Early ischemic recurrence and microembolic signals detected by transcranial Doppler.

Abstract

To the Editor: I read with great interest the article, “Microembolic Signals and Risk of Early Recurrence in Patients With Stroke or Transient Ischemic Attack,” by Valton and colleagues.1 In this study, an early, random, 20-minute sampling of microembolic signals (MES) by use of transcranial Doppler (TCD) over the middle cerebral artery on the side of recent stroke or transient ischemic attack (TIA) in a selected cohort of 73 patients was found to be an independent risk factor for early ischemic recurrence (EIR). In the article, EIR was arbitrarily defined as (1) recurrent TIA or stroke in patients presenting with TIA or (2) clinical deterioration not due to hemorrhagic transformation and cerebral edema in those presenting with stroke.1 Their findings and interpretations raised 2 interesting points. First, their data indicated that the prediction of EIR by detecting MES on TCD has a sensitivity of 62.5% (5/8), a specificity of 84.6% (55/65), a positive predictive value of 33.3% (5/15), and a negative predictive value of 94.8% (55/58). Thus, absence of MES on TCD is reassuring in an individual patient, but presence of MES does not have a high predictive value for EIR. …