The detection of microembolic signals in patients at risk of recurrent cardioembolic stroke: Possible therapeutic relevance

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.