Abdominal aortic hemodynamics in young healthy adults at rest and during lower limb exercise: quantification using image-based computer modeling
Abdominal aortic hemodynamics in young healthy adults at rest and during lower limb exercise: quantification using image-based computer modeling
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DOI：
10.1152/ajpheart.01301.2005
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发表时间：
2006-08-01
影响因子：
4.8
通讯作者：
Taylor, Charles A.
中科院分区：
文献类型：
--
作者：
Tang, Beverly T.;Cheng, Christopher P.;Taylor, Charles A.
腹主动脉粥样硬化病变的定位与不利的血流动力学状况相关，如血流再循环、低平均壁切应力和高剪切时间振荡。除了它的许多全身益处，运动也被认为通过改变这些区域血流模式而在血管系统中具有局部益处。在这项工作中，根据5名年轻、健康的受试者的磁共振血管成像，建立了特定于受试者的人体腹主动脉模型，并在静息和运动(静息心率增加50%)脉动血流条件下进行了计算机模拟。给出了平均壁面剪应力(WSS)和振荡剪切指数(OSI)的速度场和空间变化。当所有受试者的平均WSS从4.8+/-0.6增加到31.6+/-5.7dyn/cm(2)，OSI从0.22+/-0.03下降到0.03+/-0.02。在腹膜上、肾下和腹膜上水平，WSS显著增加，而OSI显著降低，且WSS在前后节段之间有显著差异。这些结果支持这样一种假设，即运动通过急性机械刺激对心血管系统提供局部好处，这些刺激触发长期的生物过程，从而防止动脉粥样硬化的发展或进展。
Localization of atherosclerotic lesions in the abdominal aorta has been previously correlated to areas of adverse hemodynamic conditions, such as flow recirculation, low mean wall shear stress, and high temporal oscillations in shear. Along with its many systemic benefits, exercise is also proposed to have local benefits in the vasculature via the alteration of these regional flow patterns. In this work, subject-specific models of the human abdominal aorta were constructed from magnetic resonance angiograms of five young, healthy subjects, and computer simulations were performed under resting and exercise (50% increase in resting heart rate) pulsatile flow conditions. Velocity fields and spatial variations in mean wall shear stress (WSS) and oscillatory shear index (OSI) are presented. When averaged over all subjects, WSS increased from 4.8 +/- 0.6 to 31.6 +/- 5.7 dyn/cm(2) and OSI decreased from 0.22 +/- 0.03 to 0.03 +/- 0.02 in the infrarenal aorta between rest and exercise. WSS significantly increased, whereas OSI decreased between rest and exercise at the supraceliac, infrarenal, and suprabifurcation levels, and significant differences in WSS were found between anterior and posterior sections. These results support the hypothesis that exercise provides localized benefits to the cardiovascular system through acute mechanical stimuli that trigger longer-term biological processes leading to protection against the development or progression of atherosclerosis.