Structural Design and Mechanical Properties of Metal Vascular Stents Fabricated via Laser Powder Bed Fusion

Against the backdrop of high cardiovascular disease prevalence, personalized vascular stents tailored to complex vascular structures have emerged as a critical research focus in interventional therapy. While laser powder bed fusion (L-PBF) offers a novel approach to customized stent manufacturing, systematic evaluations of its forming accuracy and mechanical performance remain insufficient. This study designed a novel vascular stent featuring double-period unequal-height support rings interconnected by M-shaped struts and monolithically fabricated it from 316L stainless steel using L-PBF. Surface quality was enhanced via electropolishing. Balloon expansion, radial compression, and microtensile testing quantitatively characterized stent expansion performance (radial recoil rate, axial shortening rate), radial strength, and intrinsic material mechanical properties. Results demonstrated that L-PBF achieved unsupported fabrication of fine features (150 μm wall thickness); electropolishing significantly improved surface quality, reducing dimensional deviation from 46.7% to 3.3%. The stent exhibited a radial strength of 840 mN/mm and a remarkably low radial recoil rate of 1.37%. Material yield strength (232 MPa) reached 74.1% of that of wrought 316L alloy, with a fracture elongation of 16.44%, ensuring structural integrity during expansion. However, the axial shortening rate (5.56%) exceeded expectations, primarily due to geometric deviation in high-curvature connecting struts suppressing their compensatory mechanism. The M-type stent demonstrated superior radial support via its asymmetric-height support ring design, confirming L-PBF's feasibility for producing personalized metal vascular stents. Future work necessitates optimization of connecting strut curvature to control axial shortening and integrated topological design with targeted process optimization to advance clinical translation.