Vertebral artery hypoplasia and the posterior circulation stroke

The aim of this preliminary study is to evaluate the hypothesis of a possible causal link between the anatomical findings of vertebral artery hypoplasia (VAH) and the incidence of posterior circulation stroke. We used full ultrasonographic examination to evaluate patients with stroke in the vertebrobasilar circulation territory over a period of 1.5 years. The diameter equal or less than 2.5 mm (in V1 and V2 segment of the vertebral artery) was set as a feature of vertebral artery hypoplasia. Magnetic resonance imaging and angiography (MRI and MRA) or computed tomography and angiography (CT and CTA) were performed to confirm the anatomic variation of hypoplasia and the site of the cerebral ischemic territory. In the group of 44 stroke patients, 9 (20%) had a hypoplastic vertebral artery and 35 (80%) were without VAH. Although vertebral artery hypoplasia in previously published literature is seldom shown as a leading risk factor for stroke in vertebrobasilar (posterior) circulation, its occurrence is not negligible and in coexistence with known risk factors of stroke may increase the negative clinical impact. Vertebral artery hypoplasia can be diagnosed non-invasively with duplex ultrasonography. It is therefore a useful method for detection of this anatomic variation and for follow-up examination.