EVALUATION OF INTRAVASCULAR STENT FLEXIBILITY BY MEANS OF NUMERICAL ANALYSIS

INTRODUCTION Nowadays stent therapy is widely adopted to treat atherosclerotic vessel diseases. The high commercial value of these devices and the high prototypation costs suggest to use finite element analyses, on behalf of classical trial and error technique, to design and verify new models [1-5]. In this paper a methodology based on the finite element method (FEM) is proposed to study new generation stent performance in terms of flexibility. Indeed, the stent ability to bend in order to accommodate vessel turns or angles during delivery is one of the most significant prerequisite for a good stent behavior. Herein, two different FEM models realized resembling two new generation intravascular stents were developed; the main model dimensions were obtained by means of a stereo microscope. Bending tests under displacement control in the unexpanded and expanded configuration were carried out. A curvature index defined as the ratio between the rotation angles at the extremes and the length of the stent yielded comparative information about the device capability to be delivered into tortuous vessels and to conform to their contours.