Use of Polyetherurethane to Improve the Biocompatibility of Vascular Stents

Abstract

Purpose: To investigate potential differential growth of neointima following overdilating arterial trauma with polyetherurethane-coated versus bare metalìc stents in swine. Methods: Twelve specially constructed tantalum stents, 6 coated with polyetherurethane block copolymer and 6 uncoated, were overdilated by 25% in 12 normal renal arteries of six swine. The stents were harvested 8 weeks after implantation and prepared for histologic examination. Neointimal thickness was quantified and analyzed for significant differences between coated and uncoated prostheses. Results: All specimens demonstrated fractures of the internal elastic lamina consistent with vascular injury. There was significantly less neointimal formation (0.0001 < p < 0.05) in coated specimens as compared to uncoated controls in each test animal. Conclusion: The vascular response to overdilating stent trauma appears to be moderated with the use of polyetherurethane block copolymer as compared to control.