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.