The Influence of Aortic Valve Disease on Coronary Hemodynamics: A Computational Model-Based Study

Figures

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  Figure 1. Schematic description of 0-3D multi-scale modeling of coronary hemodynamics. The left lower panel shows CCTA image-based reconstruction of a 3D geometric model for a LAD; the middle lower panel displays the connections between the 3D model of a LAD with the upstream and downstream 0D models; the right middle panel illustrates the opening state of aortic valve during systole and diastole under normal and various pathological conditions; and other panels show the configuration of 0D models.

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  Figure 2. Schematic diagram of data exchanges between 3D and 0D models at the boundaries of 3D model. tn (=n∆t) and tn+1 (=(n + 1)∆t) indicate the current and next time steps; P, Q, and U stand for blood pressure, flow rate, and flow velocity, respectively; and ‘i’ and ‘j’ denote the inlet and outlet of the 3D model. The data exchanges proceed in a time-marking manner.

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  Figure 3. Relative errors of 3D model-computed flow rate waveforms in two consecutive cardiac cycles during time-marching 0-3D simulations. Since the errors differ slightly between models, the errors for all six LAD models are statistically illustrated in form of box plot. The convergence criterion was set as <0.001, which was reached after the 0-3D simulations ran for five cardiac cycles.

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  Figure 4. Relationships between coronary perfusion pressure and normalized mean flow rate under normal conditions and in the presence of aortic valve diseases (i.e., AS and AR).

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  Figure 5. (a) Simulated pressure–volume loops of the left ventricle and (b) flow velocity waveforms in the proximal portion of a LAD under various aortic valve conditions.

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  Figure 6. Color maps of simulated TAWSS and OSI in LADs under various aortic valve conditions.

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  Figure 7. Computed SA-TAWSS (a) and SA-OSI (b) in six LADs under various aortic valve conditions, and the corresponding statistical box plots (c, d). Large box represents the lower and upper quartiles, with the line in the box denoting the mean value. ** p < 0.001 vs. control.

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  Figure 8. Spatial distribution of OSI (left) and flow streamlines (right) in a LAD with severe stenosis under control and AS conditions. The 3D flow streamlines in the vicinity of stenosis and 2D flow streamlines in a cross-section in the post-stenosis region are visualized for five representative time moments (marked on the flow waveforms in the upper panel) during a cardiac cycle. The red arrows indicate the regions where in-plane flow disturbance or recirculation occurs.

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  Figure 9. Harmonic moduli of the simulated flow waveforms in six LADs under different aortic valve conditions. Panels (a–f) display the results corresponding to LAD1 to LAD6 in sequence.