Abstract 15832: Endothelial Shear Stress Assessment in Coronary Arteries: Comparison Between 3d Reconstructions Based on Invasive and Noninvasive Imaging

Abstract

Introduction: Endothelial shear stress (ESS) identifies coronary plaques at high risk for progression and rupture leading to a future acute coronary syndrome. We developed an optimized methodology to derive ESS using computational fluid dynamics (CFD) in 3D models of coronaries from noninvasive computed tomography angiography (CTA). We hypothesized that ESS based on CTA has a high correlation with ESS based on the gold standard fusion of intravascular ultrasound (IVUS)/optimical coherence tomography (OCT) and CTA. Methods: In 14 patients, paired patient-specific CFD models based on invasive and CTA imaging of the left anterior descending (LAD) coronaries were created. 10 were used to optimize, and 4 patients to test the methodology. Time averaged ESS (TAESS) was calculated for both coronary models applying physiological data at the time of imaging. Each 3D reconstructed coronary was divided into 2 mm segments and further subdivided into 8 arcs (45 o ). TAESS was averaged per segment and arc. The paired segment and arc averaged TAESS were categorized into patient-specific tertiles (low, medium and high). Results: In the 10 LADs, used for optimization of the methodology, we found high correlations between invasively- and noninvasively-derived TAESS averaged over segments (n=263, r=0.86) and arcs (n=2104,r= 0.85,p<0.001). The correlation was also strong in the 4 test patients with r=0.95 (n=117 segments p=0.001) and r=0.93 (n=936 arcs p=0.001). There was a high concordance of 78% of the three TAESS categories comparing both imaging at the segments and 76% at the arcs in the first 10 patients. This concordance was lower in the 4 test patients (64% and 64% in segment and arc averaged TAESS). Conclusions: We showed that we can accurately assess the TAESS distribution noninvasively from CTA and demonstrated a high correlation with TAESS using IVUS/OCT 3D models. Future studies should prove the prognostic value of CTA-based TAESS for plaque progression and clinical events.