Incidence of Cholecystitis after Multihole Fully Covered Metal Stent Placement for Unresectable Malignant Distal Biliary Obstruction: A Prospective Exploratory Study

Abstract Cholecystitis and stent migration are adverse events of fully covered self-expandable metal stents (SEMS) for malignant distal biliary obstruction. The aim of this study was to evaluate the incidence of cholecystitis, clinical outcomes, and safety of a multihole fully covered SEMS (MHSEMS) in unresectable malignant distal biliary obstruction. This single-center, prospective, exploratory study included consecutive patients who underwent MHSEMS placement for unresectable malignant distal biliary obstruction between June 2023 and January 2024. The primary endpoint was the incidence of cholecystitis. Stent patency was analyzed using the Kaplan–Meier method, and categorical variables were expressed as percentages. Twenty patients were enrolled, and all were followed for up to 1 year or until death; technical and clinical success rates were both 100%. No cholecystitis occurred despite the presence of reported risk factors for cholecystitis: cholelithiasis or sludge (65%), contrast filling of the gallbladder (35%), and tumor involvement of the cystic duct (15%). Recurrent biliary obstruction occurred in six patients (30%): two stent migrations, three occlusions, and one biliary kinking. All recurrent biliary obstruction cases were managed endoscopically. Median time to recurrent biliary obstruction was not reached. One-year stent patency rate was 62%. Adverse events other than recurrent biliary obstruction were mild. No cholecystitis occurred after MHSEMS placement in this small prospective cohort, suggesting a favorable safety profile; however, larger comparative studies are needed to clarify its effect. UMIN000051182; registered June 1, 2023.