Pathological characterization of yellow and white plaques under angioscopy

Abstract

Recently it has been reported that the lipid core area and the fibrous cap thickness cannot be deduced from the stenotic ratio. However, there is no comparative study between yellow and white plaques. This study assessed the precise characterization of yellow and white plaques using angioscopy. We observed 198 segments of coronary from autopsy artery using angioscopy, then 46 yellow plaque lesions and 61 white plaque lesions of atheroma were excised and prepared for pathological examination. The stenotic ratio, the plaque area (PA), the lipid core size as a percentage of total vessel area (%C), and the minimum fibrous cap thickness (FCt) were measured and compared between yellow and white plaque groups. In this study, the stenotic ratio and the PA were significantly larger in the white plaque group (p<.001). The FCt was significantly thinner in the yellow plaque group (58±18 µm vs. 648±356 µm p<.0001). There was no correlation between the stenotic ratio and the %C in the whole cases (r=.22). Although it was the same in the white plaque group (r=.13), significant correlation between them was shown in the yellow plaque group (r=.64). No significant correlation was observed between the stenotic ratio and the FCt in each plaque group. We concluded that a yellow plaque with moderate stenosis could be diagnosed as a vulnerable plaque by the combination of coronary angiography and angioscopy.