Increased Cerebrovascular p CO 2 Reactivity in Migraine with Aura- a Transcranial Doppler Study During Hyperventilation

Cerebrovascular reactivity during hypocapnia was tested in 20 migraineurs (8 with aura, 12 without aura) and 30 sexand age-matched healthy subjects, and during nitroglycerin-induced headache in 12 healthy subjects. Before and during hyperventilation, mean blood-flow velocity (V_mean) in the middle cerebral artery was measured with transcranial Doppler. In each subject a _pCO₂ reactivity index (RI) was calculated as DV_mean/baseline V_mean)/ D_pCO₂. Interictally, patients with migraine with aura showed higher RI (p < 0.05 ANOVA and multiple range test) than controls, whereas migraineurs without aura did not differ from healthy subjects. Ictal and interictal RIs were similar in 9 patients suffering from migraine without aura. No side-to-side differences were detected in RI. During nitroglycerin-induced headache, the RIs were no different from those recorded during migraine attacks and in non-nitroglycerin-provoked healthy controls (p < 0.05, ANOVA and multiple range test). The exaggerated response in migraine with aura might predispose for the characteristic changes in rCBF seen during attacks.