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 While stroke was rare in the study, the odds of stroke within 30
days of surgery were 75 percent higher for people with a history of
migraines.
When patients had a history of migraines with aura – or visual
symptoms such as flashing or shimmering lights, zigzagging lines or
stars – the odds of stroke were more than doubled.
“Our study shows that patients with migraine, particularly migraine
with aura, undergoing a surgical procedure are at increased risk of
perioperative ischemic stroke and readmission to hospital within 30
days after discharge,” said senior study author Dr. Matthias
Eikermann of Harvard University and Massachusetts General Hospital
in Boston.
Ischemic stroke, the most common type, results from an obstruction
in a blood vessel supplying the brain. Many previous studies have
linked migraine to an increased risk of stroke.
Up to one in five people get migraines, a chronic, often
debilitating disorder characterized by severe headaches as well as
symptoms like nausea and intense sensitivity to sight or sound,
researchers note in The BMJ.
To assess how migraine history influenced the odds of stroke
following surgery, researchers examined data on 124,588 patients who
had operations requiring general anesthesia and mechanical
ventilation from 2007 to 2014.
People with a history of migraines made up about 8 percent of the
total cases. Of these 8,901 patients diagnosed with migraine, 1,278
had migraine with aura.
Overall, 771 people had a stroke within 30 days of surgery, or less
than 1 percent of the study population. Most often, strokes occurred
after vascular, heart or brain surgery.
Among all the patients who had a stroke, 89 of them, or about 12
percent, had a history of migraine with or without aura.
The absolute risk of stroke was about 2.4 cases for every 1,000
surgical patients, researchers estimated. For patients with a
history of migraine, the risk increased to about 4.3 strokes for
every 1,000 surgical patients.
In addition, researchers examined how often surgical patients were
admitted to the hospital within 30 days of being sent home.
Altogether, 10,088 people had repeat hospital admissions.
Compared to patients without any history of migraines, the risk of
repeat admissions was 59 percent higher for people with a history of
migraine with aura and 27 percent greater for migraine without aura.
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Researchers speculate that genetics may play a role, as well as
characteristics of the brains of people with migraines that make
them more susceptible to stroke.
“Patients with migraine have a hyperexcitable brain, which increases
the vulnerability to stroke during and after surgery,” Eikermann
said by email.
“When examining the electrical activity of the brain of patients
with migraine, we observe a spreading depolarization which induces
prolonged constriction of the blood vessels in the brain leading to
decreased oxygen supply during migraine aura and stroke,” Eikermann
added.
The study wasn’t a controlled experiment and it can’t prove that
migraines cause increased stroke risk.
Another limitation of the study is that it relied on billing codes
to identify people with migraines and lacked clinical information
that might offer other explanations for an increased risk of stroke
in some patients, the authors note.
Even so, the findings should prompt doctors to consider migraine
history when they assess the risks of surgery and when they monitor
patients for complications afterwards, said Dr. Samuel Wann, a
researcher at Ascension Wisconsin Cardiovascular Physicians in
Milwaukee who wasn’t involved in the study.
“This important study reminds us that migraine headaches, especially
those associated with an aura, are not benign and can be associated
with stroke,” Wann said by email.
SOURCE: http://bit.ly/2jtWBaQ The BMJ, online January 10, 2017.
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