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FYI

Vascular Theory of Migraine Debunked

Peter J. Goadsby, MD, PhD, DSc, reviewing Amin FM et al. Lancet Neurol 2013 May

Imaging of intracranial and extracranial arteries in patients with spontaneous migraine without aura shows unambiguously that the vascular theory is incorrect.

To test the century-old theory of arterial dilation as the cause of migraine, researchers studied spontaneous attacks in 19 patients with migraine without aura using magnetic resonance angiography. The primary endpoints were comparisons of the circumference of the extracranial and intracranial vessels between attack-free days and during attacks, and between brain hemispheres ipsilateral and contralateral to the pain. The authors examined both extracranial arteries (external carotid, superficial temporal, middle meningeal, and cervical internal carotid arteries) and intracranial arteries (cavernous and cerebral internal carotid, middle cerebral, and basilar arteries).

The circumferences of the extracranial vessels and the basilar artery did not differ between sides or between attack and attack-free states. Intracranial vessel circumferences differed slightly (by about 10%) in both comparisons. The authors conclude that simple arterial dilation is unlikely to play an important role in migraine.

COMMENT

Although nineteenth century neurologists seemed well aware that migraine was a brain disorder, migraine was considered primarily a vascular problem for perhaps 80 years after the publication of seminally distracting work in the early twentieth century (Arch Neurol Psychiatry 1938; 39:737). The issue is pivotal because, if the disorder is vascular, then we must have vasoactive treatments, and because other explanations would need to be found for phenomena, such as photophobia, that are associated with migraine.

This study provides unambiguous exculpatory data for vessels in the pain of migraine. First, vascular dilation was not seen in isolation, consistent with recent work from the current study authors and others (Brain 2008; 131:2192). Second, the general abandonment of the vascular theory is consistent with clinical trial work showing the efficacy of nonvascular drugs in migraine (JW Neurol May 15 2012. opens in new tab) and with brain imaging studies (J Clin Neurosci 2010; 17:547).

The new data should encourage us to redouble our efforts to understand migraine, which is very much a brain disorder (Nat Rev Neurosci 2011; 12:570). In practice, we need new, safe, effective treatments for those who do not respond to or cannot tolerate current approaches — particularly nonvascular drugs for patients with contraindications to 5-HT1B/1D receptor agonists. This is the rare study that both provides pathophysiological insight and delivers clear translational methods.

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