Design and finite element-based fatigue prediction of a new self-expandable percutaneous mitral valve stent

Percutaneous heart valve replacement is currently limited to the replacement of pulmonary and aortic valves in a targeted group of patients. Designing a heart valve for mitral valve replacement is further limited by its distinctive anatomical feature, which places a constraint on its range of design options. To overcome such limitations, the objectives of this study were to use computational modeling and simulation to design a new Nitinol-based mitral valve stent and evaluate its crimpability and fatigue behavior. A self-expandable stent with new features that could address issues of valve migration and paravalvular leaks was generated using CAD based conceptual modeling. Its expansion, crimpability, deployment patterns, and fatigue behavior were simulated and analyzed. Our simulations incorporated cyclic cardiac muscle loading, cyclic blood pressure loading, as well as cyclic valve-leaflet forces in the fatigue life assessment for mitral valves. Our results showed that the stent model passed the fatigue test under the aforementioned loading conditions. Our model provides a simple, fast and cost-effective tool to quantitatively determine the fatigue resistance of stent components. This is of great value to the design of new prosthetic heart valve models, as well as to surgeons involved in valve replacement.