Lack of asymmetry of middle cerebral artery blood velocity in unilateral migraine.

Background And Purpose: A recent transcranial Doppler study found reduced blood velocity in seven patients during migraine attacks in the middle cerebral artery at the headache side. This would implicate vasodilation of the middle cerebral artery in the pathogenesis of headache in migraine. We attempted to confirm this finding.

Methods: We determined blood velocity with transcranial Doppler ultrasonography in the middle cerebral arteries of 51 migraine patients with unilateral headache (5 with aura, 46 without aura) and of 14 patients with bilateral headache, during and outside attacks. During attacks, median time from onset of attack to transcranial Doppler examination was 6 hours (range, 1 to 35 hours).

Results: We found no difference between blood velocity at the headache and nonheadache sides nor between blood velocity during and outside attacks. Similar results were obtained in a subgroup of 11 patients who were investigated in the first 4 hours of an attack. There were also no differences between attacks with unilateral or bilateral headache.

Conclusions: We cannot support the hypothesis that migraine is associated with vasodilation of the middle cerebral artery ipsilateral to the headache.