Analysing the pattern of pulse waves in arterial networks: a time-domain study
Analysing the pattern of pulse waves in arterial networks: a time-domain study
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DOI：
10.1007/s10665-009-9275-1
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发表时间：
2009-08-01
影响因子：
1.3
通讯作者：
Sherwin, S. J.
中科院分区：
文献类型：
--
作者：
Alastruey, J.;Parker, K. H.;Sherwin, S. J.
使用顺应性血管中血流的时域一维（1-D）方程研究了系统动脉网络中脉搏波形状的机制。在网络中任意位置处的脉搏波形最初被分离成取决于网络的心输出量、总顺应性和总外周阻力的外周分量，以及由大管道动脉的接合处和主动脉瓣处的反射支配的管道分量。然后使用一种新的算法来分析管道组件的动力学，该算法描述了从根部开始的单个波前在线性1-D模型网络中产生的所有波。该算法允许系统地跟踪到达测量地点的所有波，并识别这些波访问过的所有反射地点。应用这种方法的脉搏波模拟使用的1-D模型的最大的55个人体全身动脉表明，外周组件比管道组件的主动脉压力波形作出更大的贡献。导管成分与收缩早期左室流出量密切相关。在心动周期的后期，它们是动脉连接处和主动脉瓣处反射的结果。反射波的数量大约增加为3（m），其中m是遇到的反射点的数量。与这些波相关联的压力变化可以是正的或负的，但它们的绝对值往往呈指数下降。因此，在舒张晚期，当压力和流量的外周分量占主导地位时，波活动最小，并且主动脉压往往是由心输出量、总顺应性和总外周阻力确定的空间独立值。结果还表明，脉搏波传播是动脉系统达到由心输出量和灌注微循环所需的总阻力决定的平均压力的机制。总柔量决定了当系统偏离其稳定振荡的平衡状态时该压力恢复的速率。这项研究提供了有价值的信息，识别和测量的参数和路径的动脉网络，有最大的影响，模拟脉冲波形。
The mechanisms underlying the shape of pulse waves in the systemic arterial network are studied using the time-domain, one-dimensional (1-D) equations of blood flow in compliant vessels. The pulse waveform at an arbitrary location in the network is initially separated into a peripheral component that depends on the cardiac output, total compliance and total peripheral resistance of the network, and a conduit component governed by reflections at the junctions of the large conduit arteries and at the aortic valve. The dynamics of the conduit component are then analysed using a new algorithm that describes all the waves generated in the linear 1-D model network by a single wavefront starting at the root. This algorithm allows one to systematically follow all the waves arriving at the measuring site and identify all the reflection sites that these waves have visited. Application of this method to the pulse waves simulated using a 1-D model of the largest 55 systemic arteries in the human demonstrates that peripheral components make a larger contribution to aortic pressure waveforms than do the conduit components. Conduit components are closely related to the outflow from the left ventricle in early systole. Later in the cardiac cycle, they are the result of reflections at the arterial junctions and aortic valve. The number of reflected waves increases approximately as 3 (m) , with m being the number of reflection sites encountered. The pressure changes associated with these waves can be positive or negative but their absolute values tend to decrease exponentially. As a result, wave activity is minimal during late diastole, when the peripheral components of pressure and the flow are dominant, and aortic pressures tend to a space-independent value determined by the cardiac output, total compliance and total peripheral resistance. The results also suggest that pulse-wave propagation is the mechanism by which the arterial system reaches the mean pressure dictated by the cardiac output and total resistance that is required to perfuse the microcirculation. The total compliance determines the rate at which this pressure is restored when the system has departed from its equilibrium state of steady oscillation. This study provides valuable information on identifying and measuring the parameters and pathways of the arterial network that have the largest effect on the simulated pulse waveforms.