Background:Plaque destabilization is affected by multiple factors. Not only systemic factors but also local hemodynamic factors, endothelial wall shear stress(EWSS), are associated with it. The role of spatial gradient of EWSS in advanced plaque, however, is not well understood. The purpose of present study is to evaluate the impact of spatial gradient of EWSS on plaque composition and destabilization. Methods:We accumulated image data from six patients with thin-cap fibroatheroma(TCFA) and 4 patients with non-TCFA who were taken a various imaging modalities, such as coronary CT angiography, coronary angiography, and virtual histology intravascular ultrasound(VH-IVUS). Then, vascular profiling process was performed assisted by computer-aided design. We designated a EWSS of minimum lumen area(MLA) site as P1, proximal reference site as P2, distal reference site as P3, the difference between P1 and P2 as D1, and between P1 and P3 as D2 (Figure). After that, we analyzed a characterization of EWSS, plaque composition, and vascular remodeling pattern. Results:Grayscale IVUS showed that there were no significant difference between 2 groups in lumen area and plaque burden(p=0.057, and 0.580, respectively). Vessel area(16.65짹2.15mm2 vs 11.20짹2.00mm2, p=0.019) and remodeling index(1.00짹0.07 vs 0.88짹0.02, p=0.049) were significantly higher in TCFA group. VH-IVUS showed that amount of necrotic core components were significant larger(27.18짹4.96% vs 6.90짹4.27%, p=0.002) in TCFA group than non-TCFA group. Maximal velocity of MLA site was not different between 2 groups, while EWSS was significantly greater(81.90짹23.10Pa vs 15.74짹1.94Pa, p=0.031) in TCFA group than non-TCFA group. Moreover, D1 and D2 values were significant higher in TCFA group(Table). Conclusion:A spatial gradient of EWSS as well as EWSS itself may have influence on plaque components and destabilization rather than severity of MLA site stenosis in advanced plaques.