PFOs Do Not Cause Migraines

For years, cardiologists have postulated a cause-and-effect relationship between migraine headaches and patent foramen ovale (PFO). (The foramen ovale is a hole between the right atrium and left atrium that is important during development of the fetus. Normally a flap of tissue closes up the foramen ovale after birth, but in some individuals the flap does not produce complete closure. These individuals are said to have PFO. Read all about PFOs here.) Such a relationship would mean that closing a PFO might benefit patients who have migraines.

The postulated relationship between PFOs and migraines has been greeted with great enthusiasm by migraine sufferers and by cardiologists (who are well-paid for performing the closure procedures), and has led companies who make PFO closure devices to embark on clinical trials to demonstrate how well PFO closure works in treating migraines. However, the idea that PFOs cause migraines has (it has seemed to me) always been supported more by wishful thinking than by plausible theory.

And sure enough, the notion that PFOs cause migraine headaches has taken two major blows in recent months.

First, in March, the journal Circulation published the results of the MIST trial, which showed that closing PFOs in patients with severe migraines did not affect the headaches in any way.

And last week, data from the Northern Manhattan Study (NOMAS) strongly suggested that there is not even an association between PFO and migraine headaches, let alone a cause-and-effect relationship. In NOMAS, over 1100 patients were questioned regarding a history of migraines, and then had echocardiograms to look for PFO. While 16% of the patients reported migraines and 15% had PFO on echocardiography, there was no association between the two. That is, patients without migraine were just as likely to have PFO as patients with migraine. Indeed, only 2% of patients turned out to have both.

NOMAS is the first study to systematically screen patients for both migraine and PFO, and it has shot a huge hole in the notion that PFOs are associated with (or cause) migraines. It is now extremely unlikely that clinical trials trying to show that PFO closure can improve migraines will yield positive results. Indeed, based on the results of NOMAS, at least one company has already canceled one of these trials.

The bottom line is that there is little or no reason at this point to suppose that closing PFOs can successfully treat migraine headaches, or even that the two conditions are related to one another. Migraine sufferers should look elsewhere for relief, and cardiologists should look elsewhere for income.

_Sources:

Dowson A, Mullen MJ, Peatfield R, et al. Migraine Intervention With STARFlex Technology (MIST) trial. A prospective, multicenter, double-blind, sham-controlled trial to evaluate the effectiveness of patent foramen ovale closure with STARFlex septal repair implant to resolve refractory migraine headache. Circulation 2008; 117:1397-1404.

Rundek T, Elkind MSV, Di Tullio MR, et al. Patent foramen ovale and migraine. A cross-sectional study from the Northern Manhattan Study (NOMAS). Circulation 2008; 118:1419-1424.