Wall shear stress distribution at the carotid bifurcation: influence of eversion carotid endarterectomy
A Harloff1, S Berg, A J Barker
1Department of Neurology, University Hospital Freiburg, Breisacher Strasse 64, 79106, Freiburg, Germany, andreas.harloff@uniklinik-freiburg.de.
Objectives:
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).
Methods:
Twenty patients with ≥60 % 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).
Results:
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.
Conclusions:
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.
