Numerical Investigation of Pulse Wave Propagation in Arteries Using Fluid Structure Interaction Capabilities.

Hisham Elkenani,Mhamed Souli,Essam Al-Bahkali

doi:10.1155/2017/4198095

Abstract

The aim of this study is to present a reliable computational scheme to serve in pulse wave velocity (PWV) assessment in large arteries. Clinicians considered it as an indication of human blood vessels' stiffness. The simulation of PWV was conducted using a 3D elastic tube representing an artery. The constitutive material model specific for vascular applications was applied to the tube material. The fluid was defined with an equation of state representing the blood material. The onset of a velocity pulse was applied at the tube inlet to produce wave propagation. The Coupled Eulerian-Lagrangian (CEL) modeling technique with fluid structure interaction (FSI) was implemented. The scaling of sound speed and its effect on results and computing time is discussed and concluded that a value of 60 m/s was suitable for simulating vascular biomechanical problems. Two methods were used: foot-to-foot measurement of velocity waveforms and slope of the regression line of the wall radial deflection wave peaks throughout a contour plot. Both methods showed coincident results. Results were approximately 6% less than those calculated from the Moens-Korteweg equation. The proposed method was able to describe the increase in the stiffness of the walls of large human arteries via the PWV estimates.

Highlights

Computational analysis of cardiovascular problems incorporating fluid structure interaction (FSI) is a challenging problem
Waves were reflected because of the finite tube length and fixed boundary conditions, which pointed at the tube ends
Qualitative agreement was obtained, indicating that this computational method for pulse wave velocity (PWV) analysis is accurate enough to evaluate its value with accepted accuracy

Summary

Introduction

Computational analysis of cardiovascular problems incorporating FSI is a challenging problem. The first person to investigate a formula for the velocity of pressure waves in a thin elastic tube was Young [2] in 1808. We investigated the propagation of a pulse wave through an elastic vessel. This application is of clinical relevance as PWV measurements are currently considered to be the clinical gold-standard measure of arterial stiffness [4]. PWV is typically a disturbance’s propagation speed through a vessel resulting from the flow pressure. As blood is an almostincompressible fluid [5,6,7], the finite PWV is mainly the result of the FSI between the local pressure of the blood on the vessel wall and the resultant wall deformation it causes

Objectives

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Discussion

Conclusion