Right-to-Left Shunt and the Clinical Features of Migraine with Aura: Earlier but Not More

BACKGROUND: The causal relationship between patent foramen ovale (PFO) and migraine with aura (MA) is controversial. We aimed at exploring whether attack clinical features relate to the presence of right-to-left shunt (RLS) in MA patients. METHODS: We retrospectively examined a cohort of consecutive patients diagnosed with MA in our headache center and undergoing transcranial doppler (TCD) for RLS detection. We collected from our clinical electronic dossiers, clinical features of MA attacks (type, frequency, duration of aura phenomenon, trigger factors, onset age), family history for MA, thrombophilia genotypes, and the response to preventive treatments. RLS was stratified for severity according to the results of the TCD examination. RESULTS: We found 111 patients. Binary logistic regression analysis showed that among features of MA attacks, only onset age was associated with the presence of RLS (p < 0.0001). Patients with RLS presented the first MA attack at a younger age (p < 0.0001). The greater RLS severity, the younger was onset age (p < 0.00001) and the presence of atrial septal aneurysms (ASA) was associated with a further decrease in onset age (ρ = -539, p < 0.00001). Family history for MA was associated with the presence of RLS (chi-square p = 0.022). Response to preventive treatments was not influenced by the type of treatment (antiplatelet compared with no antiplatelet drugs), comorbidity with migraine without aura, RLS presence, or by their double interactions (Logistic regression, consistently p > 0.05). CONCLUSION: Our findings support the hypothesis that although PFO does not influence MA attack frequency, it is not merely a bystander in MA physiopathology, as RLS, its severity, and the presence of ASA possibly make a difference in the disease history.