title: Pilot study of a novel, large-bore, fully covered self-expandable metallic stent for unresectable distal biliary malignancies.
abstract: OBJECTIVE
  In patients with unresectable malignant distal biliary obstruction, covered self-expandable metallic stents (CSEMS) may remain patent longer than uncovered self-expandable metallic stents as a result of tumor ingrowth prevention. One main cause of recurrent biliary obstruction (RBO) in CSEMS is sludge formation, which can be prevented using a large-bore stent. Therefore, we developed a novel, 12-mm diameter fully covered SEMS (FCSEMS) and investigated its clinical safety, efficacy, and rate of adverse events.
  
  
  METHODS
  This prospective, multicenter pilot study, which ran between June 2011 and November 2012, included 38 consecutive patients with unresectable malignant distal biliary obstruction. All patients underwent endoscopic insertion of our novel stent. Primary endpoint was non-RBO rate 6 months after placement.
  
  
  RESULTS
  Technical and functional success rates of the procedures were 100%. Six-month non-RBO rate was 50%, and median time to RBO was 184 days. Median survival time was 241 days. Twelve patients died within 6 months after stent placement without RBO. RBO was observed in 10 patients (26%), with seven experiencing stent occlusion and three experiencing stent migration. Adverse events other than RBO (at <30 days) developed in six patients (16%; cholecystitis, one; pancreatitis, one; hyperamylasemia, one; pancreatic ductitis, one; abdominal pain, two). Stent removal for reintervention was successfully completed in eight patients.
  
  
  CONCLUSIONS
  Our novel FCSEMS may be safe and effective for managing malignant distal obstruction with an acceptable incidence of adverse events.
authors.affiliation: Department of Gastroenterology, Gifu Municipal Hospital, Gifu, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Mukai
authors.affiliation: Department of Gastroenterology, Teikyo University Mizonokuchi Hospital, Kawasaki, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yasuda
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwashita
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Itoi
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.|Department of Gastroenterology and Hepatology, Center for Digestive Disease, The University of Miyazaki, Miyazaki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawakami
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kogure
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
mesh_terms: D001650:Bile Duct Neoplasms / Q000150:complications*; D002779:Cholestasis / Q000628:therapy*; D006801:Humans; D010865:Pilot Projects; D011446:Prospective Studies; D000069322:Self Expandable Metallic Stents; D015607:Stents
keywords: Covered self-expandable metallic stent (CSEMS); Endoscopic retrograde cholangiopancreatography; Extrahepatic bile duct