CENTRAL AND LOCAL MICROVASCULAR REACTIVITY IN NORMOTENSIVE SUBJECTS WITH A FAMILY HISTORY OF HYPERTENSION
Abstract
Background. Using the laser-Doppler method we measured blood flow on the nailfold skin to compare the reactivity of cutaneous microcirculation between normotensive subjects with a familial predisposition to hypertension and normotensive subjects without a familial predisposition to hypertension.
Methods. Three groups of normotensive subjects were included in the study: 11 subjects with a familial predisposition to hypertension without a previous record of high blood pressure, six predisposed subjects with a previous record of high blood pressure and 13 subjects with no predisposition to hypertension. The flow was measured after direct and indirect skin cooling and heating and during postocclusive reactive hyperemia (PRH) after a ten-minute occlusion of digital arteries. The frequency of flow oscillations in the second part of the PRH was established. Heart rate spectral analysis was performed based on the monitoring of the peripheral pulse frequency by means of the finapres device.
Results. In comparison to the other two groups of subjects, the group with a predisposition and a previous record of high blood pressure displayed a larger surface area in the low frequency band (0.05 to 0.15 Hz) of the heart rate variability power spectrum (the Bonferroni test, p < 0.05). As compared to subjects without predisposition, both groups of predisposed subjects exhibit higher frequency of flow oscillations in the second part of the PRH (the Bonferroni test, p < 0.05).
Conclusions. We conclude that there is a change in cutaneous microvascular reactivity of local (most probably myogenic) origin in normotensive subjects with a predisposition to hypertension, whereas normotensives with a predisposition and a previous record of high blood pressure exhibit also different cutaneous microvascular reactivity of central (non-vascular) origin.
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