SIMULTANEOUS IPSILATERAL AND CONTRALATERAL MEASUREMENTS OF VASOMOTIONIN CONDUIT ARTERIES OF HUMAN UPPER LIMBS

We investigated the patterns of vasomotion in various conduit arteries of the human arm. The internal diameter of the brachial, radial, ulna r, and digital artery was measured noninvasively in 17 healthy volunte ers (aged 24-40 yr), using a high-precision ultrasonic echo-tracking d evice. Under resting conditions, the radial, ulnar, and digital intern al diameter exhibited spontaneous oscillations (vasomotion) with a rel ative amplitude ranging from 1 to 5% of the mean diameter and a fundam ental frequency ranging from 0.01 to 0.05 Hz. This oscillatory behavio r was either quasi-periodic or irregular. The low-frequency mode (f le ss than or equal to 0.05 Hz) present in the diameter signal was identi fied neither in the heart rate nor in the blood pressure signal. To de termine whether the oscillatory activity was propagative, simultaneous measurements of diameter at two sites on the right radial artery were performed and revealed no significant consistent phase shift. Ipsilat eral radial and ulnar-diameters, measured at the wrist level, exhibite d similar and synchronous vasomotion patterns, despite differences in the amplitude. For all subjects, contralateral measurements, performed at two symmetrical sites of the radial arteries, showed similar oscil latory patterns with a strong correlation (0.85 < r < 0.99, n = 12). T hese results suggested the existence of a global regulatory mechanism that coordinates vasomotion in the large conduit arteries of the human arm.