Abstract 1987: The site of Thin-cap Fibroatheroma in Native Coronary Arteries: A Three-Vessel Optical Coherence Tomography Study

Abstract

Background: Plaque rupture is the most frequent cause of coronary thrombosis such as acute myocardial infarction (AMI). It has been recognized that thin-cap fibroatheroma (TCFA) is the precursor lesion of plaque rupture. It is clinically important to understand the potential sites of TCFA. Therefore, we evaluated the geographic distribution of TCFAs using optical coherence tomography (OCT) that is a high-resolution (approximately 10 μm) imaging modality. Methods: We performed three-vessel OCT examinations in 51 patients; 34 AMI and 17 stable angina pectoris (SAP) patients. OCT criteria for TCFA was lipid-rich plaque with cap thickness <65 μm. The distance between each TCFA segment and the respective coronary ostium was measured with motorized OCT transducer pullback. The overall length of the region of interest, subsequently divided into 10mm segments, was 68.2 ± 27.1 mm long (range: 18.9 – 121.1 mm). Results: The OCT detected 86 TCFAs in 41 patients: 32 were identified in AMI patients and 9 in SAP patients. Of all TCFAs, 26 were located in the left anterior descending artery (LAD), 16 in the left circumflex artery (LCX), and 44 in the right coronary artery (RCA). Most LAD TCFAs were located between 0 and 40mm from the LAD ostium (96%). Similarly, LCX TCFAs were predominantly located between 0 and 40mm from the LCX ostium (69%). Conversely, RCA TCFAs were evenly distributed in the entire coronary trees. The clustering of the TCFAs was similar in culprit segments compared with non-culprit segments. Conclusion: Three-vessel OCT imaging showed that TCFAs tend to cluster in predictable “hot spots” within the proximal segments of the LAD and LCX, and the entire segments of the RCA.