Effect on migraine of closure of cardiac right-to-left shunts to prevent recurrence of decompression illness or stroke or for haemodynamic reasons

Background A relation between migraine with aura and cardiac right-to-left shunts has been reported. Right-to-left shunts are also associated with str oke and certain forms of decompression illness. We investigated the effect of closure of right-to-left shunts on migraine symptoms. Methods A consultant neurologist, who was unaware of information about resi dual shunt, undertook a structured interview with individuals who had had t ranscatheter closure of an atrial septal defect or patent foramen ovale to assess how the procedure affected migraine symptoms. Findings 37 of 40 consecutive patients who had had a closure procedure (to permit resumption of diving after decompression illness in 29, after stroke when paradoxical thromboembolism was suspected in four, or to close a larg e atrial septal defect in lour) could be contacted. 21 (57%) had a history of migraine before the procedure (with aura in 16, without aura in five). 1 1 individuals had fortification spectra in the period immediately after clo sure. During long-term follow-up, no migraine symptoms were reported by sev en individuals who had previously had migraine with aura and three who had previously had migraine without aura. Eight others who had had migraine wit h aura before closure reported improvement in frequency and severity of mig raines. Three tone migraine with aura, two migraine without aura) reported no alteration in migraine episodes. Interpretation These observations suggest a causal association between righ t-to-left shunts and migraine with aura. There may be a subgroup of patient s who have severe migraine associated with a large right-to-left shunt in w hom closure of the atrial defect may improve or abolish migraine.