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Technical Brief

The Localized Hemodynamics of Drug-Eluting Stents Are Not Improved by the Presence of Magnetic Struts

[+] Author and Article Information
P. R. S. Vijayaratnam

School of Mechanical and Manufacturing Engineering,
University of New South Wales,
Sydney 2052, Australia
e-mail: p.vijayaratnam@unsw.edu.au

T. J. Barber

School of Mechanical and Manufacturing Engineering,
University of New South Wales,
Sydney 2052, Australia
e-mail: t.barber@unsw.edu.au

J. A. Reizes

School of Mechanical and Manufacturing Engineering,
University of New South Wales,
Sydney 2052, Australia
e-mail: j.reizes@unsw.edu.au

Manuscript received April 17, 2016; final manuscript received November 4, 2016; published online November 30, 2016. Assoc. Editor: Ram Devireddy.

J Biomech Eng 139(1), 014502 (Nov 30, 2016) (6 pages) Paper No: BIO-16-1150; doi: 10.1115/1.4035263 History: Received April 17, 2016; Revised November 04, 2016

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.

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References

Joner, M. , Finn, A. V. , Farb, A. , Mont, E. K. , Kolodgie, F. D. , Ladich, E. , Kutys, R. , Skorjia, K. , Gold, H. K. , and Virmani, R. , 2006, “ Pathology of Drug-Eluting Stents in Humans,” J. Am. Coll. Cardiol., 48(1), pp. 193–202. [CrossRef] [PubMed]
Iakovou, I. , Schmidt, T. , Bonizzoni, E. , Ge, L. , Sangiorgi, G. M. , Stankovic, G. , Airoldi, F. , Chieffo, A. , Montorfano, M. , Carlino, M. , Michev, I. , Corvaja, N. , Briguori, C. , Gerckens, U. , Grube, E. , and Colombo, A. , 2005, “ Incidence, Predictors, and Outcomes of Thrombosis After Successful Implantation of Drug-Eluting Stents,” JAMA, 293(17), pp. 2126–2130. [CrossRef] [PubMed]
Moreno, R. , Fernandez, C. , Hernandez, R. , Alfonso, F. , Angiolillo, D. J. , Sabaté, M. , Escaned, J. , Bañuelos, C. , Fernández-Ortiz, A. , and Macaya, C. , 2005, “ Drug-Eluting Stent Thrombosis: Results From a Pooled Analysis Including 10 Randomized Studies,” J. Am. Coll. Cardiol., 45(6), pp. 954–959. [CrossRef] [PubMed]
Ong, A. T. , McFadden, E. P. , Regar, E. , de Jaegere, P. P. , van Domburg, R. T. , and Serruys, P. W. , 2005, “ Late Angiographic Stent Thrombosis (LAST) Events With Drug-Eluting Stents,” J. Am. Coll. Cardiol., 45(12), pp. 2088–2092. [CrossRef] [PubMed]
Pfisterer, M. , Brunner-La Rocca, H. P. , Buser, P. T. , Rickenbacher, P. , Hunziker, P. , Mueller, C. , Jeger, R. , Bader, F. , Osswald, S. , and Kaiser, C. , 2006, “ Late Clinical Events After Clopidogrel Discontinuation May Limit the Benefit of Drug-Eluting Stents: An Observational Study of Drug-Eluting Versus Bare-Metal Stents,” J. Am. Coll. Cardiol., 48(12), pp. 2584–2591. [CrossRef] [PubMed]
Koskinas, K. C. , Chatzizisis, Y. S. , Antoniadis, A. P. , and Giannoglou, G. D. , 2012, “ Role of Endothelial Shear Stress in Stent Restenosis and Thrombosis: Pathophysiologic Mechanisms and Implications for Clinical Translation,” J. Am. Coll. Cardiol., 59(15), pp. 1337–1349. [CrossRef] [PubMed]
Akagawa, E. , Ookawa, K. , and Ohshima, N. , 2004, “ Endovascular Stent Configuration Affects Intraluminal Flow Dynamics and In Vitro Endothelialization,” Biorheology, 41(6), pp. 665–680. [PubMed]
Holme, P. A. , Ørvim, U. , Hamers, M. J. A. G. , Solum, N. O. , Brosstad, F. R. , Barstad, R. M. , and Sakariassen, K. S. , 1997, “ Shear-Induced Platelet Activation and Platelet Microparticle Formation at Blood Flow Conditions as in Arteries With a Severe Stenosis,” Arterioscler. Thromb. Vasc. Biol., 17(4), pp. 646–653. [CrossRef] [PubMed]
Tzirtzilakis, E. E. , 2005, “ A Mathematical Model for Blood Flow in Magnetic Field,” Phys. Fluids, 17(7), p. 077103. [CrossRef]
Vijayaratnam, P. R. S. , O'Brien, C. C. , Reizes, J. A. , Barber, T. J. , and Edelman, E. R. , 2015, “ The Impact of Blood Rheology on Drug Transport in Stented Arteries: Steady Simulations,” PLoS One, 10(6), p. e0128178. [CrossRef] [PubMed]
