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Cardiac surgery may ease migraine
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Apparent link found between heart, headaches
By David Kohn
Sun Reporter
October 9, 2005
Last year, Kevin Marsh had an operation to close a small hole
in his heart. He'd had a stroke, and doctors worried that
the opening could increase his chances of having another.
Since then, Marsh has not had another stroke. The procedure
had another benefit, too: He no longer suffers from the debilitating
migraine headaches that had troubled him for decades.
"The change is incredible," says the 50-year-old,
who restores vintage cars in Salt Lake City. "I have
not had one headache since the surgery."
Marsh is not the only one who is excited. A growing group
of researchers around the world are examining the link between
migraine and the heart defect. Some doctors say that up to
half of all cases of migraine might be caused by the condition,
called patent foramen ovale, or PFO.
About 28 million Americans suffer from migraine, a majority
of them women.
"This approach is a complete paradigm shift," says
UCLA cardiologist Jonathan Tobis, who is planning a study
testing PFO closure for migraines.
"Our ability to treat migraine could be significantly
improved."
The results so far are intriguing.
In a small study published this year, researchers followed
50 migraine patients who had undergone a PFO closure. More
than half stopped having migraines altogether, and an additional
14 percent had significantly fewer.
Another study found that people who suffered from certain
kinds of migraine were twice as likely to have a PFO as those
without migraine.
"We clearly saw a benefit," said the study's lead
author, Mark Reisman, a cardiologist at the Swedish Medical
Center in Seattle.
Doctors have long known about PFOs; the phenomenon was first
described by Leonardo da Vinci in his famed anatomical studies.
The condition is an opening in the wall that separates the
right and left atrial chambers of the heart. Typically more
of a flap than an outright hole, the flaw is usually a couple
of millimeters wide. Before birth, everyone has a PFO; in
utero, our lungs do not yet work, so the mother must provide
oxygen. The PFO allows oxygen-rich blood from the mother to
reach her fetus.
Blood clot risk In most people, the PFO closes in childhood.
But in about
25 percent of the population the gap remains open, allowing
blood to pass from the right atrium to the left. Until recently,
researchers thought the flaw was essentially harmless. But
15 years ago, cardiologists realized that the flap might permit
small blood clots to reach the brain, causing strokes.
Such clots are typically removed when blood flows through
the lungs; the PFO allows clots to bypass this filtering process.
The link between PFO and migraine came to light after the
stroke discovery. Patients who had had a PFO closed for a
stroke found that their migraines miraculously disappeared.
"It was total serendipity," said Memphis neurologist
Stephen Landy, a headache expert who is a principal investigator
in a soon-to-begin migraine-PFO trial.
Once aware of the connection, doctors began finding more
cases in which headaches ceased after PFO surgery.
For reasons that no one understands, PFO closure seems to
succeed more in people who have migraine with aura, a phenomenon
in which the headache is accompanied by visual disturbances
such as flashes of light or blind spots. However, some patients
who have migraine without aura also say the surgery eliminated
their headaches.
Recognition of the PFO-migraine connection has been driven
in part by technology that makes it easier to spot the heart
defect in the first place. Until the late 1980s, the only
way to detect a PFO was through open-heart surgery.
Since then, doctors have refined three imaging tests, each
of which uses a different method to discern air bubbles escaping
through the opening. In someone with a large PFO, hundreds
of bubbles can leak through in just a few seconds.
For an experienced cardiologist, closing a PFO is relatively
simple.
Through an incision in the thigh, the surgeon threads a device
about the size of a nickel into the heart. Once there, the
gadget opens like an umbrella, covering the PFO. Over the
next several months, heart tissue grows over the device like
moss, fully closing the flap.
The procedure, which takes about 45 minutes, usually costs
$15,000 to $25,000.
No one knows how PFOs might trigger migraines. Many suspect
that the opening allows excess chemicals to reach the brain,
somehow spurring a headache.
