Molecular Cardiology Research Laboratory, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA.
Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA.
Biomech Model Mechanobiol. 2021 Dec;20(6):2071-2084. doi: 10.1007/s10237-021-01495-9. Epub 2021 Jul 20.
Moyamoya disease (MMD) is characterized by narrowing of the distal internal carotid artery and the circle of Willis (CoW) and leads to recurring ischemic and hemorrhagic stroke. A retrospective review of data from 50 pediatric MMD patients revealed that among the 24 who had a unilateral stroke and were surgically treated, 11 (45.8%) had a subsequent, contralateral stroke. There is no reliable way to predict these events. After a pilot study in Acta mice that have features of MMD, we hypothesized that local hemodynamics are predictive of contralateral strokes and sought to develop a patient-specific analysis framework to noninvasively assess this stroke risk. A pediatric MMD patient with an occlusion in the right middle cerebral artery and a right-sided stroke, who was surgically treated and then had a contralateral stroke, was selected for analysis. By using an unsteady Navier-Stokes solver within an isogeometric analysis framework, blood flow was simulated in the CoW model reconstructed from the patient's postoperative imaging data, and the results were compared with those from an age- and sex-matched control subject. A wall shear rate (WSR) > 60,000 s (about 12 × higher than the coagulation threshold of 5000 s and 9 × higher than control) was measured in the terminal left supraclinoid artery; its location coincided with that of the subsequent postsurgical left-sided stroke. A parametric study of disease progression revealed a strong correlation between the degree of vascular morphology altered by MMD and local hemodynamic environment. The results suggest that an occlusion in the CoW could lead to excessive contralateral WSRs, resulting in thromboembolic ischemic events, and that WSR could be a predictor of future stroke.
烟雾病（MMD）的特征是颈内动脉远端和 Willis 环（CoW）狭窄，导致反复发作的缺血性和出血性中风。对 50 例儿科 MMD 患者的数据进行回顾性分析显示，在 24 例单侧中风并接受手术治疗的患者中，有 11 例（45.8%）发生了随后的对侧中风。目前尚无可靠的方法来预测这些事件。在 Acta 小鼠（具有 MMD 特征）的一项初步研究之后，我们假设局部血液动力学可预测对侧中风，并寻求开发一种针对特定患者的分析框架来非侵入性地评估这种中风风险。选择一名右侧大脑中动脉闭塞和右侧中风的儿科 MMD 患者进行分析，该患者接受了手术治疗，随后发生了对侧中风。在基于等几何分析框架的非定常 Navier-Stokes 求解器中，对从患者术后成像数据重建的 CoW 模型中的血流进行了模拟，并将结果与年龄和性别匹配的对照者进行了比较。在终端左侧前交通动脉中测量到壁面剪切率（WSR）>60,000 s（约比凝血阈值 5000 s 高 12 倍，比对照者高 9 倍）；其位置与随后的手术后左侧中风的位置相吻合。对疾病进展的参数研究表明，MMD 改变的血管形态程度与局部血液动力学环境之间存在很强的相关性。结果表明，CoW 的闭塞可能导致对侧 WSR 过高，从而导致血栓栓塞性缺血事件，并且 WSR 可能是未来中风的预测指标。
