Moore J E, Ku D N
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332-0405.
J Biomech Eng. 1994 Feb;116(1):107-11. doi: 10.1115/1.2895692.
This study examines the hemodynamics of the abdominal aorta during physiological changes in flow rates and pulse rate that occur under exercise and postprandial conditions. Hemodynamic measurements were performed using an in vitro model which took into account seven major branches, the curvature, and the pulsatile nature of blood flow of the abdominal aorta. Magnetic Resonance Imaging velocimetry employing phase-velocity encoding was used to measure the pulsatile axial velocity profiles for the entire cross-section at three axial locations. Under simulated exercise conditions, the forward velocities were approximately double those seen during rest, and the flow reversal seen for resting conditions was greatly reduced. Near the posterior wall of the infrarenal aorta, the velocities were negative for only 21 percent of the cardiac cycle as compared with 82 percent for resting conditions. Postprandial conditions produced a 25 percent reduction in peak velocity and a 33 percent reduction in mean velocity near the left anterior wall of the aorta just distal to the superior mesenteric artery (in comparison with resting conditions). The changes that can occur in abdominal aorta hemodynamics under different physiologic conditions may affect the rate of progression of atherosclerosis at this site.
本研究考察了在运动和餐后状态下，随着流速和脉搏率的生理变化，腹主动脉的血流动力学情况。血流动力学测量采用体外模型进行，该模型考虑了七个主要分支、腹主动脉的曲率以及血流的脉动特性。采用相位速度编码的磁共振成像测速法，在三个轴向位置测量整个横截面的脉动轴向速度分布。在模拟运动条件下，向前流速约为静息时的两倍，静息时出现的血流逆转大大减少。在肾下腹主动脉后壁附近，心动周期中速度为负的时间仅占21%，而静息时为82%。餐后状态下，在肠系膜上动脉远端主动脉左前壁附近，峰值速度降低了25%，平均速度降低了33%（与静息状态相比）。不同生理条件下腹主动脉血流动力学可能发生的变化，可能会影响该部位动脉粥样硬化的进展速度。
