By Tina Hesman Saey, St. Louis Post-Dispatch, August 29, 2007

Doctors soon will know whether sealing a small hole in the heart can cure a big pain in the head.

In worldwide clinical trials, researchers are closing a passageway through the heart in migraine sufferers and then waiting to see if the headaches go away or get better.

The first clue of a possible link emerged when stroke patients underwent experimental procedures to close the passage. Some patients who had suffered from migraines reported that the intense headaches disappeared or were greatly diminished after the operation, said Dr. John M. Lasala, director of the Cardiac Catheterization Lab at Barnes-Jewish Hospital.

Lasala is one of several area doctors participating in trials involving hundreds of patients. Currently, there are three major trials taking place at sites across the globe.

For more than 30 million Americans, migraines are a painful and often debilitating part of life. People with the severe headache change their diets, avoid certain aromas (even pleasant ones), move to different climates, pop supplements and take prescription medication in an effort to control their migraines.

For many sufferers, none of those measures is effective. The heart trials could reveal why millions of people haven''t responded to common treatments and offer them relief.

The passage through the heart is known as the patent foramen ovale, or PFO, a small hole that helps fetuses circulate oxygen-rich blood while in the womb. It usually closes after birth, though about 25 percent of people still "walk around with a hole in their heart" and are none the wiser, Lasala said.

When people with the open passage strain, cough or sneeze, the flaps can be forced open, allowing unfiltered, oxygen-poor blood to flow through the passage and into the rest of the body and brain.

Doctors suspect that the mixture of oxygen-carrying blood with oxygen-poor blood may set off inflammation that attacks the brain, triggering migraines in people already prone to the headaches.

But the hole itself doesn''t cause migraines, said Dr. James Banks, a headache specialist and associate director of the Ryan Headache Center and Mercy Health Research at St. John''s Mercy Medical Center.

Many migraine sufferers don''t have such an opening in their hearts, and plenty of people who have the hole never have migraines, said Banks, who is also participating in the trials. And there are many cases of people who continue to have migraines even though the hole is closed.

Still, people with certain types of migraines, especially those with aura - warning signs like blurred vision or flashes of light - are twice as likely to have the opening than people who don''t have migraines, Lasala said.

While the PFO usually goes unnoticed, it can allow small blood clots to pass through and cause strokes. In people under age 50, about a quarter to half of strokes are caused by clots passing through the patent foramen ovale.

Brenda Hoock, 45, of Waterloo, had suffered from migraines since she was 7. They became so frequent that she had stashes of aspirin and migraine medicine in her purse, her glove compartment, and anywhere else she goes.

Hoock was skeptical that she would be a candidate for the trial. She was pretty sure she would have known if she''d had a hole in her heart, she said.

"I was like ''Yeah, right. I have a hole in my heart,''" Hoock said.

The PFO doesn''t murmur like other valve defects and it doesn''t disrupt the heartbeat, so it can only be detected through specialized tests, Lasala said.

Hoock had the opening, and she quickly signed on to the study. "At that point in time, I was ready to go to a witch doctor or do voodoo," she said.

The procedure involves threading a catheter through the leg into the heart. A device is then inserted into the heart where it holds the flaps together until scar tissue seals them.

Hoock has been migraine-free more than a year since undergoing the procedure.

The results probably won''t be as dramatic for everyone, Lasala said. A European trial found that 40 percent of people who had the hole repaired said their headaches were less frequent or didn''t last as long. Researchers had hoped to eliminate migraines entirely in at least half of the people in the trial.

"This is not a universal or complete cure for migraine," Lasala said.

People with migraines who have the open passage should think carefully about having the procedure, Banks said.

"There''s not a lot of data to say that you should have the hole in the heart repaired just because of headache," Banks said. "Other studies haven''t been that convincing. That''s why we''re doing the trial."