Moore J E, Xu C, Glagov S, Zarins C K, Ku D N
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332-0405.
Atherosclerosis. 1994 Oct;110(2):225-40. doi: 10.1016/0021-9150(94)90207-0.
Clinically significant atherosclerosis in the human aorta is most common in the infrarenal segment. This study was initiated to test the hypothesis that flowfield properties are closely related to the localization of plaques in this segment of the arterial system. Wall shear stress was calculated from magnetic resonance velocity measurements of pulsatile flow in an anatomically accurate model of the human abdominal aorta. The wall shear stress values were compared with intimal thickening from 15 post-mortem aortas measured by quantitative morphometry of histological cross sections obtained at standard locations. Wall shear stress oscillated in direction throughout most of the infrarenal aorta, most prominently in the distal region. The time-averaged mean wall shear stress (-1.7 to 1.4 dyn/cm2) was lowest near the posterior wall in this region. These hemodynamic parameters coincided with the locations of maximal intimal thickening. Statistical correlation between oscillatory shear and intimal thickness yielded r = 0.79, P < 0.00001. Low mean shear stresses correlated nearly as well (r = -0.75, P < 0.00005). Comparison of our data with surface maps of Sudan Red staining and early lesions as reported by others revealed similar conclusions. In contrast, pulse and maximum shear stresses did not correlate with plaque localization as has been shown for other sites of selective involvement by atherosclerosis (r < 0.345). Simulated exercise conditions markedly changed the magnitude and pattern of wall shear stress in the distal abdominal aorta. These results demonstrate that in the infrarenal aorta, regions of low mean and oscillating wall shear stresses are predisposed to the development of plaque while regions of relatively high wall shear stress tend to be spared.
临床上，人类主动脉中具有显著意义的动脉粥样硬化最常见于肾下段。本研究旨在验证这样一个假设：流场特性与动脉系统该段斑块的定位密切相关。通过对人体腹主动脉解剖学精确模型中的脉动血流进行磁共振速度测量来计算壁面剪应力。将壁面剪应力值与15个死后主动脉的内膜增厚情况进行比较，这些主动脉的内膜增厚情况是通过对在标准位置获取的组织学横截面进行定量形态测量得到的。在肾下段主动脉的大部分区域，壁面剪应力的方向都在振荡，在远端区域最为明显。该区域后壁附近的时间平均平均壁面剪应力（-1.7至1.4达因/平方厘米）最低。这些血流动力学参数与内膜增厚最明显的位置一致。振荡剪应力与内膜厚度之间的统计相关性得出r = 0.79，P < 0.00001。低平均剪应力的相关性也几乎相同（r = -0.75，P < 0.00005）。将我们的数据与其他人报道的苏丹红染色表面图和早期病变进行比较，得出了类似的结论。相比之下，脉搏和最大剪应力与斑块定位没有相关性，这与动脉粥样硬化选择性累及的其他部位的情况相同（r < 0.345）。模拟运动条件显著改变了腹主动脉远端壁面剪应力的大小和模式。这些结果表明，在肾下段主动脉中，平均壁面剪应力低且振荡的区域易发生斑块形成，而壁面剪应力相对较高的区域往往不易发生。
