Hemodynamic Study Of Carotid Artery Atherosclerosis And Its Influencing Factors Based On CFD

Cardiovascular disease has become the most first killer to human life and health. Atherosclerosis is an important focal lesion for cardiovascular disease. The bifurcation of carotid artery is position where atherosclerosis mostly attacks. The physical ramification of atherosclerosis in carotid artery ranges from damage on nervous system to stroke, even cerebral infarction. According to relevant research, the hemodynamic factors, such as low wall shear stress, oscillating walls shear stress and long residence time of particles, are closely related to atherosclerosis. Therefore it has huge significance for the prediction of atherosclerosis to obtain hemodynamic parameters accurately above-mentioned.This article applies three dimensional reconstruction technique of medical image to build accurate three dimensional entity geometry model of normal bifurcated human carotid artery according to anatomy. CFD software is adopted to carry out the transient numerical simulation of pulsating blood flow in bifurcated carotid artery based on relevant flow mechanic theory. The mechanic result is combined with the biology pathogenesis. The analyses shows that there are major areas where the time-averaged wall shear stress (TAWSS for short) is much lower in the entire pulsation period around both the initial segment of internal carotid sinus lateral wall and the initial segment of external carotid artery lateral wall. The TAWSS is below 0.4 Pa. the wall shear stress vibrates severely, and maximum OSI is up to 0.458. Besides, large scale of low speed flow areas in the period of declining stage of both systole and diastole are found due to flow separation, along with secondary flow. hemocyte, thrombocyte and lipid particles are more likely to stay, even accumulate. Atherosclerosis plague is highly likely to take place in these regions.This article stimulates physiology pulsating flow in bifurcate carotid artery with different viscosity. The influence to the formation of atherosclerosis plague along with viscosity changing is studied and researched. The results show that the wall shear stress goes up along with the viscosity increases in the range of normal physical signs, the local vibration shear force is fiercer as well, and the site of action concentrates. The secondary flow weakens, however the separation zone remains. After overall consideration, increasing of viscosity will raise the risk of atherosclerosis plague attacking.The physiology pulsating flow in bifurcate carotid artery with different flux is simulated, the relation between the formation of atherosclerosis plague and the changing of flux is studied and researched. According to the research, as the blood flux raises, the low speed flow areas shrink by a large margin, the minimum wall shear stress increases. The regions affected by vibration wall shear stress decrease sharply, and the OSI value in initial segment of internal carotid sinus lateral wall and initial segment of external carotid artery lateral wall recedes, the site of action areas disperses. The flow separation area and the intensity of secondary flow increase. In conclusion, the increasing of blood flux will lower the risk of formation of atherosclerosis plague.