Characteristic Analysis Of Hemodynamics For Small Aneurysms Of Anterior Communicating Artery

Background: Subarachnoid hemorrhage(SAH)caused by intracranial aneurysms rupture has an extremely high mortality and morbidity which does serious harm to human health.Although many years past,the pathogenesis of intracranial aneurysms is still not known very well.Well known,the greater diameter,the higher risk of rupture.But the practice found that most of ruptured aneurysms were smaller than 7mm.This is also the hotspot of disputes.For now,clinical intervention is often based on non-standard index or personal experience.However,any experience of anyone is not enough to be the gold standard of clinical treatment.In recent years,people have gradually realized that hemodynamics factors play a basic role in the pathogenesis of intracranial aneurysms,but in vivo measurement of hemodynamics is extremely difficult.Using computational fluid dynamics(CFD)numerical simulation analysis to measure the hemodynamics of intracranial aneurysms is the main method nowadays.Objective: To explore the rupture factors of hemodynamics for small aneurysms of anterior communicating artery(ACom A).Methods: A total of 15 patients with small aneurysms of ACom A with the dominance of A1 segement(10 ruptured aneurysms,5 unruptured aneurysms,2mm≦diameter<7mm,for short A1 group)treated at the Department of Neurosurgery,the first hospital of Shanxi Medical University from January 2014 to June 2016 were studied retrospectively.The 15 patients with ordinary small aneurysms of ACom A with approximately the same size and the same rupture state at the same time were used as a matched control group(for short ordinary group).Each case of aneurysms was modeled and analyzed the flow pattern and the hemodynamics parameters by numerical simulation of computational fluid dynamics(CFD).Results: Compared with ordinary group,the blood flow pattern of A1 group was more complex with more vortex and slower speed.The wall shear stress(WSS)of A1 group and ordinary group was(0.46?0.07)Pa and(0.54?0.07)Pa respectively.The percentage of WSS area(LSA)was(21.77 ? 6.24)% and(15.55 ? 6.85)% respectively.There were significant differences(P=0.008,P=0.005).The oscillatory shear index(OSI)of two groups was(0.0202? 0.0038)and(0.0181? 0.0034)respectively.There was significant difference(P=0.020).The WSS of the ruptured group(n=20)and the unruptured group(n=10)was(0.47 ? 0.07)Pa and(0.56 ? 0.09)Pa respectively,and the LSA was(20.45 ? 7.42)% and(14.75 ? 5.44)% respectively.The OSI of the two groups was(0.0197?0.0033)and(0.0180?0.0042)respectively.There was no significant difference(P=0.227).Conclusion: Low WSS may be one of the reasons for the high risk of small aneurysms of ACom A with the dominance of A1 segement rupture.