Non-invasive evaluation of endothelial function in hypertensive elderly patients

Abstract

Impaired endothelium-dependent vasomotion is a diffuse disease process resulting in abnormal regulation of blood vessel tone and loss of several atheroprotective effects of the normal endothelium. The aim of the present study was to investigate the effects of aging and hypertension on endothelial function. Sixty-six geriatric subjects with ages over 60 (48 hypertensive and 18 healthy) and 40 middle-aged subjects (16 hypertensive and 24 healthy) were included in the study. Systemic vascular endothelial function was evaluated through measuring brachial arterial vasodilation, a physiologic answer to reactive hyperemia occured with increased blood flow in the vessel after transient ischemia (flow-mediated dilation, FMD%), and with carotid artery intima-media thickness (IMT) measurement, using high-resolution ultrasonography. Endothelial independent vasodilation was also measured after administration of sublingual isosorbide dinitrate (isosorbide dinitrate mediated dilation, IDNMD%). FMD% was significantly decreased in elderly and/or hypertensive (HT) patients (geriatric HT: 9.5 +/- 4.7%, geriatric non-HT: 12.7 +/- 5.5%, middle-aged HT: 12.9 +/- 4.3% and middle-aged non-HT: 18.9 +/- 8.1%) (geriatric HT versus geriatric non-HT (P = 0.02), geriatric HT versus middle-aged HT (P = 0.01), geriatric non-HT versus middle-aged non-HT (P = 0.008)). Both FMD% and IDNMD% were inversely correlated with age, baseline vessel diameter and carotid artery intima-media thickness. FMD% was also inversely correlated with diastolic blood pressure. No correlation was found between FMD% and systolic blood pressure, serum cholesterol and triglyceride levels. Endothelium dependent (EDD) and independent dilatation of large arteries decreased with aging even in the healthy elderly, and FMD further declined in HT elderly patients, indicating that age and hypertension independently impair endothelial function. Positive correlations with age and hypertension, and significant inverse correlation with FMD, makes carotid artery IMT a possible indicator of endothelial function.