Prevalence of Right to Left Shunts in Japanese Patients with Migraine: A Single-center Study

Objective Several studies have shown an increased prevalence of right-to-left shunt (RLs) in migraine patients, particularly those with aura. However, the prevalence of RLs and its relation to Japanese patients with migraine are unknown. We investigated the prevalence of RLs in Japanese patients with migraine. Methods In total, 112 consecutive patients with migraine were recruited from our headache outpatient clinic. Migraine with aura (MA) and migraine without aura (MWOA) were diagnosed according to the International Classification of Headache Disorders, 3rd edition (beta-version). Contrast transcranial Doppler ultrasound was used to detect RLs, including patent foramen ovale (PFO). Then, the associations between RLs and patients' backgrounds and presence of aura were assessed. Results The overall prevalence of RLs and PFO in migraine patients was 54.5% and 43.8%, respectively. The prevalence of RLs and PFO in the MA group were significantly higher than in the MWOA group (RLs, 62.9% vs. 44.0%, p=0.046; PFO, 54.8% vs. 30.0%, p=0.008). There were no marked differences in the prevalence of large, middle and small shunts between MA and MWOA patients. Compared with the MWOA patients, the MA patients were younger (p=0.013) and had early onset age (p=0.013) and increased prevalence of photophobia (p=0.008). Conclusion RLs were found in over half of the Japanese patients with migraine. Our study suggests a possible link between RLs and MA.