Migraine pain may not be associated with extracranial arterial dilatation and may be linked with only slight intracranial dilatation, according to research published online ahead of print on April 9 in Lancet Neurology.
Researchers found no statistically significant dilatation of patients’ extracranial arteries on the pain side on migraine days, compared with nonmigraine days. Intracranial arteries, however, were more dilated during migraine attacks, except for the basilar artery. Compared with the pain-free side, investigators detected dilatation on the pain side of the intracranial arteries, but not of the extracranial arteries, during migraine attacks. Sumatriptan relieved migraine pain as it constricted normal-caliber extracerebral arteries, but it did not affect dilated cerebral arteries.
Faisal Mohammad Amin, MD, a doctoral student at Glostrup Hospital in Denmark, and colleagues recruited 78 patients with migraine without aura between October 2010 and February 2012. The researchers performed magnetic resonance angiography on the participants during spontaneous, unilateral migraine attacks. The study’s primary end points were difference in circumference of extracranial and intracranial arterial segments between attack and attack-free days and the pain and pain-free side. Nineteen participants (all female) were included in the final analysis.
“We know of no other study to provide stronger evidence that extracranial arterial vasodilatation might not be a major source of head pain in migraine,” said Dr. Amin. “However, these findings do not refute possible nociceptive input from other extracranial structures (ie, muscles and periosteum) or from sensitized perivascular afferents in the absence of dilatation.”
Findings from the study “disprove the central tenet of the vascular hypothesis of migraine,” said Andrew Charles, MD, a neurologist at the David Geffen School of Medicine in Los Angeles, in an accompanying editorial. “This study is especially important because it captured spontaneous migraine in multiple patients, allowing for statistical comparison that was not possible in a previous study of only one patient with spontaneous migraine, and removing the potential confounding factor of triggers that have been used to provoke headache in previous similar studies.”
Amin FM, Asghar MS, Hougaard A, et al. Magnetic resonance angiography of intracranial and extracranial arteries in patients with spontaneous migraine without aura: a cross-sectional study. Lancet Neurol. 2013 Apr 9 [Epub ahead of print].
Charles A. Vasodilation out of the picture as a cause of migraine headache. Lancet Neurol. 2013 Apr 9 [Epub ahead of print].