REACTIVE HYPEREMIA UNMASKS REDUCED COMPLIANCE OF CUTANEOUS ARTERIES IN ESSENTIAL-HYPERTENSION

To evaluate changes in distal cutaneous arteries during hypertension, we used a noninvasive method to assess the compliance and vascular res istance of the hand radial arteries, mainly distributed to the skin, i n 10 normotensive and 10 hypertensive (HT) men. Radial artery diameter and blood velocity were measured by means of pulsed Doppler concomita ntly with measurements of finger arterial pressure by photoplethysmogr aphy. Hand radial vascular resistance was calculated as the ratio of m ean arterial pressure to mean radial blood flow. A simple resistive-ca pacitive model of large and small arteries of the hand allowed us to e valuate arterial compliance from the exponential slope of finger diast olic pressure decay and vascular resistance. Measurements were made at baseline and during reactive hyperemia after 5 min of complete occlus ion of the brachial artery with a pneumatic cuff. Except for pressure, there were no baseline differences between the groups. In normotensiv e and HT subjects, hyperemia increased radial artery diameter and bloo d velocity (P < 0.001) and compliance (P < 0.01 and P < 0.05, respecti vely) and decreased mean pressure P < 0.01 and P < 0.001, respectively ) and resistance (P < 0.001). During hyperemia, the only difference be tween the groups, except for pressure, was lower compliance in HT subj ects (P < 0.01). Moreover, compliance during hyperemia negatively corr elated with baseline mean pressure (P = 0.001). Thus hyperemia unmaske d reduced compliance in the HT patients but did not show abnormal resi stance, suggesting that the elastic properties of the hand skin radial arteries might be more sensitive than their resistive properties to h igh blood pressure.