Mechanical Design of a Customizable Self-Expanding Endovascular Stent

Abstract

Stent migration and endoleak are common failure mechanisms for endovascular repair, both of which can be partially attributed to a lack in understanding of the mechanical properties of endovascular stents. A novel radial extensometer and machine vision system were developed to standardize testing methodology and improve the quality of collected radial force data. A converged finite element model of the radial extensometer was validated using experimental results for an uncovered 12mm stent. Torsion, t-bending and s-bending moments are all shown to contribute to stent performance. A small batch manufacturing process was developed to produce z-stents that are analogous to those fabricated by industry. A parametric study of stent design parameters showed that a lesser increase in bend diameter was the only characteristic not to be a statistically significant contributor to radial force generation. Results were used to develop radial force prediction software for the design of patient-specific 14mm stents.