Efficacy and safety of a novel polytetrafluoroethylene-coated self-expandable metal stent for distal malignant biliary obstruction

Background Stent migration and sludge formation remain significant problems associated with covered self-expandable metal stents (CSEMSs). The EGIS biliary stent fully covered flare type (EGIS biliary stent), a new type of polytetrafluoroethylene-coated self-expandable metal stent with low axial force and an anti-migration system, was developed to overcome these disadvantages. We conducted this study to evaluate the efficacy and safety of this stent in comparison with conventional CSEMS (c-CSEMS). Methods We retrospectively analyzed consecutive patients with unresectable pancreatic cancer who received initial CSEMS for distal malignant biliary obstruction. The primary outcome was time to recurrent biliary obstruction (RBO). Secondary outcomes included technical success rate, functional success rate, stent-related adverse events, causes of RBO, and re-intervention. Results A total of 40 patients were included (EGIS group: 20; c-CSEMS group: 20). The technical and functional success rates were similar between the two groups. Stent-related adverse event rates (20% vs. 15%, p > 0.99) and overall RBO rates (56% vs. 50%, p > 0.99) were not significantly different between the two groups. Stent migration was the most common cause of RBO in the EGIS group, while stent occlusion was in the c-CSEMS group. The median time to RBO (102 vs. 434 days, p = 0.10) was not significantly different between the two groups. Endoscopic transpapillary re-intervention was successful in most patients in both groups. Conclusions The EGIS biliary stent was not associated with a longer time to RBO compared to c-CSEMS. Further improvements, especially against stent migration, are needed to improve its efficacy.