Computational Haemodynamics—An Introduction - Computational Hemodynamics: Theory, Modelling and Applications - page 11

Fig. 1.9 Virtual stent design and analysis procedures. The design of stents via medical image
reconstruction, computational modelling and reconstruction, and computational simulation fol-
lowed by analysis of wall shear stress distribution can determine if stenting is a necessity for the
atherosclerotic artery case
of less than 10 Pa) is noticed in the normal carotid artery with simulated stent in
place, and this contrasts with high wall shear stress (maximum value at approxi-
mately 85 Pa) that is observed in the stenotic carotid artery.
Figure 1.10 also shows that for a normal artery, the wall shear stress distribu-
tion is more uniform due to the lower curvature and asymmetry of the carotid sinus
and flow divider (at bifurcation point). High wall shear stress values are located at
the bifurcation and further downstream. This results from the blood flow having a
tendency to flow along the inner walls conforming to curvature of the carotid bifur-
cation. As a result, low wall shear stress values are constantly formed at the roots
and along the outer walls of sinus bulbs. Locations of low wall shear stress are in
accordance with the plaque locations of the stenosed model. Therefore, these results
affirm that low wall shear stress is related to localization of atherosclerotic lesions
(Ku et al. 1985a).
Time-dependent blood flow streamlines through a healthy and stenosed carotid
bifurcation are plotted at peak cardiac cycle (Fig. 1.11 ). Based on the stenosed mod-
el, high velocity blood flow occurs at the stenosis due to occlusion caused by the
plaque. At the peak cardiac cycle, maximum blood flow is 4.66 m/s. For the virtu-
ally stented condition, flow pressure difference between point A and point B of the
artery are reduced significantly.