Endothelial vascular function in hypertensive patients after renin-angiotensin system blockade.

It is unclear whether single and combined pharmacologic inhibition of the renin-angiotensin-aldosterone system have similar effects on endothelial function and blood pressure (BP). The authors evaluated 63 hypertensive patients divided into 4 groups (hydrochlorothiazide 25 mg/d; irbesartan [IRBE] 150 mg/d; quinapril [QUIN] 20 mg/d; or IRBE 150 mg/d + QUIN 20 mg/d) and 25 healthy normotensive subjects (normal) followed for 12 weeks. Endothelium-dependent dysfunction measured as flow-mediated dilation at Weeks 0 and 12 were: normal, 11.5%+/-2.4% vs 13.5%+/-2.0%; hydrochlorothiazide, 7.3%+/-2.0% vs 12.8%+/-3.1%; QUIN, 7.2%+/-2.8% vs 13.2%+/-2.1%; IRBE, 7.1%+/-2.8% vs 13.0%+/-2.9%; and IRBE + QUIN, 7.5%+/-1.9% vs 12.8%+/-3.0%. Nitroglycerin-mediated responses were: normal, 26.0%+/-1.9% vs 24.0%+/-2.5%; hydrochlorothiazide, 17.0%+/-2.2% vs 18.3%+/-2.6%; QUIN, 17.8%+/-3.2% vs 23.4%+/-3.0%; IRBE, 16.8%+/-3.6% vs 24.7%+/-2.0%; and IRBE + QUIN, 17.3%+/-3.0% vs 25.1%+/-2.5%. Antihypertensive therapy restored BP to normal and improved the endothelium-dependent and -independent dysfunction after renin-angiotensin-aldosterone system blockade. In a further finding, the combined effect of angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade was not superior to the action of either of these treatments separately.