Background: The pathophysiological basis for the association between metabolic syndrome (MetS) and coronary artery disease is not well understood. We sought to characterize coronary plaques in patients with MetS by using optical coherence tomography.
Methods and results: We identified 451 coronary plaques from 171 subjects who underwent optical coherence tomographic imaging in 3 coronary arteries. Subjects were divided into 3 groups: diabetes mellitus (DM, n=77), MetS (n=35), and a control group (C group, n=59) without DM or MetS. Optical coherence tomographic analysis included the presence of lipid-rich plaque, maximum lipid arc, lipid-core length, lipid index (LI), fibrous cap thickness, and thin-cap fibroatheroma. We defined LI as mean lipid arc multiplied by lipid-core length. Lipid-core length and LI were significantly greater in DM and MetS than in C group (lipid-core length: 7.7 ± 4.0 and 7.0 ± 3.8 versus 5.5 ± 2.4 mm; P<0.001 and P=0.012, and LI: 1164 ± 716 and 1086 ± 693 versus 796 ± 417 mm; P<0.001 and P=0.008). Maximum lipid arc was significantly greater in DM than in C group, whereas no significant difference was observed between MetS and C group (196 ± 45°, 187 ± 42° versus 176 ± 52°; P=0.002 and P=0.182). Fibrous cap thickness and thin-cap fibroatheroma showed no significant difference among the 3 groups. In multivariate analysis, DM and MetS were independently associated with LI, whereas only acute coronary syndrome was the independent predictor for thin-cap fibroatheroma.
Conclusions: Compared with control subjects, coronary plaques in MetS contain larger lipid. However, the MetS criteria used in this study could not distinguish the vulnerable features such as thin-cap fibroatheroma, suggesting the necessity of complementary information to identify patients at high risk for cardiovascular events.
Keywords: diabetes mellitus; metabolic syndrome; plaque; tomography, optical coherence.