EFFECTS OF HYPERTENSION ON VISCOELASTICITY OF CAROTID AND FEMORAL ARTERIES IN HUMANS

We compared the properties of common carotid and femoral arteries of 1 6 normotensive and 14 hypertensive men. Arterial pressure and diameter were recorded noninvasively in each vessel by tonometric and echotrac king devices. The x-y composition of pressure and diameter waves provi ded the diameter-pressure hysteresis loop. The elastic diameter-pressu re curve and wall viscosity index were deduced after hysteresis elimin ation. The compliance-pressure and distensibility-pressure curves were derived from the diameter-pressure curve, allowing the calculation of effective compliance and distensibility at the prevailing pressure of each subject and isobaric compliance and distensibility at the same s tandard pressure in all subjects. Systolic, diastolic, mean, and pulse pressures and diameters in each vessel were higher in the hypertensiv e than the normotensive group, except carotid pulse diameter, which di d not differ. The carotid diameter-pressure, compliance-pressure, and distensibility-pressure curves did not differ between groups. In the c arotid artery hypertensive patients had isobaric compliance and disten sibility values similar to those of normotensive subjects, despite low er effective compliance (P<.05) and distensibility (P<.01). The femora l diameter-pressure curve was higher (P<.05) and the femoral complianc e-pressure and distensibility-pressure curves were lower (P<.01) in th e hypertensive than the normotensive group. Hypertensive patients had effective and isobaric femoral compliance and distensibility values lo wer than to those of normotensive subjects (P<.001). In both arteries, viscosity index was higher in the hypertensive than the normotensive group (P<.001). In hypertension, the pressure-independent alterations of geometric and elastic properties were distributed preferentially to the femoral artery, and the alteration of wall viscosity affected car otid and femoral sites in a uniform manner.