Microembolic air load during contrast-transcranial Doppler: a trigger for migraine with aura?
BACKGROUND
There is a well-known association between migraine with aura (MA) and right-to-left shunt (RILES) because of patent foramen ovale (PFO). The occurrence of MA attacks after microbubble (MB) injection during contrast-enhanced transcranial Doppler (ce-TCD) has been recently described.


OBJECTIVE
The aim of this study was to analyze the prevalence of RILES in a consecutive cohort of MA patients and to characterize the occurrence of MA attacks after diagnostic ce-TCD.


METHODS
A total of 159 consecutive MA patients underwent ce-TCD with air-mixed saline to disclose RILES. RILES was characterized in terms of MB amount (small-moderate or large) and occurrence at rest and/or during Valsalva maneuver (permanent or latent).


RESULTS
RILES was revealed in 79/159 patients (∼ 50%). Permanent RILES were detected in 56/79 (71%) and latent RILES in 23/79 (29%) MA patients. The occurrence of a typical MA attack was overall observed in 12/159 patients (7.5%; 95% CI: 4-12.8%), but arose only in RILES-positive ones, immediately after ce-TCD (12/79; 15.2%; P< .001). All 12 patients had permanent RILES (12/56; 21.4%; P= .015) and MA attack was mostly observed in large RILES-positive patients, even without statistical significance (P= .118).


CONCLUSIONS
Microembolic air load could act as a trigger of MA attack. According to recent studies and to the clinical characteristics observed in our patients, microembolization because of MB injection might provoke a decrease in cerebral oxygen saturation, thus triggering cortical spreading depression and, thereafter, MA attack. Larger and prospective studies will be necessary to confirm our data and observe a wider correlation.
Department of Cerebrovascular Diseases, Neurological Institute C. Besta, Milan, Italy.
Luigi
L
Caputi
Susanna
S
Usai
Maria R
MR
Carriero
Licia
L
Grazzi
Domenico
D
D'Amico
Chiara
C
Falcone
Gian P
GP
Anzola
Massimo
M
Del Sette
Eugenio
E
Parati
Gennaro
G
Bussone
D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D004618:Embolism, Air / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D005260:Female; D054092:Foramen Ovale, Patent / Q000453:epidemiology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D045423:Microbubbles / Q000009:adverse effects; D008875:Middle Aged; D020325:Migraine with Aura / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods; D055815:Young Adult