Toward a further elucidation: role of vertebral artery hypoplasia in migraine with aura.

A higher frequency of hypoplastic vertebral artery (VA) in patients with migraine with aura than in normal controls has been documented. However, the role of a hypoplastic VA in a migraine attack remains unclear. The aim of our work was to measure the net VA flow volume and related spectral parameters in patients with migraine with aura and a hypoplastic VA. From January 2005 to October 2005 we reviewed the records of 250 migraine outpatients (108 men and 142 women; mean age = 30.8 +/- 14.0 years, range = 25-55). Ninety-two patients with migraine with aura were selected. Among these patients, 26 had a hypoplastic VA that was delineated by cervical magnetic resonance angiography. We performed a case-control study that included these 26 migrainous patients. Duplex color-coded ultrasonography was utilized to calculate the spectral parameters during attacks and headache-free periods. The net VA flow volume did not decrease during attacks. A reduction in the resistance index of the hypoplastic VA was noted during attacks in subjects who had migraine with aura. Our observation of VA vasomotor alteration during migraine attacks extends the understanding of the role of a hypoplastic VA. Vasomotor regulation of the VA could be neurogenic in origin. We hypothesize that VA hypoplasia contributes to migraine through complex neurovascular pathways rather than through its low flow volume.