title: Type 1 collagen as an endovascular stent-graft material for small-diameter vessels: a biocompatibility study.
abstract: OBJECTIVE
  To compare patency rates and degrees of neointimal hyperplasia between bovine type 1 collagen stent-grafts and uncovered control stents in small-diameter vessels (< or =4 mm).
  
  
  METHODS
  Uncovered stainless-steel, balloon-expandable stents (n = 5) and type 1 collagen stent-grafts (n = 6) were implanted via the femoral arteries with use of 4-mm balloon catheters into the abdominal aorta of New Zealand White rabbits. Ten animals were available for follow-up. Subjects were followed for 1 month (three uncovered stents; three collagen stent-grafts) or 4 months (two uncovered stents; two collagen stent-grafts). Angiography was performed before animal sacrifice and luminal compromise was compared between groups. Histologic and immunohistochemical analysis was performed to determine presence of neointima and neointimal thickness and area; these parameters were also compared between groups.
  
  
  RESULTS
  All stents and stent-grafts remained patent at both time points. Luminal compromise was not detectable angiographically in any subject. Maximum neointimal thickness was less than 5 mum for all subjects. Neointimal thickness and area were not statistically significantly different between groups.
  
  
  CONCLUSIONS
  Type 1 collagen stent-grafts demonstrate excellent hemocompatibility and biocompatibility in small-diameter vessels in rabbits.
authors.affiliation: Department of Radiology, University of Virginia Health System, P.O. Box 800170, 1215 Lee Street, Charlottesville, Virginia 22908, USA.
authors.forename: Naomi H
authors.initials: NH
authors.lastname: Fujiwara
authors.forename: David F
authors.initials: DF
authors.lastname: Kallmes
authors.forename: Shu-Tung
authors.initials: ST
authors.lastname: Li
authors.forename: Horng-Ban
authors.initials: HB
authors.lastname: Lin
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Hagspiel
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000187:drug effects / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D024042:Collagen Type I / Q000494:pharmacology*; D004195:Disease Models, Animal; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000601:surgery; D005500:Follow-Up Studies; D006965:Hyperplasia / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D008955:Models, Cardiovascular; D011817:Rabbits; D011859:Radiography; D015607:Stents; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000187:drug effects / Q000601:surgery; D014654:Vascular Patency / Q000187:drug effects
chemical_list: D020099:Coated Materials, Biocompatible; D024042:Collagen Type I