High Wall Shear Stress Is Related to Complicated American Heart Association Lesion Type VI Plaques in Mild-to-Moderate ICA Stenosis: A 3D Cardiovascular MRI Study

BACKGROUND AND PURPOSE: Complicated American Heart Association (AHA) lesion type VI plaques and cCAPs, characterized by the presence of intraplaque hemorrhage and a surface defect or thrombus, are strongly associated with ischemic stroke and stroke recurrence. Hemodynamics seem to play a relevant role in their development. Thus, we investigated the association of 4D-flow MRI-derived local wall shear stress (WSS) and the oscillatory shear index (OSI) with the presence of cCAPs in patients with mild-to-moderate ICA stenosis.

MATERIALS AND METHODS: From a prospective and consecutive cross-sectional study with 121 patients with high cardiovascular risk, 39 patients (49 carotid arteries) demonstrated a 10%–50% ICA stenosis and were included in this analysis. Plaque composition was determined according to the modified AHA classification of lesions by high-resolution multicontrast 3T MRI. We determined WSS (minimum, mean, and maximum) and the OSI in vivo by 4D-flow MRI at different locations within the stenosis (upstream, stenosis center, and downstream). We studied the association of each hemodynamic parameter with the presence cCAPs by logistic regression analysis adjusted for age, sex and plaque thickness.

RESULTS: Eleven (22.4%) of the 49 cases of ICA stenosis in our cohort showed cCAP. WSS and OSI at the beginning of the stenosis did not differ between complicated and stable plaques. By contrast, WSS was significantly higher in the stenosis center and poststenotic region in cCAPs. OSI was significantly higher in the stenosis center of stable plaques. Logistic regression analysis revealed a significant association for WSS_mean (OR per SD increase, 1.97; 95% CI, 1.14–3.39, P = .015) and for WSS_maximum (OR per SD increase, 1.84; 95% CI, 1.10–3.08, P = .020), but not for WSS_minimum and OSI with the presence of cCAPs.

CONCLUSIONS: Higher WSS in ICA stenosis was significantly associated with the presence of cCAPs, underlining the potential role of hemodynamics in their development.