Effects of Acute l -Arginine Administration in Coronary Atherosclerosis

Abstract

To the Editor: Lerman et al1 in their interesting study reported that supplementation with l-arginine (the precursor of nitric oxide synthesis) for 6 months in patients without significant coronary artery stenosis reversed coronary small-vessel endothelial dysfunction and improved symptoms. Furthermore, it decreased plasma endothelin concentrations in patients. However, they did not examine the effects of l-arginine on epicardial coronary arteries and stenoses. We have examined2 3 by quantitative angiography the vasomotor effects of intracoronary infusion of normal saline (2 mL/min) for 2 minutes followed by 50 and 150 μmol/min l-arginine and bolus administration of 250 μg of nitroglycerin on 38 nonstenotic epicardial coronary artery segments and 22 stenoses in patients with coronary artery disease and a positive treadmill exercise test result (≥0.1 mV ST-segment depression at between 5 and 7 metabolic equivalents [METS] using the modified Bruce protocol). The diameter of the stenosis …