Abstract 12533: Low Endothelial Shear Stress Modulates Coronary Remodeling and Plaque Eccentricity Toward a High-Risk Profile: An in-vivo Computed Tomography Angiography Human Study

Abstract

Background: Plaque eccentricity and remodeling decisively affect the natural history of atherosclerosis. Highly eccentric plaques and expansively remodeled regions are associated with a high-risk profile. Coronary hemodynamics critically influences plaque morphology and remodeling.

Hypothesis: Low endothelial shear stress (ESS) is associated with expansive remodeling and plaque eccentricity in humans non-invasively investigated for suspected coronary artery disease.

Methods: Using 128-slice computed tomography angiography, 28 coronary arteries (left anterior descending n=14, left circumflex n=5, right coronary artery n=9) were 3D-reconstructed. Plaque regions were divided in 2mm-long segments and plaque volume, eccentricity index [(max - min plaque thickness)/max plaque thickness] and remodeling were assessed. Segments were classified in terciles of high, medium and low eccentricity and high, medium and low ESS. Remodeling was classified in four types: positive expansive, positive compensatory, positive incomplete and negative.

Results: A total of 87 atherosclerotic regions were identified. Positive expansive remodeling was associated with low ESS (odds ratio [OR] 4.8, 95% confidence interval [CI] 1.9 to 12.1, p<0.001). Specifically, ESS was lower in segments with positive expansive (3.6±0.4 Pa) vs. positive incomplete (8.5±0.8 Pa, p<0.001) or negative remodeling (10.2±0.9 Pa, p<0.001). ESS was also lower in positive compensatory (6.0±0.7 Pa) vs. negative remodeling (p<0.001). Highly eccentric plaques were larger than plaques with low eccentricity (23.9±1.2 vs 17.3±0.4 mm3, p<0.001) and exhibited lower ESS values (high vs. medium/low eccentricity 7.2±0.4 vs. 8.8±0.5 Pa, p<0.001). There was a trend towards an association of high plaque eccentricity with positive expansive remodeling (odds ratio 2.4, 95% confidence interval 0.84 to 6.80, p=0.098).

Conclusions: In-vivo non-invasive investigation of coronary remodeling and plaque eccentricity is feasible with this methodology. Local low ESS is associated with high-risk plaque features, as high eccentricity and positive expansive remodeling. In-vivo estimation of local ESS could be used as surrogate marker of plaque vulnerability.