title: Polyethylene terephthalate and polyurethane coatings for endovascular stents: preliminary results in canine experimental arteriovenous fistulas.
abstract: OBJECTIVE
  To evaluate polyethylene terephthalate and polyurethane as coatings of vascular endoprostheses in the treatment of experimental arteriovenous fistulas (AVFs).
  
  
  METHODS
  Nineteen bilateral carotid artery-to-external jugular vein AVFs were created in 10 adult dogs. Fourteen polyethylene terephthalate-coated and five polyurethane-coated self-expandable nitinol stents were placed with a transfemoral approach. Angiography was performed immediately after placement, after 1 and 3 weeks, and at months 3, 6, 9, and 12. All grafts were examined histopathologically.
  
  
  RESULTS
  The AVF was successfully occluded with all but one of the polyethylene terephthalate-coated stents. Graft patency was seen with 12 polyethylene terephthalate-coated stents, while acute vessel occlusion was evident with two polyethylene terephthalate-coated stents following percutaneous transluminal angioplasty immediately after implantation. In the group with polyurethane-coated stents, three graft dislocations and two delayed vessel occlusions were observed. In both groups, histologic examination disclosed a mild foreign body reaction with a few macro-phages. No inflammatory reactions were seen. An unorganized fibrin layer was found adjacent to the polyurethane coating.
  
  
  CONCLUSIONS
  Polyethylene terephthalate-coated nitinol stents showed good biocompatibility and a high rate of occlusion of experimental AVFs. The mechanical properties of the polyethylene terephthalate coating were similar to those of the nitinol stents, which facilitated handling. Polyurethane-coated stents showed frequent dislocation.
authors: Department of Radiology, University of Cologne, Germany.
authors: F
authors: F
authors: Schellhammer
authors: M
authors: M
authors: Walter
authors: A
authors: A
authors: Berlis
authors: H G
authors: HG
authors: Bloss
authors: E
authors: E
authors: Wellens
authors: M
authors: M
authors: Schumacher
mesh_terms: D000497:Alloys; D000818:Animals; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D017536:Carotid Artery, Common; D020099:Coated Materials, Biocompatible; D004285:Dogs; D007601:Jugular Veins; D011093:Polyethylene Terephthalates; D011140:Polyurethanes; D011859:Radiography; D015607:Stents
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D011093:Polyethylene Terephthalates; D011140:Polyurethanes; C013616:nitinol