Patent foramen ovale and transcranial Doppler. Comparison of different procedures.
OBJECTIVE
The capability of transcranial Doppler sonography (TCD) to detect a patent foramen ovale (PFO) has been established. However, which provocative maneuver and what timing of contrast injection are most effective to induce a right-to-left shunt has not yet been determined.


METHODS
We selected 38 cerebrovascular patients (21 men, 17 women) with positive contrast study for PFO on transesophageal echocardiography. Patients underwent a TCD with bilateral monitoring of the middle cerebral arteries (MCAs) and injection of a contrast solution. The injection was repeated (1) during normal breathing (basal conditions); (2) before Valsalva maneuver (VM); (3) during VM; (4) immediately after VM; and (5) during cough. The latency time and the total number of microbubbles for each side were recorded.


RESULTS
TCD found positive results for PFO in 30 patients. Twenty were positive even during basal conditions. The number of positive cases varied according to the timing of the VM in relation to the contrast injection: 28, 25, and 27 cases were positive when the injection was performed before, during, and after VM, respectively, while 26 were positive during cough. There were significant differences in the number of microbubbles in the MCAs between the procedures (P < .001, ANOVA): the highest number was detected in the injection before VM and the lowest number during basal conditions (P < .001, Wilcoxon's test with Bonferroni's correction). The latency time was significantly shorter when the injection followed VM.


CONCLUSIONS
The injection performed before VM appeared to be the most effective TCD procedure in determining the transit of microbubbles through a PFO and subsequently in the MCAs.
Zanette
E M
EM
Department of Neurological Sciences, University La Sapienza, Rome, Italy.
Mancini
G
G
De Castro
S
S
Solaro
M
M
Cartoni
D
D
Chiarotti
F
F
D000328:Adult; D000368:Aged; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D003287:Contrast Media; D017548:Echocardiography, Transesophageal; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008870:Microtubules / Q000000981:diagnostic imaging; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial; D014636:Valsalva Maneuver
D003287:Contrast Media