The migraine-ischemic stroke connection: potential pathogenic mechanisms.

Strong epidemiological evidence indicates that migraine, especially migraine with aura, is associated with increased risk of ischemic stroke. However, the precise mechanisms of such a relation are currently not fully elucidated and are still a matter of speculation. Migraine may directly cause an ischemic event (i.e, migrainous infarct), by inducing cerebral microcirculatory vasoconstriction (cortical spreading depression-related oligemia), intracerebral large vessels spasm, and vascular endothelium-related hypercoagulability. On the other hand, migraine may predispose to cerebral ischemia outside of a migraine attack by affecting endothelial function, alone or in combination with traditional vascular risk factors, or by interacting with pre-existent stroke susceptibility conditions (i.e, patent foramen ovale). At least theoretically, the migraine-stroke link may be the consequence of the unfavourable effect of migraine-specific drugs (i.e, triptans or ergot alkaloids). Finally, migraine and ischemic vascular events may be linked via genetic pathways, certain genes playing a role on both diseases and influencing their relation. The coexistence of ischemic stroke and migraine in the context of specific syndromes (i.e, CADASIL) characterized by peculiar phenotype, proven inherited background and chronic alterations of the wall of cerebral small vessel arteries suggests that migraine and ischemic stroke may be the end phenotype of common pathogenic mechanisms. How to identify those migraineurs at highest risk of ischemic stroke and whether stroke can be prevented by specific therapeutic strategies are the goals of future research.