Converting enzyme inhibition: dissociation between antihypertensive and arterial effects

In this study the dose-response curves reflecting the arterial and the antihypertensive effects of converting enzyme inhibition were analysed. The BP measurement (using a random zero sphygmomanometer) and its decrease following converting enzyme inhibition were used as a marker of the arteriolar effect of the drug. The effect on conduit arteries was evaluated through determination of carotid-femoral pulse wave velocity used as an index of arterial distensibility. We compared the dose-response curves of these two parameters in a double-blind study carried out in 24 patients with essential hypertension, who were randomised between placebo and 2, 4 and 8 mg of the converting enzyme inhibitor trandolapril given for 8 days. The antihypertensive effect was observed from 2 mg, at which dose the plateau of BP reduction was already achieved. No significant correlation was found between dose and BP reduction (r = -0.34), whereas the dose was significantly related to the change in pulse wave velocity (r = -0.56, P < 0.01). No significant correlation was found between changes in BP and change of pulse wave velocity. The study provides evidence that the effect on the conduit artery was obtained for higher doses than the BP effect in patients treated for hypertension by the converting enzyme inhibitor trandolapril.