Braided bioresorbable cardiovascular stents mechanically reinforced by axial runners

Polymeric bioresorbable stents (BRSs) can eliminate the long-term stent restenosis by degrading after vascular remolding and have been recommended for the congenital heart disease treatment. However, the mechanical weakness remains one of main inferiorities of their applications. So, the aim of this study was to develop mechanically reinforced bioresorbable stents (MRBSs) based on poly(p-dioxanone) (PPDO) monofilaments and braiding technology. Axial runners were introduced and MRBSs showed greatly higher compression force and relatively lower viscous performance, as well as longer mechanical stability during degradation, compared with controls. Besides, stent compression behaviors were analyzed experimentally and numerically to investigate their deformation mechanisms. The results showed increased contacting points and friction force among yarns in MRBSs. Also, the skeleton formed in MRBSs attributed to higher yarn bending degree, strain energy and better structure stability during compression. Combined with the non-linear PPDO material stress-strain ratio and thermodynamic theory, yarn based stent compression modes were discussed. In addition, the autocatalysis and nonrandom chain scission degradation behaviors of MRBSs were revealed.