A Numerical Simulation using Efficient, Parallel Computing to Model the Effects of Mechanical Properties of the Arterial Wall and the Frequency of Pulse Waves on Pulse Waveforms and Wall Shear Stress Distribution

Atherosclerosis is a risk factor for ischemic heart disease, and its progression has been associated with wall shear stress (WSS). While pulse waveform analysis has garnered increasing attention as a diagnostic indicator for atherosclerosis, the influence of the mechanical properties of arterial walls and the frequency of pulse waves on the pulse waveform and wall shear stress distribution has not been completely elucidated.

In this study, three-dimensional fluid-structure interaction analysis was used to simulate the pulse wave propagation phenomena in the aorta. The effects of the mechanical properties of the arterial wall and the frequency of the pulse waves on the wall shear stress distribution and pulse wave dynamics were investigated.

In the investigation of wall shear stress distribution, under conditions of low Young’s modulus or high frequency, the time-averaged wall shear stress (TAWSS) was low and the oscillatory shear index (OSI) became high. In contrast, under conditions of high Young’s modulus or low frequency, TAWSS was high and OSI became low. In the pulse waveform analysis, the influence of viscous friction incorporated in the three-dimensional fluid-structure interaction analysis confirmed that the pulse waveform attenuated and diffused during propagation. A causal relationship between the TAWSS values and the attenuation or diffusion of the pulse waveform was not observed.

These results suggest that changes in arterial wall properties and differences in pulse wave frequency significantly influence WSS distribution. Furthermore, viscous friction in the three-dimensional FSI simulation led to attenuation and diffusion of the waveforms. However, the accuracy of waveform separation was insufficient, highlighting the need for improved methods that consider three-dimensional effects.