Bioresorbable polymer vascular stent: materials and structures

Abstract Coronary stent interventional therapy has become the main method of cardiovascular disease treatment due to its less trauma, high success rate, short recovery period, etc. Among the different types of implantable stents, bioresorbable polymer stents (BRPS) are highly promising for clinical applications, profiting from their good biocompatibility, non-toxic and harmless degradation products, and adjustable degradation time. In this review, the mechanical properties (e.g. radial strength, flexibility, axial foreshortening rate and radial recoil rate, etc) of stents with various biomaterials (mainly including natural polymer biomaterials like cellulose, chitosan, as well as synthetic polymer biomaterials such as polyurethane (PU), polylactic acid (PLA), polycaprolactone (PCL), and other synthetic polymer materials) and various structures (mainly including corrugated ring structure, negative Poisson’s ratio structure, and other structures) are mainly focused on. The mechanical properties of the materials are further optimized through strategies such as shape memory design, incorporation of functional nanoparticles, development of hierarchical design and copolymers. Structural optimization starts from two aspects: the support rings and the connecting ribs. By optimizing the design of the support rings, the radial strength of the stent can be enhanced, and the radial recoil can be effectively suppressed. Meanwhile, by designing the structure of the connecting ribs, the stent with greater flexibility and less axial foreshortening can be achieved, thus realizing a comprehensive improvement in overall performance of the stent. This review could provide guidance for the optimized design and broad application of the BRPS.