Sonic vibrational analysis provides continuous measurement of arterial properties

We describe a new technology for measuring artery mechanical properties, called Sonic Vibrational Analysis (SVA). We utilize SVA to study the changes in radial artery smooth muscle tone caused by intravenous infusion of vasoactive agents. Six healthy volunteers were monitored with a radial intra-arterial catheter and an SVA sensor during progressively increasing doses of nitroglycerin (NTG), phenylephrine, sodium nitroprusside (SNP), dobutamine, and nicardipine. In SVA, the propagation velocity of an audio-frequency vibration is measured over a short segment of the radial artery. The measurement has sufficient temporal resolution to track the continuous changes in arterial properties that occur due to the natural blood pressure pulse. Coupled with the measurement of radial blood pressure, SVA allowed determination of the physiological/mechanical state of the artery within a single cardiac cycle. NTG, SNP, and phenylephrine caused significant changes in both blood pressure and the physiological state of the radial artery. Nicardipine and dobutamine altered blood pressure without change in the state of the radial artery. The current results are consistent with previous studies of the effects of vasoactive agents on the radial artery. SVA is non-invasive, continuous, localized to a well-defined section of artery, and suitable for the collection of large volumes of time-resolved data in a laboratory or clinical setting.