Micro-Embolic Signals and Dissection: Association or Causation for Stroke? A Systematic Review and Meta-Analysis
Pachipala Sudheer1, Deepti Vibha2
1Department of Neurology, All India Institute of Medical Sciences, New Delhi, India, mail2sudhirpamc@gmail.com.
Insights
Micro-embolic signals (MES) were detected in 46% of patients with acute stroke or transient ischemic attack (TIA) secondary to cervical artery dissection (CAD). This supports embolism as a primary cause of stroke in CAD patients.
Area of Science:
- Neurology
- Vascular Neurology
- Neuroimaging
Background:
- Cervical artery dissection (CAD) is a significant cause of stroke in younger adults.
- The precise mechanism of stroke in CAD, whether embolic or hemodynamic, remains debated.
- Transcranial Doppler (TCD) can detect micro-embolic signals (MES), offering insights into stroke mechanisms.
Approach:
- A systematic review and meta-analysis were conducted to assess MES prevalence in stroke/TIA patients with CAD.
- Literature search included major databases up to January 26, 2021.
- Eleven studies with 112 patients were analyzed to calculate the pooled prevalence of MES.
Key Points:
- The pooled prevalence of MES in acute stroke/TIA secondary to CAD was 46.0%.
- The presence of MES was associated with an increased risk of early ischemic recurrence in CAD patients.
- Data on functional outcome and mortality related to MES were limited.
Conclusions:
- This meta-analysis indicates a substantial prevalence of MES in patients with stroke/TIA due to CAD.
- The findings support the hypothesis that embolism is a major mechanism contributing to stroke in CAD.
- Further research with larger cohorts is needed to fully elucidate the impact of MES on stroke outcomes in CAD.
Background And Objective:
Although the mechanism of stroke in cervical artery dissection (CAD) has been hypothesized to be embolization rather than hemodynamic compromise, there are a limited number of studies supporting this hypothesis. Detection of micro-embolic signals (MESs) using transcranial Doppler (TCD) helps in understanding the mechanism in these patients. A systematic review and meta-analysis were performed to estimate the prevalence of MES and its association with stroke outcomes in patients with acute stroke/TIA secondary to dissection.
Methods:
A comprehensive literature search was conducted for studies before January 26, 2021, in PubMed, Embase, Google Scholar, Cochrane Library, and ClinicalTrials.gov. Studies were identified that used TCD to detect MES in stroke/TIA patients secondary to CAD. Pooled prevalence was calculated. Entire statistical analysis was conducted in R version 3.6.2.
Results:
Eleven studies involving 112 patients (50 MES+, 62 MES-) were included in our meta-analysis. The pooled prevalence of MES among acute stroke/TIA patients secondary to dissection was 46.0% (95% CI 26.0-67.0%). The presence of MES was associated with an increased risk of early ischemic recurrence in patients with CAD. We could not estimate the functional outcome and mortality associated with the presence of MES due to the scarcity of data.
Conclusions:
Our meta-analysis showed 46% prevalence of MES in the studies which looked at acute stroke/TIA secondary to CAD using TCD. This finding supports the assumption that embolism may be a major cause of stroke in patients with dissection although this could be determined only in a small population.
