Study On The Correlation Of Vertebral Artery Dominance, Basilar Artery Curvature And Posterior Circulation Infarction

Background The basic pathological changes of posterior circulation infarction(PCI) is atheroscle-rosis. PCI has some blood vessel factors through magnetic resonance angiography(MRA).Vertebral artery dominance(VAD) and basilar artery curvature, which is a common congenital variation of artery, but usually neglected by doctors,in both patients and healthy physical examinees through MRA.Clinical and radiological doctors are more concerned with existence of vascular stenosis and occlusion.Causes of VAD and basilar artery curvature,their relationship with PCI and its role in ischemic stroke are not clear yet.When exposed to vascular risk factors, their relationship with cerebral infarction deserve our concern.Objective In order to investigate vertebral artery dominance(VAD),basilar artery(BA) curvature,posterior circulation infarction(PCI) and their correlation.We observed blood flow characteristics and spectral parameters changes of the posterior circulation infarction patients with VAD by transcranial Doppler(TCD). In the light of MRA,we analyzed the clinical risk factors of basilar artery curvature and PCI in patients, the relationship between VAD and area of PCI, and also explored the measurement parameters,exposure rates of vascular risk factors and their correlation with PCI.Methods The present study was collected data in our hospital department of neurology, including with acute posterior circulation infarction patients and with anterior circulation infarction、vertigo、headache patients from January,2013 to December, 2015.A detailed history data,related scale and auxiliary examination data were recorded,MRI and CE-MRA were performed, vascular lesions of posterior circulation artery was focused on especially.Data process was divided into 4 parts. 1.According to magnetic resonance angiography(MRA) and the diagnostic criteria of VAD, 82 patients with posterior circulation infarction(PCI) were divided into VAD group(n=44) and non-VAD group(n=38). All enrolled subjects were performed transcranial Doppler ultrasound(TCD) examination. The two groups of test results do comparative analysis, after recording systolic velocity(Vs)、mean velocity(Vm) 、diastolic velocity(Vd)、 pulsatility index(PI) and resistance index(RI) of bilateral vertebral artery(VA), basilar artery(VA), bilateral posterior cerebral artery(PCA), and observe the spectrum morphological changes. 2.160 patients with acute anterior circulation infarction(ACI)and 82 patients with acute posterior circulation infarction(PCI) were enrolled.Intracranial and extracranial vascular MRA examination was performed and vascular risk factors were screened on these patients. Based on MRA,basilar artery curvature was classified,and multivariate logistic regression analysis was used to search for risk factors of PCI. 3.According to magnetic resonance angiography(MRA) and the diagnostic criteria of VAD, 156 patients with posterior circulation infarction and dizziness were divided into VAD group and non-VAD group. Incidence of separate territory infarction in posterior circulation and incidence of BA curvature were compared between 78 VAD patients and 68 controls.VA dominance, laterality of BA curvature and separate territory infarction, and their directional relationships were observed in VAD group. 4.A total of 82 acute posterior circulation infarction patients in hospital were enrolled, and they were divided into BA bending group(n=42) and group(n=40) without bending BA according to magnetic resonance angiography(MRA). Patients with dizziness or headache who were not diagnosed with cerebral infarction but had BA bending were set as control group(n=38).BAL and BL as well as diameters of BA and bilateral vertebral arteries were measured through MRA. Exposures of vascular risk factors were carefully recorded.Multivariate and single-factor analyses were applied to explore risk factors of posterior circulation infarction patients.BL was classified to investigate its relationship with posterior circulation infarction and differences of bilateral vertebral arteries diameters were also classified to further explore their correlation with BL and BAL.Results 1.The level of Vs、Vd and Vm in the dominant VA of VAD group were higher than those in the non- dominant VA of VAD group and bilateral VA of non-VAD group(P<0.01). Compared with BA of two groups,the level of Vd and Vm in the VAD group were higher than those in the non-VAD group(P<0.05), and the level of PI and RI were less than those in the non-VAD group(P<0.01). There were no significant difference in Vs、Vd、Vm、PI and RI of PCA in two groups(P>0.05).There were abnormal spectrum morphological changes in VAD group. 2.Smoking history, diabetes history, blood LDL and Hb A1 c in PCI group were significantly higher than those in ACI group, and CHD history in PCI group was significantly less than that in ACI group. Vertebral artery stenosis,basilar artery stenosis,vertebral artery dominance,basilar artery curvature degree≥2 in PCI group were significantly higher than those in ACI group(P<0.05).Multivariate logistic regression analysis found that the patients with diabetes(OR 4.02; 95% CI: 1.80-9.01; P=0.002),basilar artery stenosis(OR 1.00; 95%CI: 1.02-1.05; P<0.001) and basilar artery curvature degree≥2(OR 1.38; 95%CI: 1.01-1.06; P=0.009) were independently correlated with PCI. 3.85.1%(40/47) patients had an opposite directional relationship between dominant VA and BA curvature(r=﹣0.704, P<0.0001). The total incidence of posterior circulation infarction in VAD group was significantly higher than that in controls(51.2%(44/86) vs. 22.9%(16/70),χ2=13.063,P<0.001),The incidences of posterior inferior cerebellar artery(PICA) territory infarction and BA territory infarction were both significantly higher than that in controls.No differences were found in superior cerebellar artery(SCA) and posterior cerebral artery(PCA) territory infarction between two groups. The incidence of posterior circulation infarction in BA curvature patients was significantly higher than that in BA straight patients. 4.There were significant differences among PCI with BA bending, PCI without BA bending and control group. Comparison of vascular risk factors in patients with and without BA bending indicated odds ratio increased in BA bending group above 65 years of age, hypertension history, type 2 diabetes history, high cholesterol and high homocys-teine history, and the difference was statistically significant(P<0.05).In BA bending patients with PCI and those without infarction,BAL and BL had significant difference(P<0.05);In terms of vascular risk factors,odds ratio increased in BA bending patients with PCI with age above 65,hypertension, and type 2 diabetes history and smoking history, and the difference was statistically significance(P<0.05).After adjusting for the relevant factors,multivariate analysis showed that BL in grade 3 was an independent predictor of PCI(OR=3.274,95%CI 1.253-10.489).Diameter difference of VA and BL was significantly positive correlated(r=0.769,P<0.001).Conclusions 1.The blood flow velocity of the dominant VA was faster than that of non-dominant VA, which due to the blood flow velocity of BA slowly. There were cerebral hemodynamic changes and abnormal spectrum morphological changes in VAD patients. TCD had certain clinical value for the vessel variation of posterior circulation. 2.Diabetes mellitus,basilar artery stenosis and basilar artery curvature degree≥2 were probably risk factors of PCI. 3.The incidence of BA curvature is higher in VAD patients, and BA usually bends to the opposite side of dominant VA.The incidence of posterior circulation infarction is higher in VAD patients, especially in PICA infarction and BA infarction patients.Most PICA infarction occurred on the opposite side of dominant VA, BA infarction were on the side of dominant VA. 4.Diameter difference of bilateral vertebral artery was positively correlated with the BL. Basilar artery curvature exposed to some vascular risk factors would increase the probability of PCI.The infarct lesions usually appeared opposite to the tortuosity, and the symptoms are relatively light.In patients with basilar artery curvature,BL beyond 3.71 mm was considered as the risk factor of PCI.