title: Newly designed stent for endoscopic bilateral stent-in-stent placement of metallic stents in patients with malignant hilar biliary strictures: multicenter prospective feasibility study (with videos).
abstract: BACKGROUND
  Endoscopic management of malignant hilar biliary strictures is difficult even for an experienced endoscopist. Moreover, endoscopic placement of bilateral metal stents is considered very difficult and complicated.
  
  
  OBJECTIVE
  We explored the feasibility and efficacy of the placement of a newly designed metal stent for an endoscopic bilateral stent-in-stent procedure for the management of malignant hilar biliary strictures.
  
  
  METHODS
  Multicenter prospective feasibility study.
  
  
  METHODS
  Five academic tertiary referral centers.
  
  
  METHODS
  Thirty-five patients with malignant hilar biliary strictures of Bismuth type II or higher were enrolled.
  
  
  METHODS
  Bilateral stent placement by an endoscopic stent-in-stent procedure.
  
  
  METHODS
  Technical success, functional success, early and late complications, stent patency.
  
  
  RESULTS
  The overall technical success rate of the newly designed metal stent was 94.3% (33/35). The success rate of the stent-in-stent procedure in a single session was 82% (27/33) per protocol and 77% (27/35) as intent to treat. In cases in which the initial stent-in-stent procedure failed, patients underwent the endoscopic stent-in-stent procedure for contralateral stent placement at 2 days (6%, 2/33) or 4 days (12%, 4/33) after the initial stent placement. There was no percutaneous insertion of a contralateral stent in these patients. There was no stent-related early or late complication in any enrolled patient. Functional success was 100% (33/33). Reintervention because of stent malfunction was 6% (2/33). These 2 patients showed sludge formation in the stent. During follow-up, there was no stent tumor ingrowth or overgrowth in the placed stent in any enrolled patient. According to the Kaplan-Meier analysis, median survival and stent patency were 180 days and 150 days, respectively.
  
  
  CONCLUSIONS
  An uncontrolled feasibility study with a small patient population and a limited follow-up period.
  
  
  CONCLUSIONS
  The newly designed metal stent for the endoscopic bilateral stent-in-stent procedure may be feasible and effective for malignant hilar biliary strictures.
authors.affiliation: Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Park
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Moon
authors.forename: Hyun Jong
authors.initials: HJ
authors.lastname: Choi
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Cha
authors.forename: Jong Hyeok
authors.initials: JH
authors.lastname: Kim
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Seo
authors.forename: Sung-Koo
authors.initials: SK
authors.lastname: Lee
authors.forename: Sang-Heum
authors.initials: SH
authors.lastname: Park
authors.forename: Moon-Sung
authors.initials: MS
authors.lastname: Lee
authors.forename: Sun-Joo
authors.initials: SJ
authors.lastname: Kim
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001661:Biliary Tract Neoplasms / Q000628:therapy*; D001672:Biocompatible Materials; D003251:Constriction, Pathologic / Q000628:therapy; D016145:Endoscopy, Digestive System; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D011446:Prospective Studies; D015607:Stents; D016896:Treatment Outcome
chemical_list: D001672:Biocompatible Materials; D008670:Metals