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Research Papers

In Vitro Quantification of Time Dependent Thrombus Size Using Magnetic Resonance Imaging and Computational Simulations of Thrombus Surface Shear Stresses

[+] Author and Article Information
Joshua O. Taylor

Department of Bioengineering,
The Pennsylvania State University,
University Park, PA 16802;
Applied Research Laboratory,
The Pennsylvania State University,
State College, PA 16803

Kory P. Witmer

Department of Bioengineering,
The Pennsylvania State University,
University Park, PA 16802

Thomas Neuberger

Huck Institutes of the Life Sciences,
The Pennsylvania State University,
University Park, PA 16802;
Department of Bioengineering,
The Pennsylvania State University,
University Park, PA 16802

Brent A. Craven

Applied Research Laboratory,
The Pennsylvania State University,
State College, PA 16803;
Department of Bioengineering,
The Pennsylvania State University,
University Park, PA 16802

Richard S. Meyer, Steven Deutsch

Applied Research Laboratory,
The Pennsylvania State University,
State College, PA 16803

Keefe B. Manning

Department of Bioengineering,
The Pennsylvania State University,
University Park, PA 16802;
Department of Surgery,
The Penn State College of Medicine,
Hershey, PA 17033
e-mail: kbm10@psu.edu

1Corresponding author.

Manuscript received November 12, 2013; final manuscript received April 25, 2014; accepted manuscript posted May 8, 2014; published online May 23, 2014. Assoc. Editor: Ender A. Finol.

J Biomech Eng 136(7), 071012 (May 23, 2014) (11 pages) Paper No: BIO-13-1526; doi: 10.1115/1.4027613 History: Received November 12, 2013; Revised April 25, 2014; Accepted May 08, 2014

Thrombosis and thromboembolization remain large obstacles in the design of cardiovascular devices. In this study, the temporal behavior of thrombus size within a backward-facing step (BFS) model is investigated, as this geometry can mimic the flow separation which has been found to contribute to thrombosis in cardiac devices. Magnetic resonance imaging (MRI) is used to quantify thrombus size and collect topographic data of thrombi formed by circulating bovine blood through a BFS model for times ranging between 10 and 90 min at a constant upstream Reynolds number of 490. Thrombus height, length, exposed surface area, and volume are measured, and asymptotic behavior is observed for each as the blood circulation time is increased. Velocity patterns near, and wall shear stress (WSS) distributions on, the exposed thrombus surfaces are calculated using computational fluid dynamics (CFD). Both the mean and maximum WSS on the exposed thrombus surfaces are much more dependent on thrombus topography than thrombus size, and the best predictors for asymptotic thrombus length and volume are the reattachment length and volume of reversed flow, respectively, from the region of separated flow downstream of the BFS.

