超声评估颈动脉粥样硬化与血流机械动力学改变的关系

Ultrasonographic evaluation of relationship between atherosclerosis and mechanical forces in carotid artery

目的探讨颈动脉粥样硬化时其血流机械力学的改变与颈动脉内-中膜厚度(IMT)和各危险因素的关系。方法以高频超声测量116例动脉粥样硬化患者及40名健康人颈动脉的IMT、内径、血流速度,计算剪切率(SR)、环壁张力(CWT)、杨氏膜量(YEM)、脉搏波速度(PWV),并做组间比较。采用直线相关分析硬化组IMT与各机械指标的关系和全部病例各危险因素与机械指标和IMT的关系;用ROC曲线评价各机械指标诊断粥样硬化的价值。结果硬化组较对照组SR降低、CWT、YEM、PWV升高(P<0.05);硬化组IMT与SR负相关、与CWT、YEM、PWV正相关(P<0.05);血压与各机械力指标及IMT相关性良好(P<0.05),血糖、血脂、吸烟相关性较差(P>0.05);CWT、PP、PWV、YEM诊断动脉粥样硬化准确度中等偏低(S=0.752、0.670、0.698、0.631)。结论局部因素的机械力(剪切力与环壁张力)在颈动脉粥样硬化发生发展过程的作用比系统危险因素更重要。

Objective To explore the alterations of mechanical forces of carotid artery and the relationship between intimamedia thickness （IMT） and risk factors in atheroselerosis. Methods IMT, vessel diameter and blood velocity of carotid artery were measured in 116 atherosclerosis patients and 40 normal controls with ultrasonography. Shear rate （SR）, circumferential wall tension （CWT）, Young＇s elastic modulus （YEM） and pulse wave velocity （PWV） were aslo calculated and compared, while relationship between IMT and mechanical forces in atherosclerosis patients was analyzed with linear coefficientsion, as well as between risk factors, IMT, and mechanical forces. ROC curve was used to assess the value of mechanical forces in diagnosis of atherosclerosis. Results SR in atherosclerosis group was lower, and CWT, YEM, PWV higher than those in the normal groups （P〈0. 05）. SR in atherosclerosis group showed negative correlation, whereas CWT, YEM and PWV showed positive correlation with IMT （P〈0.05）. Blood pressure showed significant positive correlation （P〈0.05）, hut blood-lipid, blood glucose and smoking showed no correlation with mechanical forces and IMT （P〉 0. 05）. CWT, PP, PWV and YEM had lower accuracy in diagnosis of atherosclerosis （S=0. 752, 0. 670, 0. 698 and 0. 631, respectively）. Conclusion Shear stress and circumferential wall tension as local factors play more important role in atherosclerosis than system risk factors.