Noninvasive Assessment of the Common Carotid Artery Hemodynamics with Increasing Exercise Workrate Using Wave Intensity Analysis

Abstract

Non-invasively determined local wave speed (c) and wave intensity (WI) parameters provide insight 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 are not fully established. We examined the changes in c and WI parameters in the common carotid artery (CCA) during exercise and recovery in 8 young healthy male athletes. Ultrasound measurements of CCA diameter (D) and blood flow velocity (U) were acquired at rest, during 5 stages of incremental exercise (up to 70% maximum workrate) and throughout 1 h of recovery and non-invasive WI analysis (DU approach) was performed. During exercise, c increased (+136%), showing increased stiffness with workrate. All peak and area of forward compression (FCW), backward compression (BCW) and forward expansion waves (FEW) increased during exercise (+452%, +700%, +900%, respectively). However, WI reflection indices and CCA resistance did not significantly change from rest to exercise. Further, wave speed and magnitude of all waves returned to baseline within 5 min of recovery, suggesting 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.