Longitudinal wall motion of the common carotid artery can be assessed by velocity vector imaging

Abstract In light of recently recognized independent clinical values of longitudinal wall motion ux(t) at the common carotid artery (CCA) and the struggle on appropriate arterial indices for interpreting ux(t), this paper hypothesizes a mechanistic model of ux(t) and explores clear implications of the antegrade amplitude ux0-ante and retrograde amplitude ux0-retro of ux(t) in systole to the cardiovascular (CV) system. By examining findings on ux(t) and other relevant findings through the lens of the engineering essence of ux(t), a mechanistic model of ux(t) is hypothesized: the left ventricle (LV) base rotation is the excitation source for initiating the longitudinal elastic wave propagating along the arterial tree; wall shear stress at an artery serves as a local external source for supplying energy to the longitudinal elastic wave; and longitudinal elasticity at the arterial wall dictates the wave propagation velocity. Integrating the mechanistic model with findings on ux(t) gives rise to interpretation of ux0-ante and ux0-retro for their clear implications: longitudinal elasticity Exx at the common carotid artery (CCA) is estimated from ux0-ante, and ux0-retro is an inverse indicator of the maximum base rotation of the LV and a positive indicator of longitudinal elasticity at the ascending aorta (AA). For the first time, this model reveals the mechanisms underlying those statistical-based findings on ux(t).

Download Full-text

A Hypothesized Mechanistic Model of Longitudinal Wall Motion at the Common Carotid Artery

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4050500 ◽

2021 ◽

Vol 4 (2) ◽

Author(s):

Zhili Hao ◽

Leryn Reyonds ◽

John M. Herre

Keyword(s):

Carotid Artery ◽

Boundary Value Problem ◽

Common Carotid Artery ◽

Wall Motion ◽

Mechanistic Model ◽

Boundary Value ◽

Arterial Tree ◽

System A ◽

Longitudinal Wall ◽

The Common

Abstract By adopting a physics-physiology integrative approach, this work hypothesizes a mechanistic model of longitudinal wall motion ux(t) at the common carotid artery (CCA) and explores its antegrade amplitude ux0-ante and retrograde amplitude ux0-retro in systole for their clear implications. By examining the findings on ux(t) and other relevant findings on the cardiovascular (CV) physiology in the context of the physical essence of ux(t) and the CV system, a mechanistic model of ux(t) is hypothesized and formulated as a boundary-value problem of nonhomogeneous wave propagation in a semi-infinite domain. With the aid of findings on ux(t) and other related findings in the CV system, a scaling analysis of the boundary-value problem gives rise to two longitudinal arterial indices based on the two amplitudes: longitudinal elasticity Exx at the CCA being estimated from ux0-ante, and ux0-retro as an inverse indicator of the maximum base rotation of the left ventricle (LV) and a positive indicator of longitudinal elasticity at the ascending aorta (AA). The two arterial indices are qualitatively validated by their consistency with the effect of subclinical atherosclerosis and aging on the related parameters in the CV system. The implications of longitudinal elasticity to the LV function and energy transmission in the arterial tree are also discussed.

Download Full-text

Case Studies in Physiology: Using premature ventricular contractions to understand the regulation of carotid artery longitudinal wall motion

Journal of Applied Physiology ◽

10.1152/japplphysiol.00441.2021 ◽

2021 ◽

Vol 131 (3) ◽

pp. 1157-1161

Author(s):

Kailey A. Stevens ◽

Jason S. Au

Keyword(s):

Carotid Artery ◽

Large Deviations ◽

Wall Motion ◽

Blood Velocity ◽

Longitudinal Motion ◽

Healthy Male ◽

Artery Wall ◽

Premature Ventricular Contractions ◽

Longitudinal Wall ◽

The Common

Benign arrhythmias can be a useful tool to probe new hypotheses in physiology. We tested the control of longitudinal motion of the common carotid artery wall using observations from spontaneous premature ventricular contractions in a healthy male. Forwards wall motion remained unchanged despite large deviations in local blood velocity and backwards wall motion mirrored changes in pulse pressure, blood velocity, and cardiac motion, thereby revising our original hypothesis of the control of longitudinal wall motion.

Download Full-text