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 a migraine, particularly migraine with aura, undergoing a surgical procedure are at increased risk of preoperative ischemic stroke and readmission to the 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 characterised 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 anaesthesia 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 a migraine, 1,278 had a 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 a 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 a 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.