Relation of atrial shunts to migraine in patients with ischemic stroke and peripheral emboli.

This study investigated whether the increased incidence of stroke in young subjects with migraine is because they have an increased prevalence of atrial right-to-left shunts. The investigators report the prevalence of clinically relevant atrial shunts in those with stroke and migraine compared with those with stroke but without migraine and also in historic control groups of subjects who had migraine with aura but no stroke and in population controls. Of 60 consecutive stroke patients, 42 (70%) had large- or medium-sized atrial shunts. Transcatheter shunt closure was performed in 39 patients, of whom 35 had patent foramen ovales (mean diameter 9.8 +/- 4.1 mm) and 4 had atrial septal defects. If atrial shunts were unrelated to stroke in patients with migraines, shunt prevalence in those with migraine and stroke would be the same as in those with migraine but without stroke. However, a much greater shunt prevalence was found in those with stroke and migraine with aura (84%) than in those with migraine with aura but no stroke (38.1%, p <0.001), population controls (12.2%, p <0.001), and those with stroke but no migraine (55.6%, p <0.05). Shunt prevalence was also significantly greater in patients who had stroke and migraine without aura (75%) than in population controls (p <0.001) and in those with migraine with aura but no stroke (p <0.05). In conclusion, the increased incidence of stroke in subjects with migraine compared with the general population is because they have a higher prevalence of large atrial shunts and hence an increased risk for paradoxic embolism.