Abstract 13220: Plaque Composition Analyzed by iMap-Intravascular Ultrasound Predicts Thin-Cap Fibroatheroma Determined by Optical Coherence Tomography
Background: Intracoronary imaging using novel iMap-intravascular ultrasound (iMap-IVUS) can generate objective and quantitative information about coronary plaque characteristics. The present study determines whether iMap-IVUS can detect thin-cap fibroatheroma (TCFA), which is a predominant morphology of vulnerable plaque, as determined by optical coherence tomography (OCT).
Methods: Culprit plaques (n = 77) in 58 patients with stable angina pectoris and in 19 with acute coronary syndrome were visualized using iMap-IVUS and OCT. The IVUS parameters were calculated at sites of minimal lumen area. Plaque characteristics were classified from iMap-IVUS images as fibrotic, lipidic, necrotic and calcified components that are described herein as absolute values and as ratios (%) of each area (FA, LA, NA and CA, respectively). We defined TCFA from OCT images as lipid-rich plaque with a < 65-μ m thick fibrous cap. Plaques were assigned to groups according to the presence (TCFA group, n = 41) or absence (non-TCFA group, n = 36) of TCFA.
Results: The plaque burden was significantly greater (83.1 ± 6.9 vs. 76.8 ± 9.0 %, p = 0.001) and the prevalence of positive remodeling was higher (90 vs. 55 %, p < 0.001) in the TCFA, than in the non-TCF group. Absolute LA (1.72 ± 0.84 vs. 0.95 ± 0.70 mm2, p < 0.001), NA (6.67 ± 3.27 vs. 3.46 ± 3.70 mm2, p < 0.001), %LA (11.4 ± 4.0 vs. 9.6 ± 3.2 %, p = 0.027) and %NA (43.0 ± 12.9 vs. 31.5 ± 18.2%, p = 0.002) were significantly larger, and %FA was significantly lower (44.1 ± 13.1 vs. 56.7 ± 20.1%, p = 0.002) in the TCFA, than in the non-TCF group. Absolute LA and NA among the four components inversely correlated with fibrous cap thickness (r = -0.32, p = 0.006; r = -0.25, p = 0.034, respectively). Multivariate logistic regression analysis showed that the significant factors associated with TCFA comprised a larger absolute LA (odds ratio 4.04, p = 0.004) and positive remodeling (odds ratio, 5.26; p = 0.017). The area under the receiver-operating characteristics curve for absolute LA to predict TCFA was 0.80 (optimal cut-off, 1.07 mm2; sensitivity, 81%; specificity, 72%).
Conclusions: Plaque with positive remodeling and a larger LA as determined by iMap-IVUS is closely associated with TCFA determined by OCT.
- © 2012 by American Heart Association, Inc.