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References

Lloyd-Jones, D., Adams, R., Carnethon, M., De Simone, G., Ferguson, T. B., Flegal, K., Ford, E., Furie, K., Go, A., Greenlund, K., Haase, N., Hailpern, S., Ho, M., Howard, V., Kissela, B., Kittner, S., Lackland, D., Lisabeth, L., Marelli, A., McDermott, M., Meigs, J., Mozaffarian, D., Nichol, G., O'Donnell, C., Roger, V., Rosamond, W., Sacco, R., Sorlie, P., Stafford, R., Steinberger, J., Thom, T., Wasserthiel-Smoller, S., Wong, N., Wylie-Rosett, J., and Hong, Y., 2009, “Heart Disease and Stroke Statistics 2009 Update. A Report From the American Heart Association Statistics Committee and Stroke Statistics Subcommittee,” Circulation, 119(3), pp. e1–e161. [CrossRef]
Boyle, A. J., Russell, S. D., Teuteberg, J. J., Slaughter, M. S., Moazami, N., Pagani, F. D., Frazier, O. H., Heatley, G., Farrar, D. J., and John, R., 2009, “Low Thromboembolism and Pump Thrombosis With the HeartMate II Left Ventricular Assist Device: Analysis of Outpatient Anti-Coagulation,” J. Heart Lung Transpl., 28(9), pp. 881–887. [CrossRef]
Mauri, L., Hsieh, W., Massaro, J. M., Ho, K. K. L., D'Agostino, R., and Cutlip, D. E., 2007, “Stent Thrombosis in Randomized Clinical Trials of Drug-Eluting Stents,” New Engl. J. Med., 356(10), pp. 1020–1029. [CrossRef]
Caceres-Loriga, F. M., Perez-Lopez, H., Santos-Garcia, J., and Morlans-Hernandez, K., 2006, “Prosthetic Heart Valve Thrombosis: Pathogenesis, Diagnosis and Management,” Int. J. Cardiol., 110(1), pp. 1–6. [CrossRef]
Deutsch, S., Tarbell, J. M., Manning, K. B., Rosenberg, G., and Fontaine, A. A., 2006, “Experimental Fluid Mechanics of Pulsatile Artificial Blood Pumps,” Annu. Rev. Fluid Mech., 38, pp. 65–86. [CrossRef]
Nesbitt, W. S., Westein, E., Tovar-Lopez, F. T., Tolouei, E., Mitchell, A., Fu, J., Carberry, J., Fouras, A., and Jackson, S. P., 2009, “A Shear Gradient-Dependent Platelet Aggregation Mechanism Drives Thrombus Formation,” Nat. Med., 15(6), pp. 665–673. [CrossRef]
Bluestein, D., Niu, L., Schoephoerster, R. T., and Dewanjee, M. K., 1996, “Steady Flow in an Aneurysm Model: Correlation Between Fluid Dynamics and Blood Platelet Deposition,” ASME J. Biomech. Eng., 118(3), pp. 280–286. [CrossRef]
Karino, T., and Goldsmith, H. L., 1979, “Aggregation of Human Platelets in an Annular Vortex Distal to a Tubular Expansion,” Microvasc. Res., 17(3), pp. 217–237. [CrossRef]
Karino, T., and Goldsmith, H. L., 1979, “Adhesion of Human Platelets to Collagen on the Walls Distal to a Tubular Expansion,” Microvasc. Res., 17(3), pp. 238–262. [CrossRef]
Gijsen, F. J. H., van de Vosse, F. N., and Janssen, J. D., 1998, “Wall Shear stress in a Backward-Facing Step Flow of a Red Blood Cell Suspension,” Biorheology, 35(4), pp. 263–279. [CrossRef]
Beaudoin, J. F., Cadot, O., Aider, J. L., and Wesfreid, J. E., 2004, “Three-Dimensional Stationary Flow Over a Backward-Facing Step,” Eur. J. Mech. B, 23(1), pp. 147–155. [CrossRef]
Williams, P. T., and Baker, A. J., 1997, “Numerical Simulations of Laminar Flow Over a 3D Backward-Facing Step,” Int. J. Numer. Methods Fluids, 24(11), pp. 1159–1183. [CrossRef]
Armaly, B. F., Durst, F., Pereira, J. C. F., and Schönung, B., 1983, “Experimental and Theoretical Investigation of Backward-Facing Step Flow,” J. Fluid. Mech., 127, pp. 473–496. [CrossRef]
Tamagawa, M., and Matsuo, S., 2004, “Predictions of Thrombus Formation Using Lattice Boltzmann Method (Modeling of Adhesion Force for Particles to Wall),” JSME Int. J., 47(4), pp. 1027–1034. [CrossRef]
