title: Reintervention for occluded metal stent in malignant bile duct obstruction: A prospective randomized trial comparing covered and uncovered metal stent.
abstract: OBJECTIVE
  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).
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ban Seok
authors.initials: BS
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ji Kon
authors.initials: JK
authors.lastname: Ryu
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dong Kee
authors.initials: DK
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Chung
authors.affiliation: Department of Internal Medicine, Inje University Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea.
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jaihwan
authors.initials: J
authors.lastname: Kim
authors.affiliation: Center for Liver Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Sang Myung
authors.initials: SM
authors.lastname: Woo
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sang Hyub
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Center for Liver Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D002779:Cholestasis / Q000209:etiology / Q000601:surgery*; D004067:Digestive System Neoplasms / Q000150:complications* / Q000188:drug therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation / Q000295:instrumentation / Q000379:methods; D015607:Stents; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D008670:Metals
keywords: malignant biliary obstruction; metal stent; stent occlusion; stent patency