A comparison of uncovered metal stents for the palliation of patients withmalignant biliary obstruction: nitinol vs. stainless steel

Background: Various types of self-expandable metal stents have been introduced for the palliation of malignant biliary obstruction. Aims: To compare the outcomes of WallFlex™ and Wallstent™ uncovered biliary self-expandable metal stents (SEMSs) for the palliation of patients with malignant biliary obstruction. Methods: Between October 2008 and December 2009, all SEMSs placed for malignant biliary obstruction were WallFlex™: all patients palliated were included in the study. Before October 2008, all the SEMSs placed for malignant biliary obstruction were Wallstent™, and the patients palliated from July 2007 to September 2008 were the comparative group. Results: A total of 58 WallFlex™ and 54 Wallstent™ SEMSs were placed, and efficacious biliary decompression was achieved in all patients. Early complications occurred in 5 patients in the WallFlex™ group and in 3 in the Wallstent™ group (p= ns). Late complications occurred in 6 patients in the WallFlex™ group and in 16 in the Wallstent™ group (p< 0.01). The overall patency of the self-expandable metal stent in the WallFlex™ and the Wallstent™ groups was similar (227 days vs. 215 days, p= ns). Mean patient survival was 242 days in the WallFlex™ group and 257 days in the Wallstent™ group (p= ns). Conclusions: We found no difference in terms of overall patency between the two types of SEMSs, but there was an increased rate of late adverse events in the Wallstent™ group.