Applications of FSI for Cardiovascular Haemodynamics - Computational Hemodynamics: Theory, Modelling and Applications - page 253

8.4 Flow in the Left Coronary Artery

This example presents an FSI study of flow in a coronary artery with different
branch angulation, using anatomically accurate and idealized human coronary ar-
tery models. This study aims to elucidate the link between coronary artery angula-
tion, coronary haemodynamics and local mechanical forces (tensile stress) to enable
a better understanding of the role of haemodynamics in atherosclerotic disease initi-
ation and progression in the vicinity of bifurcations. Using a coupled FSI modelling
approach, five idealized left coronary artery models with various angles ranging
from 70° to 110° were developed to investigate the influence of branch angulations.
In addition, one CT image-based model was reconstructed to further demonstrate
the medical application potential to patient specific models.

8.4.1 Geometric Models and Material Properties

The anatomical replica model was reconstructed from multi-slice CT angiog-
raphy of a left coronary segment (Chaichana et al. 2011). Figure 8.19 shows the
CT image-based model which exhibits an angle of 90° generated from CT images
3

(voxel size of 0.6 ×× using the software Blender version 2.48 (Blender

Institute, Amsterdam, Netherlands). In addition, an idealized model was developed
with averaged anatomical data for vessel diameter, length and curvature based on 19
post-mortem casts of normal human coronary artery trees (Nerem and Seed 1983).
An overview of the idealized model is shown in Fig. 8.20 and its basic dimensions
are listed in Table 8.3 . To analyse the influence of bifurcation angulation ( θ ), five
idealized models were constructed with angles of 70°, 80°, 90°, 100° and 110°
respectively, which are in the physiological range reported by Girasis et al. (2010).
To isolate the effect of a single geometric factor, the angle formed by the left main
stem (LM) and left anterior descending (LAD) was kept constant (Johnston and
Kilpatrick 1997). The angle variation was achieved by changing the orientation of
left circumflex (LCx).

0.6 0.6 mm )

Fig. 8.19 3D CT visualization and reconstruction of the image-based model. LM , left main stem;
LAD , left anterior descending; LCx , left circumflex