Covered Wallstent for the Management of Malignant Biliary Obstruction

Abstract

Purpose: We had previously reported the efficacy and complications of handcrafted polyurethane-covered Wallstent (Gastrointest Endosc 2002; 55: 366-70) and a randomized control study of “covered” vs. “uncovered” Diamond stent (Gut, in press) for management of distal malignant biliary obstruction. We evaluated Covered Wallstent (Microvasive Endscopy, Boston Scientific Corp., Natick, Mass.) that was commercially available and had silicone membrane resistant to hydrolysis. Methods: Sixty-nine patients with unresectable distal biliary malignancies underwent placement of Covered Wallstent between October 2001 and October 2003. Type of primary tumor was as follows; pancreatic cancer 41, cholangiocarcinoma 18, gallbladder cancer 1, ampullary cancer 1, metastatic cancer 8. Covered Wallstents were inserted endoscopically in 61 cases, or percutaneous-transhepatically in 8 cases. Results: The mean stent patency period and the mean survival period were 140 days and 202 days, respectively. Stent occlusion was observed in 7 cases (10.1 %) with the mean patency of 144 days, 3 cases were caused by biliary sludge, 3 by food impaction, 1 by tumor overgrowth. Tumor ingrowth was not observed. There were 23 cases with other complications including 11 stent migration, 5 cholangitis, 4 pancreatitis, and 4 cholecystitis. The biliary obstruction was at the lower portion of common bile duct in all cases with stent migration. Tumor invasion to the main pancreatic duct was absent or minimal in all 4 cases with acute pancreatitis. Three cases received immediate stent removal and 1 case received conservative therapy and recovered within 3 days. Three cases with cholecystitis had tumor invasion to the cystic duct and received percuatneous cholecystostomy. Remaining one case had no tumor invasion to the cystic duct but gallbladder stones and improved by percutaneous aspiration. Three cases of cholangitis were due to kinking of the common bile duct at the proximal edge of the stent. In the remaining 2 cases with cholangitis, reflux of duodenal juice into the bile duct caused cholangitis because of peritonitis carcinomatosa or duodenal invasion by tumor. Conclusions: Covered Wallstent was effective for distal malignant biliary obstruction. Complications that needed the re-interventional procedure increased and are due to the characteristics of Covered Wallstent. The assessment of the risk factor of complications is important, and the modification of Covered Wallstent itself is necessary.