ABSTRACT
Objective To evaluate the correlation between the types of vertebral artery occlusion and their compensatory hemodynamic changes and posterior circulation ischemia using color Doppler flow imaging combined with transcranial color-coded sonography.Methods From June 2015 to June 2016,A total of 108 patients with vertebral artery occlusion confirmed by vascular sonography,digital subtraction angiography (DSA) or CT angiography (CTA) were enrolled retrospectively.According to the magnetic resonance imaging (MRI)-diffusion weighted imaging (DWI) findings,they were divided into posterior circulation infarction (n=78 in infarction group) and non-posterior circulation infarction (n=30 in TIA group).Color Doppler flow imaging and transcranial color Doppler ultrasonography were used to examine the contralateral vertebral artery extracranial diameter, peak systolic velocity(PSV) and end diastolic velocity(EDV) of bilateral extracranial and intracranial vertebral arteries.The differences of the vertebral artery occlusion types,establishment of collateral circulation and hemodynamic changes of the contralateral vertebral artery were compared between the two groups.Results The patients with single vertebral artery occlusion in the infarction group and TIA group were 69 (88.5%) and 26 (86.7%) respectively;those with bilateral vertebral artery occlusion were 9 (11.5%) and 4 (13.3%) respectively.There was no significant difference in the number of vertebral artery occlusion between the two groups (χ2=0.000,P=1.000).The proportion of patients with vertebral artery occlusion in intracranial segment in the infarction group was higher than that in the TIA group (70.5% [55/78] vs.36.7% (11/30);χ2=10.444,P=0.001).The proportion of patients with the establishment of collateral circulation in the infarction group was lower than that in the TIA group (14.1% [11/78] vs.43.3% (13/30);χ2=10.711,P=0.001).The peak systolic velocity (PSV) and the end diastolic velocity (EDV) of contralateral extracranial vertebral artery in patients with single vertebral artery occlusion in the TIA group were higher than those in the infarction group (65±21 cm/s vs.57±15 cm/s,25±8 cm/s vs.20±7 cm/s,t=2.043 and 2.606 respectively,all P<0.05).Conclusion The establishment of collateral circulation and hemodynamic compensation of the contralateral vertebral artery after vertebral artery occlusion were closely associated with the occurrence of posterior circulation ischemia.