[Non-invasive test for aortic compliance in man]

We determined the compliance of the aortic "Windkessel" using a non-invasive method. The occlusion of the lower extremities (5 min, 180 mm Hg) elicited reactive hyperemia. An abrupt change in pressure in the occluding cuffs from 180 to 60 mm Hg increased femoral blood flow (measured by pulsed Doppler) and decreased blood pressure (measured by Penaz continuous method). During abrupt decrease in blood pressure, the compliance was calculated as a ratio of the blood volume flowing out of the aorta via the femoral arteries to the decrease of blood pressure. The measurements were made repeatedly in eight healthy men, and in patients with essential hypertension (ten patients with essential hypertension, IInd degree-WHO without treatment and six patients with essential hypertension, IInd degree-WHO treated with slow released verapamil). Compliance in the first group was 1.18 +/- 0.25 ml. mm Hg-1, in the second 0.96 +/- 0.21 ml. mm Hg-1, and in the third group 0.90 +/- 0.11 ml. mm Hg-1. We found a negative correlation between compliance and arterial blood pressure. However the relative large scatter requires repeated measurements.