Frequency of Patent Foramen Ovale and Migraine in Patients With Cryptogenic Stroke

Background and Purpose— Individuals with migraine are at higher risk for stroke, but the mechanism has not been established. On the basis of the association between migraine and intracardiac right-to-left shunt, it has been proposed that stroke in migraineurs could be caused by a paradoxical embolus passing through a patent foramen ovale (PFO) or pulmonary arteriovenous malformation. The aim of this study was to determine the prevalence of PFO with right-to-left shunt in patients who presented with cryptogenic stroke and had a history of migraine. Methods— Patients between 18 and 60 years old who presented with an ischemic stroke were characterized based on ASCOD phenotyping (atherosclerosis; small-vessel disease; cardiac pathology; other causes; dissection). A migraine diagnosis was identified by reviewing physician notes, and frequent aura was defined if present in at least 50% of attacks. A PFO with right-to-left shunt diagnosis was identified by the presence of a positive bubble contrast study with either transcranial Doppler, transthoracic, or transesophageal echocardiography. Results— Of the 712 patients who presented with ischemic stroke, 127 (18%) were diagnosed as cryptogenic; 68 patients had adequate testing for PFO and a documented migraine history. The prevalence of PFO in patients with cryptogenic stroke without migraine was elevated (59%) compared with the general population (18%). Patients with both cryptogenic stroke and migraine had a higher prevalence of PFO (79%). In patients with cryptogenic stroke who had migraine with frequent aura, the prevalence of PFO was 93%. Only 5 patients (4%) had a history compatible with migrainous infarction. Conclusions— In patients with cryptogenic stroke who have migraine, there is a high prevalence (79%) of PFO with right-to-left shunt. The timing of the stroke in migraineurs is usually not related to a migraine attack. These observations are consistent with the hypothesis that the mechanism of stroke in migraineurs is most likely because of a paradoxical embolus. Future cryptogenic stroke classification schemes should consider including PFO as a separate etiologic category.