Cerebral microembolism in symptomatic and asymptomatic high-grade internal carotid artery stenosis.
Using transcranial Doppler (TCD) ultrasonography in patients with high-grade (> or = 70%) internal carotid artery (ICA) stenosis, we examined the relation between the rate of TCD-detected silent microembolism of the ipsilateral middle cerebral artery and a history of recent (< 121 days) ischemic symptoms attributable to the diseased ICA. In the so-defined neurologically symptomatic group (n = 33 patients), silent microembolic events occurred in 27 subjects (overall mean rate, 14/h +/- 29). Among 56 neurologically asymptomatic patients matched for the degree of ICA stenosis, only nine showed such events (overall mean rate, 0.35/h +/- 1.4). Across all 89 patients studied, an individual microembolic event rate > or = 2/h had a positive predictive value of 0.88 for a history of recent symptoms. Our data suggest that TCD monitoring can provide reliable paraclinical evidence of "unstable ICA disease."
Siebler
M
M
Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany.
Kleinschmidt
A
A
Sitzer
M
M
Steinmetz
H
H
Freund
H J
HJ
D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000150:complications* / Q000000981:diagnostic imaging; D008875:Middle Aged; D011237:Predictive Value of Tests; D017585:Ultrasonography, Doppler, Transcranial