Prediction of fatigue fracture on peripheral stents

Alessandro Charini

Debora Testi

Gabriele Dubini
Politecnico di Milano

The rate of radiological and clinical failure of endovascular procedures in the peripheral circulation depends upon many factors, including the extent and anatomical distribution of disease, patient factors such as smoking, diabetes and activity levels and the mechanical behavior of the deployed stent. Fatigue resistance of Nitinol peripheral stents implanted into atherosclerotic femoro-popliteal arteries is a critical issue due to the particular biomechanical environment. Hip and knee joint movements associated with patient’s daily activities expose the superficial femoral artery, and therefore the implanted stents, to large and cyclic deformations. These loads may cause fatigue fracture of stents and may lead to re-occlusion of the artery (in-stent restenosis). In this paper we present a numerical/experimental approach aiming to compare the fatigue performance of different stents taking into account patient-specific factors in real time. This feature can be of help for planning of the endovascular intervention.