Abdominal aortic hemodynamic conditions in healthy subjects aged 50-70 at rest and during lower limb exercise: in vivo quantification using MR1
Abdominal aortic hemodynamic conditions in healthy subjects aged 50-70 at rest and during lower limb exercise: in vivo quantification using MR1
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DOI：
10.1016/s0021-9150(03)00099-6
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发表时间：
2003-06-01
期刊：
影响因子：
5.3
通讯作者：
Taylor, CA
中科院分区：
文献类型：
--
作者：
Cheng, CP;Herfkens, RJ;Taylor, CA
腹主动脉粥样硬化的患病率随着年龄的增长而增加，并被假设与不良血流动力学条件有关，包括血流再循环和低壁面剪切应力。运动已被证明可以调节在健康年轻受试者休息时肾下主动脉中观察到的这些不良状况。使用定制的磁共振（MR）兼容固定循环、开放式MRI和定制图像处理软件来量化50-70岁健康受试者在静息和骑车运动期间腹主动脉的血流动力学状况。受试者的心率从休息时的63 +/- 8 bpm增加到骑自行车运动期间的95 +/- 12 bpm。从休息到运动，腹腔上血流量从2.3 +/- 0.4 l/min增加到6.0 +/- 1.4 l/min（P 0.001），肾下血流量从0.9 +/- 0.3 l/min增加到4.9 +/- 1.7 l/min（P < 0.001）。从休息到运动，腹腔上水平的壁切应力从2.0 +/- 0.7增加到7.3 +/- 2.4 dynes/cm 2（P < 0.001），肾下水平的壁切应力从1.4 +/- 0.8增加到16.5 +/- 5.1 dynes/cm 2（P < 0.001）。在运动过程中消除了静息时存在的流动和剪切振荡。在静息状态下，与一组年轻受试者（23.6 ± 2.2岁）相比，这些老年受试者在主动脉乳糜上水平的平均壁面切应力较低，壁面切应力振荡较大。与年轻的受试者相比，老年受试者也经历了更大的平均壁剪切应力的增加和更大的壁剪切应力振荡从休息到运动的下降。(C)2003爱思唯尔科学爱尔兰有限公司保留所有权利。
The prevalence of atherosclerosis in the abdominal aorta increases with age and is hypothesized to be related to adverse hemodynamic conditions including flow recirculation and low wall shear stress. Exercise has been shown to modulate these adverse conditions observed in the infrarenal aorta of healthy young subjects at rest. A custom magnetic resonance (MR)-compatible stationary cycle, an open MRI, and custom image processing software were used to quantify hemodynamic conditions in the abdominal aorta at rest and during cycling exercise in healthy subjects aged 50-70 years. The subjects increased their heart rate from 63 +/- 8 bpm at rest to 95 +/- 12 bpm during cycling exercise. Supraceliac blood flow increased from 2.3 +/- 0.4 to 6.0 +/- 1.4 l/min (P 0.001) and infrarenal flow increased from 0.9 +/- 0.3 to 4.9 +/- 1.7 l/min (P < 0.001) from rest to exercise. Wall shear stress increased from 2.0 +/- 0.7 to 7.3 +/- 2.4 dynes/cm(2) at the supraceliac level (P < 0.001) and 1.4 +/- 0.8 to 16.5 +/- 5.1 dynes/cm(2) at the infrarenal level (P < 0.001) from rest to exercise. Flow and shear oscillations present at rest were eliminated during exercise. At rest, these older subjects experienced lower mean wall shear stress at the supraceliac level of the aorta and greater oscillations in wall shear stress as compared to a group of younger subjects (23.6 +/- 2.2 years). Compared to the younger subjects, the older subjects also experienced greater increases in mean wall shear stress and greater decreases in wall shear stress oscillations from rest to exercise. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.