By Cameron Johnston
BARCELONA, SPAIN -- September 5, 2006 -- A controlled clinical trial has determined that percutaneous repair of a patent foremen ovale (PFO) is effective in only a limited number of patients who experience severe refractory migraines with aura.
Overall, the study showed, the procedure is no more beneficial than a sham procedure and offers comparable efficacy rates to those seen in previous trials using medical management.
If it seems far-fetched that heart surgery could have an impact on migraine, it is not without good reason, according to principal investigator Andrew Dowson, MD, director, King's Headache Service, Kings College Hospital, London, United Kingdom.
Dr. Dowson presented the results of the trial results here on September 3rd at the European Society of Cardiology World Congress of Cardiology (WCC).
Nine previous studies have noted that people who have had PFO repaired for other reasons have also reported up to an 80% improvement in migraine headache frequency. However, these were all retrospective, observational studies, Dr. Dowson said.
In his trial, patients were randomized to either the PFO repair with the percutaneous catheter-fed STARflex shunt system or a sham procedure that amounted to a knock on the thigh (approved by a university safety and ethics board).
A total of 74 patients underwent PFO repair and 73 had the sham procedure. These patients had moderate to large sized PFO and experienced at least 7 migraines with aura per month, totaling at least 110 hours per month, Dr. Dowson said.
Three patients in each treatment group reported complete cessation or elimination of their migraines, while 42% of patients in the treatment arm and 23% in the sham arm reported at least a 50% improvement in migraine frequency.
These efficacy rates were not unlike what has been seen in 6 previous studies with drugs such as topiramate, divalproex gabapentin and propranolol. In those studies, response rates ranged from 37% to 54%, while the placebo rates were around 20% to 23%.
Although the study did not show a benefit to this procedure, it did show a benefit among patients whose PFO were considered large. In fact, 37% of subjects in this study had large PFOs compared with around 6% of the general population, so there could be some benefit for that population, Dr. Dowson said.
Percutaneous repair of a PFO is the most commonly performed noninvasive coronary surgery and is most commonly done in the setting of cryptogenic stroke, which itself has been associated with migraine headaches, particularly among younger female patients.
Although the trial did not show superiority of the procedure, it did demonstrate that there was a direct link between the size of the PFO and the likelihood of a patient experiencing migraines with aura.
[Presentation title: A Prospective, Multicenter, Randomised, Double-Blind, Placebo-Controlled Trial to Evaluate the Efficacy of Patients Foramen Ovale Closure With the Starflex Septal Repair Implant to Prevent Refractory Migraine Headaches: The MIST Trial. Abstract 126]
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