Computational analysis of the radial mechanical performance of PLLA coronary artery stents
Medical Engineering and Physics
Biomedical Engineering, Department of Human Biology, University of Cape Town (UCT), South Africa; Centre for Research in Computational and Applied Mechanics (CERECAM), UCT, South Africa
Stents have been an effective tool to restore and maintain the patency of narrowed blood vessels, but they must have sufficient radial strength. Biodegradable stent materials have substantially lower mechanical properties than permanent stents. The stent geometry and material properties must be considered simultaneously when assessing stent performance. Material tests were performed to determine the mechanical characteristics of high-molecular-weight poly- l-lactic acid (PLLA). The results were used to calibrate an anisotropic elastic-plastic material model. Three distinct geometries were analysed with a range of material stiffness values in a finite element analysis to investigate their comparative effect on the radial strength, recoil, and radial stiffness. The performance of the different geometries varies substantially, with one particular geometry, with the highest material stiffness of 9. GPa, exceeding the desired radial strength of 300. mmHg. © 2014 IPEM.
Biomaterials; Blood vessels; Elastoplasticity; Geometry; Lactic acid; Mechanical properties; Organic polymers; Polymer blends; Stents; Stiffness; Strength of materials; Biodegradable stents; Computational analysis; High molecular weight; Mechanical characteristics; Mechanical performance; Poly L lactic acid; Radial strength; Stent; Finite element method; polylactic acid; lactic acid; polylactic acid; polymer; anisotropy; Article; biodegradability; biomechanics; calibration; coronary stenting; elasticity; finite element analysis; geometry; mathematical analysis; mechanical torsion; molecular weight; performance; physical parameters; proton radiation; radial stiffness; radial strength; simulation; stress strain relationship; tensile strength; biodegradable implant; blood vessel prosthesis; computer simulation; coronary blood vessel; device failure analysis; prosthesis; stent; theoretical model; Young modulus; Absorbable Implants; Anisotropy; Blood Vessel Prosthesis; Calibration; Computer Simulation; Coronary Vessels; Elastic Modulus; Equipment Failure Analysis; Finite Element Analysis; Lactic Acid; Models, Theoretical; Polymers; Prosthesis Design; Stents; Tensile Strength