| BackgroundBasilar artery curvature is commonly found, but usually neglected by doctors, in both patients and healthy physical examinees through magnetic resonance angiography (hereafter as MRA) and CT angiography (hereafter as CTA). Clinical and radiological doctors are more concerned with existence of vascular stenosis and occlusion. Causes of basilar artery curvature, its relationship with and its role in ischemic stroke are not clear yet. Though more researches are on vertebrobasilar dolichoectasia(VBD) and its association with posterior circulation cerebral vascular disease, some different vertebrobasilar tortuosities as well as their relationship with vascular vertigo and cerebral infarction deserve our concern.ObjectiveIn order to investigate vertebral artery dominance(hereafter as VAD), basilar artery (BA) curvature, vascular vertigo, posterior circulation infarction and their correlation. In the light of MRA, we analyzed the clinical risk factors of basilar artery curvature and brainstem infarction in patients and also explored the measurement parameters, exposure rates of vascular risk factors and their correlation with pontine infarction.Objects and Methods The present study was collected data in our hospital department of neurology, including18years of age or older with vertigo patients or40years of age or older with acute posterior circulation infarction patients from April,2009to December,2012. A detailed history data, related scale and auxiliary examination data were recorded, vascular lesions of posterior circulation artery was focused on especially. Data process was divided into5parts.1. A total of81patients with vertigo patients were in hospital from the beginning to February,2010. This prospective study involved64patients with vertigo, including35patients with VAD (VAD group) and29without VAD (non-VAD group) as detected by head magnetic resonance angiography. Age, sex, and other clinical histories were comparable in both groups. The degree of vertigo was graded and BAEP examination was performed in each patient. BAEP changes as well as their correlations with VAD were analyzed in both groups.2. A total of269patients with vertigo patients were in hospital from the beginning to July,2011, and237were completed analysis. Intracranial and extracranial vascular MRA or CTA examination was performed and vascular risk factors were screened on vertigo. Based on MRA or CTA, basilar artery curvature was classified, and multivariate Logistic regression analysis was used to search for risk factors of basilar artery curvature.3. A total of117patients with acute posterior circulation infarction were in hospital from the beginning to July,2011, and96were included. Acute posterior circulation infarction patients confirmed by cranial magnetic resonance imaging (hereafter as MRI) were included. Vessel lesions were recorded by head and neck MRA or CTA, such as tortuosity hypoplasia or stenosis of basilar artery, vertebral artery, posterior cerebral artery and internal carotid artery. According to the location of infarction, patients were divided into brainstem infarction group, cerebellar infarction group, thalamus, medial surface of temporal lobe and occipital lobe infarction group, combined infarct group; according to age, patients were divided into more than65years old group and less than65years old group. Differences of vascular lesions in different age and location were analyzed.4. A total of129patients with acute posterior circulation infarction were in hospital from the beginning to December,2011, and65brainstem infarction patients were enrolled. Intracranial and extracranial vascular MRA or CTA examination was performed and vascular risk factors were screened on brainstem infarction patients. Based on MRA or CTA, basilar artery curvature was classified, and multivariate Logistic regression analysis was used to search for risk factors of brainstem infarction.5. A total of97acute pontine infarction patients were in hospital from the beginning to December,2012, and88were enrolled. Selected in hospital patients with acute pontine infarction diagnosed by magnetic resonance diffusion weighted imaging as research subjects, and they were divided into BA bending group and group without bending BA according to magnetic resonance angiography (MRA). BA bending in vascular vertigo patients without cerebral infarction was the control group. BAL and BL as well as diameters of BA and bilateral vertebral arteries were measured through MRI. Exposures of vascular risk factors were carefully recorded. Multivariate and single-factor analyses were