SCOTTSDALE, ARIZ. — Existing data suggest that a subset of migraine patients may benefit from closure of their patent foramen ovale, Dr. David W. Dodick said during a symposium sponsored by the American Headache Society.
However, any clinical decision of the merits of surgical closure of a patent foramen ovale for patients with migraine should await the results of a number of ongoing safety and efficacy trials, he stressed.
Closures are being done with regularity as a treatment for migraines in the United States and Europe despite the lack of safety and efficacy data. “This [procedure] is gathering momentum, to say the least. We have a responsibility to know the data and give patients proper and appropriate advice,” said Dr. Dodick, professor of neurology at Mayo Clinic Arizona. “This is something patients will come into your office wanting to talk about, if they haven't already.”
Physicians are in a tough spot between patient demand and a dearth of data to support patent foramen ovale (PFO) closure for migraine relief, he acknowledged.
Some research indicates an association between a PFO and migraines with aura, particularly in patients with a large left-to-right shunt. In one study, patients with migraine with aura were three times more likely to have a PFO than those who experienced migraines without aura (Neurology 1999;53:2213–4).
The main take-home message for now remains that PFO appears to be more prevalent in patients whose migraines involve aura, Dr. Dodick said.
A left-to-right shunt is also more common among migraine-with-aura patients. In addition, both large atrial shunts and large PFOs are dominantly inherited and might therefore share a genetic origin (Heart 2004;90:1315–20).
One of the large, prospective trials underway is the Migraine Intervention with STARFlex Technology (MIST) study. Patients with migraine with aura will be assessed by a cardiologist and then randomized to closure or no closure.
Although results are not finalized, enrollment data show 60% of 370 participants having a right-to-left shunt (versus 27% of the general population) and 38% having a large PFO (versus 7% of the general population).
Updates and an animation that shows a possible role of PFO in migraine can be viewed on www.migraine-mist.org
PFO closure might effectively treat migraine in a subgroup of patients, Dr. Dodick proposed. A number of studies suggest that closure eliminates migraines in about one-third of migraineurs, reduces frequency in another third, and does not alter attacks in another third of patients.
“Are there factors that will reliably predict which patients will benefit? If these studies are positive, how will we know that a patient in front of us in the future will benefit significantly from this invasive procedure?” he asked.
Many headache specialists are taking a conservative stance. “While many patients have disabling migraines, many people think migraines are not life threatening. They are life altering but not life threatening,” Dr. Dodick. “And the surgery is invasive.” There is an overall peri-interventional adverse-event rate of about 6% (Catheter Cardiovasc. Interv. 2004;62:512–6).
Some physicians do not believe PFO closure will make a difference. They oppose the prospective, controlled trials underway in the United States and Canada. However, Dr. Dodick said, “like it or not, the studies are being done—which I think is good.”