Cholecystitis after metallic stent placement is an issue requiring attention.
Cholecystitis seems to occur mainly in patients with tumor involvement to the cystic duct orifice.
Dr Hiroyuki Isayama and colleagues from Japan identified risk factors for cholecystitis in patients treated with covered or uncovered metallic stents.
The researchers analyzed 246 patients who received metallic stent placement between 1997 and 2005 for the treatment of unresectable distal malignant biliary obstruction.
Of these patients, 171 had covered stents, and 75 had uncovered metallic stents.
Causative diseases included pancreatic cancer in 162, papillary cancer in 10, bile duct cancer in 41, and metastatic nodes in 33 patients.
The research team diagnosed tumor involvement to orifice of the cystic duct based on cholangiography and intraductal ultrasonography.
Cholecystitis after metallic stent placement was found in 5% of patients.
The researchers observed no significant difference in the incidence of cholecystitis between covered and uncovered metallic stents.
By univariate analysis, tumor involvement of the orifice of the cystic duct, metallic stents placed above the papilla, and stricture located at midportion were associated with cholecystitis.
By using multivariate analysis, the team noted that only tumor involvement of the orifice of the cystic duct was a risk factor, with an odds ratio of 47.
Dr Isayama's team commented, “Cholecystitis after metallic stent placement is associated with tumor involvement to the orifice of the cystic duct, regardless of the type of stent.”