Relationship Between Endothelial Wall Shear Stress and High‐Risk Atherosclerotic Plaque Characteristics for Identification of Coronary Lesions That Cause Ischemia: A Direct Comparison With Fractional Flow Reserve

Abstract

Background Wall shear stress ( WSS ) is an established predictor of coronary atherosclerosis progression. Prior studies have reported that high WSS has been associated with high‐risk atherosclerotic plaque characteristics ( APC s). WSS and APC s are quantifiable by coronary computed tomography angiography, but the relationship of coronary lesion ischemia—evaluated by fractional flow reserve—to WSS and APC s has not been examined. Methods and Results WSS measures were obtained from 100 evaluable patients who underwent coronary computed tomography angiography and invasive coronary angiography with fractional flow reserve. Patients were categorized according to tertiles of mean WSS values defined as low, intermediate, and high. Coronary ischemia was defined as fractional flow reserve ≤0.80. Stenosis severity was determined by minimal luminal diameter. APC s were defined as positive remodeling, low attenuation plaque, and spotty calcification. The likelihood of having positive remodeling and low‐attenuation plaque was greater in the high WSS group compared with the low WSS group after adjusting for minimal luminal diameter (odds ratio for positive remodeling: 2.54, 95% CI 1.12–5.77; odds ratio for low‐attenuation plaque: 2.68, 95% CI 1.02–7.06; both P <0.05). No significant relationship was observed between WSS and fractional flow reserve when adjusting for either minimal luminal diameter or APC s. WSS displayed no incremental benefit above stenosis severity and APC s for detecting lesions that caused ischemia (area under the curve for stenosis and APC s: 0.87, 95% CI 0.81–0.93; area under the curve for stenosis, APC s, and WSS : 0.88, 95% CI 0.82–0.93; P =0.30 for difference). Conclusions High WSS is associated with APC s independent of stenosis severity. WSS provided no added value beyond stenosis severity and APC s for detecting lesions with significant ischemia.