USE OF POLYETHERURETHANE TO IMPROVE THE BIOCOMPATIBILITY OF VASCULAR STENTS

Purpose: To investigate potential differential growth of neointima fol lowing overdilating arterial trauma with polyetherurethane-coated vers us bare metallic stents in swine. Methods: Twelve specially constructe d tantalum stents, 6 coated with polyetherurethane block copolymer and 6 uncoated, were overdilated by 25% in 12 normal renal arteries of si x swine. The stents were harvested 8 weeks after implantation and prep ared for histologic examination. Neointimal thickness was quantified a nd analyzed for significant differences between coated and uncoated pr ostheses. Results: All specimens demonstrated fractures of the interna l elastic lamina consistent with vascular injury. There was significan tly 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 cont rol.