Treating
a common heart condition can dramatically reduce the occurrence
of debilitating migraines, suggests new research.
As
many as one in five people may suffer from patent foramen
ovale (PFO) - or a hole in the heart - which can leave them
at increased risk of both stroke and migraine.
Closing
this hole slashed the frequency of migraines in four out
of five people with PFO who had suffered stroke, shows a
study by Stephan Windecker and colleagues at the University
Hospital and the Swiss Cardiovascular Centre in Berne, Switzerland.
The PFOs were plugged using a non-surgical method called
"transcatheter PFO closure", in which a mini umbrella
is inserted through a vein into the hole and then opened.
"The
prospect that transcatheter PFO closure, a simple cardiac
intervention, may reduce migraine attacks or even cure some
patients from migraine is encouraging for all those suffering
from this disabling condition," says the team.
Flow
pattern
PFO
results from the incomplete development of the heart in
new born babies. In fetuses, blood flows between the two
upper chambers, or atria, of the heart. The wall between
these compartments seals at birth to separate de-oxygenated
blood from the body and freshly oxygenated blood from the
lungs. But in some cases, a tiny hole may be left which
allows blood to circumvent the lungs.
Windecker
and colleagues surveyed 215 young, recovering stroke victims
undergoing PFO closure, about any headaches they had experienced
in the year before and after the procedure.
Nearly a quarter of the patients experienced migraines in
the year before treatment, double the rate in the general
population. But in the year after the PFO was plugged, 80
per cent of the patients said they had markedly fewer attacks.
The
reduction applied to all types of migraine, including a
severe form in which visual disturbances are experienced,
called migraine with aura. This type has previously been
linked to strokes.
"It's
a very interesting piece of work," says Anne MacGregor,
director of clinical research at the City of London Migraine
Trust and general secretary of the International Headache
Society. "I think we now need to look at it from the
other way round - [look at] patients with migraine with
aura and see how many have a PFO.
Eaten
up
The Swiss team suggests that the PFO may allow small blood
clots to enter the brain and trigger a migraine attack.
Normally, these clots would be "eaten up along the
way" through the lungs, MacGregor told New Scientist.
Another
possibility might be that biologically active molecules
that are normally mopped up in the lungs could cross the
PFO and be carried to the brain, causing biochemical changes
that might trigger an attack. Two recent studies have shown
similar results, but this latest research is the largest
study to date to confirm the link between of PFO on migraine.
"One
has to be cautious because all these studies have looked
at patients who have had a stroke," warns MacGregor.
However, she adds that they give "sufficient reason"
to consider PFO as a possibility when treating patients
who suffer migraine with aura.
The
findings were presented at The European Society of Cardiology's
congress in Vienna, Austria, on Sunday.
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