Study Of Risk Factors Involved In Rupture Of Intracranial Aneurysm

Objective: To analyze and investigate the differences and risk factors between ruptured and unruptured aneurysms so as to make optimal clinical decision of it.Methods:341 patients suffered intracranial aneurysms from XiangYa hospital between Jan 2006 and Oct 2008 were analyzed by retrospective study. All aneurysms including ruptured, symptomatic, asymptomatic and incidental were classified into 2 types: ruptured and unruptured according whether rupture or not. Every patient was recorded the related factors such as sex , age, ruptured or not, with hypertension or not, with cigarette smoking or not ,the number of aneurysms, the size, the site, et al, and also analyzed the relation to the rupture. Then ANOVA were performed between the factors by SPSS 13.0 software.Results :1. descriptive studyThere were 341 patients in the study ,125 males(36.7%) and 216 females (63.3%).The mean age of patients was 50.19±10.73 years, of male was 46.64±10.58 years, of female was 52.24±10.29 years. There were 63.93% patients whose age were between 49 and 59 years,62.6% patients in ruptured team. There were 113 male patients and 169 female patients whose ages were under or at 60 years. The male to female ratio was 1:1.50 under or at 60 years and 1:3.90 beyond 60 years. There were 286 ruptured and 55 unruptured. The mean age of ruptured was 50.15±10.82 years, of unruptured was 50.40±10.33 years. Patients with ruptured intracranial aneurysms had a higher proportion of smoking history and hypertension than patients with unruptured aneurysms (6.99%, 3.64%; 26.57%, 14.55%) .There were 399 aneurysms in the study, 286 ruptured aneurysms (71.7%), 113 unruptured aneurysms (28.3%).The mean max diameter of all was 8.92±6.44 mm, of ruptured aneurysms was 8.55±4.76 mm, and of unruptured aneurysms was 9.86±9.41 mm. The aneurysms with 5-10mm max diameter had the largest rupture rate(81.00%),with > 25mm had the smallest(25.00%).77.7% of all aneurysms were smaller than 10mm or at 10mm. And there were 80.4% of ruptured aneurysms , 70.8% of unruptured aneurysms. The most common site of ruptured aneurysms was PCoA aneurysm(44.7%), and of unruptured aneurysms was PCoA aneurysm too(51.3%).The ACoA aneurysms had the largest rupture rate (84.7%), ICA aneurysms had the smallest(33.3%).2. The analyze of the factors affecting rupture of intracranial aneurysm1) There was no statistical difference in rupture rate between≤60 years old group and > 60 years old group (x~2=0.035, p>0.05).2) There was no statistical difference in rupture rate between male patients and female patients (x~2=2.487, p>0.05).3) Patients combined with hypertension had a higher rupture rate than non-hypertension patients (90.5%,81.7%), but there were no statistical difference in rupture rate between the two groups(x~2=3.595, p>0.05).4) Patients with smoking history had a higher rupture rate than patients without smoking history (90.9%,83.4%), but there were no statistical difference in rupture rate between the two groups(x_c~2 =0.395, P>0.05) . 5) The size of intracranial aneurysms was a risk factor affecting rupture of intracranial aneurysm(P <0.01). Aneurysms in≤10mm group had a higher rupture rate than that in>10mm group (x~2=4.328, P <0.05). Aneurysms in< 5mm group had a lower rupture rate than that in > 5mm group (x~2=4.959, P <0.05). Aneurysms in≤3mm group had a lower rupture rate than that in > 3mm group (x~2=16.527, P <0.01).6) The site of intracranial aneurysms was a risk factor affecting rupture of intracranial aneurysm (z~2=33.719,P <0.01). The ACoA aneurysms had the largest rupture rate (84.7%), ICA aneurysms had the smallest (33.3%).Conclusion:1.The result described the clinical and angiographic features of inhospitable intracranial aneurysms patients in Hunan in some extent which similar to other large clinical studies in some factors such as: female preponderance, incidence of age ,sites of aneurysms, et al.2.The result suggested that the cut-off point of rupture size in intracranial aneurysm was 3mm, low than 3mm may have a low rupture rate.3.The size and site of intracranial aneurysms were the risk factors affecting rupture of intracranial aneurysm. ACoA aneurysms had a high rupture rate, and small aneurysms may be more vulnerable to rupture.4.Female, age> 60 years, combined with history of hypertension, with smoking history still can not be considered to be the risk factors affecting rupture of intracranial aneurysm.