Abstract 3430: Positive Coronary Artery Remodeling is Associated with Underlying Vulnerable Plaque Characterized by Intravascular Optical Coherence Tomography
Background: Positive coronary artery remodeling is associated with unstable coronary syndromes and ex-vivo histological characteristics of plaque vulnerability such as a large lipid core and high macrophage content. Optical coherence tomography (OCT) is a unique imaging modality capable of characterizing important morphological features of vulnerable plaque.
Aim: To evaluate the association between coronary artery remodeling and plaque characteristics identified by OCT
Methods: OCT and intravascular ultrasound (IVUS) was performed at corresponding sites in patients undergoing catheterization. OCT plaque characteristics for lipid content, fibrous cap thickness and macrophage density were derived using previously validated methods. Thin cap fibroatheroma (TCFA) were defined as lipid rich plaque (≥2 quadrants) with fibrous cap thickness <65μm. Remodeling index (RI) was calculated as the ratio of lesion to reference external elastic membrane area on IVUS. Positive remodeling was defined as RI>1.05, absent remodeling as RI 1.05 – 0.95, and negative remodeling as RI <0.95.
Results: 57 lesions from 50 patients were imaged. Positive remodeling compared to negative remodeling was associated with lipid rich plaque (53% vs 24%, p=0.001), a thin fibrous cap (median 40.1μm vs 87μm, p=0.002) and TCFA (figure⇓). Fibrous cap macrophage density was higher in plaques with positive remodeling (figure⇓) and showed a significant positive correlation with the RI (r=0.58, p < 0.001).
Conclusion: Coronary plaques with positive remodeling exhibit characteristic features of vulnerable plaque. This may explain the link between positive remodeling and unstable clinical presentations.