Cardiac surgery may ease migraine

Apparent link found between heart, headaches

October 09, 2005|By DAVID KOHN | DAVID KOHN,SUN REPORTER

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.

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