Application of the Finite Element Method in the Fatigue Life Prediction of a Stent for a Percutaneous Heart Valve

Abstract

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.

Fluid–Structure Interaction Model of a Percutaneous Aortic Valve: Comparison with an In Vitro Test and Feasibility Study in a Patient-Specific Case

“…Although in recent years numerical studies in this field have emerged, as far as the authors are aware, fluid-structure simulations of percutaneous valves are absent. Only structural 3,6,14,17,23,32,39 or fluid dynamics 3,13,31,37 studies have been carried out. This study used FSI simulations both in the in vitro durability testing and in the patient-specific set-up.…”

“…In the literature, mathematical models related to TAVR are increasing. They can be related to the understanding of the mechanical behavior of the stented valve, the aortic root and the leaflet dynamics from a structural point of view 3,6,14,17,23,32,39 or to the hemodynamics inside the treated aortic root. 3,13,31,37 To the best of our knowledge, scientific publications which take into account both the mechanical and the fluid aspects in a coupled manner are absent.…”

Development and testing of a transcatheter heart valve with reduced calcification potential

“… THV. On the left is a computer design of the valve that was developed using finite-element analysis ( 41 – 44 ). Note the balloon expandable stent frame with pericardial leaflets and a braided PTFE hemostatic cuff on the inside of the stent.…”

Focus areas of cardiovascular medical device research in South Africa

“…Examples include the development of a percutaneous aortic heart valve, [9] numerical simulation of the behaviour of aortic valves [10] and the application of finite element methods to improve stent design for a percutaneous heart valve. [11] Similar in proportion to valvular devices were devices for vascular diseases (17%), addressing conditions related to blood vessels. A large proportion of the devices (12%) were classified as 'nonspecific' as these either addressed several aspects of the cardiovascular system or did not clearly define the disease, structure or condition addressed.…”