P. Batista et al., The detection of microembolic signals in patients at risk of recurrent cardioembolic stroke: Possible therapeutic relevance, CEREB DIS, 9(6), 1999, pp. 314-319
The clinical predictors and potential therapeutic implications of microembo
lic signals (MES) were investigated in 104 patients with ischemic stroke or
transient ischemic attack associated with high-risk (n = 60) or low-risk (
n = 44) cardiac emboligenic conditions. Patients with artificial valves and
carotid stenosis were excluded. MES counts were based on 30-min bilateral
middle cerebral artery transcranial Doppler (TCD) monitoring recordings. ME
S were detected in 15 subjects (14%). The mean number of MES per hour was 1
.9. MES prevalence and counts were influenced neither by age, gender or typ
e of cerebral event, nor by cardiac disease. MES were more frequently detec
ted and greater in number in patients with multiple cerebral ischemic event
s and in subjects monitored within 1 month of the last event, By multiple l
ogistic regression, TCD recording within 1 month of the last event [Odds ra
tio (OD)= 13.5; 95% confidence intervals (CI) = 3.3-54.3] and multiple cere
bral events (OD = 4.7; 95% CI = 1.3-17.3) were the best MES predictors. MES
were detected in 40% (4/10) of patients on heparin, 5% (2/4) of untreated
subjects and 13% (5/39) of those on antiplatelet drugs, For patients on war
farin, MES counts and prevalence were similar in subjects with internationa
l normalized ratios (INR) below and within/above the therapeutic range. MES
were detected in only 2 out of 16 subjects with INR <2 and in 1 with INR >
2. MES detection can be potentially relevant to the selection of antithromb
otic treatment in acute stroke associated with cardioembolic disease, but f
urther studies are necessary to assess its effectiveness as an additional g
uide to monitor oral anticoagulant intensity.