Effects of Different Therapeutic Ultrasound Waveforms on Endothelial Function in Healthy Volunteers: A Randomized Clinical Trial

The purpose of this study was to determine the effects of different therapeutic 1-MHz ultrasound waveforms on endothelial function before and after cyclooxygenase (COX) inhibition. Forty-two healthy volunteers aged 27.2 ± 3.8 y underwent interventions and an evaluation for endothelial function (n = 15; with COX inhibition, n = 15; duration of the vasodilator effect, n = 12) by technique flow-mediated dilation. Continuous ultrasound therapy (0.4 W/cm2 SATA), pulsed ultrasound therapy (20% duty cycle, 0.08 W/cm2 SATA) or placebo (equipment power off) was randomly applied over the brachial artery for 5 min. COX inhibition (aspirin) was carried out 30 min before treatments. In relation to the placebo, flow-mediated dilation increased by 4.8% using continuous ultrasound and by 3.4% using pulsed ultrasound. After COX, flow-mediated dilation was enhanced by 2.1% by continuous ultrasound and 2.6% by pulsed ultrasound. This vasodilation persisted for 20 min. Continuous and pulsed therapeutic 1-MHz ultrasound waveforms improved endothelial function in humans, which provided them with anti-inflammatory vascular effects.