Abstract 4411: Relationship of Longitudinal Morphology of Thin-cap Fibroatheroma Assessed by Optical Coherence Tomography With TIMI Risk score in Patients With Non-ST Segment Elevation Myocardial Infarction
Backgrounds: Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS), and it is suggested that thin-cap fibroatheroma (TCFA) is responsible as a precursor for the majority of acute coronary syndromes or sudden cardiac deaths. The relationship between longitudinal characteristics of TCFA and TIMI risk score in patients with non-ST segment elevation myocardial infarction (NSTEMI) has not been investigated.
Method and Results: Forty-four consecutive patients with single vessel NSTEMI who underwent primary percutaneous coronary intervention were investigated. In 8 patients, preprocedural OCT image quality for target lesions was not sufficient, or not obtained, the remaining 36 lesions from 36 patients were examined. Preprocedural OCT analysis included the presence or absence of TCFA, thinnest cap thickness of TCFA, longitudinal length of TCFA, lipid arc, and the presence of ruptured plaque. Two independent observers performed OCT image analysis, and disagreement was resolved by consensus reading. TCFA was defined as fibroatheroma with cap thickness less than 100μm, and lipid arc was measured. TIMI risk score was determined at admission, and compared with OCT findings. Thirty TCFA was detected in 36 patients (0.83/patients). Mean thickness of the thinnest part of the fibrous cap was 67±14μm, and mean longitudinal length of TCFA was 6.9±4.8μm. Ten ruptured plaque were detected 10 lesions (33%). Ruptured plaque showed a significant association with TCFA length (p<0.01). Mean TIMI risk score was 3.76, and significant correlation between TCFA length and lipid arc (p<0.01). And Cap thickness of TCFA was inversely correlated with TCFA length. Patients with TIMI risk score >4 showed a trend for longer TCFA length compared with those of TIMI risk score <4(8.2±5.4mm,5.1±3.0mm,p=0.06).
Conclusion: Plaque volume and composition as assessed by TCFA length and lipid arc of the target lesion may be correlated with a risk status in patients with NSTEMI.