Noninvasive assessment of the common carotid artery hemodynamics with increasing exercise work rate using wave intensity analysis.

N Pomella,E N Wilhelm,J González-Alonso,A W Khir,M Rakobowchuk,C Kolyva

doi:10.1152/ajpheart.00667.2017

N Pomella, E N Wilhelm + Show 4 more

Open Access

https://doi.org/10.1152/ajpheart.00667.2017

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Abstract

Noninvasively determined local wave speed (c) and wave intensity (WI) parameters provide insights into arterial stiffness and cardiac-vascular interactions in response to physiological perturbations. However, the effects of incremental exercise and subsequent recovery on c and WI have not been fully established. We examined the changes in c and WI parameters in the common carotid artery (CCA) during exercise and recovery in eight young, healthy male athletes. Ultrasound measurements of CCA diameter and blood flow velocity were acquired at rest, during five stages of incremental exercise (up to 70% maximum work rate), and throughout 1 h of recovery, and noninvasive WI analysis [diameter-velocity (DU) approach] was performed. During exercise, c increased (+136%), showing increased stiffness with work rate. All peak and area of forward compression, backward compression, and forward expansion waves increased during exercise (+452%, +700%, and +900%, respectively). However, WI reflection indexes and CCA resistance did not significantly change from rest to exercise. Furthermore, wave speed and the magnitude of all waves returned to baseline within 5 min of recovery, suggesting that the effects of exercise in the investigated parameters of young, healthy individuals were transient. In conclusion, incremental exercise was associated with an increase in local CCA stiffness and increases in all wave parameters, indicative of enhanced ventricular contractility and improved late-systolic blood flow deceleration.NEW & NOTEWORTHY We examined hemodynamics of the common carotid artery using noninvasive application of wave intensity analysis during exercise and recovery. The hemodynamic adjustments to exercise were associated with increases in local common carotid artery stiffness and all waves’ parameters, with the latter indicating enhanced ventricular contractility and improved late systolic blood flow deceleration.

Highlights

Wave intensity analysis (WIA) is a time-domain technique that provides surrogates of cardiac performance, vascular re-sistance, and the interaction of these parameters from blood pressure and blood flow velocity (U) measurements [26, 27]
WIA is a unique tool with the potential to examine the cardiac-peripheral interaction during rapid vascular alterations induced by exercise [33]; the aim of the present study was to examine WIA parameters measured at the common carotid artery (CCA) during incremental exercise work rates and throughout subsequent recovery
The peak magnitude and area of the FCW increase with exercise work rate, indicating enhanced ventricular contractility, which increases the magnitude of the BCW

Summary

Introduction

Wave intensity analysis (WIA) is a time-domain technique that provides surrogates of cardiac performance, vascular re-sistance, and the interaction of these parameters from blood pressure and blood flow velocity (U) measurements [26, 27]. Typical WIA contours obtained in large arteries include three main peaks: forward- and backward-traveling compression waves (FCW and BCW, respectively) as well as a forward expansion wave (FEW) These waves provide information about left ventricular contractility in early systole (FCW) [23], left ventricular-induced deceleration of flow in late systole (FEW), and reflected waves returning toward the left ventricle in midsystole (BCW). The temporally dispersed acquisition using applanation tonometry becomes especially erroneous when rapid physiological perturbations are involved Another advantage of the ultrasound Doppler approach is the lnDU loop [8], often associated with the DU approach of WIA, which enables the noninvasive determination of local wave speed (c). This offers a useful tool to investigate local stiffness under different conditions, such as graded exercise, and enables the separation of the wave intensity waveform into forward and backward components [8]

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