颅内动脉瘤形态对血流动力学的影响及破裂风险研究

Effect of intracranial aneurysm morphology on wall shear stress and the risk of rupture

目的探讨颅内动脉瘤形态对血流动力学的影响,分析动脉瘤破裂的血流动力学机制和相应的病理表现。方法使用计算流体力学软件比较71个动脉瘤中破裂与未破裂动脉瘤的壁面剪应力(WSS)及其与载瘤动脉的比值,以及窄颈动脉瘤和宽颈动脉瘤中破裂和未破裂动脉瘤的WSS,并对处于不同WSS的动脉瘤壁作病理学分析。结果破裂动脉瘤相对于未破裂动脉瘤有更大的低WSS区域(LSA)(P<0.05),更小的平均WSS(MWSS)比值(P<0.05)。在宽颈动脉瘤中破裂动脉瘤比未破裂动脉瘤有更大的最高WSS(HWSS)比值(P<0.05);在窄颈动脉瘤中破裂动脉瘤比未破裂动脉瘤有更大的LSA(P<0.05),更小的MWSS比值(P<0.05)。高、低WSS的动脉瘤壁有不同的病理学表现。结论相对于单纯计算WSS的大小,WSS比值是一个更可靠的破裂指标。不同结构动脉瘤破裂的血流动力学原因不一致:宽颈动脉瘤中HWSS是导致动脉瘤破裂的原因;窄颈动脉瘤中低WSS是动脉瘤破裂的指征。不同WSS的动脉瘤壁有不同的病理学表现。

Objective To examine the effect of intracranial aneurysm morphology on wall shear stress(WSS)and the risk of rupture.Methods Clinical data of 62 patients with intracranial aneurysm(71 aneurysms)were analyzed retrospectively.The aneurysms were divided into two categories:narrow(n=22)and wide-necked(n=49).Computational fluid dynamics was used to determine the distribution of WSS and its ratio of parent vessel,which was compared between different morphological groups and between ruptured and unruptured aneurysms.Sections of the walls of clipped aneurysms were stained with hematoxylin-eosin,observed under a microscope.Results Ruptured aneurysms were more likely to have a greater LSA(P<0.05)and smaller mean aneurysm-parent WSS ratio(P<0.05)than unruptured aneurysms.Narrow-necked aneurysms were more likely to have a larger LSA(P<0.05)and lower aneurysm-parent WSS ratio(P<0.05)than wide-necked aneurysms.Ruptured aneurysms were more likely to have a greater LSA(P<0.05)and smaller mean aneurysm-parent WSS ratio(P<0.05)than unruptured aneurysms in narrow-necked aneurysms.In contrast ruptured aneurysms were more likely to have a greater highest aneurysm-parent WSS ratio(P<0.05)than unruptured aneurysms in wide-necked aneurysms.The aneurysm wall showed two different pathological changes associated with high or low WSS.Conclusion Aneurysm morphology can affect the distribution and magnitude of WSS on the basis of differences in blood flow.Both high and low WSS can contribute to focal wall damage and rupture through different mechanisms associated with each morphological type.The ratio between aneurysm WSS and parent artery is a more sensitive index than WSS only.