APPLICATION OF THE FINITE ELEMENT METHOD IN THE FATIGUE LIFE PREDICTION OF A STENT FOR A PERCUTANEOUS HEART VALVE

The fatigue failure of the stent component of a percutaneous aortic heart valve (PAHV) is an event that could be fatal to the patient. Therefore, the fatigue life prediction of a stent intended for application in a PAHV is a major consideration during the design and development phase of the device. Since the stent component will be subjected to both cyclic blood pressure as well as cyclic valve-leaflet forces, the combined effect of these loads must be taken into account for the analysis of the fatigue life. This paper expands on a methodology developed by Marrey et al.(10) to incorporate the combined loading of both the cyclic blood pressure as well as the cyclic leaflet forces in the fatigue life assessment of stents intended for application in percutaneous aortic heart valves. It was found that the developed methodology, which utilizes the finite element method (FEM), provides a simple and cost-effective tool to quantitatively determine the fatigue resistance of the stent component, thereby enabling the designer to compare different stent designs with respect to their resistance against fatigue. Two different stent designs were analyzed using this approach and it was found that they exhibited similar resistances to fatigue and that resistance to fatigue is influenced by strut width.