Endo S, Sohara Y, Karino T
Department of Thoracic and Cardiovascular Surgery, Jichi Medical School, Tochigi, Japan.
Heart Vessels. 1996;11(4):180-91. doi: 10.1007/BF02559990.
To elucidate the possible connection between blood flow and localized pathogenesis and the development of atherosclerosis in humans, we studied the flow patterns and the distribution of fluid axial velocity and wall shear stress in the aortic arch in detail. This was done by means of flow visualization and high-speed cinemicrographic techniques, using transparent aortic trees prepared from the dog. Under a steady flow condition at inflow Reynolds numbers of 700-1600, which simulated physiologic conditions at early- to mid-systole, slow, spiral secondary, and recirculation flows formed along the left anterior wall of the aortic arch and at the entrance of each side branch adjacent to the vessel wall opposite the flow divider, respectively. The flow in the aortic arch consisted of three major components, namely, an undisturbed parallel flow located close to the common median plane of the arched aorta and its side branches, a clockwise rotational flow formed along the left ventral wall, and the main flow to the side branches, located along the right dorsal wall of the ascending aorta. Thus, looking down the aorta from its origin, the flow in the aortic arch appeared as a single helical flow revolving in a clockwise direction. Regions of low wall shear stress were located along the leading edge of each side branch opposite the flow divider where slow recirculation flows formed, and along the left ventral wall where slow spiral secondary flows formed. If we assume that the flow patterns in the human aortic arch well resemble those observed in the dog, then it is likely that atherosclerotic lesions develop preferentially at these sites of low wall shear stress in the same manner as in human coronary and cerebral arteries.
为了阐明人体中血流与局部发病机制以及动脉粥样硬化发展之间的可能联系，我们详细研究了主动脉弓中的血流模式、流体轴向速度分布和壁面剪应力。这是通过血流可视化和高速电影显微技术完成的，使用从狗身上制备的透明主动脉树。在流入雷诺数为700 - 1600的稳定流动条件下，该条件模拟了收缩早期至中期的生理状况，在主动脉弓的左前壁以及与分流器相对的血管壁相邻的每个侧支入口处分别形成了缓慢、螺旋状的二次流和再循环流。主动脉弓中的血流由三个主要部分组成，即靠近主动脉弓及其侧支共同中位面且未受干扰的平行流、沿左腹壁形成的顺时针旋转流以及沿升主动脉右后壁流向侧支的主流。因此，从主动脉起始处向下看，主动脉弓中的血流呈现为顺时针旋转的单一螺旋流。低壁面剪应力区域位于与分流器相对的每个侧支前缘处，此处形成缓慢的再循环流，以及沿左腹壁处，此处形成缓慢的螺旋状二次流。如果我们假设人体主动脉弓中的血流模式与在狗身上观察到的非常相似，那么动脉粥样硬化病变很可能以与人体冠状动脉和脑动脉相同的方式优先在这些低壁面剪应力部位发展。
