Vascular structure in the forearm and calf after 6 months of angiotensin converting enzyme inhibition in elderly hypertensive subjects with left ventricular hypertrophy.

OBJECTIVE: To investigate the effects of angiotensin converting enzyme inhibition on the structure of resistive arteries assessed from minimal vascular resistance in the forearm and the calf and on left ventricular mass index of elderly hypertensive subjects with left ventricular hypertrophy.

DESIGN AND METHODS: We evaluated 23 elderly patients [12 women and 11 men, aged 70 +/- 1 years (mean +/- SEM)] with essential hypertension assessed with ambulatory blood pressure monitoring and left ventricular hypertrophy before and at the end of 6 months' treatment with quinapril. Minimal vascular resistance was calculated as the ratio of mean arterial pressure to regional blood flow measured upon restoration of circulation after 13 min of ischaemia combined with exercise and taken as an index of resistive vessel structure (i.e. media:lumen ratio).

RESULTS: Daytime ambulatory blood pressure had decreased from 164 +/- 2/95 +/- 1 to 147 +/- 3/86 +/- 2 mmHg (P < 0.001) and left ventricular mass index decreased from 138 +/- 4 to 120 +/- 5 g/m2 (P < 0.001) at the end of treatment. Minimal vascular resistance in the forearm had decreased from 3.1 +/- 0.3 to 2.4 +/- 0.2 mmHg/ml per 100 ml per min (P < 0.01) whereas we observed no change in minimal vascular resistance in the calf after treatment (4.6 +/- 0.7 versus 4.2 +/- 0.4 mmHg/ml per 100 ml per min, NS). The decrease in minimal vascular resistance in the forearm was correlated significantly to the fall in 24 h ambulatory mean arterial pressure (r = 0.58, P < 0.01). Changes in left ventricular mass index were not correlated to those in ambulatory blood pressure or to those in minimal vascular resistance in the forearm.

CONCLUSIONS: A 6-month reduction in blood pressure under quinapril treatment was associated with decreases in left ventricular hypertrophy and in minimal vascular resistance in the forearm of elderly hypertensive patients. Absence of structural changes in leg vasculature could be related to the greater arterial pressure prevalent in the lower limbs while patients stood upright and, consequently, a proportionately smaller decrease in blood pressure, as well as greater structural changes and fibrous damage than those of the upper limbs.