Abstract 3063: Assessment of Fibrous Cap Thickness of the Coronary Plaque by Optical Coherence Tomography: Comparison with Coronary Angioscopic Image
[Background] Coronary angioscopy (CAS) can provide detailed information of the luminal surface characteristics of the coronary artery, such as plaque color, presence or absence of thrombus, or fibrous cap disruption. It has been suggested that plaque color might be associated with plaque vulnerability, although CAS is limited to obtain structural and pathohistological information of the plaque. Optical coherence tomography (OCT) has recently been proposed as a histology-grade imaging modality (resolution, 10 μm; wavelength, 1300 nm; probe size, 0.018 inch; Lightlab Imaging). Previously, we reported the ability to detect lipid-core and to measure intima-media thickness accurately in postmortem histological examination. In the present study, we assessed structural differences by OCT between yellow and white plaques identified by CAS.
[Methods and Results] Thirty-three coronary artery lesions in patients with acute coronary syndrome were observed by CAS, and the results were compared with OCT findings. The incidences of yellow and white plaque evaluated by CAS were 73% and 28%, respectively. In all plaques, Lipid core was observed clearly and fibrous cap thickness was measured accurately by OCT. The lipid core arches estimated by OCT were not different between yellow and white plaques (172 +/− 113 vs. 161 +/− 101 degrees, p=0.80). Fibrous cap thickness of yellow plaque was significantly thinner than that of white plaque (59 +/− 13 vs. 246 +/− 112 micrometer, p<0.001). The sensitivity, specificity, positive predictive value and negative predictive value that yellow color of plaque by CAS identified thin cap fibroatheroma (TCFA; fibrous cap thickness estimated by OCT < 65 micrometer) were 100%, 53%, 67% and 100%, respectively.
[Conclusions] Yellow color of coronary plaques observed by CAS was a useful predictor for identification of TCFA. The plaque color might be determined not by the amount of lipid core but by the thickness of the fibrous cap, which was able to be measured by OCT in vivo.