Abstract 15279: Relationship Between Severity of Coronary Artery and Optical Coherence Tomography Findings in Stable Angina Pectoris
Backgrounds: Acute myocardial infarctions were widely believed to result from rupture of thin-capped fibroatheroma (TCFA) and thrombosis at the site of a mild to moderate stenosis. In contrast to this belief constituted form retrospective studies, prospective studies demonstrated that future occlusion was strongly related with stenosis severity. The aim of the present study is to investigate the relationship between stenosis severity and lesion instability assessed by optical coherence tomography (OCT) in patients with stable angina pectoris (SAP).
Methods and Results: We investigated 189 culprit and nonculprit lesions of 173 SAP patients, who underwent preprocedural OCT imaging. Stenosis severity was measured by quantitative coronary angiographic analysis (QCA), and lesions were divided into tertiles: Severe stenosis group >67.2%, Moderate stenosis group 57.3 to 67.2%, and Mild stenosis group <57.3%. OCT findings were compared among these groups. TCFA was defined as lipid-rich plaque (one or more quadrants) with fibrous cap thickness <70μm. OCT analysis included presence of TCFA, ruptured plaque (RP), lipid quadrants (LQ), and the thinnest cap thickness (CT). The mean diameter stenosis of each group was 75.3±5.5%, 61.7±2.8%, and 52.4±4.2%, respectively. There was no significant difference in reference diameter between each group (Severe: 2.8±0.5mm, Moderate: 2.9±0.5mm, Mild: 2.8±0.6mm, p=0.95). In OCT analysis, there was no significant difference in the frequency of RP. However, there were significant differences in CT (Severe: 92±45μm, Moderate: 119±53μm, Mild: 100±40μm, p<0.01), number of LQ (Severe: 2.2±1.5, Moderate: 1.5±1.3, Mild: 1.5±1.4, p<0.01), and frequency of TCFA (Severe: 30.1%, Moderate: 12.7%, Mild: 12.7%, p=0.01). Lesions of most stenotic tertile showed significantly higher prevalence of TCFA and thinner fibrous cap thickness than other 2 tertiles combined.
Conclusions: Severity of coronary stenosis in SAP lesions might be correlated with lesion instability assessed by OCT. These findings may challenge the concept that lesions responsible for acute myocardial infarction are mild in most cases provided that plaque rupture of TCFA evenly results in coronary events in the wide range of stenosis severity.
- © 2010 by American Heart Association, Inc.