Continuum damage model for bioresorbable magnesium alloy devices — Application to coronary stents

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

“…This study employs a similar approach in investigating the ability of AMS to match the performance of permanent stents over metrics such as radial strength, recoil and flexibility. To date, a small number of FE studies have investigated the performance of magnesium alloy stents (Wu et al, 2010;Gastaldi et al, 2011;Grogan et al, 2011) with predicted device stresses, strains and recoil reported. However, to the authors knowledge, this is the first study in which the performances of magnesium alloy, iron and permanent stents have been directly contrasted on a common stent geometry over a range of performance metrics, such as radial strength and flexibility.…”

Magnesium Modeling Using SolidWorks

“…Stress corrosion is one specific form of corrosion that was not considered in this study. In skeletal environments, stress corrosion is frequently observed and can potentially lead to quick failure at generally safe loads [5]. Future studies will consider the potential for Mg to pick up particulates, which add to the volume over time [8].…”

“…Wu et al 2010 used FEA to optimize stent designs in order to minimize the principal strain experienced by a cardiovascular stent and in turn, slow degradation [4]. Gastaldi et al [5] proposed a corrosion model based on continuum damage mechanics (CDM) to simulate Mg corrosion experienced by stents. Even with these successful simulations, significant difficulty in modeling Mg degradation exists.…”

“…Of these difficulties three were summarized as follows: 1) the elements exposed to a corrosive environment must be gradually weakened and removed when the damage is severe enough, 2) after the said elements are deleted new contact must be assigned to the remaining surface elements and, 3) a changing equilibrium must be displayed between the stent and arterial vessel as the constant compressive load of the vessel is applied to the gradually weakened and damaged stent [6]. By adapting the CDM approach proposed by Gastaldi et al [5], a refined model of stent degradation was later validated with experimental results and found accurate [6]. The purpose of this study was to use the finite element functionality within SolidWorks to model of Mg degradation and determine changes the mechanical integrity, of Mg samples, over time.…”

Cytotoxicity and its test methodology for a bioabsorbable nitrided iron stent

“…14 Iron-based and magnesium-based alloys have been under research and development as biodegradable metallic materials for application in cardiovascular intervention. [15][16][17][18][19] In vivo studies have demonstrated that iron stents can be safely implanted without significant obstruction of the stented vessel as a result of inflammation, neointimal proliferation, or thrombotic events, but a faster degradation rate is desirable. [20][21][22] However, many previous studies also reported in vitro cytotoxicity of iron for endothelial cells (ECs), smooth muscle cells, and L929 fibroblasts.…”