Migraine: Are Blood Vessels to Blame After All?

A new study from the University of Pennsylvania School of Medicine is making the headlines – and the headlines are bringing blood vessels back into the migraine conversation.

Before we get into the study, a little background.  Migraine was once very commonly believed to be a “vascular disease”.  Migraine, it was thought, came from the way blood vessels expanded and constricted.  Research and treatments focused around this idea.

But as we learned more about the brain and migraine’s connection to neurological systems in the body, migraine was increasingly believed to be a neurological disease, at least primarily.  A study released in April demonstrated that some patients actually have little if any blood vessel dilation.

Now we’re seeing headlines about arteries and migraine again.  Are we just bouncing back and forth from one theory to another?  Is the research just going around in circles?

Absolutely not.

The study, which we’ll look at in a moment, does not say that migraine is caused by blood vessel dilation.  Even if it was suggesting that all migraine involves blood vessel issues (which it’s not), this still wouldn’t change what we said here even back in 2008 and have been saying ever since (see What is Migraine? (the scientific story).

Migraine is not likely a clear chain of events, but more like a web of events.  This impacts that, this part of your body sends a message here and a message comes back, two things work together – and an attack begins.  Yes, there are chain reactions, but that doesn’t mean that only the brain or only blood vessels (or whatever you add to the list) causes all migraine attacks.

So what does the study tell us?

Simply, that people with migraine are more likely to have a congenital abnormality (something they were born with) in blood vessels.  Yes, non-migraineurs may have this difference.  And people with migraine may not.

That’s it.

Here’s the summary at the beginning of a news release from Penn Medicine:

The network of arteries supplying blood flow to the brain is more likely to be incomplete in people who suffer migraine, a new study by researchers in the Perelman School of Medicine at the University of Pennsylvania reports.  Variations in arterial anatomy lead to asymmetries in cerebral blood flow that might contribute to the process triggering migraines.

The arterial supply of blood to the brain is protected by a series of connections between the major arteries, termed the “circle of Willis” after the English physician who first described it in the 17th century.  People with migraine, particularly migraine with aura, are more likely to be missing components of the circle of Willis.

This is an interesting discovery, confirming an earlier study in 2009, but it’s no surprise that blood vessels are involved in many migraine attacks.

Is is interesting that abnormalities were most prominent in the part of the brain that processes visual information.  This could be a further clue into the visual aura that many migraineurs experience.  In fact, people who had migraine with aura were more likely to have this abnormality, though it seems to be common in non-aura types of migraine.

In the end, researchers were careful to say that changes in blood flow related to this abnormality may “trigger” a migraine attack, not that this is the cause of migraine.

Take-aways?

• A congenital abnormality in blood vessels may be another “internal” trigger of migraine (not the only one).
• Blood flow does seem to be involved in many migraine attacks.
• Understanding the connection between this abnormality and migraine gives us more clues into how migraine works and how it can be treated in individual patients in particular.
• Our overall understanding of migraine has not drastically changed, but this is still an important study that may help us understand migraine better.