Effects of L-Arginine on Coronary Artery Spasm Induced by Intracoronary Acetylcholine in Patients with Angina Pectoris with Normal Coronary Angiogram

Park, Chang Gyu; Oh, Dong Joo; Seo, Hong Seog; Lee, Eun Mi; Ahn, Jung Chun; Song, Woo Hyuk; Lim, Do Sun; Kim, Young Hoon; Shim, Wan Joo; Ro, Young Moo

Abstract

BACKGROUND
Coronary spasm can be induced by acetylcholine (ACh) ACh casues vasodilation when the endothelium is intact by releasing nitric oxide (NO). The aim of this study was to investigate whether L-arginine, the precursor of NO, could preserve endothelium-dependent vasodilation in patients with coronary artery spasm. METHOD: NO precusor L-arginine (20mg/kg/min) was infused intravenous for 30 minutes in nineteen patients with coronary spastic angina. Coronary spasm of the epicardial coronary artery (>75%) was induced by intracoronary injection of acetylcholine in incremental doses (ACh: A1 20ug, A2 50ug, A3 100ug) the spasm was then documented angiographically in all patients with coronary spastic angina. After the administration of L-arginine, intracoronary injection of acetylcholine was repeated as the same method in all coronary spastic angina patients.
RESULTS
After systemic infusion of L-arginine, the constrictor response to ACh was significanfly attenuated : no spastic response in 8 cases (42%), increased doses of ACh for provoking spasm in 8 cases (42%) and no change in 3 cases (16%). There were no significant change in blood pressure and heart rate after the administration of L-arginine.
CONCLUSION
The fact that L-arginine attenuated vasospasm provoked by ACh in human coronary arteries, suggests the possibilities that L-arginine may be used in the prevention and treatment of coronary spasm.