About 27% of the population has a patent foramen ovale (PFO), an unsealed septum between the 2 atria in the heart. Over the years, researchers have linked PFO with migraines but no one has established a definitive connection.
Researchers from the University of Birmingham Centre for Cardiovascular Sciences, City Hospital in Birmingham, United Kingdom, reviewed relevant literature to assess the relationship between PFO and migraine attacks. They also sought to examine whether closing the PFO would improve migraine symptoms. Their study included 20 articles on the association between PFO and migraine and 21 articles on the effect of PFO closure on migraine.
The results showed a high prevalence of PFO among migraineurs, ranging as high as 66.5%. However, the researchers found a “noticeable difference” between the presence of PFO in migraine with aura and migraine without aura. In patients with aura, the prevalence of PFO ranged from 46% to 88%, compared with 16% to 35% in migraineurs without aura. Moreover, in the one study that looked at both typical and atypical aura in migraine, patients with atypical aura had a PFO prevalence of 79%, compared with 46% in those with typical aura.
Data from 8 case control studies allowed a comparison between the general population and migraineurs. Those studies found 16% to 26% of the general population had a PFO, compared with 27% to 96% of migraineurs with aura, and 23% to 72% of migraineurs without aura.
Findings from the 18-case series on the effect of PFO closure were varied. Resolution of migraine with aura ranged from 29% to 92%, and from 14% to 83% in migraine without aura. The range of improvement among patients with aura also varied widely: from 1 patient (4%) in one study to 9 (64%) in another. Similarly, improvement ranged from 0 to 15 patients (68%) with migraine without aura.
Only 1 published prospective, randomized controlled study found that closing the PFO improved migraine. In that trial, 74 patients were randomly assigned to closure with septal repair implant and 73 underwent a sham procedure. Migraines ceased in 4.05% of patients who underwent the real procedure and 4.11% of those who underwent the sham procedure, so the difference was not significant. However, an exploratory analysis that excluded 2 study result outliers found that the implant group had a greater reduction in total migraine headache days (P = .0027).
Each study varied in the length of follow-up. Several chose only to document full resolution and did not distinguish between improvement and no change in migraine attacks. Most of the studies also failed to provide data on whether patients had worsening or no change, or sample sizes were too small to make reliable comparisons. The most important difficulty, however, according to the review authors, was the placebo effect, which in migraineurs ranged from 35% to 40% and could have had “significant effects” on the outcomes.
Given the irregular results and dearth of randomized trial data, the authors suggest further large randomized trials.
Source
Lip PZ, Lip GY. Am J Med. 2014;127(5):411-420.
doi: 10.1016/j.amjmed.2013.12.006.
