Identification of risk factors for obstructive cholecystitis following placement of biliary stent in unresectable malignant biliary obstruction: a 5-year retrospective analysis in single center.

BACKGROUND: The risk factors for acute cholecystitis following biliary stent placement in patients with malignant biliary obstruction (MBO) have not been identified. We determined these risk factors and the efficacy of endoscopic ultrasound (EUS)-guided gallbladder drainage (GBD) as treatment. METHODS: We retrospectively analyzed patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) for MBO from October 2013 to September 2018, and those with unresectable MBO with intact gallbladder (GB) were enrolled. RESULTS: Acute cholecystitis occurred in 30 (15.7%) of 191 patients who underwent biliary stent placement for unresectable MBO. Logistic regression analysis confirmed that biliary stent across the orifice of the cystic duct (OCD) (odds ratio [OR] 6.02, 95% confidence interval [CI] 1.43-25.41, P = 0.015), GB opacification during ERCP (OR 13.07, 95% CI 4.22-40.50; P < 0.0001), and self-expandable metal stent (SEMS) (OR 14.19, 95% CI 4.36-46.18; P < 0.0001) were independent risk factors for cholecystitis. Subgroup analysis of patients who only underwent SEMS placement showed that biliary stent across the OCD and GB opacification were significant risk factors. Among the 25 patients who underwent EUS-GBD, the technical and clinical success rates were 100% and 96%, respectively. CONCLUSIONS: Biliary stent across the OCD, GB opacification, and SEMS were established as potential risk factors for post-ERCP cholecystitis. Thus, the strategy of using shorter stent length and avoiding unnecessary contrast injection could be a reasonable treatment option for selected patients with high risk of cholecystitis. Furthermore, EUS-GBD is not only safe and reliable for acute cholecystitis, but it also improves quality of life.