The clinical relevance of vertebral artery hypoplasia.

Congenital vertebral artery (VA) hypoplasia is an uncommon embryonic variation of posterior circulation. The frequency of this congenital variation was reported to be 2-6% from autopsy and angiograms. Is it a congenital risk factor of ischemic stroke? In this review, we gave an overview of the literature concerning vertebral artery hypoplasia. VA hypoplasia served as an independent factor of a reduction of the posterior circulation blood flow velocity. VA hypoplasia can play a negative role in cases of occlusion of a major brain vessel since it limits the potential of compensatory blood circulation. VA hypoplasia may also lead to regional hypoperfusion and complex neurovascular consequences which correspond to vestibular neuronitis and migraine pathogenesis.