Risk factors for cholecystitis after metal stent placement in malignant biliary obstruction

Background: Cholecystitis related to metal stent placement is a morbid event. Objective: This study evaluated the risk factors of cholecystitis after metal stenting for malignant biliary obstruction. Patients: Between December 1997 and April 2003, 155 patients who were treated with a metal stent for malignant biliary obstruction were retrospectively enrolled. Main Outcome Measurements: The incidence and characteristics of patients with cholecystitis were evaluated and compared with those of patients without cholecystitis. Patient characteristics and tumor or procedure-related data were recorded for the following variables: sex, age, tumor and stent length, stent type (covered vs uncovered), cholangitis before ERCP, degree of gallbladder filling with contrast medium during ERCP, primary disease type (Klatskin vs others), presence of gallbladder stones, and the relationship of the cystic duct orifice to the location of the tumor (across vs others). Results: There were 15 (9.7%) patients diagnosed with cholecystitis after metal stent insertion. The onset of cholecystitis was on average 4.6 days (range 1 to 26) after the procedure. We found that an obstruction across the cystic duct orifice by tumor (P < .01, odds ratio 12.7) and the presence of gallbladder stone (P = .01, odds ratio 6.6) were positively related to the cholecystitis after metal stent insertion. Limitations: The limitations of the study were the use of multiple types of stents and the retrospective design. Conclusions: This study demonstrated that an obstruction across the cystic duct by tumor and the presence of gallbladder stone were risk factors for the development of cholecystitis after metal stent placement.