Association Between Vertebral Artery Hypoplasia And Distribution Of Acute Posterior Circulation Infarction And Vascular Morphology

Objective: More and more studies show vertebral artery hypoplasia(VAH)is a risk factor of acute posterior circulation infarction(APCI).However,the exact pathogenesis is unclear.We observed and analyzed the association between VAH and APCI distribution and vascular morphology to explore the pathogenesis of APCI contributing to VAH,hoping to provide some evidence for APCI patients with VAH in clinical diagnosis and prevention.Method: We constantly recruited patients hospitalized in the department of neurology,Liaoning Provincial People's Hospital from April 1,2016 until May 31,2017.Inclusion criteria were sudden focal neurological deficit that was confirmed as acute infarction in the territory of posterior circulation with brain magnetic resonance(MR)imaging including diffusion-weighted imaging(DWI).Exclusion criteria were as followed: unclear intracranial vertebral artery imaging,extracranial vertebral artery localized stenosis or occlusion,bilateral VAH,other non-atherosclerotic stenosis.According to the lesion location in the sequence of DWI,APCI were classified into infarctions in the proximal,middle and distal segment.VAH and fetal-type posterior cerebral artery(FTP)was assessed with MR angiography.All the APCI patients were divided into VAH and non-VAH group according to the presence of VAH.General information,vascular risk factors,laboratory blood test results,APCI distribution and vascular morphology were compared between VAH and non-VAH group.APCI distribution and vascular morphology was observed in VAH and non-VAH,in the side ipsilateral and contralateral to VAH.Also we analyzed the association between basilar artery curvature and APCI distribution as well as vascular morphology.Results: 1.According to the inclusion criteria and exclusion criteria,we recruited 229 patients with APCI,of which 116 patients had VAH and 113 had non-VAH.There were no significant differences in age,sex,vascular risk factors and laboratory blood test results between VAH group and non-VAH group.The proportion of APCI in middle segment in VAH group(47/116,40.52%)was lower than that in non-VAH group(61/113,53.98%),the difference was statistically significant(P=0.041).But there was no significant difference in the proportion of proximal and distal territory segment between two groups.The basilar artery tortuosity index in VAH group was significantly higher than that in non-VAH group(0.031 vs 0.018,P=0.039),the difference was statistically significant.The proportion of combining FTP in VAH group(33/116,28.45%)was higher than that in non-VAH group(12/113,10.62%),the difference was statistically significant(P=0.001).There was no significant difference in the stenosis of left and right intracranial vertebral artery,calcification of left and right vertebral artery,basilar artery stenosis and basilar artery hypoplasia between two groups(P>0.05).Multivariate logistic regression analysis also showed the incidence of FTP in VAH group was higher than that in non-VAH group(OR=2.932,95% CI: 1.403-6.130,P=0.004).2.In 116 patients with VAH,46 on the left and 70 the right side.The incidence of APCI in proximal segment ipsilateral to VAH was significantly higher than that contralateral(15.52% vs 6.90%,P=0.003),the difference was statistically significant.The incidence of APCI in middle and distal segment had no significant difference ipsilateral and contralateral to VAH.The incidence of intracranial vertebral artery stenosis ipsilateral to VAH was greater than that contralateral(10.34% vs 2.59%,P=0.016),the difference was statistically significant.In VAH patients,the ratio of basilar artery convex to ipsilateral was greater than convex to contralateral(55.17% vs 21.55%,P=0.000),the difference was statistically significant.Conditional logistic regression analysis also showed that the incidence of APCI in proximal segment ipsilateral to VAH was higher than that contralateral(OR=4.397,95% CI: 1.417-13.642,P=0.010);The incidence of intracranial vertebral artery stenosis ipsilateral to VAH was higher than contralateral(OR=11.996,95% CI: 2.083-69.087,P=0.005);The basilar artery convex to ipsilateral VAH was more than convex to contralateral(OR=4.076,95% CI: 2.236-7.431,P=0.000),the differences were statistically significant.3.There were no significant differences in APCI of proximal,middle and distal segment between the convex and concave sides of basilar artery.The diameter difference of bilateral vertebral artery and basilar artery tortuosity index had no correlation in VAH and non-VAH group,but had positive correlation in all patients with APCI(r=0.218,P=0.001).Conclusion: 1.APCI in proximal segment was more common in the side ipsilateral to VAH.2.VAH was accompanied,more often than non-VAH,by changes in the morphology of posterior circulation vascular including a high probability of FTP,high incidence of ipsilateral intracranial vertebral artery stenosis.Basilar artery was convex to ipsilateral to VAH more than to contralateral.