A 2D computational model of chemically- and mechanically-induced platelet plug formation

Figures

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  Fig. 1. Schematic of the platelet plug formation process involving platelet activation, adhesion, and aggregation. These processes are governed by both chemical and mechanical factors (Fig. generated using images from Suzuki et al. (2012) for a, Bayer for b, Periayah et al. (2017) for e, and Nesbitt et al. (2009) for f)

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  Fig. 2. Validation of the computational model against the experimental results of Nesbitt et al. (2009) for the time evolution of platelet aggregate size. Incorporating the effects of spatial shear gradients is essential

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  Fig. 3. Geometry and inlet boundary conditions considered for the stenosed vessel simulations. a Flow domain. Arrow at the inlet denotes the flow direction. b Shear rate distribution in a stenosed vessel. c) Shear gradient distribution in a stenosed vessel. d Normalized flow rate as a function of percent stenosis for either a prescribed inlet velocity or a prescribed inlet pressure. The normalization is relative to flow in a straight (unstenosed) vessel

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  Fig. 4. Velocity field, shear rate distribution, and activated platelet concentration for vessels with different percent stenosis and a constant inlet velocity of 17 cm/s. a Velocity contours and streamlines for different percent stenosis values. b Normalized shear rate distribution for different percent stenosis values. The normalization is relative to the critical shear rate needed for platelet activation. c Activated platelet concentration distribution for different percent stenosis values

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  Fig. 5. Effect of stenosis severity on platelet plug formation for a prescribed inlet velocity of 17 cm/s and h=3. a–e Platelet plug formation after 120 s for 80%, 60%, 40%, 20%, and 0% stenosis, respectively. f Time evolution of platelet plug size for vessels with different percent stenosis

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  Fig. 6. a Platelet plug after 120 s driven by only biochemical factors vs. that driven by both biochemical and mechanical factors in a vessel with 80% stenosis. b Platelet plug after 120 s in a vessel with 80% stenosis assuming that platelet aggregation is driven by negative shear gradients regardless of whether or not the endothelium is damaged or inflamed. c Left: Effect of blood flow pulsatility on the time evolution of platelet plug aggregate size in a vessel with 80% stenosis. Right: Platelet plug after 120 s for stationary flow vs. pulsatile flow

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  Fig. 7. Effect of thrombus growth on the blood velocity field in a vessel with 80% stenosis at time points ranging from 0 to 120 s. Zoom on the thrombus peak for 30 s, 60 s, 90 s

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  Fig. 8. Velocity field, shear rate distribution, and platelet activation for vessels with different percent stenosis and a prescribed inlet pressure of 2.8 kPa.a Velocity contours and streamlines for different percent stenosis values. b Normalized shear rate distribution for different percent stenosis values. The normalization is relative to the critical shear rate needed for platelet activation. c Activated platelet concentration distribution for different percent stenosis values

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  Fig. 9. Effect of stenosis severity on platelet plug formation for a prescribed constant inlet pressure of 2.8 kPa and h=3.a–e Platelet plug formation after 120 s for 80%, 60%, 40%, 20%, and 0% stenosis, respectively. f Time evolution of platelet plug size for vessels with different percent stenosis

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  Fig. 10. Bifurcation geometry and associated shear rate and shear gradient distributions. a Computational domain considered. b Shear rate distribution. c Shear gradient distribution

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  Fig. 11. Distributions of normalized shear rate (left) and activated platelet concentration (right) in the considered bifurcation for different Reynolds numbers ranging from 50 to 250. For the normalized shear rate maps, the normalization is relative to the critical shear rate needed for platelet activation

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  Fig. 12. a–d Platelet plug formation after 120 s in the considered bifurcation for different Reynolds numbers ranging from 50 to 250. e Time evolution of platelet plug size in the considered bifurcation for the different values of Reynolds number