Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age.
BACKGROUND
A number of studies has addressed the possible association between patent foramen ovale (PFO) and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke.


METHODS
To address the role of PFO for the occurrence of cerebral ischemia, we investigated the prevalence of right-to-left shunt in a large group of patients with acute stroke or TIA. 763 consecutive patients admitted to our hospital with cerebral ischemia were analyzed. All patients were screened for the presence of PFO by contrast-enhanced transcranial Doppler sonography at rest and during Valsalva maneuver. Subgroup analyses were performed in patients stratified for gender, age and origin of stroke.


RESULTS
A right-to-left shunt was detected in 140 (28%) male and in 114 (42%) female patients during Valsalva maneuver, and in 66 (13%) and 44 (16%) at rest respectively. Patients with right-to-left shunt were younger than those without (P < 0.001). PFO was associated with stroke of unknown origin in male (P = 0.001) but not female patients (P > 0.05). After adjusting for age no significant association between PFO and stroke of unknown origin was found in either group.


CONCLUSIONS
Our findings argue against paradoxical embolization as a major cause of cerebral ischemia in patients with right-to-left shunt. Our data demonstrate substantial gender-and age-related differences that should be taken into account in future studies.
Department of Neurology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaningerstr. 22, 81675 Muenchen, Germany. poppert@neurovasc.de
Holger
H
Poppert
Melanie
M
Morschhaeuser
Regina
R
Feurer
Angelina
A
Bockelbrink
Jens
J
Schwarze
Lorena
L
Esposito
Peter
P
Heider
Dirk
D
Sander
Bernhard
B
Hemmer
D000367:Age Factors; D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000209:etiology*; D005260:Female; D054085:Foramen Ovale / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D017585:Ultrasonography, Doppler, Transcranial; D014636:Valsalva Maneuver