applied to explore risk factors of pontine infarction patients. BL was classified to investigate its relationship with pontine infarction and differences of bilateral arteries diameters were also classified to further explore their correlation with BL and BAL.Results1. Compared with that of non-VAD group, the vertigo severity level of patients with VAD was statistically significant (P＜0.01); there was statistical significance between the rate of abnormal BA shapes in VAD group and non-VAD group (P＜0.05). Peak latencies (Ⅰ, Ⅲ, and Ⅴ) in the VAD group were longer than those in the non-VAD group (P＜0.01), but the difference in the III did not reach statistical significance (t=1.916, P＞0.05). Interpeak latencies (Ⅲ-Ⅴ and Ⅰ-Ⅴ) were longer in the VAD group than those in the non-VAD group (P＜0.05); there was no significant difference in the interpeak latencies of Ⅰ-Ⅲ (P＞0.05). The Ⅲ-Ⅴ/Ⅰ-Ⅲ ratios were higher in the VAD group than those in the non-VAD group. The vertigo severity level was significantly higher in the VAD group than that in the non-VAD group (3.2±1.0versus2.2±0.7). The vertigo severity level correlated with VAD and every major anomaly index of BAEP; its correlations with Ⅲ-Ⅴ/Ⅰ-Ⅲ were remarkably significant (r=0.617, P=0.013).2. Logistic multiple regression analysis showed that the basilar artery extension (OR21.56,95%CI:6.74-18.24, P=0.001) and vertebral artery dominance (OR36.34,95%CI:6.98-24.38, P＜0.001) were the risk factors for basilar artery curvature.3. There was no statistical significance between group above the age of65and group under65in VAD, vertebrobasilar artery development or origin abnormality(P>0.05) but in vertebrobasilar artery stenosis or occlusion, vertebrobasilar artery tortuosity (P<0.05). Vertebral artery stenosis or occlusion, basilar artery stenosis or occlusion, vertebral artery dominance, vertebral artery and basilar artery tortuosity were all correlated with brainstem infarction group, cerebellar infarction group, whereas thalamus, medial surface of temporal lobe and occipital lobe infarction group, combined infarct group were only linked to vertebral artery stenosis or occlusion, basilar artery stenosis or occlusion.4. Multivariate Logistic regression analysis found that the patients with diabetes (OR=4.02,95%CI:1.80-9.01; P=0.001), 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 brainstem infarction.5. In pontine infarction patients with BA bending, vertebral artery dominance(VAD) accounted for71.7%, while in patients without basilar artery bending, VAD accounted for54.8%, and there was significant difference (x2=8.696, P=0.003). Comparison of vascular risk factors in patients with and without BA bending indicated odds ratio increased in BA bending group above65years of age, hypertension history, smoking history and high homocysteine history, and the difference was statistically significant (P＜0.05). In BA bending patients with pontine infarction 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 pontine infarction with age above65, hypertension, high cholesterol and type2diabetes history, and the difference was statistically significance (P＜0.05). After other relevant factors were adjusted, multivariate analysis showed that BL in grade3was an independent predictor of pontine infarction (OR=2.74,95%CI1.27to4.48). Diameter difference of VAs and BL showed positive correlation, and there was statistical significance (r=0.769, P＜0.001).Conclusions1. The incidence of abnormal BA shapes and abnormal BAEP, and the vertigo severity level were higher in VAD patients. Moreover, VAD was found to correlate with abnormal BAEP, suggesting that VAD contributed to vertigo of vascular origin.2. Basilar artery extension and VAD were probably risk factors of basilar artery curvature.3. Patients with posterior circulation infarction had high rates of vertebrobasilar artery developmental abnormalities and tortuosity. Vertebrobasilar artery tortuosity occurred more frequently in patients aged above65years whereas vertebrobasilar artery developmental abnormalities occurred with similar frequency in patients aged under65years and beyond65years.4. Diabetes mellitus, basilar artery stenosis and basilar artery tortuosity≥2grade were probably risk factors of brainstem infarction.5. 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 pontine infarction. The infarct lesions usually appeared opposite to the tortuosity, and the symptoms are relatively light. In patients with basilar artery curvature, BL beyond3.77mm was considered as the risk factor of pontine infarction. |
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