Computational modelling of magnesium stent mechanical performance in a remodelling artery: Effects of multiple remodelling stimuli

Significant research has been conducted in the area of coronary stents/scaffolds made from resorbable metallic and polymeric biomaterials. These next‐generation bioabsorbable stents have the potential to completely revolutionise the treatment of coronary artery disease. The primary advantage of resorbable devices over permanent stents is their temporary presence which, from a theoretical point of view, means only a healed coronary artery will be left behind following degradation of the stent potentially eliminating long‐term clinical problems associated with permanent stents. The healing of the artery following coronary stent/scaffold implantation is crucial for the long‐term safety of these devices. Computational modelling can be used to evaluate the performance of complex stent devices in silico and assist in the design and development and understanding of the next‐generation resorbable stents. What is lacking in computational modelling literature is the representation of the active response of the arterial tissue in the weeks and months following stent implantation, ie, neointimal remodelling, in particular for the case of biodegradable stents. In this paper, a computational modelling framework is developed, which accounts for two major physiological stimuli responsible for neointimal remodelling and combined with a magnesium corrosion model that is capable of simulating localised pitting (realistic) stent corrosion. The framework is used to simulate different neointimal growth patterns and to explore the effects the neointimal remodelling has on the mechanical performance (scaffolding support) of the bioabsorbable magnesium stent. The finite element results presented in this paper show the neointima has a significant impact on the mechanical performance of the biodegradable magnesium stent as it degrades in a remodelling artery. The findings of this paper and the comparison of the neointimal remodelling patterns with the literature indicate that the wall shear stress (WSS) stimulus is more significant than the arterial stress stimulus and that the neointimal remodelling pattern predicted by the WSS simulation and is most likely to occur in vivo.