Nitinol Stents: Does the Level of Coldwork on the Nitinol Tube Have an Impact on the Thermomechanical Properties of the Final Device?

摘要

Nitinol has become the best candidate material for manufacturing self-expanding peripheral stents, heart valve frames, endovascular grafts and many other cardiovascular devices (annuloplasty rings, catheter components, guidewires, etc.) [1]. Manufacturing companies and researchers have mainly paid their attention to design features and shape setting process to optimize nitinol device performances. Conversely, the raw material (nitinol tube) has been of low interest [2, 3] or not investigated as a source of variability for the stent properties. The purpose of the present study is an investigation on the impact of different raw material properties (strongly related to cycles of cold working) on radial forces and thermo-mechanical properties achieved by the final device.