Reintervention for occluded metal stent in malignant bile duct obstruction: A prospective randomized trial comparing covered and uncovered metal stent

Background and Aim: No prospective data are available on comparing covered and uncovered self-expandable metal stent (SEMS) for reintervention of occluded uncovered metal stents during endoscopic retrograde cholangiopancreatography in patients with malignant distal biliary obstruction. Methods: From June 2010 to November 2014, 43 patients with inoperable distal biliary obstruction of a previously placed uncovered SEMS were enrolled from three centers in Korea and randomly assigned to covered (n = 22) or uncovered SEMS group (n = 21). The primary outcome was overall stent patency. Secondary outcome was time-to-stent occlusion, patient survival, cause of stent occlusion, and adverse events. Results: Overall median patency of secondary stent was 112.0 days. Median stent patency of covered and uncovered SEMS was 112.0 and 181.0 days, respectively, (P = 0.373). There was a tendency towards a longer time-to-stent occlusion in uncovered SEMS group (median: 112.0 vs 181.0 days). However, it did not reach statistical significance (P = 0.214). Most common causes of occlusion were stent clogging (36.4%) and tumor ingrowth (33.3%) in covered and uncovered SEMS groups, respectively. There was no significant difference in median survival between the groups (median: 308 vs 300 days; P = 0.325). Acute cholangitis occurred in four patients (three in covered vs one in uncovered SEMS group, P = 0.607). Conclusions: In this exploratory trial, there were no statistically significant differences in stent patency, time-to-stent occlusion, patient survival, and complication rates between covered and uncovered SEMS groups. Larger confirmatory multicenter trial is needed for the clear conclusion (ClinicalTrials.gov: NCT01315522).