Tamagawa, M., Kaneda, H., Hiramoto, M., and Nagahama, S., 2009, “Simulation of Thrombus Formation in Shear Flows Using Lattice Boltzmann Method,” Artif. Organs, 33(8), pp. 604–610. [CrossRef]
Cooper, B. T., Long, G. D., Knight, L. C., and Manning, K. B., 2009, “A Novel Approach to the Correlation of Fluid Dynamics and Thromboembolism Associated With Cardiovascular Prosthetic Devices,” O.Dossel, and W. C.Schlegel, eds., “World Congress on Medical Physics and Biomedical Engineering,” IFMBE Proceedings, Vol. 25/4, Springer, Berlin, Heidelberg, pp. 1396–1399.
Long, G. D., 2009, “Computational Simulations of Flow Over the Surface of a Formed Thrombus in a Backward-Facing Step,” M.S. thesis, The Pennsylvania State University, University Park, PA.
Bluestein, D., Niu, L., Schoephoerster, R. T., and Dewanjee, M. K., 1997, “Fluid Mechanics of Arterial Stenosis: Relationship to the Development of Mural Thrombus,” Ann. Biomed. Eng., 25(2), pp. 344–356. [CrossRef]
Zhao, R., Marhefka, J. N., Shu, F., Hund, S. J., Kameneva, M. V., and Antaki, J. F., 2008, “Micro-Flow Visualization of Red Blood Cell-Enhanced Platelet Concentration at Sudden Expansion,” Ann. Biomed. Eng., 36(7), pp. 1130–1141. [CrossRef]
Robaina, S., Jayachandran, B., He, Y., Frank, A., Moreno, M. R., Schoephoerster, R. T., and Moore, J. E., Jr., 2003, “Platelet Adhesion to Simulated Stented Surfaces,” J. Endovasc. Ther., 10(5), pp. 978–986. [CrossRef]
Sukavaneshvar, S., and Solen, K. A., 1998, “Effects of Hemodynamics on Thromboembolism in Coronary Stents and Prototype Flow Cells in vitro,” ASAIO J., 44(5), pp. M388–M392. [CrossRef]
Goodman, P. D., Hall, M. W., Sukavaneshvar, S., and Solen, K. A., 2000, “in vitro Model for Studying the Effects of Hemodynamics on Device Induced Thromboembolism in Human Blood,” ASAIO J., 46(5), pp. 576–578. [CrossRef]
Goodman, P. D., Barlow, E. T., Crapo, P. M., Mohammad, S. F., and Solen, K. A., 2005, “Computational Model of Device-Induced Thrombosis and Thromboembolism,” Ann. Biomed. Eng., 33(6), pp. 780–797. [CrossRef]
Kuharsky, A. L., and Fogelson, A. L., 2001, “Surface-Mediated Control of Blood Coagulation: The Role of Binding Site Densities and Platelet Deposition,” Biophys. J., 80(3), pp. 1050–1074. [CrossRef]
Fogelson, A. L., and Tania, N., 2005, “Coagulation Under Flow: The Influence of Flow-Mediated Transport on the Initiation and Inhibition of Coagulation,” Pathophysiol. Haemost. Thromb., 34(2–3), pp. 91–108. [CrossRef]
Tokarev, A., Sirakov, I., Panasenko, G., Volpert, V., Shnol, E., Butylin, A., and Ataullakhanov, F., 2012, “Continuous Mathematical Model of Platelet Thrombus Formation in Blood Flow,” Russ. J. Numer. Anal. Math. Model., 27(2), pp. 191–212. [CrossRef]
Wang, W., and King, M. R., 2012, “Multiscale Modeling of Platelet Adhesion and Thrombus Growth,” Ann. Biomed. Eng., 40(11), pp. 2345–2354. [CrossRef]
Xu, Z., Kamocka, M., Alber, M., and Rosen, E. D., 2011, “Computational Approaches to Studying Thrombus Development,” Arterioscler. Thromb. Vasc. Biol., 31(3), pp. 500–505. [CrossRef]
Leiderman, K., and Fogelson, A. L., 2011, “Grow With the Flow: A Spatial-Temporal Model of Platelet Deposition and Blood Coagulation Under Flow,” Math. Med. Biol., 28(1), pp. 47–84. [CrossRef]
Cook, S., Ladich, E., Nakazawa, G., Eshtehardi, P., Neidhard, M., Vogel, R., Togni, M., Wenaweser, P., Billinger, M., Seiler, C., Gay, S., Meier, B., Pichler, W. J., Juni, P., Virmani, R., and Windecker, S., 2009, “Correlation of Intravascular Ultrasound Findings With Histopathological Analysis of Thrombus Aspirates in Patients With Very Late Drug-Eluting Stent Thrombosis,” Circulation, 120(5), pp. 391–399. [CrossRef]
