A randomized trial comparing uncovered and partially covered self-expandable metal stents in the palliation of distal malignant biliary obstruction

Background: The most common complication of uncovered biliary self-expandable metal stents (SEMSs) is tumor ingrowth. The addition of an impenetrable covering may prolong stent patency. Objective: To compare stent patency between uncovered and partially covered SEMSs in malignant biliary obstruction. Design: Multicenter randomized trial. Setting: Four teaching hospitals. Patients: Adults with inoperable distal malignant biliary obstruction. Interventions: Uncovered or partially covered SEMS insertion. Main Outcome Measures: Time to recurrent biliary obstruction, patient survival, serious adverse events, and mechanism of recurrent biliary obstruction. Results: From October 2002 to May 2008, 129 patients were randomized. Recurrent biliary obstruction was observed in 11 of 61 uncovered SEMSs (18%) and 20 of 68 partially covered SEMSs (29%). The median times to recurrent biliary obstruction were 711 days and 357 days for the uncovered and partially covered SEMS groups, respectively (P = .530). Median patient survival was 239 days for the uncovered SEMS and 227 days for the partially covered SEMS groups (P = .997). Serious adverse events occurred in 27 (44%) and 42 (62%) patients in the uncovered and partially covered SEMS groups, respectively (P = .046). None of the uncovered and 8 (12%) of the partially covered SEMSs migrated (P = .0061). Limitations: Intended sample size was not reached. Allocation to treatment groups was unequal. Conclusions: There was no significant difference in time to recurrent biliary obstruction or patient survival between the partially covered and uncovered SEMS groups. Partially covered SEMSs were associated with more serious adverse events, particularly migration. (Clinical trial registration number: NCT01047332.) (Gastrointest Endosc 2010;72:907-14.)