Abstract

Introduction

Small arteries in hypertension

Effects of antihypertensives in rats

Effect of antihypertensives in humans

Discussion

Discussion
Board

Small arteries may play a role in the development and complications of hypertension. The changes occurring in small arteries may result in part from the action of hormones (such as angiotensin II) and calcium-dependent mechanisms. These changes may include cell growth and apoptosis, and increased extracellular matrix and collagen deposition. Treatment of spontaneously hypertensive rats with angiotensin converting enzyme (ACE) inhibitors, calcium channel antagonists, and angiotensin receptor antagonists has improved the altered structure and endothelium-dependent relaxation of small arteries. In hypertensive patients some ACE inhibitors or extended release calcium channel antagonists induced similar effects in small arteries obtained from gluteal subcutaneous biopsies: both structure and endothelial dysfunction improved. Equally controlled patients receiving the beta blocker atenolol did not exhibit in any of 3 studies any improvement in small artery structure or endothelial function. Thus, hypertensive patients with good blood pressure control treated for more than one year with ACE inhibitors or long acting calcium antagonists exhibit normal structure and function of small arteries, whereas similarly controlled beta blocker-treated patients present abnormally thick small arteries with impaired contractility and endothelium-dependent relaxation. It will be important to determine whether this contributes to a reduced morbidity and mortality in hypertensive patients.

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Presentation Number SAschiffrin0304
Keywords: resistance artery, angiotensin, calcium blockers, vascular growth, remodeling