Micro-embolic signal monitoring in stroke subtypes: A systematic review and meta-analysis of 58 studies

Pachipala Sudheer; Shubham Misra; Manabesh Nath; Pradeep Kumar; Deepti Vibha; M V Padma Srivastava; Manjari Tripathi; Rohit Bhatia; Awadh Kishor Pandit; Rajesh K Singh

doi:10.1177/23969873211060819

Micro-embolic signal monitoring in stroke subtypes: A systematic review and meta-analysis of 58 studies

Eur Stroke J. 2021 Dec;6(4):403-411. doi: 10.1177/23969873211060819. Epub 2021 Nov 13.

Affiliation

¹ Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.

Abstract

Introduction: Micro-embolic signals (MESs) detected using transcranial Doppler (TCD) help in risk stratification in stroke patients. A systematic review and meta-analysis were performed to estimate the prevalence of MES and its association with stroke recurrence, functional outcome, and mortality in different stroke subtypes.

Methods: A comprehensive literature search was conducted before 26^th January 2021 in PubMed, Embase, Google Scholar, Cochrane Library, and ClinicalTrials.gov. Studies were identified that used TCD to detect MES in stroke/TIA patients. Pooled prevalence and odds ratio (OR) along with 95% confidence interval (95% CI) were calculated for different outcome measures. The entire statistical analysis was conducted in R version 3.6.2.

Findings: Fifty-eight studies involving 5123 patients (1329 MES+, 3794 MES-) were included in our meta-analysis. The pooled prevalence of MES among all acute stroke/TIA patients was 30% (95% CI 25-34%). The pooled prevalence adjusted after the trim-and-fill analysis among all acute stroke/TIA patients was 18% (95% CI 14-23%). The prevalence of MES was high among all stroke subtypes except in patients with small vessel disease (SVD). In patients with new-onset stroke/TIA, the presence of MES was associated with a high risk of recurrence of cerebral ischemia (OR 4.03; 95% CI 2.38-6.82). Although no significant association was observed for the presence of MES with increased mortality (OR 2.37; 95% CI 0.75-7.50) and poor functional outcome (OR 2.11; 95% CI 0.20-22.50) among patients with new-onset stroke/TIA, this could only be determined in a smaller sample size of 477 patients.

Conclusions: Our meta-analysis showed a 30% prevalence of MES following acute stroke/TIA. The presence of MES increased the chance of recurrence of cerebral ischemia but was not associated with poor functional outcomes and mortality in the studied subgroup.

Keywords: Micro-embolic signals; meta-analysis; prevalence; stroke; systematic review; transcranial Doppler.