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Properties of the Arterial Wall
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
Taking eqn 4.49 a step further and substituting the derived value for dV/dP of eqn 4.26 for a unit length of circumference, L, and taking the mean value of P as an arbitrary zero, we obtain, with E as the Young’s modulus in the circumferential direction, and h the wall thickness, This is known as the Moens–Korteweg equation. It was used with the addition of a constant outside the square-root term by Moens (1878) in his experimental studies of the velocity of a pressure wave in a rubber tube filled with water. He used a value of 0.9 for this arbitrary constant.
Arterial stiffness in women previously with preeclampsia from a semi-rural region of South Africa
Published in Clinical and Experimental Hypertension, 2019
A. Namugowa, J Iputo, J Wandabwa, A Meeme, G A B Buga, S Abura, Y Y Stofile
Pulse wave pressure (PWV carotid-femoral) is considered as the ‘gold standard’ measurement of arterial stiffness (30). Pulse wave velocity (femoral-carotid) is a measure of regional (aortic) arterial stiffness (31). Stiffness is the resistance to deformation. Arterial stiffness measurement depends on three independent variables of the vessel; elastic modulus or Young modulus E = stress/compliance, h-vessel wall thickness, r-radius of the vessel. The Moens-Korteweg equation defines pulse wave velocity as, PWV2 = Einch/2r ρ where Einc is incremental elastic modulus; ρ is the density of blood Moens, 1878; Kortewg, 1878 cited by (32). Pulse wave velocity is therefore proportional to the square root of vessel stiffness and is not particularly sensitive to vessel dimensions or thickness.
Evaluation of different metrics as an index for the assessment of arterial stiffness
Published in Clinical and Experimental Hypertension, 2018
Camille Leblanc, Hilary R Strong, Reza Tabrizchi
This study has a number of limitations, including the use of fluid-filled catheters rather than pressure sensor devices that can measure pressure at the tip of the catheters. As well, the calculation of the elastic modulus relies on the use of the value obtained for PWV in the current investigation since the Moens-Korteweg equation used relies on PWV for the determination of the elastic modulus values. Therefore, the calculated PWV has an indirect effect on the value obtained for the elastic modulus. It is also recognized that parameters such as PWV and the elastic modulus are pressure-dependent, thus differential pressure as a parameter can impact the calculated values for stiffness (4). It is well known that aortic stiffness is dependent on the architecture of the blood vessel wall, which varies throughout the length of the aorta. In this study, PWV was measured in the abdominal aorta and thus reflects a general measure of stiffness in this area. However, the equation for the pressure-strain modulus only allows measurements where the ultrasound images were taken, and thus may not reflect the true mechanical properties of the entire abdominal aorta. Hence, most studies assessing arterial stiffness are usually carried out using isolated blood vessels. However, the major disadvantage of the in vitro investigation is that the true hemodynamic effects of blood flow on the vascular wall are absent, and values obtained under such circumstances could miss a host of physiological parameters that continuously influence arterial stiffness.
Continuous cuffless and non-invasive measurement of arterial blood pressure—concepts and future perspectives
Published in Blood Pressure, 2022
Niklas Pilz, Andreas Patzak, Tomas L. Bothe
In 1984, Callaghan et al. have shown the applicability of the Moens-Korteweg-equation for canine arteries, which describes the dependency of the PWV on BP differences [15]. This equation has been interpreted for human BP levels and subsequently successfully applied for experimental BP estimation. To achieve this, a surrogate marker for PWV had to be found. Modern physiological cuffless BP estimations predominantly rely on PWV surrogates. Generally, the pulse arrival time (PAT) presented itself suitable, as for its comparably easy detection, as well as its direct connection to the PWV [16].