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

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.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, and10 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, p0.0001). WML load was then correlated between patients with and without RLS.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 (p0.001).The presence of right-to-left shunt does not increase white matter lesion load in patients who have migraine with aura.