Overoye-Chan, K., Koerner, S., Looby, R. J., Kolodziej, A. F., Zech, S. G., Deng, Q., Chasse, J. M., McMurry, T. J., and Caravan, P., 2008, “EP-2104R: A Fibrin-Specific Gadolinium-Based MRI Contrast Agent for Detection of Thrombus,” J. Am. Chem. Soc., 130(18), pp. 6025–6039. [CrossRef]
Miserus, R. J. H. M., Herias, M. V., Prinzen, L., Lobbes, M. B. I., Suylen, R. V., Dirksen, A., Hackeng, T. M., Heemskerk, J. W. M., van Engelshoven, J. M. A., Daemen, M. J. A. P., van Zandvoort, M. A. M. J., Heeneman, S., and Kooi, M. E., 2009, “Molecular MRI of Early Thrombus Formation Using Bimodal α2-Antiplasmin-Based Contrast Agent,” JACC Cardiovasc. Imaging, 2(8), pp. 987–996. [CrossRef]
Wang, X., Jin, P., Zhou, T., Zhao, T., Ding, Q., Wang, D., Zhao, G., Jing-Dai, W. H., and Ge, H., 2010, “MR Molecular Imaging of Thrombus: Development and Application of a Gd-Based Novel Contrast Agent Targeting p-Selectin,” Clin. Appl. Thromb./Hemostasis, 16(2), pp. 177–183. [CrossRef]
Von zur Muhlen, C., von Elverfeldt, D., Moeller, J. A., Choudhury, R. P., Paul, D., Hagemeyer, C. E., Olschewski, M., Becker, A., Neudorfer, I., Bassler, N., Schwarz, M., Bode, C., and Peter, K., 2008, “Magnetic Resonance Imaging Contrast Agent Targeted Toward Activated Platelets Allows in vivo Detection of Thrombosis and Monitoring of Thrombolysis,” Circulation, 118(3), pp. 258–267. [CrossRef]
Nair, S. A., Kolodziej, A. F., Bhole, G., Greenfield, M. T., McMurry, T. J., and Caravan, P., 2008, “Monovalent and Bivalent Fibrin-Specific MRI Contrast Agents for Detection of Thrombus,” Angew. Chem., Int. Ed., 47(26), pp. 4918–4921. [CrossRef]
Lassila, R., Badimon, J. J., Vallabhajosula, S., and Badimon, L., 1990, “Dynamic Monitoring of Platelet Deposition on Severely Damaged Vessel Wall in Flowing Blood. Effects of Different Stenoses on Thrombus Growth,” Arterioscler. Thromb. Vasc. Biol., 10(2), pp. 306–315. [CrossRef]
Riedel, C. H., Jensen, U., Rohr, A., Tietke, M., Alfke, K., Ulmer, S., and Jansen, O., 2010, “Assessment of Thrombus in Acute Middle Cerebral Artery Occlusions Using Thin-Slice Nonenhanced Computed Tomography Reconstructions,” Stroke, 41(8), pp. 1659–1664. [CrossRef]
Wang, E. H. J., Makaroun, M. S., Webster, M. W., and Vorp, D. A., 2002, “Effect of Intraluminal Thrombus on Wall Stress in Patient-Specific Models of Abdominal Aortic Aneurysm,” J. Vasc. Surg., 36(3), pp. 598–604. [CrossRef]
Maiora, J., Garcia, G., Macia, I., Legarreta, J. H., Boto, F., Paloc, C., Grana, M., and Abuin, J. S., 2010, “Thrombus Volume Change Visualization After Endovascular Abdominal Aortic Aneurysm Repair,” Hybrid Artificial Intelligence Systems, M. G.Romay, E.Corchado, and M. G.Sebastian, eds., Springer-Verlag, Berlin, Heidelberg, pp. 524–531.
Mu, J., Liu, X., Kamocka, M. M., Xu, Z., Abler, M. S., Rosen, E. D., and Chen, D. Z., 2010, “Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images,” EURASIP J. Adv. Signal Process., 25(3), pp. 1–8. [CrossRef]
Tolouei, E., Butler, C. J., Fouras, A., Ryan, K., Sheard, G. J., and Carberry, J., 2011, “Effect of Hemodynamic Forces on Platelet Aggregation Geometry,” Ann. Biomed. Eng., 39(5), pp. 1403–1413. [CrossRef]
Windberger, U., Bartholovitsch, A., Plasenzotti, R., Korak, K. J., and Heinze, G., 2003, “Whole Blood Viscosity, Plasma Viscosity and Erythrocyte Aggregation in Nine Mammalian Species: Reference Values and Comparison of Data,” Exp. Physiol., 88(3), pp. 431–440. [CrossRef]
Gottschall, J. L., Rzad, L., and Aster, R. H., 1986, “Studies of the Minimum Temperature at Which Human Platelets can be Stored With Full Maintenance of Viability,” Transfusion, 26(5), pp. 460–462. [CrossRef]
