Pulsed Wave Doppler Ultrasonography for the Assessment of Peripheral Vasomotor Response in an Elderly Population

Purpose: To assess sympathetic vasomotor activity and its changes with age, using pulsed wave Doppler ultrasound. Methods: We recruited 20 young adults (24-37 years old) and 20 older individuals (60-81 years old). Pulsed wave Doppler ultrasound was applied over the right radial artery to measure blood flow at rest and after a voluntary inspiratory cough eliciting sympathetic activation. The maximal (Vmax), minimal (Vmin), time-averaged (TAMaxV) blood flow velocity, and the pulsatility index (PI) were calculated and compared between groups. Results: At rest, PI was similar in both groups but Vmax and TAMaxV were higher in the older group (p < 0.05). Vmax, Vmin, and TAMaxV decreased, and PI increased after inspiratory cough in both groups (p <= 0.001), but this increase was lower in the older group (p < 0.001). TAMaxV after coughing was higher in the older group (p < 0.05). Heart rate did not differ significantly within or between groups. Conclusions: The older group exhibited reduced vasomotor reactivity of the radial artery after sympathetic stimulus. Peripheral vasomotor response should be interpreted with caution in elderly populations. (C) 2011 Wiley Periodicals, Inc. J Clin Ultrasound 39: 383-389, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jcu.20819