MIST: First Study of Migraine Patients Finds High Rate of Heart Defect

Main Category: Headache / Migraine
Also Included In: Cardiovascular / Cardiology
Article Date: 25 May 2005 - 15:00 PDT

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Initial findings from MIST (Migraine Intervention with STARFlex(R) Technology), the first prospective clinical trial in migraine patients, today reported a higher rate of heart defects than previously expected at Europe's largest annual interventional cardiology conference in Paris, EuroPCR.

Dr Peter Wilmshurst, consultant cardiologist, Royal Shrewsbury Hospital and MIST co-lead investigator says: "In our evaluation of 370 migraine with aura patients we found that 59.5 per cent had heart defect. What is remarkable is that more than 40 per cent of the migraine patients studied had a large shunt allowing a flow of venous blood into the arterial circulation. This is six times greater than that usually observed in the general population."

"Interestingly this unusually high incidence was found in a group of people who have frequent migraine attacks with aura, but are otherwise healthy and have no symptoms to indicate a heart defect."

Previous studies have reported finding PFOs in 27 per cent of the general population(1,2) with only 7 per cent of them being large(2). PFO closure - currently used to treat certain types of stroke and decompression sickness - has been associated in some patients as a treatment, which eliminates or reduces the frequency and severity of migraine attacks(3,4,5) .

Dr Andrew Dowson, director, Headache Service, Kings College Hospital and MIST co-lead investigator says: "The initial data from MIST is intriguing. We are not certain what causes migraine headaches. If however, shunts like the PFO allow venous blood to enter the cerebral circulation, unfiltered and unmanaged by the lungs, perhaps that venous blood contains materials that trigger migraines in some patients. The next question the MIST study is designed to answer is whether closing the PFO with reduces or eliminates migraine headaches. We should be able to provide an answer to that question by the end of this year or early next year."

"There is currently no cure for migraine and undoubtedly, while some people manage with the available treatments for others it seriously affects their ability to live a normal life. This unprecedented rate of PFO is a major scientific breakthrough and the headache professionals will be looking to the results of this trial with Keen interest."

These defects will now be closed in half of the patients using an umbrella like device - STARFlex� - in a minimally invasive procedure, which avoids heart surgery. The other patients are randomised to a sham treatment, which mimics the procedure. Incidence of migraine will be followed for six months and at the end of the trial those in the sham group will be offered closure of their defect.

Around one in ten people suffer from migraine and it is estimated that around 15 per cent of migraines are accompanied by aura presenting as bright flashing lights, black spots or partial loss of vision and even pins and needles. Attacks normally last between 4 and 72 hours and commonly prevent the sufferer from carrying out normal day to day activities.

MIST is supported by the Migraine Action Association (MAA) and Migraine in Primary Care Advisors (MIPCA), with sponsorship from NMT Medical, Inc. (Nasdaq:NMTI), the manufacturer of STARFlex(R).

NMT Medical (http://www.nmtmedical.com) is an advanced medical technology company that designs, develops and markets proprietary implant technologies that allow interventional cardiologists to treat cardiac sources of migraine headaches, stroke and other potential brain attacks through minimally invasive, catheter-based procedures. More than 16,000 PFO's have been closed globally with NMT's minimally invasive, catheter-based implant technology. Its STARFlex(R) Technology is already commercially available in Europe under the CE Mark for use in closure of defects between the upper chambers of the heart.

More details of the clinical trial can be found http://www.mist-migraine.org

References:
1 Mayo Clin Proc 1984; 59:17-20
2 Clin Science 2000; 99:65-75
3 JACC 2005;45(4): 489-92
4 JACC 2005; 45(4):493-495
5 Lancet 2000; 356:1648-1651

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