Right-to-left shunt does not increase white matter lesion load in migraine with aura patients

BACKGROUND: White matter lesions (WMLs) are commonly found on brain MRI of migraine patients. Migraine with aura (MA+) is associated with an increased frequency of right-to-left shunt (RLS) mostly due to patent foramen ovale. The relationship between WML load and RLS in MA+ is currently unknown. METHODS: MA+ patients were consecutively enrolled as part of the Shunt Associated Migraine (SAM) study. Patients underwent a standardized headache and vascular risk factors questionnaire, contrast-enhanced transcranial Doppler, blood coagulation tests, and brain MRI. RLS was categorized into four grades: no shunt, <10 microbubbles (mb), >10 mb single spikes pattern, and >10 mb shower/curtain pattern. Standard and fluid-attenuated inversion recovery T2-weighted MRI sequences were inspected for WMLs by three independent raters blinded to RLS grade. WML load was scored in the periventricular areas (PV-WMLs) with the Fazekas scale and in the deep white matter (D-WMLs) with the Scheltens scale. Interobserver agreement was good to excellent (kappa = 0.64 to 0.96, p < 0.0001). WML load was then correlated between patients with and without RLS. RESULTS: One hundred eighty-five patients (77% women) were included. PV-WML load was similar between patients with and without RLS. D-WML load decreased in patients with RLS (p = 0.045). On logistic regression analysis, only age was associated with WMLs (p < 0.001). CONCLUSIONS: The presence of right-to-left shunt does not increase white matter lesion load in patients who have migraine with aura.