Effects of age on endothelium-dependent vasodilation of resistance coronary artery by acetylcholine in humans

Abstract

Background. It has been suggested that endothelium-related vasomotion is important in the control of coronary circulation. Our goal was to determine if endothelium-dependent dilation of the coronary vasculature was altered with aging in 18 patients with atypical chest pain (age, 23-70 years) who had angiographically normal coronary arteries and no coronary risk factors. Methods and Results. We infused an endothelium-dependent vasodilator acetylcholine (1, 3, 10, and 30 μg/min) and an endothelium-independent vasodilator papaverine (10 mg) into the left coronary artery. The large coronary diameter was assessed by arteriography, and the increase in coronary blood flow was measured using the intracoronary Doppler catheter technique. Acetylcholine increased coronary blood flow in a dose-dependent manner with no changes in arterial pressure and heart rate. The maximum increase in coronary blood flow evoked by acetylcholine varied widely among patients (increase in coronary blood flow ranged from 200% to 560%) and was correlated significantly with aging (r=-.86, P