The Effects of the Presence of a Secondary Stenosis on Flow Patterns Around a Primary Stenosis

Angioscopic studies have shown that instead of a single arterial stenosis, multiple stenoses may also develop in series in an arterial segment. The secondary stenoses can have an important effect on hemodynamic changes around a primary stenosis. In order to understand this effect we have performed numerical simulations using double stenosis in artery models with a flexible wall and non-Newtonian blood flow. Flow related parameters such as wall shear stress and wall pressure distribution along the arterial wall were used in this study. Our results has shown that wall shear stress decreases in the proximal shoulder and the apex of the primary stenosis by addition of the secondary stenosis. However it increases in the distal shoulder of the plaque. Presence of the secondary stenosis increases the oscillations of the wall shear stress in the distal region of the primary stenosis. The length of the recirculation region is also decreased in the presence of the second stenosis. Also the presence of the second stenosis increases the pressure on the primary stenosis thus can lead to a higher tensile stresses within the plaque. In general, we concluded that presence of the secondary stenosis can lead to the instability of the primary plaque.