Migraines Linked to Vein Blood Clots

Migraine sufferers appear to be at increased risk for stroke , and now a new study may
help explain why.

One theory has been that people with migraines develop hardened plaque
within the arteries -- known as atherosclerosis -- earlier than
people without migraines. Atherosclerosis is a major risk factor for
stroke.

But this was not seen in the study, which was the first to use
high-resolution ultrasound to examine the
hypothesis.

The imaging did not show more plaque buildup in the arteries of the people
with migraines. But a review of medical records did reveal an increase in
vein-related blood clots (such as deep vein thrombosis, DVT, and pulmonary
embolism) in these people, compared to people without migraines.

The findings must be confirmed, says study researcher Stefan Kiechl, MD. But
they could help explain the link between migraine and stroke.

"This is very strong evidence that atherosclerosis is not driving this
link," he tells WebMD. "And the association between migraine and blood
clots is a new and exciting finding."

Migraines and Stroke

The study included 574 Italians age 55 and older, including 111 people with
a history of migraines followed for five years.

Researchers reviewed the medical records of all the participants and used
ultrasound to determine the extent of plaque buildup within their arteries.

More than twice as many people with migraines -- 19% vs. 8% -- also had a
history of venous thrombosis.

But migraine sufferers were no more likely to have atherosclerosis than
study participants without migraines.

Venous thrombosis has been linked to an increased risk for stroke in several
large and well-respected studies, Kiechl notes.

His study appears in the Sept. 16 issue of the journal Neurology.

Mutation May Explain Link

More than 23 million Americans suffer from migraines, and three out of four
are women.

Over the last decade, an increasing number of studies have shown an
increased risk for stroke among women and men with migraines, especially those
with a migraine subtype known as migraine with aura.

Migraine with aura has also been linked to an increased risk for a genetic
disorder associated with blood clots, known as the factor V Leiden
mutation.

This mutation might explain the migraine-stroke link, or the link may be due
to a stress reaction that promotes blood clotting, Kiechl says.

Neurologist Stephen Silberstein, MD, tells WebMD that the observations in
the study by Kiechl and colleagues should change the thinking about migraines
and stroke.

"The venous thrombosis link was a surprise and it is very
interesting," the Jefferson Medical College professor of neurology tells
WebMD. "We don't know if this is because of this genetic mutation or if
something else is going on. But it is a very important observation."

By Salynn Boyles
Reviewed by Louise Chang
©2005-2008 WebMD, LLC. All rights reserved