NEW METHOD OF COVERED WALLSTENTS FOR DISTAL MALIGNANT BILIARY OBSTRUCTION TO REDUCE EARLY STENT‐RELATED COMPLICATIONS BASED ON CHARACTERISTICS

Aim: We previously reported a low occlusion rate with covered Wallstents for malignant biliary obstruction, but stent‐related complications other than occlusion posed a problem. A modified covered Wallstent insertion method based on stent characteristics was evaluated to reduce stent‐related complications. Methods: A total of 138 patients with distal malignant biliary obstruction received covered Wallstent placement. From October 2001 to October 2003, 69 patients received covered Wallstent placement (Group 1). Thereafter, we modified our stent insertion method and 69 patients received stent placement using this modified method from November 2003 to January 2007 (Group 2). The modified insertion method consists of endoscopic sphincterotomy carried out in patients without pancreatic duct invasion and longer stent placement with the center of the stent located in the center of the biliary stricture to prevent pancreatitis, kinking of the bile duct, and stent dislocation. A comparative analysis was carried out using prospectively collected data in these two cohorts. Results: Tumor ingrowth was not observed, and stent occlusion rate was 18.8% in Group 1 and 23.2% in Group 2. The overall rates of stent‐related complications did not differ (39.1% in Group 1 and 30.4% in Group 2), but stent‐related complications within 3 months decreased from 22 episodes in Group 1 to 13 episodes in Group 2. Median event‐free survival was prolonged by modified stent insertion method (125 days in Group 1 and 268 days in Group 2, P = 0.020), although cumulative survival and stent patency were not significantly different. Conclusions: Our modified method of covered Wallstent placement showed improved event‐free survival.