Risk factors for cholecystitis after stent placement in patients with distal malignant biliary obstruction.

Background /Purpose Limited data are available for acute cholecystitis after Self-Expandable Metallic Stent (SEMS) placement in patients with malignant distal biliary obstruction. We aimed to identify risk factors for cholecystitis. Methods This was a retrospective, single-center study of 280 patients (336 stents) who received endoscopic SEMS placement between May 2005 and April 2016. Clinical records were used to perform risk factor analyses. Results Of 336 SEMS placement procedures, 25 (7.4%) led to development of cholecystitis. Logistic regression analysis revealed three independent risk factors: covered SEMS (P = .014), tumor involvement to the cystic duct (P = .017), and presence of gallstones (P = .022). Median time to cholecystitis onset was shorter with covered SEMS than with uncovered SEMS (P = .034), and in patients with pancreatic cancer compared to those with other cancers (P = .001). Severe cholecystitis developed within 30 days after covered SEMS placement in three patients with pancreatic cancer without tumor involvement to the cystic duct. Conclusions Use of covered SEMS might be a risk factor for cholecystitis onset within 30 days after placement. Clinicians should be aware of the risk for severe cholecystitis after covered SEMS placement, even if the tumor does not invade the cystic duct.