[The compliance of the large elastic arteries after blood pressure-lowering therapy with a calcium antagonist].

A decrease in the vascular compliance of the large elastic vessels (reduction of their "Windkessel" function) is of decisive importance for the pathogenesis and prognosis of cardiovascular complications such as arteriosclerosis, left ventricular hypertrophy and heart failure. The effect of the antihypertensive calcium antagonist isradipine on the "Windkessel" function of the aorta was measured in terms of the central haemodynamics in ten patients (eight men, two women; mean age 58 +/- 3 years) with essential hypertension (WHO stage I-II) before and 3 months after treatment. The mean arterial blood pressure was obtained invasively from the aortic arch, cardiac output or stroke volume being obtained by the indicator dilution method. The ratio stroke volume/blood pressure amplitude was calculated as a measure of vascular compliance. After 3 months of treatment with isradipine the mean arterial blood pressure fell from 114 +/- 4 to 97 +/- 3 mm Hg (P < 0.01), and total peripheral resistance from 22 +/- 1 to 18 +/- 1 U, P < 0.05), while vascular compliance rose from 1.07 +/- 0.10 to 1.58 +/- 0.10 ml/mm Hg, P < 0.05. The increase in compliance resulted from both the fall in blood pressure per se and the pressure-independent increase in the distensibility of the vessel wall (87 +/- 8% as against 107 +/- 13%, P < 0.05). As the fall in afterload favoured regression in left ventricular hypertrophy and heart failure, this pressure-independent structural and (or) functional change in the great elastic arteries could be decisive for the cardiovascular prognosis of hypertensives.