Additively manufactured reinforced polymeric stents for peripheral artery disease: design, manufacture and performance evaluation

Stent failure in the peripheral arterial system remains a major clinical challenge due to high mechanical demands caused by limb movement. Unlike coronary arteries, below-the-knee vessels are exposed to continuous flexion, torsion and axial movement, increasing the risk of structural failure, stent collapse, fracture or migration. Due to their tuneable mechanical properties, polymeric stents enabled by advanced additive manufacturing emerge as a potential candidate to overcome the current limitations of metallic stents. This study examines whether polymeric stents made with the ST3DT process and reinforced photoresin can endure all phases of manufacturing and deployment - including printing, rinsing, post-curing, crimping, and sterilisation - while retaining suitable mechanical properties for vascular use. Nine different stent geometries were produced by varying strut angle and printing feedrate, thus achieving different strut profiles. Curing was assessed by DSC and FTIR and mechanical properties were evaluated with radial and axial compressions tests, three-point bending and crimping. Finally, a CT-scan was performed to analyse radiopacity of reinforced polymeric stents with promising results. The findings indicated that although decreasing strut angles and reducing printing speeds led to better mechanical performance, they also made the crimping process more challenging. Two stents were selected with a balance of all criteria to continue the development of novel photopolymerised polymeric stents.