Wall shear stress distribution at the carotid bifurcation: influence of eversion carotid endarterectomy

To test the feasibility of four-dimensional (4D) flow MRI to quantify the systolic wall shear stress (WSSsystole) and oscillatory shear index (OSI) in high-grade internal carotid artery (ICA) stenosis before and after endarterectomy (CEA). Twenty patients with a parts per thousand yen60 % ICA stenosis were prospectively and consequently included. Four-dimensional flow MRI was used to measure individual time-resolved 3D blood flow velocities. Segmental WSSsystole and OSI were derived at eight wall segments in analysis planes positioned along the ICA, common (CCA) and external carotid artery (ECA). Regional WSSsystole of all patients decreased after CEA (P < 0.05). Changes were most prominent at the ICA bulb but remained unchanged in the CCA and ECA. OSI was significantly lower after CEA in the lateral vessel walls (P < 0.05). For analysis planes at the stenosis in- and outlet, a reduction of mean WSSsystole by 32 % and 52 % (P < 0.001) and OSI distal to the stenosis (40 %, P = 0.01) was found after CEA. Our findings show the potential of in vivo 4D flow MRI to quantify haemodynamic changes in wall shear stress even in patients with complex flow conditions. aEuro cent The 4D flow MRI allows in vivo measurement of individual 3D blood flow. aEuro cent Regional wall shear stress can be derived from such 3D flow data. aEuro cent Even complex flow in high-grade internal carotid artery stenosis can be analysed. aEuro cent This technique could be valuable for future studies of carotid atherosclerosis.