3D printed auxetic cardiovascular stents: a state-of-the-art review on topological design, manufacturing, mechanical and biological properties

Purpose Cardiovascular diseases caused by arterial blockage remain a leading cause of mortality all across the globe. Conventional stents, though effective in restoring blood flow, are often limited due to mechanical issues like stent foreshortening. Auxetic stents with their characteristic feature of negative Poisson’s ratio have emerged as a promising solution to combat this issue. This study aims to review a comprehensive and critical evaluation of the recent advancements in additively manufactured auxetic stents, focusing on their design, mechanical performance and biocompatibility. Design/methodology/approach This study provides a cutting-edge summary of experimental and simulation-based research, with a focus on topological design strategies for conventional, modified and hybrid auxetic stents. Additionally, this review contains additive and 4D printing technologies, design for additive manufacturing (DfAM) strategies and regulatory considerations. Findings Auxetic structures demonstrate enhanced radial strength with a reduction in recoil and minimum foreshortening compared to conventional stents while maintaining good flexibility for navigation and placement of the stent in complex arterial channels. Hybrid auxetic structures demonstrate the best combination of strength and flexibility. However, significant challenges remain in the lack of standardized testing, in vivo validation, variability in degradation kinetics and scalability using additive manufacturing (AM). Originality/value This review elucidates the potential of auxetic stents, highlighting the underexplored areas such as patient-specific customization, biointerface engineering and fatigue durability. Addressing both the opportunities and challenges in their development provides valuable guidelines for future research in the design, additive manufacturing and clinical adoption of next-generation cardiovascular stents.