Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex, UB8 3PH, UK.
Department of Bioengineering, Imperial College London, London, UK.
J Biomech. 2014 Jan 3;47(1):87-95. doi: 10.1016/j.jbiomech.2013.10.007. Epub 2013 Oct 30.
Wave speed (also called pulse wave velocity) is the speed by which disturbance travels along the medium and it depends on the mechanical and geometrical properties of the vessel and on the density of the blood. Wave speed is a parameter of clinical relevance because it is an indicator of arterial stiffness and cardiovascular diseases. The aim of this work is to compare different methods for the determination of local wave speed in bench experiments and investigate their relative accuracy when reflections are present. Pressure (P), flow (Q) and diameter (D) were measured along a flexible tube far and close to three positive and three negative reflection sites. Wave speed was calculated using PU-loop, (lnD)U-loop, QA-loop, D(2)P-loop, sum of squares and characteristic impedance methods. Results were compared to the foot-to-foot method. We found that far from the reflections almost all methods give uniform results. Close to positive reflections the methods that rely on P and Q (or U) overestimate the wave speed value, while techniques based on D (or A) and Q (or U) underestimate it. On the contrary, close to negative reflections the methods that rely on P and Q (or U) underestimate the wave speed value, while techniques based on D (or A) and Q (or U) overestimate it. The D(2)P-loop does not seem to be affected by positive or negative reflections. Most of the methods currently used to determine local wave speed are affected by reflections, but the (lnD)U-loop remains the easiest technique to use in the clinic.
波速（也称为脉搏波速度）是指扰动沿着介质传播的速度，它取决于血管的力学和几何特性以及血液的密度。波速是一个具有临床相关性的参数，因为它是动脉僵硬和心血管疾病的指标。本工作的目的是比较在台架实验中确定局部波速的不同方法，并研究在存在反射时它们的相对准确性。在柔性管上测量了远和近三个正反射点和三个负反射点的压力（P）、流量（Q）和直径（D）。使用 PU 环、（lnD）U 环、QA 环、D(2)P 环、平方和特征阻抗方法计算波速。结果与足对足方法进行了比较。我们发现，在远离反射的地方，几乎所有方法都给出了一致的结果。在靠近正反射的地方，依赖于 P 和 Q（或 U）的方法高估了波速值，而基于 D（或 A）和 Q（或 U）的技术则低估了波速值。相反，在靠近负反射的地方，依赖于 P 和 Q（或 U）的方法低估了波速值，而基于 D（或 A）和 Q（或 U）的技术则高估了波速值。D(2)P 环似乎不受正或负反射的影响。目前用于确定局部波速的大多数方法都受到反射的影响，但（lnD）U 环仍然是最容易在临床中使用的技术。
