Wall Shear Stress Is Associated With Atheroscleros And Integrated Risk Of Cardiovascular Disease

Objective:Carotid intima-media Thickness,carotid wall shear stress and restenosis after femoro-popliteal percutaneous transluminal angioplasty .Atherosclerosis is a chronic,inflammatory,fibroproliferative disease primarily of large-and medium-sized conduit arteries.Although the entire vasculature is exposed to the atherogenic effects of the systemic risk factors(e.g.,hypertension,hyperlipidemia,cigarette smoking etc.),atherosclerotic lesions form at specific regions of the arterial tree,such as inthe vicinity of branch points,the outer wall of bifurcations,and the inner wall of curvatures,where disturbed flow occurs.The phenomenon has become Shear stress study of atherosclerosis pathogenesis of the best starting point and biomechanical study of hot spots.In recent years,many studies suggest that shear stress plays a major role in determining the location,extent,and severity of the lesions.However,due to a variety of detection technology is not yet mature enough,most studies remain in the in vitro experiments,less research on the human body.Shear stress on the body of research those on the human carotid artery shear stress research ,of ten in healthy people or patients with risk factors alone for the study,very few studies based on risk stratification to shear stress.We know that accompanied with the more risk factors,the occurrence of the greater risk of cardiovascular disease.So how is the shear stress changes in the risk stratification? And will they be able to predict cardio vascular events happen? So we study on shear stress in vivo measurement and analyze the differences in shear stress between subjects with atherosclerosis and in those without atherosclerosis in order to investigate the shear stress and atherosclerosis relationship.To investigate the relationship between shear stress and integrated risk of cardiovascular disease,through the analysis of low-risk,medium risk,high-risk groups in the changes in shear stress.Shear stress will also analyze the correlation with the IMT.In addition,subjects with symptomatic and athero-sclerosis would be grouped by TCM.We analyze shear stress and system of risk factors difference among the different groups in order to make TCM more objective,standardization. Methods:One hundred thirty-six subjects were grouped into low-risk, medium-risk,high-risk groups according to China's 2007 program of dyslipidemia risk stratification.Further,Each of the there groups were divided into subjects with atherosclerosis and in those without athero-sclerosis.Systolic Blood velocity,internal diameter,and intima-media thickness were measured by high-resolution echo Doppler.Blood viscosity at the shear rate of 225/s was measured in vitro with a cone/plate viscometer .Wall shear stress was calculated according to the Poiseuillean formula:Shear Stress= 4×Blood Viscosity×Blood Velocity / Internal Diameter.Statistics was used to study the association of shear stress in each group with atherosclerosis,integrated risk of cardiovascular dis-ease and IMT.In addition,subjects with symptomatic and atherosclerosis would be divided into four types by TCM:Liver-kidney yin Deficiency, spleen hypofunction and dampness accumulation,qi stagnation and blood stasis,endoretention of damp heat.Statistics was used to study shear stress and systems risk factors in the differences in each group.Results:shear stress in subjects with atherosclerosis was significantly lower than in those without atherosclerosis in low-risk,medium-risk, high-risk groups(P<0.05).Only shear stress in low-risk group was signi-ficantly highter than the shear stress in medium-risk and high-risk groups with atherosclerosis in right common carotid artery(P<0.05).No signi-ficant difference in wall shear stress was found in low-risk,medium-risk, high-risk groups with atherosclerosis in left common carotid artery and without atherosclerosis(P>0.05).Shear stress and IMT were inversely correlated(P<0.05).Type of qi stagnation and blood stasis was not found in those with symptomatic and atherosclerosis.Only age was significantly difference in Liver-kidney yin Deficiency,spleen hypofunction and damp-ness accumulation,and endoretention of damp heat.Kidney-yin deficiency patients was older than subjects with liver than spleen dampness and heat connotation.Shear stress and the risk factors of other systems in the group had no significant difference(P>0.05).Conclusions:Low shear stress is closely associated with atherosclerotic plaque and is a local risk factor for atherosclerosis.The correlation with the IMT further prove the association between shear stress and athero-sclerosis.Shear stress may be one of the predictor of atherosclerosis.In intima-media thickness of posterior wall in the common carotid arteries 1cm proximal to the bulb have strong predictability of atherosclerotic plaque.Wall shear stress is not reduced with the increase of integrated risk of cardiovascular disease in subjects with atherosclerosis and without atherosclerosis.So it isn't prove that shear stress can predict cardiovascular ischemic events.In addition,this study suggest that age can be used as reference for the atherosclerosis of TCM but not do shear stress and other risk factors of systems.