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Comparison of the Effects of 1MHz and 3MHz Therapeutic Ultrasound on Endothelial Function:

A Randomised Clinical Trial

Physiotherapy. 2017 Dec 5. pii: S0031-9406(17)30336-X. doi: 10.1016/j.physio.2017.08.010. [Epub ahead of print] Comparison of the effects of 1MHz and 3MHz therapeutic ultrasound on endothelium-dependent vasodilation of humans: a randomised clinical trial. Hauck M1, Noronha Martins C1, Borges Moraes M1, Aikawa P1, da Silva Paulitsch F1, Méa Plentz RD2, Teixeira da Costa S3, Vargas da Silva AM3, Signori LU4. Author information 1 Institute of Biological Sciences, Federal University of Rio Grande, RS, Brazil. 2 Graduate Programme in Healthy Sciences, Federal University of Health Sciences of Porto Alegre, RS, Brazil. 3 Graduate Programme in Physiotherapy and Rehabilitation, Federal University of Santa Maria, RS, Brazil. 4 Institute of Biological Sciences, Federal University of Rio Grande, RS, Brazil; Graduate Programme in Physiotherapy and Rehabilitation, Federal University of Santa Maria, RS, Brazil. Electronic address: l.signori@hotmail.com. Abstract OBJECTIVE: To compare the effects of different waveforms of 1MHz and 3MHz therapeutic ultrasound on endothelialfunction in healthy subjects. DESIGN: Randomised placebo-controlled, crossover study with concealed allocation and assessor blinding. SETTING: Imaging Centre of the University Hospital. PARTICIPANTS: Thirty volunteers aged between 18 and 35 years were divided into two homogeneous groups (1MHz and 3MHz). INTERVENTIONS: Continuous (CUT; 0.4W/cm2SATA), pulsed (PUT; 20% duty cycle, 0.08W/cm2SATA) and placebo waveforms (equipment off) of ultrasound (1MHz and 3MHz) were randomized and applied over the brachial artery for 5minutes. MAIN OUTCOME MEASURES: Endothelialfunction was evaluated using the flow-mediated dilation (FMD) technique. RESULTS: Both 1MHz [CUT: mean difference 4%, 95% confidence interval (CI) 2 to 6%, P<0.001; PUT: mean difference 4%, 95% CI 2 to 6%, P<0.001] and 3MHz (CUT: mean difference 4%, 95% CI 2 to 6%, P<0.001; PUT: mean difference 4%, 95% CI 2 to 6%, P<0.001) of therapeutic ultrasound increased %FMD by approximately 4% compared with the placebo waveforms. The endothelium-dependent vasodilator responses were the same for both types of waves and frequencies. No differences in baseline diameter, hyperaemic flow, and nitroglycerin-mediated diameter and vasodilation were observed between groups. CONCLUSION: Both CUT and PUT ultrasound waveforms improved endothelialfunction. The 1MHz and 3MHz frequencies of therapeutic ultrasound led to similar improvement in endothelialfunction in healthy volunteers. Clinical trial registration number RBR-4z5z3t. Copyright © 2017 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved. KEYWORDS: Endothelial function; Nitric oxide; Ultrasonic therapy; Ultrasound; Vascular endothelium