prognostic information.