Abstract 4335: Correlation Between Plaque Rupture and Morphological Features of Thin Cap Fibroatheroma in Acute Coronary Syndrome Assessed by Optical Coherence Tomography
Backgrounds: Plaque rupture (PR) and secondary thrombus formation (TF) play key roles in the onset of acute coronary syndrome (ACS), and thin cap fibroatheroma (TCFA) is believed to be prone to rupture. We sought to determine the relationship between morphological features and PR in vivo by optical coherence tomography (OCT).
Methods: We studied 26 lesions from 26 consecutive patients with NSTEMI/UAP who underwent percutaneous coronary intervention (PCI) for culprit lesions with OCT examination. OCT imaging was performed before any device passage in the present study, and was analyzed by two independent observers. TCFA was defined as a fibroatheromatous with cap thickness <100μm. OCT analysis included presence of PR and TF, lipid arc (LQ), thickness of thinnest cap (CT), longitudinal length of TCFA (L-TCFA). Each parameter was compared between two groups of lesions with PR (RG) and those without PR (NRG). Receiver-operator characteristic curve analysis (ROC) was performed to determine the best cut-off value of L-TCFA to diffrenciate RG and NRG.
Results: PR, TF, and TCFA was detected in 10 (38.4%), 16 (61.5%), and 25 lesions (96.2%), respectively. Mean L-TCFA was 6.9±5.2mm, and fibroatheroma with LQ >2 quadrants was observed in 14 lesions (53.8%). Plaque with LQ >2 quadrants was frequently observed in RG than in NRG (90.0% vs 31.3%, p<0.01). Mean value of L-TCFA was significantly greater in RG (11.3±5.9mm vs 4.1±2.0mm, p<0.01), whereas no significant difference in CT between two groups (63.0±12.2μm vs 68.6±10.6μm, p=0.25). In vivo OCT-derived value including more than 95% of longitudinal length of TCFA was 6.7mm in the present study. The best cut-off value to differentiate RG and NRG was 6.6mm (sensitivity: 80.0%, specificity: 93.8%, AUC:0.89, p<0.0001) by ROC analysis.
Conclusions: This study suggested the importance of the length of TCFA in plaque rupture. Longitudinal length of TCFA, fibrous cap thickness, and lipid arc showed a significant correlation with the presence of plaque rupture.