All patients in the MIST study had general anesthesia and transesophageal echocardiography before randomization to determine the presence and size of the PFO. Patients who were assigned to the sham intervention woke up from anesthesia with a cut in the groin just as treated patients did. To further avoid the possibility of a placebo effect or bias in determining the effect of PFO closure on migraine frequency and severity, all patients were evaluated at monthly intervals over six months by neurologists unaware of which group the patients had been assigned to. If PFO closure works as hoped, it could help an estimated one in three patients with severe migraine, Dr. Wilmshurst said.
Dr. Wilmshurst and co-principal investigator Dr. Andrew Dowson, director of the Headache Service at King's College Hospital, London, England, will present the results of the MIST trial at a Late Breaking Clinical Trials session on Monday, March 13, at 9:00 a.m.