基于血流动力学的大脑中动脉分叉处与侧壁动脉瘤破裂风险研究

目的旨在结合血流动力学研究大脑中动脉瘤(MCAA)分叉和侧壁部位对其破裂风险的影响。方法本研究回顾性分析术前行头颅CT血管成像(CTA)并经颅内血管造影或手术确诊的MCAA病人193例,未破裂组24例(58.5±8.5)岁],破裂组169例(54.9±10.3)岁],收集病人的临床资料及动脉瘤的形态学参数,同时对2组进行流体力学计算分析,获得壁剪应力、振荡剪切指数(OSICV)等血流动力学参数。采用独立样本t检验、Mann-Whitney U检验或χ2检验、Fisher精确检验比较破裂/未破裂组间各参数差异,采用Logistic回归分析破裂的独立风险因素,并分别比较分叉和侧壁处动脉瘤破裂相关的血流动力学差异。结果破裂和未破裂组间临床资料的差异无统计学意义(P>0.05)。与未破裂组相比,破裂组动脉瘤多分布于大脑中动脉分叉处,血流模式复杂、集中,血流冲击区域小且不稳定,OSICV低(均P<0.05)。Logistic回归分析显示复杂的血流模式、血流冲击面积小及小的OSICV是预测MCAA破裂状态的独立风险因素(均P<0.05)。侧壁动脉瘤破裂组的血流冲击小,而分叉处动脉瘤破裂组则血流更复杂、更集中,血流冲击区域更小,更不稳定(均P<0.05)。结论血流复杂程度、冲击面积和OSICV是MCAA破裂的独立危险因素,MCAA所处部位会影响破裂风险。

Hemodynamics-based analysis of rupture risk of middle cerebral artery aneurysms at bifurcation and sidewall

Objective This study aimed to analyze the influence of hemodynamics on rupture of MCA aneurysm(MCAA)at bifurcation and sidewall.Methods We retrospectively analyzed 193 MCAA cases diagnosed with CT angiography(CTA)and invasive cerebral angiography(or surgery).There were 24 unruptured(mean age 58.5±8.5 years)and 169 ruptured MCAAs(mean age 54.9±10.3 years).Clinical information and aneurysms’morphological characteristics were collected.Hemodynamic parameters,such as wall share stress and oscillatory shear index(OSICV),were obtained using computational fluid dynamics simulation.The characteristics were compared between the ruptured and unruptured groups with Student’s t test,Mann-Whitney U test,and chi-square,or Fisher exact test.Logistic regression analysis was applied to identify the in dependent risk factors,and the hemodynamics were also compared between the bifurcation and sidewall aneurysms.Results Univariate analysis demonstrated that there was no significant difference in clincal information between the ruptured and unruptured aneurysms(all P>0.05).The ruptured MCAA was more frequently located at bifurcation,and the flow was more complex,more concentrated and more unstable,and had smaller impingement zone and OSICV(all P<0.05).Logistic regression demonstrated that complex flow pattern,small impingement zone and smaller OSICV were independently associated with rupture status(P<0.05).The ruptured MCAA located at sidewall had smaller impingement zone,while those at bifurcation had more complex,concentrated and unstable flow pattern,and smaller impingement zone.Conclusion Flow complexity,impingement zone and OSICV are independently associated with rupture status of MCAA,and the locations of MCAA could influence the rupture risk.