Abstract 18396: In-vivo Assessment of Wall Stiffness and Wall Shear Stress in Human Coronary Arteries using Computed Tomography Angiography
Introduction: Wall stiffness has been an important factor in the pathophysiology of coronary artery disease. The in-vivo non-invasive assessment of the role of wall stiffness in atherosclerosis has not been studied. Hypothesis: Atherosclerotic regions as well as their adjacent areas are characterized by decreased wall stiffness and lower wall shear stress (WSS) compared to non-atherosclerotic regions.
Methods: Using 128-computed tomography angiography 10 coronary arteries (6 left anterior descending arteries and 4 right coronary arteries) were 3D-reconstructed. Thirty eight atherosclerotic regions of interest were identified, and the non-atherosclerotic regions served as controls. A computational grid was created in the reconstructed arteries in diastole and the WSS was calculated in each region of interest using computational fluid dynamics. In each region of interest plaque morphology measurements were performed in both cardiac phases and the wall stiffness was measured with the formula ΔP x V/ΔV, where ΔP is the pulse pressure, V is the initial arterial volume and ΔV is the change in that volume between systole and diastole.
Results: Plaques with increased volume were located in arterial regions with lower WSS (Pearson Chi-square=4.675, sig=0.031, OR=2.286, 95% Confidence Interval=1.075–4.862). These plaques were more distensible compared to plaques with reduced volume. (91.73mmHg SEM=15.31 vs 174.31mmHg SEM=40.55). Adjacent regions proximal to plaques trend to be more distensible (62.52mmHg SEM=8.23 vs 112.77mmHg SEM=26.65, p=0.082) and were with lower WSS (Pearson Chi-square=4.628, sig=0.031, OR=3.617, 95% Confidence Interval=1.068–12.258) compared to normal non-atherosclerotic segments. Less stenotic plaques had also reduced stiffness (92.46mmHg SEM=12.85 vs 264.35mmHg SEM=78.72, p<0.00001) compared to plaques with lumen stenosis over 25.
Conclusions: In-vivo 3D reconstruction of human coronary arteries using computed tomography angiography is feasible and enables the non-invasive investigation of the role of wall stiffness and WSS in the evolution of atherosclerosis. Atherosclerotic regions, as well as their adjacent proximal areas are characterized by decreased wall stiffness and lower WSS.
- © 2010 by American Heart Association, Inc.