Holme, S., and Heaton, A., 1995, “in vitro Platelet Ageing at 22 °C is Reduced Compared to in vivo Ageing at 37 °C,” Br. J. Haematol., 91(1), pp. 212–218. [CrossRef]
OpenFOAM, “OpenFOAM User Guide.” Available at: http://www.openfoam.org/docs/user/index.php
Guj, G., and Stella, F., 1988, “Numerical Solutions of High-Re Recirculating Flows in Vorticity-Velocity Form,” Int. J. Numer. Methods Fluids, 8(4), pp. 405–416. [CrossRef]
Sohn, J. L., 1988, “Evaluation of FIDAP on Some Classical Laminar and Turbulent Benchmarks,” Int. J. Numer. Methods Fluids, 8(12), pp. 1469–1490. [CrossRef]
Roache, P. J., 1994, “Perspective: A Method for Uniform Reporting of Grid Refinement Studies,” ASME J. Fluid Eng., 116, pp. 405–413. [CrossRef]
Craven, B. A., Paterson, E. G., Settles, G. S., and Lawson, M. J., 2009, “Development and Verification of a High-Fidelity Computational Fluid Dynamics Model of Canine Nasal Airflow,” ASME J. Biomech. Eng., 131, p. 091002. [CrossRef]
Ihlenfeld, J. V., Mathis, T. R., Riddle, L. M., and Cooper, S. L., 1979, “Measurement of Transient Thrombus Deposition on Polymeric Materials,” Thromb. Res., 14(6), pp. 953–967. [CrossRef]
Lelah, M. D., Lambrecht, L. K., and Cooper, S. L., 1984, “A Canine Ex Vivo Series Shunt for Evaluating Thrombus Deposition on Polymer Surfaces,” J. Biomed. Mater. Res., 18(5), pp. 475–496. [CrossRef]
Chou, J., Mackman, N., Merrill-Skoloff, G., Pedersen, B., Furie, B. C., and Furie, B., 2004, “Hematopoietic Cell-Derived Microparticle Tissue Factor Contributes to Fibrin Formation During Thrombus Propagation,” Blood, 104(10), pp. 3190–3197. [CrossRef]
Dubois, C., Panicot-Dubois, L., Gainor, J. F., Furie, B. C., and Furie, B., 2007, “Thrombin-Initiated Platelet Activation in vivo is VWF Independent,” J. Clin. Invest., 117(4), pp. 953–960. [CrossRef]
Ku, D. N., 1997, “Blood Flow in Arteries,” Annu. Rev. Fluid Mech., 29(1), pp. 399–434. [CrossRef]
Mills, C. J., Gabe, I. T., Gault, J. H., Mason, D. T., Ross, J., Jr., Braunwald, E., and Shillingford, J. P., 1970, “Pressure-Flow Relationships and Vascular Impedance in Man,” Cardiovasc. Res., 4(4), pp. 405–417. [CrossRef]
Basmadjian, D., 1984, “The Hemodynamic Forces Acting on Thrombi, From Incipient Attachment of Single Cells to Maturity and Embolization,” J. Biomech., 17(4), pp. 287–298. [CrossRef]
Furie, B., and Furie, B. C., 2008, “Mechanisms of Thrombus Formation,” New Engl. J. Med., 359(9), pp. 938–949. [CrossRef]
Zhang, J., Gellman, B., Koert, A., Dasse, K. A., Gilbert, R. J., Griffith, B. P., and Wu, Z. J., 2006, “Computational and Experimental Evaluation of the Fluid Dynamics and Hemocompatibility of the CentriMag Blood Pump,” Artif. Organs, 30(3), pp. 168–177. [CrossRef]
Snyder, T. A., Watach, M. J., Litwak, K. N., and Wagner, W. R., 2002, “Platelet Activation, Aggregation, and Life Span in Calves Implanted With Axial Flow Ventricular Assist Devices,” Ann. Thorac. Surg., 73(6), pp. 1933–1938. [CrossRef]
Bonchek, L. I., and Braunwald, N. S., 1967, “Modification of Thrombus Formation on Prosthetic Heart Valves by the Administration of Low Molecular Weight Dextran,” Ann. Surg., 165(2), pp. 200–205. [CrossRef]
Soloviev, M. V., Okazaki, Y., and Harasaki, H., 1999, “Whole Blood Platelet Aggregation in Humans and Animals: A Comparative Study,” J. Surg. Res., 82(2), pp. 180–187. [CrossRef]
Ku, D. N., Giddens, D. P., Zarins, C. K., and Glagov, S., 1985, “Pulsatile Flow and Atherosclerosis in the Human Carotid Bifurcation. Positive Correlation Between Plaque Location and Low Oscillating Shear Stress,” Arterioscler. Thromb. Vasc., 5(3), pp. 293–302. [CrossRef]

