Abstract 17758: Lower Coronary Wall Shear Stress is Associated with Endothelial Dysfunction in Patients with Non-Obstructive Coronary Artery Disease
Background: Both low wall shear stress (WSS) and endothelial dysfunction have been associated with various stages of coronary atherosclerosis. However, the relationship between WSS and endothelial dysfunction remains unknown. We hypothesized that low WSS is associated with endothelial dysfunction.
Methods: Twenty-one patients with recurrent angina and non-obstructive coronary artery disease (CAD), underwent coronary angiography, Doppler velocity measurements, endothelial function testing using intracoronary acetylcholine (ACh) [18 mcg/ml] and computational fluid dynamics to calculate WSS in left coronary artery. All patients also underwent virtual histology intravascular ultrasound (VH-IVUS) to assess plaque burden and composition. 3-dimensional angiographic reconstructions of baseline and post-ACh geometries were performed and co-registered using branching points as fiduciary anatomical landmarks. Endothelial dysfunction was defined as percent diameter change (%ΔD) <10% (%ΔD= [post-AChD - BaselineD]/BaselineD × 100). WSS was related to %ΔD in each 0.25mm angiographic coronary segment.
Results: Mean age was 52±14 years, 81% were females, 14% had diabetes and mean IVUS plaque burden was 24.8±13.6%. In 2,264 segments analyzed, segments with endothelial dysfunction showed a significantly lower WSS (36.0 ± 25.2 dynes/cm2) compared to segments with normal endothelial function (54.5 ± 37.3 dynes/cm2, p<0.001). Analysis of pooled data showed a significant linear relationship between WSS and %ΔD (r= 0.21, p<0.001). When patient-specific correlations were analyzed, 14 of 21 patients demonstrated significant positive linear relationships between WSS and %ΔD with r values ranging from 0.25 to 0.90, while the remaining 7 of 21 did not show significant positive relationships. Interestingly, no statistically significant differences in age, sex, race, diabetes, hypertension, serum cholesterol, smoking, and plaque burden and composition were observed between these two groups.
Conclusion: In patients with CAD, lower WSS is associated with coronary endothelial dysfunction. Prospective studies are warranted to further investigate the mechanistic and clinical implications of these findings.
- Endothelial function
- Intravascular ultrasound/Doppler
- Coronary artery disease
- © 2012 by American Heart Association, Inc.