Van Jaarsveld, B. C. , Krijnen, P. , Pieterman, H. , Derkx, F. H. M. , Deinum, J. , Postma, C. T. , Dees, A. , Woittiez, A. J. , Bartelink, A. K. , Man in 't Veld, A. J. , and Schalekamp, M. A. , 2000, “ The Effect of Balloon Angioplasty on Hypertension in Atherosclerotic Renal-Artery Stenosis,” N. Engl. J. Med., 342(14), pp. 1007–1014. [CrossRef] [PubMed]
White, C. J. , Ramee, S. R. , Collins, T. J. , Jenkins, J. S. , Escobar, A. , and Shaw, D. , 1997, “ Renal Artery Stent Placement: Utility in Lesions Difficult to Treat With Balloon Angioplasty,” J. Am. Coll. Cardiol., 30(6), pp. 1445–1450. [CrossRef] [PubMed]
Rocha-Singh, K. , Jaff, M. R. , and Rosenfeld, K. , 2005, “ ASPIRE-2 Trial Investigators Evaluation of the Safety and Effectiveness of Renal Artery Stenting After Unsuccessful Balloon Angioplasty: The ASPIRE-2 Study,” J. Am. Coll. Cardiol., 46(5), pp. 776–783. [CrossRef] [PubMed]
Dorros, G. , Prince, C. , and Mathiak, L. , 1993, “ Stenting of a Renal Artery Stenosis Achieves Better Relief of the Obstructive Lesion Than Balloon Angioplasty,” Catheterization Cardiovasc. Diagn., 29(3), pp. 191–198. [CrossRef]
Yamamoto, T. , Ogasawara, Y. , Kimura, A. , Tanaka, H. , Hiramatsu, O. , Tsujioka, K. , Lever, M. J. , Parker, K. H. , Jones, C. J. , Caro, C. G. , and Kajiya, F. , 1996, “ Blood Velocity Profiles in the Human Renal Artery by Doppler Ultrasound and Their Relationship to Atherosclerosis,” Arterioscler. Thromb. Vasc. Biol., 16(1), pp. 172–177. [CrossRef] [PubMed]
Gabriel, S. , Lau, R. W. , and Gabriel, C. , 1996, “ The Dielectric Properties of Biological Tissues—III: Parametric Models for the Dielectric Spectrum of Tissues,” Phys. Med. Biol., 41(11), pp. 2271–2293. [CrossRef] [PubMed]
Frewer, R. A. , 1974, “ The Electrical Conductivity of Flowing Blood,” Biomed. Eng., 9(12), p. 552. [PubMed]
Motta, M. , Haik, Y. , Gandhari, A. , and Chen, C. J. , 1998, “ High Magnetic Field Effects on Human Deoxygenated Hemoglobin Light Absorption,” Bioelectrochem. Bioenerg., 47(2), pp. 297–300. [CrossRef]
Haik, Y. , Pai, V. , and Chen, C. J. , 1999, “ Biomagnetic Fluid Dynamics,” Fluid Dynamics at Interfaces, W. Shyy and R. Narayanan , eds., Cambridge University Press, Cambridge, UK, pp. 439–452.
Furlani, E. P. , 2001, Permanent Magnet and Electromechanical Devices: Materials, Analysis, and Applications, Academic Press, San Diego, CA, Chap. 4.
O'Brien, C. C. , Kolachalama, V. B. , Barber, T. J. , Simmons, A. , and Edelman, E. R. , 2013, “ Impact of Flow Pulsatility on Arterial Drug Distribution in Stent-Based Therapy,” J. Controlled Release, 168(2), pp. 115–124. [CrossRef]
Roache, P. J. , 1997, “ Quantification of Uncertainty in Computational Fluid Dynamics,” Annu. Rev. Fluid Mech., 29(1), pp. 123–160. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

The prothrombotic effects of nonphysiological wall shear stresses

Grahic Jump Location
Fig. 2

Geometry and boundary conditions. A single 0.1-mm square cross section DES strut was positioned halfway between the inlet and outlet with one side of the strut in direct contact with the vessel wall.

Grahic Jump Location
Fig. 3

Magnetic flux density contours of the magnetic DES strut used in this study. The magnet has been modeled as an infinitely long permanent rectangular magnet with height 2h = 70 μm and width 2w = 70 μm. The cases in which Bmax = 1 T are depicted for the configurations in which the poles are (a) on the top and bottom strut faces and (b) on the fore and aft strut faces. Note that the positions of the north and south poles are interchangeable in each case and do not affect the results.

Grahic Jump Location
Fig. 4

The magnetically altered hemodynamics of oxygenated blood in a vessel with a well-apposed DES strut: (a) top–bottom and (b) fore–aft

Grahic Jump Location
Fig. 5

The magnetically altered hemodynamics of deoxygenated blood in a vessel with a well-apposed DES strut: (a) top–bottom and (b) fore–aft

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