From the Departments of Radiology and Nuclear Medicine (K.C.J.C., K.D., A.C.G.M.v.E., A.v.d.L.).
Neurology (K.C.J.C., D.W.J.D.).
AJNR Am J Neuroradiol. 2019 Apr;40(4):703-708. doi: 10.3174/ajnr.A6012. Epub 2019 Mar 14.
Carotid webs are increasingly recognized as an important cause of (recurrent) ischemic stroke in patients without other cardiovascular risk factors. Hemodynamic flow patterns induced by these lesions might be associated with thrombus formation. The aim of our study was to evaluate flow patterns of carotid webs using computational fluid dynamics.
Patients with a carotid web in the Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands (MR CLEAN) were selected for hemodynamic evaluation with computational fluid dynamics models based on lumen segmentations obtained from CT angiography scans. Hemodynamic parameters, including the area of recirculation zone, time-averaged wall shear stress, transverse wall shear stress, and the oscillatory shear index, were assessed and compared with the contralateral carotid bifurcation.
In our study, 9 patients were evaluated. Distal to the carotid webs, recirculation zones were significantly larger compared with the contralateral bifurcation (63 versus 43 mm, = .02). In the recirculation zones of the carotid webs and the contralateral carotid bifurcation, time-averaged wall shear stress values were comparable (both: median, 0.27 Pa; = .30), while transverse wall shear stress and oscillatory shear index values were significantly higher in the recirculation zone of carotid webs (median, 0.25 versus 0.21 Pa; = .02 and 0.39 versus 0.30 Pa; = .04). At the minimal lumen area, simulations showed a significantly higher time-averaged wall shear stress in the web compared with the contralateral bifurcation (median, 0.58 versus 0.45 Pa; = .01).
Carotid webs are associated with increased recirculation zones and regional increased wall shear stress metrics that are associated with disturbed flow. These findings suggest that a carotid web might stimulate thrombus formation, which increases the risk of acute ischemic stroke.
颈动脉壁是一种越来越被认为是无其他心血管危险因素的患者（复发性）缺血性卒中的重要病因。这些病变引起的血流动力学模式可能与血栓形成有关。我们的研究目的是使用计算流体动力学评估颈动脉壁的血流模式。
从荷兰多中心急性缺血性卒中血管内治疗随机临床试验（MR CLEAN）中选择颈动脉壁患者，基于 CT 血管造影扫描获得的管腔分段进行计算流体动力学模型的血流动力学评估。评估并比较了包括再循环区面积、时均壁切应力、横向壁切应力和振荡剪切指数在内的血流动力学参数与对侧颈动脉分叉处的参数。
本研究共评估了 9 例患者。与对侧颈动脉分叉相比，颈动脉壁远侧的再循环区明显更大（63 比 43mm， =.02）。在颈动脉壁和对侧颈动脉分叉的再循环区内，时均壁切应力值相当（均为中位数 0.27Pa； =.30），而颈动脉壁再循环区内的横向壁切应力和振荡剪切指数值明显更高（中位数 0.25 比 0.21Pa； =.02 和 0.39 比 0.30Pa； =.04）。在最小管腔面积处，模拟显示壁处的时均壁切应力明显高于对侧分叉处（中位数 0.58 比 0.45Pa； =.01）。
颈动脉壁与再循环区增加和局部壁切应力增加有关，这些增加与血流紊乱有关。这些发现表明，颈动脉壁可能会刺激血栓形成，从而增加急性缺血性卒中的风险。
