An Overhang-like Constraint for the Design of Topologically Optimized Vascular Stents
Please login to view abstract download link
Stent implantation is a common treatment for various vascular diseases. The selection of an appropriate device depends on multiple variables, including the patient’s condition and the specific body region requiring treatment. In this context, the geometry of the stent plays a critical role in influencing the success of the medical procedure and the risk of post-surgical complications. Therefore, optimizing the device design requires careful consideration of several factors, including structural, mechanical, and hemodynamic effects as well as manufacturing requirements. In this study, we present a fully computational pipeline that employs topology optimization (TO) to design self-expandable artery stents, accounting for clinical and manufacturing requirements. The stent is modeled as a cylindrical surface generated by the periodic repetition of a planar unit cell, which is optimized through inverse homogenization TO. With a view to meet prescribed mechanical requirements, the TO process is guided by the homogenized elasticity equation, linking the stiffness tensor components of the device to clinically relevant quantities such as foreshortening, radial and axial stiffness. Additionally, the optimization incorporates an overhang constraint - originally developed for Additive Manufacturing (AM)-oriented design - to indirectly ensure desirable fluid dynamic properties. In this presentation, we detail the inverse homogenization TO formulation from a modeling viewpoint, including all the physical and design requirements of interest. Subsequently, we present the algorithm for the problem discretization and we showcase some numerical test cases. Such results are analyzed in terms of stent geometries and clinical properties, demonstrating the potential of combining TO and AM-oriented constraints for effective biomedical solutions. This study was carried out within the RESET project, funded by the European Union – NextGenerationEU, Italian Ministry of University and Research, Italy, within the PRIN 2022 PNRR program (D.D.1409 del 14/09/2022).