Incidence of Cholecystitis After Endoscopic Biliary Drainage Using a Low Axial Force Covered Self-Expandable Metallic Stent in Patients With Malignant Distal Biliary Obstruction: A Multicenter Prospective Study.

Background and aim: No prospective studies have verified the incidence of cholecystitis in patients using the covered self-expandable metallic stent. In this study, we aimed to investigate the incidence of cholecystitis and its risk factors after low axial force covered self-expandable metallic stent placement for malignant distal biliary obstruction.

Methods: This multicenter prospective study included patients diagnosed with unresectable distal biliary obstruction between November 2019 and October 2022 who underwent low axial force covered self-expandable metallic stent placement.

Results: The technical success in the 93 analyzed patients was 100% and clinical success was 98.9%. The 70-mm covered self-expandable metallic stent was the most used in 53 patients (57.0%), followed by the 80-mm type in 27 patients (29.0%), 60-mm type in 12 patients (12.9%), and 50-mm type in 1 patient (1.1%). Cholecystitis after covered self-expandable metallic stent placement occurred in six patients (6.5%). The median time to onset was 46 days (range, 16-315 days), with 1 case in the early stage and five cases in the late stage. There was one mild case, one moderate case, and four severe cases. The presence of tumor involvement at the orifice of the cystic duct was identified as an independent risk factor (odds ratio, 17.0; 95% confidence interval, 1.5-195.1; p = 0.023).

Conclusions: The presence of tumor involvement at the orifice of the cystic duct was an independent risk factor for the development of cholecystitis after low axial covered self-expandable metallic stent placement.

Trial registration: University Hospital Medical Information Network (UMIN) (http://www.umin.ac.jp, registration number: UMIN 000038209).