Ultrasound Findings Disclose the Mutual Impact of Vertebrobasilar Dolichoectasia and Vertebral Artery Hypoplasia

OBJECTIVES: Vertebrobasilar dolichoectasia (VBD) and vertebral artery hypoplasia (VAH) are known predisposing factors of posterior circulation stokes. These vascular conditions have unique hemodynamic patterns in neuroimaging studies; however, they have been presented as a single entity in some reports. The aim of this retrospective study was to clarify the relationship between these conditions with regard to ultrasound (US) findings. METHODS: A total of 465 patients with strokes were recruited. Brain magnetic resonance imaging of vertebrobasilar arteries and differences in extracranial side-to-side vertebral artery (VA) flow were recorded by US and compared in groups. RESULTS: The mean age of the 465 patients ± SD was 67.23 ± 12.13 years; 296 were men. The prevalence of VBD was 13.5% (n = 63), and 10.8% (n = 50) of the patients had coexisting VAH and VBD. These patients also had the highest prevalence of posterior circulation strokes (58% [n = 29]). A cutoff value of 55.65 mL/min and a ratio discrepancy of 5.28 (group median) for the side-to-side extracranial VA flow volume as detected by conventional US were also observed in the patients with both VAH and VBD. CONCLUSIONS: Our study revealed a higher prevalence of posterior circulation strokes in the patients with both VBD and VAH. Chronic asymmetric hemodynamic shear force in extracranial VAs leading to deformity of the vertebrobasilar system may explain our observations. Accordingly, the blood flow volume and the ratio difference could potentially be used to detect patients at risk of VBD and reduce stroke risk factors.