Potential source of cerebral embolism in migraine with aura - A transcranial Doppler study

Background: The recently found association between patent foramen ovale (PF O) and transient global amnesia (TGA) has suggested that; paradoxical micro embolization in the terminal vertebrobasilar territory might underlie at le ast some TGA cases. Migraine with visual aura is another paroxysmal. distur bance in which a sudden dysfunction of cortical areas fed by the terminal b ranches of the basilar artery is believed to trigger the attack. Therefore we investigated the prevalence of PFO in a consecutive unselected cohort of migraine patients. Objective: To investigate the prevalence of PFO in a co nsecutive unselected cohort of migraine patients to search for a possible m echanism far the reported association of migraine with stroke. Methods and Results: A total of 113 patients, consecutively referred by the Headache Ou tpatient Clinic for migraine with aura (MA+, mean age 34 +/- 12 years) were compared with 53 patients with migraine without aura (MA-, mean age 36 +/- 13 years) and with 25 age-matched nonmigraine subjects (mean age 31 +/- 10 years) selected from the hospital staff. PFO was assessed with transcrania l Doppler sonography with IV injection of agitated saline, a technique that is 90% sensitive and 100% specific. The prevalence of PFO was 48% (54/113) in MA+ patients, 23% (12/53) in MA- patients, and 20% (5/25) in control su bjects. The difference between MA+ and MA- patients was significant (odds r atio [OR] = 3.13, 95% confidence interval [CI] = 1.41 to 7.04, chi(2) = 9.5 2, P = 0.002) as was the difference between MA+ patients and controls (OR = 3.66, 95% CI = 1.21 to 13.25, chi(2) = 6.46, p = 0.01), whereas MA- patien ts did not differ from controls (OR = 1.17, 95% CI = 0.32 to 4.45, chi(2) = 0.07). MRI was negative in 22 MA+ and 8 MA- patients. Conclusions: Patency of the foramen ovale is associated with migraine with aura but not with mi graine without aura. The increased risk, of stroke found in epidemiologic s tudies in patients with migraine with aura may be explained by an increased propensity to paradoxical cerebral embolism.