Onaizah O, Poepping T L, Zamir M
Department of Medical Biophysics, The University of Western Ontario, London, Canada.
Department of Medical Biophysics, The University of Western Ontario, London, Canada; Department of Physics and Astronomy, The University of Western Ontario, London, Canada.
Med Eng Phys. 2017 Nov;49:121-130. doi: 10.1016/j.medengphy.2017.08.009. Epub 2017 Sep 13.
The carotid artery is one of the major supply routes of blood to the brain and a common site of vascular disease. Obstructive and sclerotic disorders within the carotid artery impact local blood flow patterns as well as overall impedance and blood supply to the brain. A lumped parameter model and an experimental in-vitro flow loop were used to study the effects of local stenosis and stiffness in the carotid artery based on a family of phantoms with different degrees of stenosis and compliance. The model also allows independent examination of the effects of downstream resistance and compliance. Mild to moderate stenosis was found to lead to minimal (∼1%) reduction in blood supply to the brain. Reduction in mean internal carotid artery (ICA) flow was statistically significant (p< 0.01) only above 70% stenosis. On the other hand, a three-fold increase in stiffness of the carotid artery, as might occur in aging, was found to lead to a modest yet statistically significant reduction (p< 0.01) in mean ICA flow. Effects of changing downstream resistance and compliance were examined. For a given pressure waveform, reduction in downstream compliance led to altered waveform shape and reduction in peak systolic flow rates where the mean flow rates were not altered. Increased downstream resistance resulted in drastic reduction in mean flow rates.
颈动脉是大脑主要的血液供应途径之一，也是血管疾病的常见部位。颈动脉内的阻塞性和硬化性疾病会影响局部血流模式以及大脑的整体阻抗和血液供应。基于一系列具有不同狭窄程度和顺应性的模型，采用集总参数模型和体外实验血流回路来研究颈动脉局部狭窄和硬度的影响。该模型还允许独立研究下游阻力和顺应性的影响。发现轻度至中度狭窄导致大脑血液供应减少最少（约1%）。仅在狭窄超过70%时，颈内动脉（ICA）平均血流量的减少才具有统计学意义（p<0.01）。另一方面，颈动脉硬度增加三倍（如在衰老过程中可能发生的情况）会导致ICA平均血流量适度但具有统计学意义的减少（p<0.01）。研究了改变下游阻力和顺应性的影响。对于给定的压力波形，下游顺应性降低会导致波形形状改变以及收缩期峰值流速降低，而平均流速不变。下游阻力增加会导致平均流速急剧降低。
