Real time prediction of the fatigue behavior of peripheral stents

Fatigue resistance of Nitinol peripheral stents implanted into atheroscelorotic femoro-popliteal arteries is a critical issue due to the particular biomechanical environment of this district. Hip and knee joint movements associated with patient´ daily activities expose the superficial femoral artery, and therefore the implanted stents, to large and cyclic deformations. These loadings may cause fatigue fracture of stents and may lead to re-occlusion of the artery. Since this is a clinical relevant issue, the aim of project RT3S (Real Time Simulations for Safer vascular Stenting) is to develop a software to help surgeons in the decision making process. The software provides the clinician with the risk of stent fatigue fracture, associated to a particular stent design, vessel morphology and loading conditions, while he/she is planning the operation. In this paper we present the development of a 3D finite element model, based on a set of parameters, including stent type, size and length, degree of stenosis and patient stenosis features; the parametric model aims to pre-compute a huge number of results to store, later, in the software database for the real time prediction of stent fatigue behavior.