Coronary artery wall shear stress is associated with endothelial dysfunction and expansive arterial remodelling in patients with coronary artery disease

Aims: To investigate in vivo relationships between segmental wall shear stress (WSS), endothelium-dependent vasoreactivity and arterial remodelling. Methods and results: Twenty-four patients with minor angiographic coronary arterial disease (<= 30% stenosis severity) underwent intracoronary (IC) salbutamol provocation during intravascular ultrasound (IVUS)-upon-Doppler guidewire imaging. Macrovascular response (change in segmental lumen volume [SLV] at baseline and following IC salbutamol), plaque burden (percent atheroma volume [PAV]), remodelling indices (RI), eccentricity indices (El) and WSS were evaluated in 179 consecutive 5 mm coronary segments. Baseline WSS was directly related to endothelium-dependent epicardial coronary vasomotion (% change SLV, coefficient 17.2, p=0.004), and inversely related to RI (coefficient -0.23, p=0.02) and El (coefficient -10.0, p=0.001). Baseline WSS was lower in segments displaying endothelial dysfunction (defined as any change in SLV <= 0) compared with preserved function (0.66 +/- 0.33 vs. 0.71 +/- 0.22 N/m(2), p=0.046). Independent of plaque burden, segments with the lowest tertile of WSS displayed less vasodilatation, or vasoconstriction, than segments with the highest tertile of WSS. Higher plaque burden segments harbouring the lowest tertiles of WSS displayed vasoconstriction, expansive arterial remodelling and greater plaque eccentricity. Conclusions: In patients with stable coronary syndromes and minor angiographic coronary disease, coronary segments with lower in vivo WSS values display functional and morphological features of plaque vulnerability.