, according to a discussion at the 2023 Scottsdale Headache Symposium.
In two clinical trials evaluating whether PFO closure reduces migraine risk, the primary endpoints were not met, but a signal of benefit on secondary endpoints and the association between PFO, migraine, and stroke are among the reasons that PFO closure should be reevaluated, according to Andrew Charles MD, Director of the Goldberg Migraine Program, University of California, Los Angeles.
UCLA
Dr. Andrew Charles
Other right-to-left shunt defects have also been associated with both migraine and stroke, leading Dr. Charles to suggest these defects are more a common denominator.
“Stroke during a migraine is, in fact, very uncommon,” Dr. Charles said. “This raises the possibility that it is not the migraine causing the stroke but rather there is a shared risk factor for stroke and migraine,” said Dr. Charles, referring to PFO as well as other right-to-left shunt defects, such as hereditary hemorrhaging telangiectasia in the lungs.
One Intervention, Two Potential Benefits
Fixing these defects is therefore at least theoretically attractive for preventing both migraine and stroke, but Dr. Charles said the opportunity for preventing both migraine and stroke is most attractive in migraine patients who have additional stroke risk factors.
Use of oral contraceptives, which produce a hypercoagulable state, is an example.
“Are these the people we should really be thinking about if they have PFO and migraine, particularly migraine with aura?” Dr. Charles asked.
The association between right-to-left shunts and migraine is strong. Although PFO is common, presenting in 20%-25% of the adult population, it has been found in up to 50% of individuals who have migraine with aura. In patients with migraine but no aura, the prevalence of PFO has been estimated to be approximately 35% or still somewhat elevated relative to the general population.
Primary Endpoint Missed in Clinical Trials
The question of whether risk of migraine can be reduced with repair of PFO or other right-to-left shunts remains unresolved. In two high-quality randomized trials undertaken in PFO repair, neither met its primary endpoint. In one of these, called PRIMA, which was terminated early for slow enrollment, the reduction in mean headache attacks was not significant relative to medical therapy.
In the second, called PREMIUM, device closure of PFO also failed to significantly reduce migraine attacks over sham procedure although it was associated with complete migraine remission (10% vs 1%).
A pooled analysis of these two studies that was conducted subsequently concluded that PFO closure reduces mean monthly migraine days (-3.1 vs. -1.9 days; P = -.02) and increases the likelihood of complete migraine cessation (9% vs. 0.7%; P < .001), but Dr. Charles pointed out the primary endpoint was migraine attacks not migraine days, so other analyses can only be considered hypothesis-generating.
There are several reasons to relook at the relationship between migraine and PFO but the potential to prevent both migraine and stroke with PFO closure could be one of the most important.
Several years ago, Dr. Charles and his coinvestigators from UCLA evaluated more than 700 ischemic strokes. Of these, 127 strokes were characterized as cryptogenic because of lack of another identifiable etiology. While 59% of these patients had PFO, which is several times higher than the general population, the prevalence of PFO in patients with a cryptogenic stroke and a history of migraine was 79% in this published study.
“So, in this group of patients who did not have any other clear cause for a stroke, a diagnosis of PFO was very much overrepresented,” Dr. Charles said.