Effects of Hypertension on Viscoelasticity of Carotid and Femoral Arteries in Humans

Abstract

Abstract We compared the properties of common carotid and femoral arteries of 16 normotensive and 14 hypertensive men. Arterial pressure and diameter were recorded noninvasively in each vessel by tonometric and echotracking devices. The x - y composition of pressure and diameter waves provided the diameter-pressure hysteresis loop. The elastic diameter-pressure curve and wall viscosity index were deduced after hysteresis elimination. 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 standard pressure in all subjects. Systolic, diastolic, mean, and pulse pressures and diameters in each vessel were higher in the hypertensive than the normotensive group, except carotid pulse diameter, which did not differ. The carotid diameter-pressure, compliance-pressure, and distensibility-pressure curves did not differ between groups. In the carotid artery hypertensive patients had isobaric compliance and distensibility values similar to those of normotensive subjects, despite lower effective compliance ( P <.05) and distensibility ( P <.01). The femoral diameter-pressure curve was higher ( P <.05) and the femoral compliance-pressure and distensibility-pressure curves were lower ( P <.01) in the hypertensive than the normotensive group. Hypertensive patients had effective and isobaric femoral compliance and distensibility values lower 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 carotid and femoral sites in a uniform manner.