Ku D N, Glagov S, Moore J E, Zarins C K
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332-0405.
J Vasc Surg. 1989 Feb;9(2):309-16. doi: 10.1067/mva.1989.vs0090309.
Specific hemodynamic factors have been shown to be associated with atherosclerotic plaque localization at the human carotid bifurcation. Flow field characteristics may also determine plaque distribution in the abdominal aorta. We therefore characterized flow patterns in a glass model abdominal aorta that included its major branches under conditions of steady flow. Outflow resistances of the celiac, superior mesenteric, renal, inferior mesenteric, and iliac arteries were varied to produce flow distributions consistent with rest, the postprandial state, and vigorous lower limb exercise. Flow patterns were visualized with three colors of dye injected simultaneously through capillary tubes at selected locations and recorded as still photographs and by cinephotography on videotapes. Under resting conditions a large region of flow separation and stagnation occurred at the posterior wall of the aorta directly opposite the orifices of the superior and inferior mesenteric arteries. Similar separation regions were observed during the simulated postprandial state but diminished markedly when distal outflow was increased to levels consistent with exercise. In the highly susceptible infrarenal aortic segment, beginning about 2 cm below the renal artery orifices, multiple secondary flow patterns with three to four counterrotating vortex formations were observed under both resting and postprandial conditions but disappeared in the exercise state. Secondary flow patterns were not noted in the suprarenal abdominal aorta, which is usually relatively spared. Such features have been related to plaque localization elsewhere, and the disappearance of these patterns with increased flow velocity during exercise is consistent with the previously noted protective effect of unidirectional laminar high-flow states. The beneficial effects of physical fitness programs may be related in part to these hemodynamic modifications.
特定的血流动力学因素已被证明与人类颈动脉分叉处动脉粥样硬化斑块的定位有关。流场特征也可能决定腹主动脉中斑块的分布。因此，我们对一个玻璃模型腹主动脉及其主要分支在稳定血流条件下的流动模式进行了表征。通过改变腹腔干、肠系膜上动脉、肾动脉、肠系膜下动脉和髂动脉的流出阻力，以产生与静息状态、餐后状态和剧烈下肢运动相一致的血流分布。通过在选定位置通过毛细管同时注入三种颜色的染料来可视化流动模式，并记录为静态照片和通过录像带进行电影摄影。在静息条件下，在主动脉后壁与肠系膜上动脉和肠系膜下动脉开口正对面的位置出现了一大片血流分离和停滞区域。在模拟餐后状态下观察到了类似的分离区域，但当远端流出量增加到与运动相一致的水平时，分离区域明显减少。在高度易损的肾下腹主动脉段，大约在肾动脉开口下方2厘米处开始，在静息和餐后条件下都观察到了多个具有三到四个反向旋转涡旋形成的二次流动模式，但在运动状态下消失了。在通常相对不易发生病变的肾上腹主动脉中未观察到二次流动模式。这些特征与其他部位的斑块定位有关，并且这些模式在运动期间随着流速增加而消失，这与先前指出的单向层流高流量状态的保护作用一致。健身计划的有益效果可能部分与这些血流动力学改变有关。
