Microembolism and Other Links Between Migraine and Stroke: Clinical and Pathophysiologic Update

Migraine and stroke are highly prevalent diseases with a high effect on quality of life, with multiple epidemiologic, pathophysiologic, clinical, and prognostic areas of overlap. Migraine is a risk factor for stroke. This risk is explained by common risk factors, migraine-specific mechanisms, and non-migraine-specific mechanisms that have a relevant role in patients with migraine with aura (e.g., atrial fibrillation and paradoxical embolism through a patent foramen ovale). Another important link between migraine aura and ischemic stroke is cardiac embolism. Cardioembolism is the most frequent cause of ischemic stroke, and increasing evidence suggests that microembolism, predominantly but not exclusively originating in the heart, is a contributing mechanism to the development of migraine aura. In this review, we discuss epidemiologic aspects of the association between migraine and ischemic stroke, the clinical presentation of ischemic strokes in patients with migraine, and the differentiation between migrainous and nonmigrainous infarctions. After that, we review migraine-specific and non-migraine-specific stroke mechanisms. We then review updated preclinical and clinical data on microembolism as a cause of migraine aura. In the last section, we summarize knowledge gaps and important areas to explore in future research. The review includes a clinical vignette with a discussion of the most relevant topics addressed.