Morphological Findings in Typical Variant Angina Presenting as Acute Coronary Syndrome Using Optical Coherence Tomography

Abstract

BackgroundCoronary vasospasm causes variant angina, as well as acute myocardial infarction, ventricular tachycardia, and sudden cardiac death. We evaluated morphological changes due to vasospastic lesions, which may cause acute coronary syndrome (ACS), using a novel technique called optical coherence tomography (OCT). MethodsTwenty patients (40-83 years old, 19 males) with vasospasm-induced ACS who visited the emergency room because of continuous chest pain and displayed transient ST segment elevation in their electrocardiogram were enrolled in the study. None of these patients had significant coronary artery disease and all had positive results in the provocation test. OCT examinations were performed for evaluation of vasospastic lesions. ResultsIntraluminal thrombi and intimal erosion were found in 6 (33.3%) and 2 patients (10%), respectively. High-sensitivity C-reactive protein levels were significantly higher in patients with microthrombi (2.663.33mg/L) compared with those in patients without microthrombi (0.49 +/- 0.30mg/L; P=0.022). Serum cardiac troponin-I levels were not significantly different between patients with or without microthrombi (2.37 +/- 5.31ng/mL vs. 1.45 +/- 4.68ng/mL; P=0.704). Other parameters, including creatinine kinase-myocardial band isoenzyme, total cholesterol, pain duration, residual stenosis, lesion length, and coronary risk factors, were not significantly different between the 2 groups. ConclusionIn patients with vasospasm-induced ACS, microthrombi with or without intimal erosion are major abnormal morphologic findings of OCT examinations. However, further large-scale studies are required for validation.