Key result
A nonlinear Kelvin-Voigt model accurately captured arterial wall viscoelasticity, revealing a constant viscoelastic relaxation time across the network that increasingly damps high-frequency pulse waves in peripheral arteries.
A nonlinear Kelvin-Voigt model accurately describes arterial viscoelasticity and demonstrates increased damping of high-frequency pulse waves in peripheral arteries.
Supports nonlinear arterial modeling in vitro; leaves open translation to human pulse wave diagnostics.
This work deals with the viscoelasticity of the arterial wall and its influence on the pulse waves. We describe the viscoelasticity by a nonlinear Kelvin-Voigt model in which the coefficients are fitted using experimental time series of pressure and radius measured on a sheep's arterial network. We obtained a good agreement between the results of the nonlinear Kelvin-Voigt model and the experimental measurements. We found that the viscoelastic relaxation time-defined by the ratio between the viscoelastic coefficient and the Young's modulus-is nearly constant throughout the network. Therefore, as it is well known that smaller arteries are stiffer, the viscoelastic coefficient rises when approaching the peripheral sites to compensate the rise of the Young's modulus, resulting in a higher damping effect. We incorporated the fitted viscoelastic coefficients in a nonlinear 1D fluid model to compute the pulse waves in the network. The damping effect of viscoelasticity on the high-frequency waves is clear especially at the peripheral sites.
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Ghigo et al. (2016) studied Healthy (animal model) (n=11). Nonlinear Kelvin-Voigt viscoelastic model vs. Linear elastic model was evaluated on Viscoelastic relaxation time and pressure-radius loop agreement. A nonlinear Kelvin-Voigt model accurately captured arterial wall viscoelasticity, revealing a constant viscoelastic relaxation time across the network that increasingly damps high-frequency pulse waves in peripheral arteries.
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