PROSPECTIVE TRIAL OF EFFECTS OF AN ANGIOT ENSIN I-CONVERTING ENZYME-INHIBITOR OR A BETA-BLOCKER ON STRUCTURE AND FUNCTION OF RESISTANCE ARTERIES IN MILD ESSENTIAL-HYPERTENSION

Seventeen male untreated mild essential hypertensive patients with a m ean age of 41 years agreed to participate in a double-blind randomized trial to test the effects of treatment with cilazapril, an inhibitor of angiotensin I converting enzyme, in comparison to treatment with at enotol, a beta-blocker, on the structure and function of subCutaneous resistance arteries. Patients were randomized to receive either cilaza pril 2-5-5 mg or atenolol 25-100 mg per day per day. Blood pressure be fore treatment was 147/99 and 148/99 mmHg in both groups respectively. At 1 year of treatment blood pressure was 1.32/86 and 131/85 mmHg in both groups of patients respectively- Treatment for one year with cila zapril resulted in a reduction iii the media/lumen ratio of resistance arteries (150-400 mum lumen diameter) dissected from subcutaneous glu teal biopsies from 7.5 +/- 0.3 % before treatment to 6-3 +/- 0,2 % 1 y ear later (p < 0.05), still slightly but significantly larger (p < 0.0 5) than the media/lumen ratio of resistance arteries of normotensive c ontrols (5.1 +/- 0.3 %). In arteries from patients treated with atenol ol there was no significant change with treatment (8.0 +/- 0.6 % befor e and 8.1 +/- 0.5 % after 1 year of treatment). Active wall tension re sponses to endothelin-1 were blunted in hypertensive patients and norm alized in the cilazapril-treated patients, but were unchanged in those taking atenolol. Relaxation in response to acetylcholine of norepinep hrine pre-contracted arteries was still significantly reduced after on e year (< 0.05) in comparison to those of normotensive patients in the patients treated with atenolol, whereas they were not in those who ha d received cilazapril. Treatment for one year with the converting enzy me inhibitor cilazapril thus corrects some structural and functional a bnormalities of resistance arteries from mil essential hypertensive pa tients.