Treatment with irbesartan or atenolol improves endothelial function in essential hypertension

Objectives To investigate if antihypertensive treatment could improve endot helium-dependent vasodilatation in hypertensive patients, and whether the a ngiotensin II subtype-1 (AT(1))-receptor antagonist irbesartan and the beta (1)-receptor antagonist atenolol would differ in this respect. Subjects and methods Thirty-four patients (28 men and six women) with mild- to-moderate essential hypertension (diastolic blood pressure 90-120 mmHg) w ere randomized to once daily 150-300 mg irbesartan or 50-100 mg atenolol in a double-blind fashion, preceded by a placebo run-in period. Forearm blood flow (FBF) was assessed by venous occlusion plethysmography during local i ntra-arterial infusions of methacholine and sodium nitroprusside, to evalua te endothelium-dependent and endothelium-independent vasodilatation, respec tively. Measurements of FBF were undertaken at the end of the run-in placeb o period and repeated after 3 months of active antihypertensive treatment. Results Irbesartan and atenolol induced a similar decline in blood pressure (from 171/107 to 158/98 mmHg, P < 0.05), and improved endothelium-dependen t vasodilatation (e.g. an increase in FBF response to 4 mug min methacholin e from 325 +/- 29% to 411 +/- 41%, P < 0.05), with no difference between th e two study drugs. No significant changes in endothelium-independent vasodi latation were induced by irbesartan or by atenolol. Conclusions The present study shows that 3 months of antihypertensive thera py with irbesartan or atenolol improves endothelium-dependent vasodilatatio n. (C) 2001 Lippincott Williams & Wilkins.