Self-expanding aortic valve stent-material optimization

Abstract

Vascular support structures are important devices for treating valve stenosis. Large population of patients is treated for valvular disease and the principal mode of treatment is the use of percutaneous valvuloplasty. Stent devices are proving to be an improved technology in minimal invasive cardiac surgery. This technology now accounts for 20% of treatments in Europe. This new technology provides highly effective results at minimal cost and short duration of hospitalization. During the development process, a number of specific designs and materials have come and gone, and a few have remained. Many design changes were successful, and many were not. This paper discusses the physical behavior of a hooked percutaneous aortic valve stent design using a finite element analysis. Specifically, the effects of crimping was simulated and analyzed for two types of realistic but different Nitinol materials (NITI-1 and NITI-2). The results show that both NITI-1 and NITI-2 had good crimping performance. The analysis performed in this paper may aid in understanding the stent's displacement ranges when subjected to physiological pressures exerted by the heart and cardiac blood flow during abnormal cardiovascular conditions. It may also help to evaluate the suitability of a Nitinol for fabrication purposes.