Nitric Oxide Activity Is Deficient in Spasm Arteries of Patients With Coronary Spastic Angina

Background Coronary spasm can be induced by acetylcholine, serotonin, ergonovine, or histamine, all of which cause vasodilation when the endothelium is intact by releasing nitric oxide (NO). Coronary spasm is promptly relieved by nitroglycerin, which vasodilates through its conversion to NO. It is thus possible that NO release may be deficient in the spasm arteries in patients with coronary spastic angina (CSA). The aim of this study was to determine whether NO release is deficient in coronary arteries of patients with CSA. Methods and ResultsNG-monomethyl-l-arginine (L-NMMA), an inhibitor of NO synthase, was infused into coronary arteries in 21 patients with coronary spastic angina (CSA) and in 28 control patients. Coronary spasm was induced by intracoronary injection of acetylcholine and was documented angiographically in all patients with CSA. L-NMMA dose-dependently decreased basal luminal diameter of coronary arteries in control patients, whereas it had no effect on basal diameter of the spasm arteri...