title: Novel antireflux covered metal stent for recurrent occlusion of biliary metal stents: a pilot study.
abstract: BACKGROUND
  Feasibility of antireflux metal stent (ARMS), designed to prevent duodenobiliary reflux, was reported in patients with distal malignant biliary obstruction. In this prospective pilot study, we aimed to evaluate a newly designed ARMS as a reintervention for self-expandable metallic stent (SEMS) occlusion believed to be caused by duodenobiliary reflux.
  
  
  METHODS
  Patients with non-resectable distal malignant biliary obstruction were included in whom a prior SEMS was occluded as a result of sludge or food impaction between March 2010 and January 2012 at two Japanese tertiary referral centers. The occluded SEMS were endoscopically removed, if possible, and subsequently replaced by a newly designed ARMS. We evaluated the technical success rate and complications of ARMS and compared the time to occlusion of ARMS with that of prior SEMS.
  
  
  RESULTS
  A total of 13 patients were included. ARMS was successfully placed in all patients in a single procedure. No procedure-related complications were identified. ARMS occlusion occurred in two patients (15%), the causes of which were sludge in one patient and unknown in the other. ARMS migration occurred in four patients (31%). ARMS patency time was significantly longer than that of prior SEMS (median, not available vs 58 days; P = 0.039).
  
  
  CONCLUSIONS
  This newly designed ARMS is a technically feasible, safe, and effective reintervention for SEMS occlusion as a result of sludge or food impaction. An anti-migration mechanism to improve the outcomes of ARMS should be considered.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Gastroenterology, Japanese Red Cross Medical Center, Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hamada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kogure
authors.forename: Osamu
authors.initials: O
authors.lastname: Togawa
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Kawakubo
authors.forename: Natsuyo
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tsujino
authors.forename: Naoki
authors.initials: N
authors.lastname: Sasahira
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirano
authors.forename: Minoru
authors.initials: M
authors.lastname: Tada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D000368:Aged; D001655:Bile Reflux / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D001706:Biopsy; D002760:Cholangiopancreatography, Endoscopic Retrograde; D002779:Cholestasis / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D020099:Coated Materials, Biocompatible; D004067:Digestive System Neoplasms / Q000150:complications* / Q000175:diagnosis; D013505:Digestive System Surgical Procedures / Q000379:methods*; D004867:Equipment Design; D004868:Equipment Failure; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D010865:Pilot Projects; D011446:Prospective Studies; D012008:Recurrence; D015607:Stents; D016896:Treatment Outcome
chemical_list: D020099:Coated Materials, Biocompatible
keywords: antireflux; distal malignant biliary obstruction; self-expandable metallic stent (SEMS)