Prevalence and extent of right-to-left shunt on contrast-enhanced transcranial Doppler in Chinese patients with migraine in a multicentre case-control study.

Background The association between RLS and migraine is still debated. The aim of this study is to investigate the prevalence and grade of RLS in Chinese patients with migraine and to evaluate the relationship between RLS and migraine. Methods A multi-center case-control study of contrast-enhanced transcranial Doppler was conducted in 931 consecutive patients with migraine (240 of 931 had migraine with aura and 691 of 931 were in the migraine without aura group) and 282 were healthy adults. Clinical trial no. NCT02425696. Results The prevalence of RLS was 63.8% and 39.9% in the migraine with aura group (MA+) and migraine without aura group (MA-), respectively, significantly higher than that of the healthy group (29.4%, p < 0.001; p < 0.001). The positive rate of large RLS in the MA+ group and MA- group was 32.1% and 16.5%, respectively, significantly higher than healthy group (6.4%, p < 0.001; p < 0.001). There was no difference among groups in terms of positive rate of permanent RLS ( p = 0.704). Conclusion This multi-centre case-control study suggested that there is an association between RLS and migraine with and without aura, especially when the shunt is large.