title: In vivo study of polyurethane-coated Gianturco-Rosch biliary Z-stents.
abstract: OBJECTIVE
  Prototypes of Gianturco-Rosch Z-stents coated with polycarbonate urethane (PCU) were placed in the biliary tree of pigs, in order to test their biomechanical behavior, stability, and biocompatibility.
  
  
  METHODS
  The stents were surgically implanted in the common bile duct of three pairs of pigs, which were killed after 1, 3, and 6 months respectively. Explanted livers from pigs of the same race, age, and size were used to provide comparative data. The bile ducts were radiologically and histopathologically examined; the stents were processed and examined by scanning electron microscopy.
  
  
  RESULTS
  No complications occurred and the animals showed a normal weight gain. The main bile duct appeared radiologically and macroscopically dilated, but the stents proved to be in place. Histologically, the bile duct epithelium was destroyed, but neither hyperplastic nor inflammatory fibrotic reactions of the wall were evident. Both the metallic structure and the polymeric coating of the stents were intact. A layer of organic material with a maximum thickness of approximately 3 micron was evident on the inner surface of the stents.
  
  
  CONCLUSIONS
  The present in vivo study demonstrates the biocompatibility, efficacy, and stability of PCU-coated Gianturco-Rosch stents in the biliary environment.
authors.affiliation: Divisione di Radiologia Gastroenterologica, Istituto Nazionale Tumori, Via Venezian 1, I-20133 Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Severini
authors.forename: S
authors.initials: S
authors.lastname: Mantero
authors.forename: M C
authors.initials: MC
authors.lastname: Tanzi
authors.forename: A
authors.initials: A
authors.lastname: Cigada
authors.forename: F
authors.initials: F
authors.lastname: Addis
authors.forename: G
authors.initials: G
authors.lastname: Cozzi
authors.forename: M
authors.initials: M
authors.lastname: Salvetti
authors.forename: S
authors.initials: S
authors.lastname: Andreola
authors.forename: A
authors.initials: A
authors.lastname: Motta
authors.forename: E
authors.initials: E
authors.lastname: Regalia
authors.forename: A
authors.initials: A
authors.lastname: Pulvirenti
authors.forename: E
authors.initials: E
authors.lastname: De Pedri
authors.forename: R
authors.initials: R
authors.lastname: Doci
mesh_terms: D000818:Animals; D017734:Bile Ducts, Extrahepatic; D001651:Cholestasis, Extrahepatic / Q000628:therapy*; D020099:Coated Materials, Biocompatible; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes; D015607:Stents; D013552:Swine
chemical_list: D020099:Coated Materials, Biocompatible; D011140:Polyurethanes