Coronary spasm (CS) plays an important role in the pathogenesis of many kinds of ischemic heart disease. However, morphological characteristics of coronary artery of CS remain unknown. We evaluated 37 patients with coronary spastic angina (CSA) who underwent diagnostic acetylcholine (ACh) provocation test, and 2 acute coronary syndrome patients suspected to have severe CS. The intravascular optical coherence tomography (OCT) was performed after complete dilatation of coronary artery in all patients and additionally performed during ACh-induced CS in 4 patients. Based on the ACh provocation test, 23 patients who developed CS and ischemic ECG changes were diagnosed as coronary spastic angina (CSA), and other 14 patients without CS were referred as CS-negative patients. CS-negative patients were further divided into 2 sub-groups according to the lipid and/or calcification content in coronary arterial wall by OCT findings. Intravascular OCT revealed most coronary segments with ACh-induced CS had homogenous intima thickening, and quantitative OCT analysis showed that CS-positive segments had significantly larger intima area compared with CS-negative segments without lipid and/or calcification (2.73±0.07 vs. 1.36±0.06 mm
2
, P<0.001). By contrast, CS-positive segments had significantly smaller intima area compared with CS-negative segments with lipid and/or calcification (2.73±0.07 vs. 4.51±0.17 mm
2
, P<0.001). During ACh-induced CS, lumen and total vascular area significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. Furthermore, luminal surface of intimal layer formed markedly wavy configuration during CS. In CSA cases with acute coronary syndrome, we observed additional findings of intima injury as erosion and thrombus formation at spasm site. Coronary spasm occurs in coronary artery with diffuse intima thickening without lipid and/or calcification content but not in artery either without intima thickening or with lipid and/or calcification, and coronary spasm sometimes induces intimal injury by itself which may cause acute coronary event.
Complete Healing of Spontaneous Coronary Artery Dissection Demonstrated by Optical Coherence Tomography in a Young Postpartum Female Presenting With Acute Coronary Syndrome