4649 Preliminary results of new covered biliary nitinol stent in patients with malignant obstruction of extrahepatic bile duct (ehd).

Abstract

Background : In malignant EHD obstruction, the endoscopic insertion of biliary stent is one of the available palliative therapies. Major problems of uncovered metal stents are tumor ingrowth, stent incorporation into the tumor, and impossibility in exchange of the stent. A newly developed covered self-expandable metal stent(SEMS) was designed to overcome such disadvantages of uncovered metal stent. However, Early serious complications such as pancreatitis or cholecystitis seems to be occurred frequently due to ductal obstruction by covering structure in covered SEMS. To compare the clinical efficacy and early complications of new nitinol SEMS covered with polyurethane(covered Niti-s biliary stent, Tae Woong Medical Inc, Seoul, Korea) with uncovered biliary metal stent(Wallstent, Schneider AG,Switzerland), we studied patients with malignant EHD obstuction. Methods : By prospective multicenter study, biliary stents were endoscopically inserted in 76 patients. Thirty five patients(M:F=20:15, mean age:68.8 years) received covered SEMS(covered stent group), and 41 patients (M:F=25:16, mean age:70.1 years) received Wallstent(Wallstent group). The causes of malignant EHD obstruction were bile duct cancer(21), pancreatic cancer(35), gallbladder cancer(12), and ampulla of Vater cancer(8). Results : 1) The success rate of endoscopic stent insertion was 100% in each groups. 2) There was no statistical difference in length of stenosis of common bile duct and stent between the two groups. 3) The mean follow-up period after placement of stent was 145.8±69.5 days in covered stent group, and 122.9±45.1 days in Wallstent group(p>0.05) 4) Early complications (within 30 days) such as stent migration into duodenum(2 cases) and mild acute pancreatitis(1 case) were developed in covered stent group(p>0.05). Acute pancreatitis was improved after removal of the covered nitinol SEMS. Late complications have not been noted in the two groups during follow-up period. 5) The 3 month patency rate was 88.0%(21/24) in covered stent group, 86.0%(18/21) in Wallstent group(p>0.05). 6) The causes of stent obstruction were bile sludge(1 case) and tumor ingrowth(2 cases) in Wallstent group(p>0.05). Conclusion : New covered biliary nitinol stent was as effective as Wallstent without early serious complications such as pancreatitis, cholecystitis and cholangitis, although long-term follow-up about its patency rate and complications are needed.