Deformation behaviour of self-expanding magnesium stents based on auxetic chiral lattices

Abstract

Current stenting solutions commonly employ metal alloys and are permanent. This fact has the consequence of diverse long term risks for the patients, e.g. Restenosis, late-term stent Thrombosis, etc. One possible solution to attenuate these problems is the use of polymer or metallic based bioabsorbable stents that tend to be degraded by corrosion and completely eliminated after their scaffolding duties are fulfilled. Additionally, there is a need to find new ways of deploying these devices. A route to fulfill this goal, can be the design of stents that eliminate the necessity of balloon expansion and are able to self-expand by their own deformation mechanism, for example by possessing auxetic behavior. The objective of this study is the modeling of a stent that reveals auxetic behavior and is composed by a biodegradable material (AZ91D Magnesium alloy), to embrace both recent tendencies on stenting designs. It is shown that the defined stent modeling is able to expand when stretched (auxetic behavior) and reveals a deformation mechanism that may be interesting for further development. In conclusion, the combination of both biodegradable and auxetic characteristics shown in this study may be a future step in the evolution of these medical devices.