OBJECTIVETo investigate the role of coronary artery spasm in the etiology of chest pain lacking significant coronary stenosis and to identify the clinical risk factors related to coronary artery spasm.

METHODSTwo hundred and seventy five patients with chest pain, but without significant coronary artery stenosis underwent the intracoronary acetylcholine test. Coronary artery spasm was diagnosed while coronary artery stenosis increased to 90% and was accompanied by the usual chest pain with or without ischemic changes on electrocardiogram. Logistic regression was employed to investigate the relationships between coronary artery spasm and sex, age, hypertension, diabetes mellitus, smoking, hyperlipidemia and results of electrocardiographic treadmill stress test. Left ventricular ejection fraction and end diastolic pressure were compared between spasm group and non-spasm group.

RESULTSCoronary artery spasm was detected in 103 out of 271 patients, a rate of 38%. Logistic regression analysis showed that smoking and hyperlipidemia increased the relative risk of coronary artery spasm 4.2 times and 2.3 times, respectively. There was a significantly negative relationship between diabetes mellitus and coronary artery spasm. Furthermore, there was no significant difference of left ventricular ejection fraction and end diastolic pressure between spasm group and non-spasm group.

CONCLUSIONSCoronary artery spasm was one of the important etiological factors for patients with chest pain but no coronary artery stenosis. Smoking and hyperlipidemia were the main clinical risk factors for coronary artery spasm.