A 2006 study published in the Journal of the American Medical Association found that active migraines with aura in women were associated with an increased risk of cardiovascular disease, including myocardial infarction, stroke, angina, and death. Interestingly, active migraines without aura in women were not found to be correlated with any increased risk of cardiovascular disease. It is theorized that the same vascular problems that cause migraines could also extend to the coronary arteries, increasing the risk of heart attacks and other events.

It can be hard to determine the exact relationship between migraine and stroke because the timing of a stroke with respect to the onset of a migraine is rarely recorded with any degree of accuracy. There does seem to be an increased risk of ischemic stroke for women diagnosed with migraines who are under forty-five years old, as reported by the British Journal of Medicine in 1993. A 1989 study in the journal Acta Neurologica Scandinavica also found that between 1 and 17 percent of strokes in patients less than fifty years old had an association with migraines.

A 2005 study in Neurology found an association between patients with migraine and patients with symptoms of heart disease. Patients who had migraine with aura were found to be 43 percent more likely to have high cholesterol than the general population, and they were 76 percent more likely to have high blood pressure. Such patients had a higher risk from the effects of heart disease with age, and reported a fourfold increase in the incidence of stroke or heart disease before they reached the age of forty-five.

It's important to note that migraineurs are also more likely to smoke, which is a major risk factor for heart disease and stroke. The Norweigan Head-HUNT study found that prevalance rates for head-ache were higher among smokers compared with those who have never smoked. And a study published in 2008 in the journal Headache found that individuals who suffered from frequent headaches during mid-adolescence were twice as likely to smoke in adulthood than those without headache.

Another study, from the Journal of Neurology, Neurosurgery, and Psychiatry in 2004, suggests that a link could exist between stroke and migraines on a more fundamental level. A platelet dysfunction, in which proinflammatory platelets adhere to leukocytes, has been observed in stroke patients. A similar process has been observed in migraine patients. It is thought that this dysfunction takes place during the interval in between migraine attacks, when the patient is headache free. It is possible, therefore, that there is a connection between migraines and strokes on a level as fundamental as the interactions between single cells. Future study is needed to determine if there are other biochemical links between the two conditions.

The overall occurrence of a stroke during or immediately following a migraine attack is fortunately a rare event. A 2003 study in the journal Archives of Neurology describes two cases in which patients suffered from “migrainous infarction.” In these cases, pathogenesis appeared in some way as a direct result of the migraine and took place during the course of a normal migraine with aura. The exact nature of the relationship between stroke and migraine in this circumstance is unknown.

A complex relationship seems to exist between migraine and stroke. In cases where a stroke occurs in a migraineur that is unrelated to a recent or current migraine, it is likely that the cooccurrence is either coincidental or is due to shared risk factors. Another category of interrelationship is when a structural cerebral defect is found that can produce the clinical signs of a migraine, or when a stroke happens to include a migraine-like headache that is unrelated to any typical migraine triggers or patterns. It is only when a stroke occurs during or immediately following a migraine that the migraine can be considered to have caused the stroke, and only after all other possible causes of the stroke have been ruled out.

Beta-blockers or calcium channel blockers can successfully treat patients who have hypertension or angina along with migraines. Sumatriptan (Imitrex) and other “triptan” drugs should not be taken by patients who have previously had a myocardial infarction, heart disease, or angina, or who have hypertension that is not controlled. Beta-blockers should not be used in migraine patients who also have hypotension (low blood pressure), diabetes, or asthma.