OBJECTIVEThis study is aimed to compare the clinical characteristics of patients with typical and atypical coronary artery spasm.

METHODSOut of 64 patients with chest pain at rest and without significant coronary artery stenosis, coronary artery spasm was provoked by intracoronary injection of acetylcholine in 46 patients, including 12 with ST segment elevation (typical coronary artery spasm group) and 34 without ST segment elevation (atypical coronary artery spasm group). The demographic data, coronary angiographic findings, treadmill electrocardiogram, dipyridamole and rest thallium-201 myocardial perfusion computed tomography, and the follow-up clinical data of the two groups were compared.

RESULTSThe patients with typical coronary artery spasm were younger (47 +/- 6 vs. 58 +/- 12, P < 0.05) than patients with atypical coronary artery spasm group. Hyperlipidemia were more common in atypical coronary artery spasm group (74% vs. 33%, P < 0.05) and myocardial bridging was more common in patients with typical coronary artery spasm group (67% vs. 32%, P < 0.01). Focal coronary spasm during acetylcholine provocation was seen in 92% patients with typical coronary spasm and in 32% patients with a atypical coronary artery spasm (P < 0.01) while diffuse coronary spasm was seen in 8% patients with typical coronary spasm and in 68% patients with a atypical coronary artery spasm (P < 0.01). All patients with coronary artery spasm were treated with aspirin, calcium channel blockers, long-acting nitroglycerine, with or without lipid-lowering drugs, 2 patients with typical coronary spasm and 4 patients with atypical coronary spasm were rehospitalized due to chest pain and rest of the patients remained free of chest pain during the median follow-up period of 18 +/- 14 months.

CONCLUSIONAtypical coronary artery spasm is common in patients with rest angina and diffuse coronary microvascular spasm might be the cause of chest pain in these patients.