title: Covered metallic stenting for malignant distal biliary obstruction: clinical results according to stent type.
abstract: BACKGROUND
  In the endoscopic management of unresectable malignant biliary obstructions, covered metallic stents (CMSs) showed longer patency and lower incidence of stent occlusion than uncovered metallic stents (UMCs). However, there are very few reports on factors influencing the results of inserting CMSs. We evaluated differences in clinical results according to stent type.
  
  
  METHODS
  We reviewed the results of four types of CMS (polyurethane-covered Diamond stent (PCD), silicone-covered WALLSTENT (SCW), ComVi stent, and VIABIL biliary stent) and an uncovered MS (UMS), based on our experience and the literature. CMSs were characterized according to the axial and radial forces, covering (partial, full), smoothness of the inner surface, and presence of an anti-migration system.
  
  
  RESULTS
  CMSs were patent significantly longer than UMSs. There were differences in stent patency among the CMSs, including the cause of occlusion and other complications. The PCD had good patency and a low incidence of migration. The ComVi stent occluded early due to food impaction, but had the longest median stent patency and a low migration rate. The incidence of migration of SCW was relatively high and the SCW was occluded primarily by sludge.
  
  
  CONCLUSIONS
  We should assess the differences between the various CMSs and select the best one for each patient.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. isayama-tky@umin.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Kawakubo
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kogure
authors.forename: Osamu
authors.initials: O
authors.lastname: Togawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hamada
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Natsuyo
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Sasahira
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirano
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tsujino
authors.forename: Minoru
authors.initials: M
authors.lastname: Tada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D001650:Bile Duct Neoplasms / Q000150:complications* / Q000601:surgery; D002760:Cholangiopancreatography, Endoscopic Retrograde; D002779:Cholestasis / Q000209:etiology / Q000601:surgery*; D020099:Coated Materials, Biocompatible; D006801:Humans; D011474:Prosthesis Design; D015607:Stents
chemical_list: D020099:Coated Materials, Biocompatible