title: The Localized Hemodynamics of Drug-Eluting Stents Are Not Improved by the Presence of Magnetic Struts.
abstract: The feasibility of implementing magnetic struts into drug-eluting stents (DESs) to mitigate the adverse hemodynamics which precipitate stent thrombosis is examined. These adverse hemodynamics include platelet-activating high wall shear stresses (WSS) and endothelial dysfunction-inducing low wall shear stresses. By magnetizing the stent struts, two forces are induced on the surrounding blood: (1) magnetization forces which reorient red blood cells to align with the magnetic field and (2) Lorentz forces which oppose the motion of the conducting fluid. The aim of this study was to investigate whether these forces can be used to locally alter blood flow in a manner that alleviates the thrombogenicity of stented vessels. Two-dimensional steady-state computational fluid dynamics (CFD) simulations were used to numerically model blood flow over a single magnetic drug-eluting stent strut with a square cross section. The effects of magnet orientation and magnetic flux density on the hemodynamics of the stented vessel were elucidated in vessels transporting oxygenated and deoxygenated blood. The simulations are compared in terms of the size of separated flow regions. The results indicate that unrealistically strong magnets would be required to achieve even modest hemodynamic improvements and that the magnetic strut concept is ill-suited to mitigate stent thrombosis.
authors.affiliation: School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney 2052, Australia e-mail: p.vijayaratnam@unsw.edu.au.
authors.forename: P R S
authors.initials: PR
authors.lastname: Vijayaratnam
authors.affiliation: School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney 2052, Australia e-mail: t.barber@unsw.edu.au.
authors.forename: T J
authors.initials: TJ
authors.lastname: Barber
authors.affiliation: School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney 2052, Australia e-mail: j.reizes@unsw.edu.au.
authors.forename: J A
authors.initials: JA
authors.lastname: Reizes
mesh_terms: D001158:Arteries / Q000033:anatomy & histology / Q000502:physiology* / Q000528:radiation effects*; D001783:Blood Flow Velocity / Q000502:physiology* / Q000528:radiation effects; D001794:Blood Pressure / Q000502:physiology / Q000528:radiation effects; D003198:Computer Simulation; D017076:Computer-Aided Design; D004307:Dose-Response Relationship, Radiation; D054855:Drug-Eluting Stents; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006801:Humans; D060526:Magnetic Fields; D059346:Magnets; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D011829:Radiation Dosage; D033081:Shear Strength / Q000502:physiology / Q000528:radiation effects; D013314:Stress, Mechanical