Cerebral Microembolism and Early Recurrent Cerebral or Retinal Ischemic Events

T o date, the degree of luminal narrowing by a carotid artery plaque is used to estimate the risk of recurrence of cerebrovascular events and to stratify therapeutic options.1 However, other plaque characteristics have gained interest. Detection of atherosclerotic plaques, which are prone to rupture, the socalled vulnerable plaques, might help in determining the best therapeutic approach, especially for patients with a mild to moderate carotid artery stenosis.Intraplaque hemorrhage (IPH) and fibrous cap (FC) status, as evaluated with MRI, are important features of plaque vulnerability and are associated with an increased risk of future ischemic stroke or transient ischemic attack.

Section: November 2014mentioning

confidence: 99%

Intraplaque Hemorrhage, Fibrous Cap Status, and Microembolic Signals in Symptomatic Patients With Mild to Moderate Carotid Artery Stenosis

Truijman

Rotte

Aaslid

et al. 2014

“…In total, 14 different experienced observers from 8 different centers were involved: 1 Münster, Germany (6 investigators) 2 ; Glasgow, United Kingdom (2 investigators) [3][4][5][6][7][8] ; Bern, Switzerland; Düs-seldorf, Germany; Gießen, Germany; London, United Kingdom; Lübeck, Germany; and Toulouse, France (1 investigator each).…”

Section: Primary Quality Control: Interobserver Agreement For a Refermentioning

confidence: 99%

“…[1][2][3][4][5] Several small studies have shown that MES predict recurrent stroke or transient ischemic attack (TIA) and stroke alone in patients with symptomatic carotid stenosis. [5][6][7][8] MES-positive patients with symptomatic carotid stenosis therefore define a subset of high-risk patients for stroke recurrence. In this group, MES offer an attractive surrogate marker to evaluate antiplatelet efficacy.…”

mentioning

confidence: 99%

The Use of Embolic Signal Detection in Multicenter Trials to Evaluate Antiplatelet Efficacy

Dittrich

Ritter

Kaps

et al. 2006

Background and Purpose-The CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotidStenosis) trial proved the effectiveness of the combination of clopidogrel and aspirin compared with aspirin alone in reducing presence and number of microembolic signals (MES) in patients with recently symptomatic carotid stenosis. The present study aimed at installing primary and secondary quality control measures in CARESS because MES evaluation relies on subjective judgment by human experts. Methods-As primary quality control, centers participating in CARESS evaluated a reference digital audio tape (DAT) before the study containing both MES and artifacts. Interobserver agreement of classifying signals as MES was expressed as proportions of specific agreement of positive ratings (psϮvalues). For all DATs included in CARESS (nϭ300), online number of MES and off-line number of MES read by the central reader were compared using correlation coefficients. As secondary control, a sample of 16 of 300 DATs was cross-validated by another independent reader (post-trial validator). Results-For the reference tape, the cumulative psϮvalue was 0.894 based on 12 of 14 observers. Two observers with very different results improved after a training procedure. Agreement between post-trial validator and central reader was psϩϭ0.805, indicating very good agreement. Correlation between online evaluation and off-line evaluation of DATs was very good overall (cumulative ϭ0.84; PϽ0.001). Conclusion-Multicenter studies using MES as outcome parameter are feasible. However, primary and secondary quality control procedures are important.

“…The Neurovascular Laboratory's methods and criteria for identification of microembolic signals have been described previously. 23,28 The criteria for identification of microembolic signals are similar to the ones established by the Consensus Committee. 29 …”

Section: Tcd Studiesmentioning

confidence: 99%

Cerebral Microembolism in Patients With Retinal Ischemia

Wijman

Babikian

Matjucha

et al. 1998

Self Cite

Background and Purpose-We investigated the frequency of cerebral microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. Methods-Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. Results-Microembolism was detected in 40.0% of study MCAs and 9.2% of controls (PϽ0.001). In the study group, microembolic signals were detected in 61.9% of MCAs tested within a week of symptom onset and 20.8% of those tested afterward (PϽ0.001). Severe (Ն70%) carotid stenosis or occlusion was more frequent in the study group (PϽ0.001). Microembolic signals were detected in 25.3% and 11.2%, respectively, of MCAs distal to carotid arteries with 70% to 100% and 0% to 69% stenosis (Pϭ0.013). Conclusions-In patients without cardiac embolic sources, cerebral microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.