7259 Which are the best metallic stents for palliating inoperable malignant biliary strictures; original, polyurethane-covered or newly designed covered metallic stent ?

BACKGROUND: Implantation of self-expanding metallic stents is anestablished palliation therapy for malignant biliary strictures. Wedesigned the polyurethane covered metallic stents and treated fiftypatients with them. We confirmed many merit of covered stents, but severalcomplications after the stent implantation remain still now. Recentlywe newly modified covered metallic stents to avoid the stent migration. AIM: We studied the clinical effectiveness of the covered metallic stents and the modified covered stents compared with the uncoverd stents. PATIENTS AND METHODS: Sixty eight patients (36 males, 32 females, mean age 73) with malignant biliary strictures have been treated with polyurethane-covered metallic stents (n= 50), modified covered stents (n= 8) and uncovered metallic stents (n= 10).We made the polyurethane membrane , using solid polyurethane and a glass tube and covered it outside the stent. We originally designed polyurethane membrane with the thickness of 0.05mm. Recently we modified the covered stent: i.e. we put the polyurethane membrane inside the stent.We treated twenty eight patients transhepaticaly and thirty eight endoscopically. For the hilar strictures two fully covered setnts were implanted like Y shape, using percutaneous transhepatic cholangioscopy. RESULTS: Stent placement was technically successful in all patients. None of procedure-related complication was confirmed. Patency period was 7.4 months of uncovered group and 11.84 months of covered group in the longer follow-up period than six months. Stent obstruction due to tumor ingrowth occurred in five ptients (50%) of uncovered metallic stents with a median time to obstruction of 24 weeks and none of covered group except two cases with tumor ingrowth due to technical immaturity. Stent migration was cofirmed in four patients (8%) of fully covered group but not confirmed in the patients treated with the modified stents. Tumor overgrowth was confirmed in six patients (12%) of covered group because of short length of the stents. Mucosal hyperplasia was confirmed in one patient (2%) of partially covered group. CONCLUSION:We think that the covered and modified covered metallic stents are good alternatives for palliating malignant biliary strictures.We believe the best stent will be newly modified covered stent.