Effect of Bifurcation on Pulse Wave Propagation in Human Arteries

Author(s):  
Yusuke Kawai ◽  
Shigehiko Kaneko

In recent years, arteriosclerotic cardiovascular disease becomes a serious problem in the developed countries. The degree of the arteriosclerosis should be examined routinely and invasively, and the measurement of pulse wave is considered as an effective estimation method. Nowadays, pulse wave is widely used in clinical practice as a noninvasive method of examining circulatory kinetics, but the mechanism in the process of the systolic wave generated at heart and propagating to the peripheral artery remains to be elucidated. In this research, to investigate the effect of bifurcation on pulse wave propagation, numerical simulations by a dynamic model of arteries and in vitro experiments were conducted. A one-dimensional model of arteries is coupled by partial differential equations describing mass and momentum conservation with the tube law that relates the local cross-sectional area to the local radial pressure difference. In the case of a bifurcated artery model, the governing equations were solved by introducing the momentum caused by the reactive force at bifurcation into the equation of momentum conservation. The momentum by the reactive force at bifurcation was supposed to be proportional to the momentum flowing into the bifurcation, and the proportionality coefficient was derived from experiments. Then, the proposed one-dimensional model was validated by a comparison to experimental data. In the experimental setup, elastic tubes with different values of Young’s modulus were tested to simulate human arteries. From the numerical and experimental results, it turns out that the characteristic waveforms of the pressure and velocity obtained from experiments are also captured by the numerical calculations.

Author(s):  
Ye Chang ◽  
Shigehiko Kaneko

To investigate the mechanism and the usage of the information of pulse wave propagation and reflection in human arteries are the objects of this study. In this study, an experimental apparatus simulating human circulatory system by using silicon tubes to examine the pulse wave propagation and reflection with and without branches has been developed. We examined the effect of eight parameters, such as flow rate, tube diameter, tube thickness etc., affecting waveform, PWV (Pulse Wave Velocity) and PV loop (Pressure-Velocity Loop). Numerical analyses were also carried out, and the relation between PV Loop and local impedance was discussed. Finally, the effect of eight parameters on the PWV and PV loop were clarified. It was also found that, the PV Loop includes much information on the tube characteristics, impedance, boundary condition, tube connection and reflection condition. Therefore, the PV loop method might be promising to be used in health diagnosis systems. In addition, we found that the effects of bifurcation angle on wave propagation and reflection were so little that they can be neglected in wave calculation models.


2010 ◽  
Vol 2010 (0) ◽  
pp. 425-428
Author(s):  
Hironori SATO ◽  
Hideo UTSUNO ◽  
Toshihiko OGURA ◽  
Hiroshi MATSUHISA ◽  
Keisuke YAMADA

2021 ◽  
Vol 2103 (1) ◽  
pp. 012081
Author(s):  
G V Krivovichev ◽  
N V Egorov

Abstract The models of hemodynamics, corresponding to the inviscid, Newtonian, and non-Newtonian models, are compared. The models are constructed by the averaging of the hydrodynamic system on the vessel cross-section. For the inviscid case, the analytical solution of the problem for pulse propagation is obtained. As the result of the comparison, the deviations of the solutions for non-Newtonian models from the Newtonian and inviscid cases are demonstrated.


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