Hello and welcome to MigraineCast the weekly podcast brought to you by MyMigraineConnection.com and the HealthCentral Network. Over the last few years, more and more questions have arisen about patent foramen ovale -- PFO for short -- and its possible connection to Migraine disease. A PFO is a hole in septum, the wall that separated the chambers of the heart. We all have them during fetal development, but they usually close by birth.
The right side of the heart receives blood and pumps it to the lungs for oxygenation. The blood then goes through the left side of the heart to be pumped to the brain and other organs. A PFO can allow blood that hasn't been oxygenated by the lungs to get into the left side of the heart, thus being pumped to the brain and other organs. If this happens, the body doesn't get enough oxygen. It's also possible that blood clots can pass through the PFO and cause a stroke. PFO is diagnosed with a TEE (transesophageal echocardiogram), which is performed by passing an ultrasound probe down the esophagus, near the heart to get better results than the traditional echocardiogram, which is performed with a standard ultrasound wand outside the chest.
Research has shown a higher prevalence of PFO among Migraineurs than among people without Migraine. Small observational and case-control studies indicate that patients with stroke of unknown origin have a higher incidence of PFO. You may remember the stroke that Ariel Sharon experienced in January of 2006. It was caused by a PFO.
So, what does all of this mean for Migraineurs? It's theorized that a PFO causing unoxygenated blood to be circulated to the brain may trigger Migraines. In 2004, research was published that seemed to confirm this theory. The problem with that research was that the studies asked patients for information about headaches and Migraines that occurred in the past as opposed to gathering information at the time of the episodes. Also, the data for this research was gathered from studies performed to evaluate PFO and stroke. Thus, more conclusive research is needed before the connection between PFO and Migraine can be evaluated and PFO closure considered as a treatment for the prevention of Migraine. This research is underway now.
One such trial, the MIST trial has already concluded in England. MIST stands for Migraine Intervention with STARFlex Technology. This is a small closure device that resembles an umbrella. It's inserted into the heart via a catheter. Once through the PFO, it opens to close the PFO. The MIST trial resulted in a 37% reduction in Migraine burden - the number of Migraines multiplied by the length, in hours -- in those patients who received a STARFlex® implant and a 17% reduction in those who received the procedure and no implant -- essentially a placebo procedure.
There are trials in the enrollment phase and in progress in the U.S. now. The results of these trails will be used to determine the potential value of PFO closure for Migraine prevention and to allow manufacturers to request FDA approval of devices used to perform the closure. At this time, if you are diagnosed with a PFO, the closure procedure is not available for Migraine prevention except through the clinical trials. There are two main Web sites where you can get more information and see if you qualify for these trials.* The Web addresses for these sites will be published online with the transcript of this podcast.