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Abstract：
BACKGROUND: Previously published computational fluid dynamics (CFD) studies regarding intracranial aneurysm (IA) formation present conflicting results. Our study analysed the involvement of the combination of high wall shear stress (WSS) and a positive WSS gradient (WSSG) in IA formation.
METHODS: We designed a case-control study with a selection of 38 patients with an unruptured middle cerebral artery (MCA) aneurysm and 39 non-aneurysmal controls to determine the involvement of WSS, oscillatory shear index (OSI), the WSSG and its absolute value (absWSSG) in aneurysm formation based on patient-specific CFD simulations using velocity profiles obtained from transcranial colour-coded sonography.
RESULTS: Among the analysed parameters, only the WSSG had significantly higher values compared to the controls (11.05 vs - 14.76 [Pa/mm], P = 0.020). The WSS, absWSSG and OSI values were not significantly different between the analysed groups. Logistic regression analysis identified WSS and WSSG as significant co-predictors for MCA aneurysm formation, but only the WSSG turned out to be a significant independent prognosticator (OR: 1.009; 95% CI: 1.001-1.017; P = 0.025). Significantly more patients (23/38) in the case group had haemodynamic regions of high WSS combined with a positive WSSG near the bifurcation apex, while in the control group, high WSS was usually accompanied by a negative WSSG (14/39). From the analysis of the ROC curve for WSSG, the area under the curve (AUC) was 0.654, with the optimal cut-off value -0.37 Pa/mm. The largest AUC was recognised for combined WSS and WSSG (AUC = 0.671). Our data confirmed that aneurysms tend to form near the bifurcation apices in regions of high WSS values accompanied by positive WSSG.
CONCLUSIONS: The development of IAs is determined by an independent effect of haemodynamic factors. High WSS impacts MCA aneurysm formation, while a positive WSSG mainly promotes this process.
METHODS: We designed a case-control study with a selection of 38 patients with an unruptured middle cerebral artery (MCA) aneurysm and 39 non-aneurysmal controls to determine the involvement of WSS, oscillatory shear index (OSI), the WSSG and its absolute value (absWSSG) in aneurysm formation based on patient-specific CFD simulations using velocity profiles obtained from transcranial colour-coded sonography.
RESULTS: Among the analysed parameters, only the WSSG had significantly higher values compared to the controls (11.05 vs - 14.76 [Pa/mm], P = 0.020). The WSS, absWSSG and OSI values were not significantly different between the analysed groups. Logistic regression analysis identified WSS and WSSG as significant co-predictors for MCA aneurysm formation, but only the WSSG turned out to be a significant independent prognosticator (OR: 1.009; 95% CI: 1.001-1.017; P = 0.025). Significantly more patients (23/38) in the case group had haemodynamic regions of high WSS combined with a positive WSSG near the bifurcation apex, while in the control group, high WSS was usually accompanied by a negative WSSG (14/39). From the analysis of the ROC curve for WSSG, the area under the curve (AUC) was 0.654, with the optimal cut-off value -0.37 Pa/mm. The largest AUC was recognised for combined WSS and WSSG (AUC = 0.671). Our data confirmed that aneurysms tend to form near the bifurcation apices in regions of high WSS values accompanied by positive WSSG.
CONCLUSIONS: The development of IAs is determined by an independent effect of haemodynamic factors. High WSS impacts MCA aneurysm formation, while a positive WSSG mainly promotes this process.
摘要：
背景：先前发表的关于颅内动脉瘤（IA）形成的计算流体动力学（CFD）研究结果相互矛盾。我们的研究分析了高壁剪切应力（WSS）和正WSS梯度（WSSG）在IA形成中的结合。
方法：我们设计了一项病例对照研究，选择了38例未破裂的大脑中动脉（MCA）动脉瘤患者和39例非动脉瘤对照患者，以确定WSS的受累情况。振荡剪切指数(OSI)，动脉瘤形成中的WSSG及其绝对值(absWSSG)基于患者特定的CFD模拟，使用经颅彩色编码超声检查获得的速度曲线。
结果：在分析的参数中，与对照组相比，只有WSSG具有明显更高的值（11.05vs-14.76[Pa/mm]，P=0.020)。WSS,absWSSG和OSI值在分析组之间没有显着差异。Logistic回归分析确定WSS和WSSG是MCA动脉瘤形成的重要共同预测因子，但只有WSSG被证明是一个显著的独立预测因子(OR:1.009;95%CI:1.001-1.017;P=0.025)。病例组中更多的患者（23/38）在分叉顶点附近出现高WSS合并阳性WSSG的血流动力学区域，而在对照组中，高WSS通常伴有阴性WSSG(14/39)。从WSSG的ROC曲线分析，曲线下面积(AUC)为0.654,最佳临界值为-0.37Pa/mm。WSS和WSSG组合的AUC最大(AUC=0.671)。我们的数据证实，动脉瘤倾向于在高WSS值区域的分叉顶点附近形成，并伴有阳性WSSG。
结论：IAs的发展取决于血流动力学因素的独立作用。高WSS影响MCA动脉瘤形成，而积极的WSSG主要促进了这一过程。
方法：我们设计了一项病例对照研究，选择了38例未破裂的大脑中动脉（MCA）动脉瘤患者和39例非动脉瘤对照患者，以确定WSS的受累情况。振荡剪切指数(OSI)，动脉瘤形成中的WSSG及其绝对值(absWSSG)基于患者特定的CFD模拟，使用经颅彩色编码超声检查获得的速度曲线。
结果：在分析的参数中，与对照组相比，只有WSSG具有明显更高的值（11.05vs-14.76[Pa/mm]，P=0.020)。WSS,absWSSG和OSI值在分析组之间没有显着差异。Logistic回归分析确定WSS和WSSG是MCA动脉瘤形成的重要共同预测因子，但只有WSSG被证明是一个显著的独立预测因子(OR:1.009;95%CI:1.001-1.017;P=0.025)。病例组中更多的患者（23/38）在分叉顶点附近出现高WSS合并阳性WSSG的血流动力学区域，而在对照组中，高WSS通常伴有阴性WSSG(14/39)。从WSSG的ROC曲线分析，曲线下面积(AUC)为0.654,最佳临界值为-0.37Pa/mm。WSS和WSSG组合的AUC最大(AUC=0.671)。我们的数据证实，动脉瘤倾向于在高WSS值区域的分叉顶点附近形成，并伴有阳性WSSG。
结论：IAs的发展取决于血流动力学因素的独立作用。高WSS影响MCA动脉瘤形成，而积极的WSSG主要促进了这一过程。
