Comparing coronary stent material performance on a common geometric platform through simulated bench testing

Abstract

Absorbable metallic stents (AMSs) are a newly emerging cardiovascular technology which has the potential to eliminate long-term patient health risks associated with conventional permanent stents. AMSs developed to date have consisted of magnesium alloys or iron, materials with inferior mechanical properties to those used in permanent stents, such as stainless steel and cobalt-chromium alloys. However, for AMSs to be feasible for widespread clinical use it is important that their performance is comparable to modern permanent stents. To date, the performances of magnesium, iron, and permanent stent materials have not been compared on a common stent platform for a range of stent performance metrics, such as flexibility, radial strength, and recoil. In this study, this comparison is made through simulated bench testing, based on finite-element modelling. The significance of this study is that it allows potential limitations in current AMS performance to be identified, which will aid in focusing future AMS design. This study also allows the identification of limitations in current AMS materials, thereby informing the on-going development of candidate biodegradable alloys. The results indicate that the AMSs studied here can match the recoil characteristics and radial strength of modern permanent stents; however, to achieve this, larger strut dimensions are required. It is also predicted that the AMSs studied are inferior to permanent stents in terms of maximum absolute curvature and longitudinal stiffness.