AIM: To study spontaneous variations in radial artery compliance. METHODS: Compliance was evaluated non-invasively by an echo-tracking system, and variations in sympathovagal tone were analysed by a spectral analysis of continuous blood pressure recordings using a Fast Fourier algorithm. We studied 23 healthy volunteers, aged 25 +/- 4 years (mean +/- SD), at rest, on two occasions at least one day apart (5 +/- 3 days). RESULTS: There were no significant differences between the means of the arterial compliance measurements and those of the corresponding spectral analysis. However, the magnitude of change in the low-frequency periods (4-66 mHz) was significantly related (P less than 0.01) to a significant and inverse change in compliance for the same level of blood pressure. CONCLUSIONS: While it is possible to use spectral analysis to measure the effect of autonomic nervous regulation on radial artery properties, low-frequency periods cannot be safely ascribed to sympathetic effects alone. Other effects must also be taken into account in measurements of radial artery distensibility.
AIM: To study spontaneous variations in radial artery compliance. METHODS: Compliance was evaluated non-invasively by an echo-tracking system, and variations in sympathovagal tone were analysed by a spectral analysis of continuous blood pressure recordings using a Fast Fourier algorithm. We studied 23 healthy volunteers, aged 25 +/- 4 years (mean +/- SD), at rest, on two occasions at least one day apart (5 +/- 3 days). RESULTS: There were no significant differences between the means of the arterial compliance measurements and those of the corresponding spectral analysis. However, the magnitude of change in the low-frequency periods (4-66 mHz) was significantly related (P less than 0.01) to a significant and inverse change in compliance for the same level of blood pressure. CONCLUSIONS: While it is possible to use spectral analysis to measure the effect of autonomic nervous regulation on radial artery properties, low-frequency periods cannot be safely ascribed to sympathetic effects alone. Other effects must also be taken into account in measurements of radial artery distensibility.