Similar performance but higher cholecystitis rate with covered biliary stents: results from a prospective multicenter evaluation

Background and study aims Endoscopic biliary stenting is now a well-established treatment method in patients with unresectable malignant biliary obstruction. Despite advances with metal stents, the problem of stent occlusion has not yet been resolved. Covered metal stents could reduce the occlusion rate by preventing tumor ingrowth, but have not been well evaluated. A prospective multicenter study was therefore conducted to evaluate the efficacy and disadvantages of covered Wallstents. Patients and methods Covered Wallstents were implanted endoscopically in 62 patients with inoperable distal malignant biliary obstruction. Complications, stent patency, and patient survival were analyzed. Results Stent insertion was achieved in 61 of the 62 patients (98.4 %). Procedure-related complications were observed in four patients, consisting of minor pancreatitis (n = 2) and abdominal pain due to stent expansion (n = 2). There was no procedure-related mortality. Seven patients died too early for proper assessment, so that a total of 54 patients were ultimately evaluated. Stent dysfunction occurred in 17 of the 54 patients (31.5 %). The reasons for dysfunction were proximal tumor overgrowth (n = 5), migration (n = 3), lithiasis or food impaction (n = 3), cholangitis without the need for a repeat biliary intervention (n = 5), and unknown (n = 1). The median period of stent patency was 142 days. No tumor ingrowth was observed. Acute cholecystitis was diagnosed in five patients (10 %) and was responsible for one death. Three stents were successfully removed. Conclusions Covered biliary metal stents are effective for the drainage of distal malignant biliary obstruction, with a dysfunction rate apparently similar to that of uncovered stents. However, the risk of acute cholecystitis appears to be a major concern with this type of stent in patients with gallbladder in situ. Further comparative studies are needed.