Three dimensional mesh model of a right coronary artery.

<p>Panel (A) shows the inflow (arrow) at the ostium of a right coronary artery and outflows of two small side branches (chevrons). Panel (B) shows a magnification of the outflow shown in panel (A). Notice the three boundary layers with small cell size (arrow head), necessary to accurately calculate ESS. Towards the inner lumen of the vessel, cell size increases to reduce the total number of cells and thus computation time.</p

Wall thickness.

<p>Mean wall thickness was highest in quartile 1 (low endothelial shear stress (ESS)) and lowest in quartiles 2 and 3 (intermediate ESS). Vessel wall thickness in quartile 4 (high ESS) was in between. Differences were not significant between quartile 2 and 3 (p = 0.15). All other differences were statistically significant (p < 0.001).</p><p>SD: standard deviation</p><p>Wall thickness.</p

Distribution of plaque tissue composition in areas exposed to different levels of endothelial shear stress (ESS).

<p>Panel (A) shows an example of an early, panel (B) an example of a more advanced atherosclerotic lesion as assessed by intravascular ultrasound radiofrequency data analysis. Fibrous tissue is represented by dark green, fibrofatty tissue by light green, necrotic tissue by red and calcified tissue by white colour. We observed a significantly higher amount of fibrofatty (*) tissue in areas exposed to the lowest level of ESS (quartile 1) in comparison to low-intermediate ESS (quartile 2), intermediate-high ESS (quartile 3) or high ESS (quartile 4) (p≤0.023) (C). There was no difference in the amount of other tissue types depending on the level of ESS (p≥0.061).</p

Color encoded illustration of endothelial shear stress (ESS) on a 3D model of a right coronary artery obtained by coronary computed tomography angiography.

<p>After segmentation side branches were cut 1–2 cm from the branching point. The volume mesh consisted of about 400,000 polyhedral cells. The Navier-Stokes equations were solved by the finite element method. The level of ESS increases from blue to red as shown in the color map on the left.</p

Plaque prevalence.

<p>There was a significantly higher prevalence of atherosclerotic plaques in areas of very low (quartile 1) and very high (quartile 2) endothelial shear stress (ESS) as compared to areas of intermediate ESS (quartile 2 and 3) (p < 0.001). Furthermore plaque prevalence was higher in quartile 1 compared to quartile 4 (p < 0.001). Differences between quartile 2 and 3 were not significant (p = 0.56).</p><p>Plaque prevalence.</p