Heterogeneity of response of peripheral arteries to antihypertensive drugs in essential hypertension. Basic effects and functional consequences.

The vascular impact of different antihypertensive drugs was assessed in patients with mild to moderate essential hypertension by the use of the forearm circulation as a simple model to characterise the geometrical and distensible properties of the arterial system. The acute and chronic responses of the forearm arteries, expressed in terms of geometry (vasodilatation or vasoconstriction) and distensibility (arterial compliance, pulse-wave velocity), were not solely dependent on blood pressure levels. For similar blood pressure decreases, the dilatation of the forearm resistive vessels was associated either with an increase (calcium antagonists, angiotensin-converting enzyme inhibitors) or with a reduction (hydralazine-like drugs) or with no change (alpha- and beta-blocking drugs) in the calibre of the large forearm vessel. These non-homogeneous geometrical responses to antihypertensive drugs had important haemodynamic effects on the conduit, the buffering and the baroreflex functions of the arterial tree.