Coronary stents made from degradable biomaterials such as magnesium alloy are an emerging technology in the treatment of coronary artery disease. Biodegradable stents provide mechanical support to the artery during the initial scaffolding period after which the artery will have remodelled. The subsequent resorption of the stent biomaterial by the body has potential to reduce the risk associated with long term placement of these devices such as in-stent restenosis, late stent thrombosis.
Computational modelling such as finite element analysis has proven to be an extremely useful tool in the continued design and development of these medical devices. 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 (neointimal remodelling). The phenomenon of neointimal remodelling is particularly interesting and significant in the case of biodegradable stents, when both stent degradation and neointimal remodelling can occur simultaneously, presenting the possibility of a mechanical interaction and transfer of load between the degrading stent and the remodelling artery.
In this paper a computational modelling framework is developed that combines magnesium alloy degradation and neointimal remodelling, that is capable of simulating both uniform (best case) and localised pitting (realistic) stent corrosion in a remodelling artery. The framework is used to evaluate the effects of the neointima on the mechanics of the stent, when the stent is undergoing uniform or pitting corrosion, and to assess the effects of the neointimal formation rate relative to the overall stent degradation rate.