Study on Bending Stiffness of Stents.

The stent implantation is a low invasive and effective method to treat the coronary artery blockage. The problem of stenting is restenosis because of initimal thickening, which occurs in 20%. Restenosis rate is related to the radial stiffness and bending stiffness of a stent. In order to prevent the recurrences of coronary stenosis, it is necessary to investigate the mechanical properties of a stent. However, test method about these properties is little known. The purpose of this study is to propose a method to estimate the flexibility of a stent. To achieve the aim, we developed a test apparatus by use of four points bending and measured the bending stiffness of 4 stent structures. The result showed that the link stent structure was more flexible than the tube one. Considering a link configuration, S shaped link stent structure was flexible. The flexible stent deformed smoothly by bending moment. On the other hand, the low flexible stents deformed with buckling. This feature was clear in compressive side when stent was bent.