Abstract
Objective To explore the associations of vascular geometric parameters and blood pressure with middle cerebral artery(MCA)bifurcation aneurysms.Methods The study used participants from a publicly available database.The original database retrospectively and consecutively included 1 021 participants who underwent head CT angiography(CTA)at the Second Affiliated Hospital of Anhui Medical University from January 2012 to January 2018 as the initial screening cohort.After screening based on imaging quality and vascular disease-related criteria,a publicly available dataset was formed that included patients with MCA bifurcation aneurysms and those without MCA bifurcation aneurysms.Patients with MCA bifurcation aneurysms were included in the aneurysm group,while participants without aneurysms at the bifurcation of the MCA were assigned to the control group.Baseline data,geometric parameters of the MCA bifurcation,and local hemodynamic parameters were collected from the aneurysm group and the control group,including sex,age,smoking history,hypertension,systolic and diastolic blood pressure recorded during CTA examination,diameter of the vessel at the MCA bifurcation entrance(M1 segment)and the diameters of the two branch vessels,MCA bifurcation angle and vessel centerline,maximum wall shear stress(Max WSS)and Max WSS gradient(Max WSSG)in the area near the MCA bifurcation point.The area expansion ratio(AER),Murray ratio,and non-planarity index(NPI)between the two groups were calculated and compared.The formula of the AER is(D21+D22)/D2,and the formula of the Murray ratio is(D31+D32)/D3,where D is the diameter of the inlet vessel,and D1 and D2 are the diameters of the two branch vessels.The formula of the NPI is(γ1+γ2)-γ,where γ is the angle between the centerlines of the two branch vessels,and γ1 and γ2 are the angles between the centerline of the inlet vessel and the centerlines of the two branch vessels,respectively.According to the purpose of the study and previous studies,a multivariate Logistic regression model was constructed with sex,age,smoking history,systolic blood pressure,diastolic blood pressure,hypertension,Murray ratio and NPI as independent variables and the presence of an MCA bifurcation aneurysm as dependent variable.Multicollinearity analysis was performed on the three variables of systolic blood pressure,diastolic blood pressure and hypertension,and a variance inflation factor of＜3 was considered to indicate the absence of multicollinearity.The inverse probability treatment weighting(IPTW)was used for sensitivity analysis,and the standardized mean difference(SMD)＜0.1 was used to achieve a good balance.Results A total of 143 participants were included,including 61 males and 82 females,aged from 27 to 83 years,with an average of(59±11)years.There were 99 cases in the aneurysm group and 44 cases in the control group.(1)Compared with the control group,a lower proportion of smoking history,a higher proportion of females,and higher systolic and diastolic blood pressure were had in the aneurysm group(all P＜0.05).There were no statistically significant differences in age and the proportion of patients with hypertension between the two groups(all P＞0.05).(2)The NPI in the aneurysm group was lower than that in the control group([105±57]° vs.[176±29]°,P＜0.01),while the Murray ratio(0.909[0.678,1.301]vs.0.778[0.672,0.993],P=0.047)and the proportion of patients with Murray ratio＞1.0(45.5％[45/99]vs.25.0％[11/44],P=0.033)were both higher in the aneurysm group than in the control group.There were no statistically significant differences in the AER and the proportion of patients with AER＞1.0 between the two groups(both P＞0.05).(3)The Max WSS(68.4[47.7,119.2]Pavs.40.4[33.7,53.6]Pa,P＜0.01)and Max WSSG(141.9[98.5,287.9]Pa/mm vs.93.3[63.5,123.8]Pa/mm,P＜0.01)in the bifurcation region of the aneurysm group were both higher than those in the control group.(4)Multicollinearity analysis was performed on the three variables of systolic blood pressure,diastolic blood pressure and hypertension.The results showed that the variance expansion factor was＜3 and there was no multicollinearity.A multivariate Logistic regression model was constructed with female sex,age,smoking history,systolic blood pressure,diastolic blood pressure,hypertension,Murray ratio,and NPI as independent variables,and the presence of aneurysm at the MCA bifurcation as the dependent variable.The results showed that female sex(OR,7.121,95％CI2.287-22.171,P＜0.01)and NPI(OR,0.967,95％CI 0.955-0.980,P＜0.01)were independently associated with the presence of aneurysm at the MCA bifurcation.To improve the clinical interpretability of the results,the NPI effect was further converted.The results showed that for every 10° increase in NPI,the risk of MCA bifurcation aneurysms decreased by 28.2％(OR,0.718,95％CI 0.630-0.817,P＜0.01).IPTW sensitivity analysis showed that the SMD for age was 0.139,whereas the absolute SMDs for the other covariates were＜0.1,indicating that the overall baseline balance was improved compared with that before weighting,but there was still a slight residual imbalance.The weighted multivariate Logistic regression analysis showed that only NPI was still associated with MCA bifurcation aneurysm(OR,0.964,95％CI 0.949-0.979,P＜0.01).Conclusions NPI was independently associated with the presence of MCA bifurcation aneurysms.The findings require further validation in large-scale prospective studies.关键词
大脑中动脉分叉部/动脉瘤/Murray比值/非平面度指数/血压Key words
Middle cerebral artery bifurcation/Aneurysm/Murray ratio/Non-planarity index/Blood pressure
