| Objective Based on Computed Tomographic Angiography(CTA),computational fluid dynamics(CFD)was used to extract normal human and stenotic carotid artery models and analyze the distribution differences of wall shear stress(WSS),pressure,velocity and blood flow state.To explore the relationship between local hemodynamic changes of carotid artery and the formation and development of carotid atherosclerosis(CAS)plaque.To provide guidance for the next clinical treatment.Methods The patients who were examined in our hospital from September 2020 to November2022 were selected.Eighteen carotid arteries with no plaque proved by imaging examination and 30 carotid arteries with different degrees of stenosis(10 with mild stenosis,20 with moderate stenosis and 10 with severe stenosis)were collected and included in the study.The original CTA images in DICOM format were collected and the carotid artery model was extracted by CFD to obtain the distribution of carotid blood flow dynamics.1.The distribution differences of WSS,pressure,velocity and blood flow status between the carotid sinus of 18 normal human carotid arteries(the common carotid plaque prone area)and the distal end of the common carotid artery,the distal end of the internal carotid artery were analyzed,and the local hemodynamic data of different parts were statistically analyzed.2.Three regional planes of interest(maximum stenosis and upstream and downstream stenosis)were collected from 20 moderately stenosis carotid arteries.CFD analysis was used to compare the differences of WSS,pressure,velocity and blood flow status among the upstream,center and downstream stenosis of moderate carotid artery stenosis.3.The local maximum,minimum,average WSS,pressure and velocity of carotid arteries with different stenosis degrees(10 carotid arteries with mild stenosis,20 carotid arteries with moderate stenosis and 10 carotid arteries with severe stenosis)were collected,and the differences in local hemodynamic parameters of carotid arteries with different stenosis degrees were analyzed.Results 1.Through CFD analysis of 18 normal carotid arteries,it was found that the minimum WSS and average velocity were the lowest in the carotid sinus,which were both lower than the distal common carotid artery(0.53±0.16vs1.54±0.27,P=0.007;0.29± 0.09vs0.40±0.08,P<0.001)and distal internal carotid artery(0.53±0.16vs6.31±1.33,P<0.001;0.29±0.09vs0.57±0.16,P<0.001),and a turbulent flow characteristic was found in the carotid sinus.The inplane pressure difference in carotid sinus was greater than that in the other two areas(177.16±45.81vs35.76±9.82,P<0.001;177.16±45.81 vs 118.15±23.35,P<0.001).2.Through CFD simulation analysis of 20 moderately narrow carotid arteries,obvious changes in hemodynamics were found,WSS and velocity increased at the stenosis,the maximum,minimum and average WSS at the stenosis were higher than those at the upstream of the stenosis(122.58±73.62vs51.42±31.86,P<0.05;46.20±27.16 vs17.35±10.00,P<0.05;86.59±48.57vs31.46±22.29)and the downstream of stenosis(122.58±73.62 vs21.55±15.58,P<0.05;46.20± 27.16 vs2.91 plus or minus 1.71,P < 0.05;86.59± 48.57vs10.49 ±5.54,P<0.05);the mean velocity in the stenosis was higher than that in the upstream(1.27±0.59vs0.55±0.26,P<0.05)and downstream(1.27±0.59 vs 0.35±0.14P<0.05);The maximum,minimum and average pressure at the stenosis was significantly lower than that at the upper reaches of the stenosis(-3.78±457.98vs1636.36± 1013.69,P<0.05;-819.54±845.19vs1137.22±866.64,P<0.05;-441.18±646.37vs1442.59±956.96,P<0.05)and downstream stenosis(-3.78±457.98 vs 304.09±253.86,P<0.05;-819.54±845.19 vs 26.61±319.14,P<0.05;-441.18±646.37vs144.36±323.37,P<0.05);and the maximum,minimum and average WSS in the upper reaches of stenosis were higher than those in the lower reaches of stenosis(51.42±31.86vs21.55±15.58,P<0.05;17.35 ±10.00 vs2.91 plus or minus 1.71,P <0.05;31.46±22.29 vs10.49±5.54,P<0.05),the maximum,minimum and average wall pressure in the upper reaches of stenosis was higher than that in the lower reaches(1636.36±1013.69vs304.09±253.86,P < 0.05;1137.22±866.64vs26.61±319.14,P<0.05;1442.59±956.96vs144.36±323.37,P<0.05).3.Through CFD analysis of hemodynamic changes in carotid artery stenosis with different degrees of stenosis,it was found that with the increase of stenosis degree,the blood flow velocity and WSS at the stenosis were higher and higher,while the pressure was lower and lower,but only the minimum pressure(P<0.001)and the average pressure(P<0.001)were statistically significant among the three stenosis groups.Conclusion 1.Using CFD,it is found that low WSS,high plane pressure difference,low velocity and turbulence can be observed in normal human carotid sinus,which is related to the easy formation of atherosclerotic plaque there.2.Velocity,WSS and Pressure have a certain distribution trend in the upstream,downstream and stenosis of carotid artery plaques,which provides a theoretical basis for the further development of carotid artery plaques and clinical intervention. |
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