A severe migraine attack can be agonizingly painful and accompanied by extreme light sensitivity and powerful nausea. Medications control some people's headaches, but for some sufferers no drug completely prevents debilitating attacks.
For such people, hope may come from a new clinical trial, conducted in part at Washington University School of Medicine in St. Louis. The trial offers an unexpected solution — doctors are closing a hole in the heart to try to fix the ache in the head.
AdvertisementAbout 600 million people around the world, including some 28 million Americans, get migraine headaches. Physicians and researchers suspect a link between migraines and a particular heart defect in some people.
The defect is called a patent foramen ovale or PFO. A remnant of fetal development, a PFO is a hole between the two upper chambers of the heart and is generally smaller than a pencil eraser. In about 25 percent of people, the hole stays partially open after birth, leaving a PFO, a tiny, flap-covered passage between the atria.
"A PFO serves as a strain valve," explains John M. Lasala, M.D., Ph.D., who oversees the Washington University portion of the migraine/PFO study. "If the pressure gets too high on the right side of the heart, the PFO can open, and blood can travel from the right to the left side. We think something usually cleared out by the lungs is in that blood and can trigger migraines."
Estimates now hold that PFOs are present in about half of migraine sufferers who experience aura — an arc of zigzag lines in the visual field, numbness of one side of the face, weakness or altered consciousness — and in about a quarter of those who don't have aura with their migraines.
Early results from a set of ongoing British clinical trials of PFO closure in migraine patients found a 37 percent reduction in migraine frequency and duration. Now the Washington University School of Medicine is one of 13 centers conducting a new trial called the ESCAPE trial. (ESCAPE stands for Effect of Septal Closure of Atrial PFO on Events of Migraine with Premere™.) Led by St. Jude Medical in Minnetonka MN, the study aims to close PFOs in 500 migraine patients who haven't responded well to current medications.
"We don't believe this will be a cure for all migraines," says Lasala, medical director of the cardiac catheterization laboratory and professor of medicine. "But even if it's effective in just 50 percent of migraine patients with PFOs, it could benefit a lot of people."
The apparatus used to close PFOs in the ESCAPE trial, invented by Dennis W. Wahr, M.D., of St. Jude Medical, delivers a small device to the heart through a vein in the leg. Once in place at the PFO, the tip of the device can be opened like a miniature umbrella with two opposing canopies that press on either side of the wall separating the atria.
"I designed Premere specifically for sealing PFOs — it has a very minimal, open architecture," Wahr says. "With a PFO, you just have to hold the door shut for a while until it heals, so you don't need a lot of metal and fabric."