Risk Factors for Cholecystitis After Self-expandable Metallic Stent Placement for Malignant Distal Biliary Obstruction: A Systematic Review and Meta-analysis.

Background and goals: Endoscopic biliary stenting is a standard palliative procedure to improve the quality of life in patients with unresectable malignant distal biliary obstruction (MDBO). Self-expandable metallic stents (SEMS) are preferred for their longer patency than plastic stents. However, cholecystitis can complicate SEMS placement by obstructing the cystic duct. This meta-analysis aims to identify risk factors for cholecystitis after SEMS placement for MDBO.

Study: We conducted a comprehensive database search to identify published studies. Only full-text articles using multivariate models to assess risk factors were included. Pooled adjusted odds ratios (OR) with 95% CIs were obtained.

Results: Eleven retrospective cohort studies (4291 patients who underwent SEMS placement for MDBO) were included, analyzing 8 unique risk factors. Predictors of cholecystitis after SEMS placement for MDBO included tumor involvement of the cystic duct take-off (OR 5.61, 95% CI 3.36-9.36, P< 0.001; I²=65%), SEMS placement across the orifice of the cystic duct (OR 1.97, 95% CI 1.27-3.07, P=0.003; I²=0%), gallstones presence (OR 2.56, 95% CI 1.65-3.98, P< 0.001; I²=0%), flow of contrast agent into gallbladder (OR 3.91, 95% CI 1.11-13.79, P=0.03; I²=75%), and use of covered metal stent (OR 2.77, 95% CI 1.42-5.43, P=0.003; I²=0%). Prior biliary drainage, tumor invasion to the feeding artery, and stent length ≤60 mm were not associated with an increased cholecystitis risk.

Conclusions: Our meta-analysis examined adjusted risk factors to reliably estimate the main risk factors associated with cholecystitis after SEMS placement for MDBO. Integrating our findings into a prediction model may help identify high-risk individuals.