News extra

Nearly half of patients with migraine with aura are found to have a heart defect, study finds

Abergavenny Roger Dobson

A study has found that nearly half of a group of patients with long term migraine with aura had a heart defect. The defect was a right to left shunt caused by a patent foramen ovale.

The study, by cardiologists and neurologists at University Hospital, Bern, Switzerland, appeared online ahead of print publication on 7 September in Neurology (www.neurology.org/papbyrecent.html ). It used transoesophageal contrast echocardiography to examine the participants.

The study looked at a group of 93 patients who had had migraine with aura for an average of 18.5 years and 93 healthy control patients without migraine. The most common right to left shunt in adults, a patent foramen ovale (a remnant of fetal circulation), is present in around a quarter of the general population.

Forty four of the patients with migraine with aura and 16 of the control patients had the defect (odds ratio 4.56 (1.97 to 10.57)).

Among the patients in both groups with the defect, shunt size was on average larger in the patients with migraine with aura than in the control patients, and the presence of a moderate sized or large shunt increased the odds of having migraine with aura by 7.78 (95% confidence interval 2.53 to 29.3).

"Nearly half of all patients with migraine aura had a patent foramen ovale, and if present, the shunt size was larger when compared with the corresponding control group," wrote the authors. "The presence of a more than small cardiac shunt increased the odds of having migraine with aura nearly 8-fold.

"The uniqueness of this study is the use of transesophageal contrast echocardiography to prove that these shunts were patent foramina ovalia."

The finding of a larger shunt size in patients with migraine with aura than in the control patients suggests a causal link, the authors say. "The dose–response relationship between shunt size and migraine likelihood lends further support to a causal association between them.

"We acknowledge that other factors are certainly as important in migraine pathophysiology as right to-left shunting, simply because a patent foramen ovale is present in only half of patients with migraine with aura," they write.

The authors say that a randomised clinical trial to investigate the effects of shunt closure on migraine frequency is now needed to verify the hypothesis that a patent foramen ovale contributes to migraine attacks.

Although the causal link between patent foramen ovale and migraine is still being investigated, a number of theories have been proposed. One is that substances such as serotonin pass through the ovale, bypass pulmonary circulation, and trigger a migraine attack. Another is that an embolism may pass through the right to left shunt. This theory is supported by a reduced frequency of migraine seen in patients who are started on oral anticoagulation. This observation cannot be explained by the serotonin theory, the authors say.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• (2005). Hit parade. BMJ 331: 1277-1277 [Full text]  
• Hall, G H (2005). Do GPs deserve their pay rise?: IBM is replacing EBM. BMJ 331: 966-966 [Full text]  
• Wheatley, G. (2005). Do GPs deserve their pay rise?: Of course successful hard work deserves reward. BMJ 331: 965-965 [Full text]  
• Colligan, D. (2005). Do GPs deserve their pay rise?: What do GPs earn?. BMJ 331: 965-965 [Full text]  
• Rosin, R. (2005). Do GPs deserve their pay rise?: Do chief executives deserve their pay rises?. BMJ 331: 965-966 [Full text]  

Rapid Responses:

Read all Rapid Responses

PFO in migraine and therapeutic PFO-closure for migraine: “innovation” versus scientific equipoise

Vinod K Gupta
bmj.com, 9 Oct 2005 [Full text]