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CardioVascular and Interventional Radiology

, Volume 24, Issue 5, pp 324–328 | Cite as

Evaluation of Silicone as an Endovascular Stent Membrane: In Vivo Canine Studies

  • Arthur B. Fontaine
  • John J. Borsa
  • Eric Hoffer
  • Robert Bloch
  • Corali So
Laboratory Investigation

Abstract

Purpose: Comparative evaluation of the biological effects of a silicone-covered stent versus a bare-metal stent, in an animal model.

Methods: Twelve stent implants were placed in the iliac arteries of six adult dogs. Each animal received one 8-mm × 20-mm silicone-covered stent (Permalume; Boston Scientific Vascular, Watertown, MA, USA), in the right iliac artery and one Wallstent (Boston Scientific Vascular) of the same diameter and length in the left iliac artery, during systemic anticoagulation. Angiography was performed before and after implantations. Animals were then allowed to recover and no platelet suppression was given during a 6-week interval, after which the animals were euthanized. The stented arteries were isolated and pressure-fixed in situ with 10% buffered formalin at a pressure of approximately 100 mmHg for a period of 1 hr. Two of 12 stented specimens were opened lengthwise and the luminal surfaces were photographed. Ten of 12 stented arterial segments were encased in methacrylate, then stained with hematoxylin and eosin. Neointimal thickness was quantified on histologic cross-section, for both bare and covered stents. The mean neointimal thicknesses were compared for significant difference using a student t-test.

Results: All implants were widely patent at 6-week follow-up angiography. Histologic analysis showed bare metal stents covered by a thin uniform lining of neointima composed of smooth muscle cells in a hyaline matrix (mean thickness of 189 ± 47 μm). Silicone covered stents were devoid of neointima. There was no chronic thrombus or mature endothelium noted anywhere upon the internal silicone surfaces of any of the specimens. There was no foreign body reaction to the silicone cover.

Conclusion: Short-term implantation of a silicone-lined Wallstent in canine iliac arteries is well tolerated. Silicone appears to be inert at 6 weeks in this experimental application.

Key words: Stents—Stent grafts—Prostheses, silicone 

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Copyright information

© Springer-Verlag New York Inc. 2001

Authors and Affiliations

  • Arthur B. Fontaine
    • 1
  • John J. Borsa
    • 1
  • Eric Hoffer
    • 1
  • Robert Bloch
    • 1
  • Corali So
    • 1
  1. 1.Department of Radiology, University of Washington Medical Center, 1959 NE Pacific Street, RR-215, Seattle, WA 98195USA

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