Electron-microscopic examination of silicon-carbide-coated endovascular stents

The problem of restenosis in blood vessels after balloon angioplasty could not be overcome by the use of metallic stents as had been anticipated. With respect to restenosis, clinical and experimental results now focus the attention on the risk that stents could initiate or potentiate vascular lesions, especially by inhomogenous stent expansion. Here the stent design seems to dominante depending on the use of well rounded structural stent-elements with appropriate surfaces and a material deposition which is compatible with a homogeneous stent expansion. With respect to hemocompatibility the surface quality of the stents is of great importance, too. Coating of surfaces of metallic stents for the enhancement of hemocompatibility might create new risks of blood vessel damages and requires a careful consideration of the co-expansional behaviour of the metallic substrate and the coating material. With these problems in mind the surface coated stent Tensum 3 of the Biotronik company was investigated.