Transcranial Doppler detection of venous-to-arterial circulation shunts: criteria for patent foramen ovale.
OBJECTIVE
As paradoxical embolism is associated with stroke in young adults, migraine, and decompression sickness, the detection of venous-to-arterial circulation shunt (v-aCS), such as patent foramen ovale (PFO), is increasingly important. We compared a rigorous transcranial Doppler (TCD) protocol with transesophageal echocardiography (TEE) to develop criteria for PFO.


METHODS
Standardized TCD was performed 2 weeks before simultaneous TEE and TCD in 39 patients aged 15-39 following ischemic stroke (n = 33) or myocardial infarction (n = 6). V-aCS was investigated by contrast sonography. During standardized TCD, contrast injections were performed twice, at rest and with cough and Valsalva maneuvers. TCD and TEE were recorded and analyzed independently by 'blinded' observers.


RESULTS
All 16 of the 39 patients with PFO on TEE had more than 15 micro-emboli on standardized TCD; in 14 of these 16, paradoxical embolization required no provocation. Three of 9 patients with 'major' v-aCS (>50 microbubble emboli at rest or >10 at rest with >80 on provocation) on standardized TCD were not identified by TEE as having large shunts.


CONCLUSIONS
The standardized TCD protocol is sensitive in the diagnosis of PFO and with the use of provocation maneuvers measures the functional importance of v-aCS more accurately than TEE.
Department of Academic Surgery, South Manchester University Hospital, Manchester, United Kingdom.
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Sastry
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MacNab
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Daly
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Ray
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McCollum
D000293:Adolescent; D000328:Adult; D003287:Contrast Media; D017548:Echocardiography, Transesophageal / Q000379:methods*; D019320:Embolism, Paradoxical / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016037:Single-Blind Method; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D020246:Venous Thrombosis / Q000150:complications
D003287:Contrast Media