A Comparison of the Finite Element Method and Bench Testing for the Fatigue to Fracture Evaluation of a Group of Self-Expanding Nitinol Stents

The design of self-expanding nitinol stents to treat peripheral arterial disease offers a number of unique challenges. Primary among these is the potentially complex loading environment that these stents must endure, without fracture, for an extended period. As an example, for the superficial femoral artery (SFA), the loading environment on a stent can consist of axial, bending, torsional and pulsatile loads. These loads induce alternating strain that must be accommodated in the device design to ensure suitable fatigue life. Other stent design criteria relate to satisfactory radial force, as well as the ability to achieve delivery system requirements (i.e., volumetric constraints, good compression and deployment characteristics).