Cerebral microembolism in symptomatic and asymptomatic high-grade internal carotid artery stenosis

Neurology. 1994 Apr;44(4):615-8. doi: 10.1212/wnl.44.4.615.


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."

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Brain Ischemia / complications
  • Carotid Artery, Internal
  • Carotid Stenosis / complications*
  • Carotid Stenosis / diagnostic imaging
  • Humans
  • Intracranial Embolism and Thrombosis / complications*
  • Intracranial Embolism and Thrombosis / diagnostic imaging
  • Middle Aged
  • Predictive Value of Tests
  • Ultrasonography, Doppler, Transcranial