Considering the Influence of Coronary Motion on Artery-Specific Biomechanics Using Fluid–Structure Interaction Simulation

Figures

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  Fig. 1. Summary of applied fluid-domain boundary conditions. Plots showing time-varying waveforms of flow velocity (vessel inlet), pressure (vessel outlet) and bending amplitude, for a the LAD, b the LCx, and c the RCA. Waveforms are normalised to the R-R interval for comparison, but cardiac cycle time periods vary between vessels due to difference in subject heart rates at the time of measurement. Accompanying images show the diastolic (dark green) and systolic (light green) configurations of the d LAD, e LCx and f RCA, providing qualitative description of the bending displacements applied to each vessel. The inlet extension part of the model is not shown

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  Fig. 2. Results for fluid and solid domain of LAD FSI simulation without-bending, providing verification of physiologically valid results. a Plot showing flow velocity boundary condition applied at the vessel inlet, and pressure boundary condition applied at the outlet. Computed values of flow velocity at the vessel mid-point and outlet show increase in velocity as the vessel tapers. Computed value of pressure at the inlet confirms the presence of a pressure gradient. b Plot showing variation of computed mean vessel diameter with time, confirming distension of vessel wall in response to computed blood pressure forces. Values presented for a point located 25% along the length of the vessel. c Plot of percentage diameter change of vessel between diastole and systole along the length of the vessel. Mean dilation calculated over the proximal first 1/3 of the vessel of 5.3% compares well to in vivo measurement via IVUS of 4.5% ± 1%, measured in the proximal region of LAD

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  Fig. 3. Results of Time Averaged Wall Shear Stress (TAWSS) for rigid-wall CFD, FSI without (w/o) bending, and FSI with-bending, for LAD, LCx and RCA. Maps of each artery are presented as opened and flattened, showing magnitude and location of TAWSS for flow from proximal (left) to distal (right). Histograms compare the CFD, FSI without-bending, and FSI with-bending TAWSS datasets for each vessel

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  Fig. 4. Results of transverse Shear Stress (tSS) for rigid-wall CFD, FSI without (w/o) bending, and FSI with-bending simulations, for LAD, LCx and RCA. Maps of each artery are presented as opened and flattened, showing magnitude and location of tSS for flow from proximal (left) to distal (right). Histograms compare the CFD, FSI without-bending, and FSI with-bending tSS datasets for each vessel

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  Fig. 5. Summary of vessel wall response comparing results of FSI simulations of the LAD with- and without-bending simulations. Cyclic logarithmic strain (%) results for FSI without-bending simulation showing a circumferential, b axial and c radial components. d Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI without-bending simulation. e First spatial derivative of bending vector magnitude along the length of the vessel applied to FSI with-bending model. Cyclic logarithmic strain (%) results for FSI with-bending simulation showing f circumferential, g axial and h radial components. Circumferential location of bending loading application demarcated by black bars. i Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI with-bending simulation. All strain maps presented as opened and flattened, proximal region on the left, distal on the right

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  Fig. 6. Summary of vessel wall response comparing results of FSI simulations of the LCx with- and without-bending simulations. Cyclic logarithmic strain (%) results for FSI without-bending simulation showing a circumferential, b axial and c radial components. d Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI without-bending simulation. e First spatial derivative of bending vector magnitude along the length of the vessel applied to FSI with-bending model. Cyclic logarithmic strain (%) results for FSI with-bending simulation showing f circumferential, g axial and h radial components. Circumferential location of bending loading application demarcated by black bars. i Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI with-bending simulation. All strain maps presented as opened and flattened, proximal region on the left, distal on the right

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  Fig. 7. Summary of vessel wall response comparing results of FSI simulations of the RCA with- and without-bending simulations. Cyclic logarithmic strain (%) results for FSI without-bending simulation showing a circumferential, b axial and c radial components. d Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI without-bending simulation. e First spatial derivative of bending vector magnitude along the length of the vessel applied to FSI with-bending model. Cyclic logarithmic strain (%) results for FSI with-bending simulation showing f circumferential, g axial and h radial components. Circumferential location of bending loading application demarcated by black bars. i Percentage change of vessel wall diameter between diastole and systole along the length of the vessel for FSI with-bending simulation. All strain maps presented as opened and flattened, proximal region on the left, distal on the right