Washington, Feb 17: A catheter-based closure of patent foramen ovale (PFO)-a slight opening in the wall between the right and left atria-can help reduce the frequency and severity of disabling migraines in sufferers.

The new finding support previous studies that demonstrated that when a PFO is closed, whether it''s following a stroke or decompression illness, migraine also tends to improve in almost 75 percent of cases.

But the current study was the first to recruit patients with severe migraine, a large PFO and no history of stroke or transient ischemic attacks, but with silent brain lesions on magnetic resonance imaging.

"The study suggests closure of a large PFO may improve migraine in patients with subclinical brain lesions, as well as those with prior strokeIn the past, the beneficial effect on migraine was occasionally seen after PFO closure was performed for other reasons, for example, unexplained stroke," said Carlo Vigna, M. D., of Casa Sollievo della Sofferenza IRCCS Hospital, San Giovanni Rotondo, Italy.

He added: "Conversely, the recently published MIST trial did not show significant improvement of symptoms in ''pure migraneurs'' in the absence of symptomatic or subclinical cerebral ischemia. As compared with these two extremes, we enrolled patients with an intermediate subset of characteristics."

For the study, the researchers divided the patients into either the closure (n=53) or control (n=29) group based on their consent to undergo percutaneous PFO closure, and prospectively examined for 6 months.

It was found that in comparison to the medically treated control group, closure of a PFO resulted in greater numbers of patients who had cessation of migraine attacks, cessation of disabling attacks and over 50 percent reduction in migraine attacks.

But the researchers said that despite the success, a larger randomised trial focusing on this patient population is needed.

Also, the relationship between PFO and migraine must be further examined and understood.

"We don''t really know what''s going on. A stroke could be caused if a blood clot passes across a PFO and travels to the brain, but with migraine we don''t yet know what the trigger substance is that crosses the shunt. Not everyone with migraine has a PFO, and not everyone with a PFO has migraine; there are other causes that we don''t yet understand," said Dr. Peter Wilmshurst, Royal Shrewsbury Hospital, United Kingdom.

The study has been published in the latest issue of JACC: Cardiovascular Interventions. (ANI)