Helal M A, Watts K C, Marble A E
Department of Design and Study, Ministry of Health, Riyadh, Kingdom of Saudi Arabia.
Med Biol Eng Comput. 1993 Nov;31(6):562-8. doi: 10.1007/BF02441802.
A hydrodynamic model for the part of the human arterial network below the renal arteries has been constructed using specially fabricated distensible tubes and a pulsatile pump to simulate an aortoiliac bypass. The experiments and the computer model indicated that no 'steal' occurred due to the insertion of the bypass graft. Also, the results showed that the length of the stenosis had a non-systematic apparent effect on the physiological significance of the obstruction and that the kinetic power represented only a small percentage of the total power. The total power efficiency of the bypass graft was unaffected by its elastic properties. The experimental investigation also indicated that the pressure drop across the stenosis was considerably larger than the drop calculated using the Poiseuille flow relationship when the stenosis was severe. Therefore, a critical arterial stenosis value cannot be defined as an obstruction of a constant percentage reduction of luminal area. It varies directly with the effective cross-sectional area and inversely with the flow rate. The value of angiography in assessing the functional significance of any arterial stenosis is therefore limited. A better method for evaluation requires quantitative measurements of local blood pressure and blood flow, not only at rest, but also under conditions creating augmented flows due to exercise.
利用特制的可扩张管和脉动泵构建了一个肾动脉以下人体动脉网络部分的流体动力学模型，以模拟主髂动脉搭桥术。实验和计算机模型表明，旁路移植物的植入未导致“窃血”现象。此外，结果显示狭窄长度对梗阻的生理意义没有系统性的明显影响，且动能仅占总功率的一小部分。旁路移植物的总功率效率不受其弹性特性的影响。实验研究还表明，当狭窄严重时，狭窄处的压降远大于使用泊肃叶流动关系计算得出的压降。因此，不能将临界动脉狭窄值定义为管腔面积恒定百分比减少的梗阻。它与有效横截面积成正比，与流速成反比。因此，血管造影在评估任何动脉狭窄功能意义方面的价值有限。一种更好的评估方法需要定量测量局部血压和血流，不仅要在静息状态下测量，还要在因运动导致血流增加的情况下测量。
