Study On The Influencing Factors Of Incomplete Occlusion Of Unruptured Intracranial Aneurysms After Flow Diversion Based On Computational Fluid Dynamics

ObjectiveTo explore the related factors affecting the occlusion of unruptured intracranial aneurysms(UIA)after flow diversion and provide experimental basis for the establishment of individualized precise treatment scheme.MethodsThis study collected the clinical data,preoperative,postoperative immediately and follow-up DSA data and the occurrence of neurological complications of patients with different types of unruptured intracranial aneurysms treated with flow diverter(FD)in the Department of Neurosurgery,the First Affiliated Hospital,Air Force Medical University.To explore the effectiveness and safety of flow diverter in the treatment of intracranial aneurysms,the occlusion of aneurysms was evaluated by the O’Kelly-Marotta(OKM)grading system,and the clinical prognosis of patients was evaluated by the modified Rankin Scale(MRS).The morphology of aneurysms and hemodynamic parameters after FD implantation were calculated by 3D reconstruction,finite element simulation and computational fluid dynamics methods,including aneurysm diameter,aspect ratio(AR),size ratio(SR),inflow angle,ostium ratio(Os R),neck ratio(NR),wall shear stress(WSS)normalized wall shear stress(NWSS),blood inflow,aneurysm average velocity,residual flow volume(RFV).The aneurysms were divided into insufficient occlusion group and sufficient occlusion group according to the occlusion in follow-up.The general clinical characteristics,morphological characteristics of aneurysms and hemodynamic parameters were statistically analyzed to explore the independent risk factors for predicting the occlusion of aneurysms.ResultsA total of 62 aneurysms from 52 patients who met the criteria were included in this study.38 patients were implanted with FD alone,14 patients were combined with spring coil embolization,and a total of 58 FDs were implanted.The success rate of the operation was 100%.The median follow-up time after surgery was 11(3-27)months.The incidence rate of neurological complications was 5.8%(3/52),86.5%(45/52)of the patients had a good clinical prognosis during clinical follow-up,and there was no death.83.9%(52/62)of the aneurysms were fully occluded(OKM grade of C or D)during imaging follow-up.There were statistically significant differences in age,follow-up time,aspect ratio(AR),ostium ratio(Os R),inflow angle,normalized wall shear stress(NWSS)and residual flow volume(RFV)between the incomplete occluded group and the fully occluded(P<0.05).Logistic regression analysis showed that residual flow volume RFV was an independent influencing factor of the insufficiently occluded aneurysm(OR,4.407;95%CI,1.035-19.135,P=0.048).The related hemodynamic study may help guide the individualized treatment of patients with intracranial aneurysms and improve the prognosis of patients.ConclusionsThe flow diverter shows excellent safety and effectiveness in the treatment of different types of aneurysms.Residual flow volume(RFV)is an independent risk factor for incomplete occlusion of unruptured intracranial aneurysms after flow diversion.