Analysis On The Rupture Related Morphological Risk Factors Of Small(<5mm)Anterior Communicating Artery Aneurysm

ObjectiveIntracranial aneurysm is a common but dangerous disease,and is also the main cause of non-traumatic subarachnoid hemorrhage.The mortality and morbidity can be quite high once it ruptures.So the study of the rupture related factor and the identification of the aneurysm which is risky to burst is of paramount importance.Anterior communicating artery is a high-risk area for aneurysm,and it is now still a controversial topic as regard to the treatment of the aneurysms,grow in this specific region,with diameter less than 5 mm.According to the literature,such type of aneurysm is regarded as too small to rupture.So,in many times,regular follow-up is recommended.However,clinically,we have found that the rupture of small-sized(<5mm)anterior communicating artery aneurysm is not so rare as it reported to be.Meanwhile,with the rapid development of the medical image technology,and the popularized using of CTA and MRA,the detection rate of the unruptured small anterior communicating artery aneurysm is increasing.So,in this study,we conducted a retrospective analysis,aiming to find the rupture related morphological factor,thus providing a reference for the clinical work.MethodThis thesis is a retrospective case control study,totally 256 patients is found be diagnosed with anterior communicating artery aneurysm in our hospital from Jan 2013 to Dec.2016.Finally,according to the inclusion criteria,70 patients(ruptured group 40 vs unruptured group 30),with sound clinical and image date,is filtered into this study.Mimics 17.0 and 3-matic are used to three-dimensionally reconstruct of the anterior communicating artery,bilateral A1 A2 segment of the anterior cerebral artery and the aneurysm.All the morphological data are measured and calculated by two skilled neurosurgeons.ResultThe baseline data,including gender,age,hypertension,smoking history,alcoholism history,is without significant difference between the two groups.The bleb(P=0.002)is significant more common to be seen in the rupture group.The result of perpendicular height(P=0.001),maximum height(P=0.001),aspect ratio(P=0.003)and size ratio(P<0.001)are all significantly larger in the rupture group as well.The multi-factor binary logistic regression analysis indicates that bleb formation(OR=0.121,95%CI:0.019-0.769;P=0.025)and size ratio(OR=65.994,95%CI:1.768-2462.954;P=0.023)are the independent risk factors.Application of ROC analysis on predication of size ratio for the rupture of the small-sized anterior communicating artery aneurysm shows that 1.19 is the critical value.ConclusionSignificant differences of bleb formation,perpendicular height,maximum height,aspect ratio and size ratio can exist between ruptured and unruptured small anterior communicating artery aneurysms.But only bleb formation and size ratio are proved to be the independent risk factors.According to the ROC analysis result,we suggest that bleb formation and size ratio?1.19 be used as the reference index to predict the possible adverse outcome of unruptured small anterior communicating artery aneurysm.