"We think it allows chemicals to bypass the lung filter,"
says Dr. Peter Wilmshurst. A cardiologist at Royal Shrewsbury
Hospital in London, he has been one of the strongest proponents
of the PFO link.
Some believe the culprit could be neurotransmitters, particularly
serotonin. Wilmshurst notes that the lungs remove 98 percent
of circulating serotonin from the blood. He says that in people
with PFO, some of this serotonin might end up in the brain,
overloading the circuitry. Others think that blood clots,
too small to cause strokes, might somehow generate a migraine
pain response.
The PFO-migraine link remains mysterious in part because
the headaches themselves are not well understood. Most experts
think the ailment occurs when the brain misinterprets normal
nerve signals as painful. But the exact mechanisms are far
from clear.
Although some sufferers can control their headaches with
a variety of pain relievers and preventative medicines, many
of these medicines have side effects such as drowsiness or
constipation. A significant number of people find no relief
and must simply endure excruciating attacks. More than 40
percent get at least one migraine a week.
"Many patients are very dissatisfied with their current
treatments," said John Ahern, president of NMT, a Boston
company that makes a PFO closure device.
Take Marsh, the car restorer. Before having his PFO closed,
he was getting two or three headaches a week. When they hit,
he often had to spend the rest of the day lying quietly in
a dark room, waiting for the pain to subside.
Even the most ardent believers say that not all migraines
are caused by PFOs. A range of factors likely contributes
to the ailment, including stress, diet and sleep patterns.
But many long-suffering migraine patients are excited by the
prospect of an effective - and permanent - treatment.
When NMT began a trial of PFO closure in the United Kingdom,
it received an overwhelming response. "We had about 4,000
people trying to enroll, which is 10 times more than we needed,"
says Wilmshurst, one of the study's leaders.
NMT's study is the largest yet. Four-hundred migraine sufferers
with a PFO were divided into two groups; half had their PFOs
sealed, while the rest received sham surgery without actual
closure. Wilmshurst says results should be available by early
next year.
'Very convincing' "The preliminary results are very
convincing," says Ahern. The company expects to begin
a U.S. trial within a few months.
Three other companies that make PFO closure devices are also
planning migraine trials.
So far, few migraine patients have undergone the procedure.
In Europe, a handful of doctors have begun offering PFO closure
as a migraine treatment.
In the United States, the Food and Drug Administration, which
regulates medical devices, has given limited approval for
PFO closure but only for certain kinds of stroke. As a result,
the only people to get headache relief through PFO closure
have been stroke patients who also happen to have migraines.
Among this group - there are perhaps a thousand such patients
around the country - is Ray Gossett, a 72-year-old retired
dentist who lives in Riverton, Wyo. Since childhood he had
suffered from agonizing migraines, sometimes as many as three
or four a week. When he got a migraine, he often had to shut
his dental practice for the rest of the day.
Since having his PFO closed 18 months ago, Gossett has had
only three or four small headaches. "It was a dramatic
change," says his wife, Gail.
Not everyone is convinced: "We need to be very careful,"
says neurologist Stephen Silberstein, director of the Jefferson
Headache Center at the University of Pennsylvania. "We
don't know that [PFO closure] works." For one thing,
he says, some migraine patients experience more headaches
after having a PFO sealed.
He notes that the operation can have side effects, sometimes
causing the heart to beat out of rhythm. Even so, he thinks
the connection is plausible, and he is helping to organize
a migraine trial in the United States.
Neurologists - who see migraine as part of their domain -
tend to be more skeptical of the PFO theory than heart experts.
"Cardiologists are inherently more aggressive,"
says Sherman Sorensen, a Salt Lake City heart specialist who
operated on Marsh and Gossett.
He estimates that over the past decade he has closed more
than 1,000 PFOs, almost certainly more than anyone else the
country. The patients were all stroke victims, but about half
suffered from migraines; of those, 80 percent found relief.
"The neurologists say it's a placebo effect," he
says. "But the response is so dramatic, it's tough to
say it's a placebo."
David.Kohn@baltsun.com
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