血压和心率对颈动脉管壁切应力影响的初步研究

Preliminary Study for Association of Blood Pressure and Heart Rate on Carotid Hemodynamics

目的研究血压、心率对颈总动脉管壁切应力(wall shear stress,WSS)的影响。方法 16例健康志愿者的双侧颈动脉分别行磁共振(magnetic resonance,MR)扫描,在颈动脉分叉部位下2 cm颈总动脉平面上,把颈总动脉壁平均分为24等份,利用相位对比MR成像和三维抛物面模型拟合的方法 ,计算每个空间位置一个心动周期内的平均WSS以及空间位置上最小的WSS。观察收缩压、舒张压、平均动脉压、心率对颈动脉血流动力学参数的影响。结果 16例健康志愿者的32条血管中,有3条血管因伪影排除在本研究之外。对剩下的29条血管进行分析,无论是双侧颈动脉,还是左侧或右侧颈动脉,平均WSS及空间位置上最低WSS与收缩压、舒张压、平均动脉压、心率均无明显相关性(P>0.05)。结论健康志愿者颈总动脉平均WSS和最低WSS与血压、心率无明显相关。

Objective To study the effect of blood pressure and heart rate on the hemodynamics of common carotid artery（CCA）. Methods Sixteen healthy volunteers were studied. Wall shear stress（WSS） values localized at CCA 2 cm below the bifurcation were calculated with cine phase-contrast magnetic resonance（MR） imaging combined three-dimensional paraboloid（3DP） model. On the spatial distribution, carotid wall was divided by 24 equal parts. Calculate the mean WSS in a cardiac cycle on the each part, and choose the minimal WSS value. Then we observed the effect of systolic pressure, diastolic pressure, mean arterial pressure, or heart rate on the average WSS and minimal WSS. Results Total 32 carotid arteries of 16 health volunteers were examined, in which 3 carotid arteries were excluded because of uninterpretable high-resolution magnetic resonance imaging（MRI） findings. In the remaining 29 common carotid arteries analyzed, the average WSS and the minimal WSS during a cardiac cycle on the spatial distribution have no significant correlation with systolic pressure, diastolic pressure, mean arterial pressure, or heart rate（P〉0.05） in spite of bilateral carotids, left carotids or right carotids. Conclusion In health population, both average WSS and minimal WSS have no significant correlation with blood pressure or heart rate.