Computational Optimization of a Stent for the Femoropopliteal Artery

Clinical outcomes of peripheral artery disease (PAD) stenting, particularly in the highly dynamic regions of the femoropopliteal artery at the adductor hiatus and behind the knee, leave significant room for improvement. Despite the availability of various stent designs, few are capable of accommodating the severe deformations induced by limb flexion at these locations without causing adverse stent-artery interactions.

This study employed finite element analysis and response surface methodology to optimize the geometric design of nitinol PAD stents, with the objectives of improving stent-artery apposition, reducing arterial wall stress, minimizing stress concentrations, and decreasing arterial pinching under limb flexion-induced deformations. Five geometric parameters - strut width, thickness, amplitude, number, and link amplitude - were analyzed to assess their influence on stent performance.

Strut width, thickness, amplitude, and the number of struts significantly impacted arterial stress and apposition, while link amplitude had an insignificant effect. We identified two optimized stent configurations that achieved > 97% stent-artery apposition, < 0.6% of the artery with stress > 100 kPa, an average arterial stress of < 29 kPa, and pinching of < 1.15. The findings revealed that lower strut amplitude and reduced strut cross-sections improved apposition and stress distribution but required careful balancing to minimize arterial pinching and maintain structural integrity.

This study underscores the potential of multi-objective optimization in stent design, paving the way for PAD stents that more effectively accommodate femoropopliteal biomechanics and promote favorable mechanical conditions for healing.