Analysis On The Relationship Between The Carotid Artery Plaque And The Morphology And Hemodynamics Of Common Artery Bifurcation

Part I Analysis on the relationship between the carotid artery plaque and the anatomy of common artery bifurcation with ultrasonographyObjective: To assess the morphological and hemodynamic characters of common carotid artery bifurcation and to investigate the relationship between the carotid artery artherosclerosis plaque and these characters. Materials and Methods:1. The common carotid artery (CCA),common carotid artery bifurcation (CCAB),internal carotid artery (ICA) and external carotid artery (ECA) of 426 patients between January, 2009 and December, 2010 were studied continuously using the Philips iU22 and Siemens-Antares ultrasound instruments with 3~9 MHz transducers.2. The bifurcate angle, carotid intima-media complex thickness (IMT) and carotid hemodynamic indexs were measured. Hemodynamic parameters in each vessel including peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI).3. The patients were divided into 3 groups according to the anatomy of carotid bifurcation:"Y"shaped(groupⅠ),"Tuning-Fork"shaped(groupⅡ),"spoon"shaped(groupⅢ) carotid bifurcation.4. Statistics:the angles of CCAB and the velocity indexes were demonstrated with x±s,one-factor analysis of variation(ANOVA) was used to compare the PSV,EDV,RI and PSVICA/PSVCCA.The results of the rate were test with chi-square test respectively. P<0.05 were considered significant。The SPSS 13.0 was used to statistical computations. Results: 1. The CCABs of 365 patients were displayed clearly with ultrasound bilaterally, and the CCAB angles were measured.2. The carotid artery diameter was enlarged markedly at CCAB level, and the velocity was declined. Pulsed-wave Doppler showed direct spectra on the early diastolic period. Super-speed hydraulic flow, turbulent flow and reverse flow were demonstrated at the position of plaques.3. The distribution of the three anatomy groups of carotid bifurcation was ( from high to low )"Tuning-Fork"shaped(groupⅡ),"spoon"shaped(groupⅢ) and"Y"shaped(groupⅠ)carotid bifurcation.4. The mean value of CCAB angle was 29.71±7.83°. The angle of CCAB mainly lay between 20°～30°(43.84%) , the right side amounting to 45.75% and the left side amounting to 41.92%.5. In comparison with the PSVCCA,PSVICA,EDVCCA,EDVICA,RICCA,RIICA in each group, no difference was shown on statistics. However, in comparison with PSVICA/PSVCCA ,apparent difference appeared between groupⅠand groupⅡ(P<0.05 ), and the similar result was noted between groupⅠand groupⅢ(P<0.05 ).6. The relationship between the anatomy groups of carotid bifurcation and the detection rate of artherosclerosis plaque were: The apparent difference was demonstrated on statistics between groupⅠand groupⅡ, (P<0.05 ), and the similar result was noted between groupⅠand groupⅢ(P<0.05 ).7. The relationship between the angle groups of carotid bifurcation and the detection rate of artherosclerosis plaque were: The apparent difference was demonstrated on statistics among the groups.Conclusion:US can clearly demonstrate the normal anatomy of CCAB. It provides a new convenient method to measure the angle of CCAB. Significant intra-subject variations exist in anatomy of common artery bifurcation thought to impact atherosclerosis. The maximum detection rate of artherosclerosis plaque is observed in"Y"shaped carotid bifurcation (groupⅠ). The maximum detection rate of artherosclerosis plaque is observed in the largest angle of CCAB group.Part II Analysis on the relationship between the carotid artery plaque and the relative position of the initial segment of ICA and ECA Objective: To assess relative position of the initial segment of ICA and ECA and to investigate the relationship between the position of plaque and these characters.Materials and Methods:1. The common carotid artery (CCA),common carotid artery bifurcation (CCAB),internal carotid artery (ICA) and external carotid artery (ECA) of 426 cases were examined continuously ,using the Philips iU22 and Siemens-Antares US instruments with 3~9 MHz transducer.2. The relative position of the initial segment of ICA and ECA was observed. The carotid intima-media complex thickness (IMT) and carotid hemodynamic index were examined. Hemodynamic parameter in each vessel included: peak systolic velocity (PSV), ending diastolic velocity (EDV), and resistance index (RI).3. The patients were divided into 2 groups according to relative position of the initial segment of ICA and ECA :ICA on the lateral side of ECA (groupⅠ) and ICA on the internal side of ECA (groupⅡ).4. Statistics:the velocity indexes were demonstrated with x±s,a least significant t-test was used to compare the PSV,EDV,RI.The results of the rate were test with chi-square test respectively. P<0.05 were considered significant。The SPSS 13.0 was used to statistical computations.Results:1. The initial segments of ICA were observed to be located on the lateral side of ECA in 698 cases (90.41%).2. The relationship between the relative position of the initial segment of ICA and ECA and the position of artherosclerosis plaque: The apparent difference was demonstrated on statistics between groupⅠand groupⅡ, (P<0.05 ).Conclusion: Significant intra-subject variation exists in relative position of the initial segment of ICA and ECA, while most ICA is located on the lateral side of ECA initially. The majority of AS plaques are located at the posterior wall of CCAB.The detection rate of plaques located on the anterior wall is higher in groupⅡ.Part III Analysis on the relationship between the hemodynamics characters and the incidence of cerebral infarction in patients with severe stenosis of CCAObjective: To investigate the relationship between hemodynamics characters and the incidence of cerebral infarction, to analyze the characters of carotid plaques and changes of carotid artery blood flow by ultrasonography as well as select patients at high risk for cerebral infarction.Materials and Methods:1. 75 patients with CCA stenosis detected by US and MRI were enrolled in our study. Carotid arterial IMT, the characters of plaques, severity of artery stenosis and hemodynamics of carotid artery were studied by color Doppler ultrasound.2. Hemodynamic indexes were measured at CCA,ICA,and the distal side of the stenosis position. Hemodynamic parameter in each vessel included: peak systolic velocity (PSV), ending diastolic velocity (EDV), and resistance index (RI).3. The patients were divided into 4 groups according to the outline of plaque:"band-formed"plaque(length/depth,L/D>3:1),"hill-formed"plaque(3:1≥L/D>2:1),"pillar-formed"plaque (L/D≥2:1),and"irregular-formed"plaque. The plaques were divided into soft plaque (low echo level), iso-echoic plaque, hard plaque (high echo level) and mixed plaque according to the echo intensity.4. Statistics:the velocity indexes were demonstrated with x±s,a least significant t-test was used to compare the PSV,EDV,RI.The results of the rate were test with chi-square test respectively. P<0.05 were considered significant。The SPSS 13.0 was used to statistical computations. Results:1. The"irregular-formed"and"band-formed"plaques were most common.2. The soft plaque was the most common type of carotid plaques in CI and non-CI groups,3. In comparison with PSVCCA,PSVICA,EDVCCA,EDVICA,RICCA,RIICA between CI and non-CI group,significant difference appeared (P<0.05 ).4. In comparison with PSVST,PSVpost-ST,EDVST,EDVpost-ST,RIST,RIpost-ST between CI and non-CI group,significant difference appeared (P<0.05 ).5. The pulsed wave was abnormal at the distal side of the stenosis position.Conclusion:The presence of soft plaque is closely associated with cerebral infarction. Compared with the non-CI group,part of the hemodynamic characters of CCA,ICA are significantly different in CI group. According to the characters of carotid plaques and changes of carotid artery blood flow wave,we may select patients at high risk for cerebral infarction,which give guidance to clinical prevention and treatment.