Validity of the Moens-Korteweg Equation

Abstract

The pulse wave velocity (c) in an infinitely thin-walled elastic vessel may be predicted from its viscoelastic properties using the so-called Moens-Korteweg equation

$${C^2} = Eh/2Rp$$

((1))

where E is the Young’s modulus of the wall, h the wall thickness, R the internal vessel radius, and p the density of the wall material. In thicker walled vessels, a commonly quoted variation (1) of Eq. 1 is

$${C^2} = Ep\left( {1 - \gamma } \right)/2p$$

((2))

where γ is the ratio of wall thickness to external vessel radius and Ep is the pressure elastic modulus [7] defined as

$$Ep = \Delta P \cdot R/\Delta R$$

((3))

where ΔR is the change in external radius of the vessel associated with a pressure change ΔP and R is the mean vessel radius. The validity of Eq. 1 or 2 have not been fully explored in vivo, but they would be expected to apply only in vessels in which there are no wave reflections [3]. This paper presents some results of simultaneous measurements of arterial elasticity and pulse propagation velocity in the abdominal aorta of anesthetized dogs under both vasodilated and vasoconstricted conditions.