A multiscale model was proposed to calculate the circumferential stress （CS） and wall shear stress （WSS） and analyze the effects of global and local factors on the CS, WSS and their synergy on the arterial endothelium in large straight arteries. A parameter pair [Zs, SPA] （defined as the ratio of CS amplitude to WSS amplitude and the phase angle between CS and WSS for different harmonic components, respectively） was proposed to characterize the synergy of CS and WSS. The results demonstrated that the CS or WSS in the large straight arteries is determined by the global factors, i.e. the preloads and the afterloads, and the local factors, i.e. the local mechanical properties and the zero-stress states of arterial walls, whereas the Zs and SPA are primarily determined by the local factors and the afterloads. Because the arterial input impedance has been shown to reflect the physiological and pathological states of whole downstream arterial beds, the stress amplitude ratio Zs and the stress phase difference SPA might be appropriate indices to reflect the influences of the states of whole downstream arterial beds on the local blood flow-dependent phenomena such as angiogenesis, vascular remodeling and atherosgenesis.
Kairong QinZonglai JiangHui SunKeqin GongZhaorong Liu
In this paper, by solving the fundamental e-qualions of periodicallyoscillatory blood flow, the distributions of pressure gradient and blood velocity in varying-areae-lastic vessel were obtained, and then the wall shear stress and its gradient were calculated. Asan example, the pulsatile blood flow in human carotid was analyzed and the effects of vessel taperangle on the distribution of wall shear stress and its gradient were discussed in detail. Numercialresults show that the wall shear stress will enlarge when the taper angle increases. Meantime, nomatter whether the vessel is converging or diverging, with the increase of the absolute value oftaper angle, the amplitude of wall shear stress gradient will enlarge significantly.
