Multi-Objective Structural Optimization of Vascular Stents With Varied Materials Based on Numerical Simulation

Stent implantation would alter local blood flow within the vessel. Minimizing blood flow disturbance is critical to prevent recurrent blockage, and the stent should have specific mechanical properties. Improvements in both mechanical and hemodynamic properties are essential in stent optimization. Stents made from different materials exhibit significantly varying mechanical properties, whereas their hemodynamic performance depends primarily on geometry. A multi-objective structural optimization was employed with the four structural parameters of the stent as design variables. Hemodynamic performance was measured by the oscillatory shear index, while the mechanical performance of the stent was assessed based on the maximum equivalent plastic strain and stent support force. The structural optimization of vascular stents fabricated from magnesium alloy (Mg) and poly-l-lactic acid (PLLA) was conducted with varying weights as the optimization objectives. The proposed radial basis function (RBF) model accurately predicted the stent structural performance. Single-objective optimization achieved maximal improvements in targeted performance but compromised other performance, while multi-objective optimization yielded more balanced overall performance. Structural parameters exhibited material-specific sensitivities. Specifically, hemodynamic performance was structure-dependent and, under the rigid-wall assumption, material-independent, whereas mechanical performance was strongly material-dependent. These findings underscore the need to consider both stent structure and material properties in optimization, providing comprehensive guidance for rational stent design.