Figures

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Fig. 1

(a) A schematic of the flow loop containing the acrylic BFS model used for MRI experiments. The inlet and outlet tubes were only used for filling/draining the loop and were clamped during blood circulation. Arrows indicate the direction of flow. (b) A cross-sectional view of both segments of the BFS model at the seam.

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Fig. 2

(a) Inlet, (b) outlet, (c) acrylic, and (d) thrombus STL files exported from Avizo for a thrombus formed after 10 min of blood circulation

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Fig. 3

An image obtained from histology sectioning displaying a magnified view of a thrombus surface that was exposed to blood flow. The primary components of the thrombus, red blood cells, and fibrin have been stained a pinkish-red color by H&E. A purple stained nucleus of a white blood cell can also be observed in the slice. Black circles illustrate two surface features (one valley and one protrusion) that are too small to be resolved in this study.

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Fig. 4

Velocity map and contours presented for the empty BFS model. The recirculation region can clearly be observed downstream of the step, with the site of initial thrombus formation indicated with a white “X.” The reattachment length measures 16.9 mm (6.76 S) and flow is from left to right.

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Fig. 5

Reconstructions of thrombi formed after all blood circulation times considered in this study (one representative thrombus for each time). The blood circulation time is displayed in the left column, a side view of the thrombus is presented in the middle column, and a top view of the thrombus is presented in the right column. The asymptotic behavior of both thrombus height and length can be observed qualitatively. The scale bar represents a distance of 5 mm, and the thrombi were formed in flow moving from left to right.

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Fig. 6

(a) Changes in normalized thrombus height (measured at the step) and length with increasing blood circulation time are presented. These values were normalized with the BFS height, 2.5 mm. The reattachment length of the initial recirculation region was normalized by the step height and marked on the right vertical axis. Error bars represent the SEM and n = 3 for all blood circulation times. (b) The changes in thrombus volume and exposed surface area (SA) with increasing blood circulation time are presented. Error bars represent the SEM and n = 3 for all blood circulation times.

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Fig. 7

Both the mean and maximum WSS and WSR calculated on the thrombus surfaces are presented with increasing blood circulation time. Error bars represent the SEM and n = 3 for all blood circulation times.

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Fig. 8

WSS distributions and corresponding histograms for all three thrombi imaged after 30 min of blood circulation. For panels (a)–(c), the mean/maximum WSS values are 0.13/2.2, 1.45/11.0, and 0.35/5.1 dyn/cm2, respectively.

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Fig. 9

Three axial slices of the lumen through a representative thrombus after (a) 10, (b) 30, and (c) 60 min of blood circulation. Velocity contours are shown to illustrate recirculation regions, and the acrylic model has been outlined in white after the BFS to show the thrombus boundaries. The positions of the slices are indicated with white lines across the WSS distribution on the thrombus surface. A white arrow on each velocity plot denotes the location of the step, and flow is from left to right in all plots. The length scales are different for the velocity and WSS plots. (a) Regions of high WSS are predicted on protrusions from the thrombus surface, even though the entire thrombus is contained within a recirculation region. (b) Location 1 in the velocity plot indicates a portion of the thrombus protruding into the lumen which causes a small recirculation region to develop downstream. This same location in the WSS plot has heightened WSS on the peak followed by a region of very low WSS. Location 2 indicates a recirculation region extending nearly the length of the thrombus, and this corresponds to a strip of low WSS. An example recirculation region has been magnified to provide a better view. (c) Location 3 in the velocity plots indicates a small recirculation region immediately downstream of the step which is reflected as a low WSS region on the upstream portion of the thrombus surface. Location 4 indicates a protrusion that extends far into the lumen of the model. This corresponds to the highest WSS calculated on any of the thrombus surfaces in this study. Location 5 indicates a small recirculation region that forms after this peak and the low WSS region that the CFD predicted at the same location.

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Fig. 10

Histograms of the WSS magnitude for the representative thrombi shown in Figs. 9(a)9(c). (a) Corresponds to the 10 min thrombus in Fig. 9(a), 9(b) corresponds to the 30 min thrombus in Fig. 9(b), and 9(c) corresponds to the 60 min thrombus in Fig. 9(c).

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