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Published on: June 4, 2021
Clinical relevance of microbleeds in acute stroke thrombolysis: Comprehensive meta-analysis
Andreas Charidimou1, Ashkan Shoamanesh2,
1From the Hemorrhagic Stroke Research Group (A.C.) and Harvard Medical School (A.C.), Massachusetts General Hospital, Boston; and Department of Medicine (Neurology) (A.S.), McMaster University and Population Health Research Institute, Hamilton, Canada. andreas.charidimou.09@ucl.ac.uk.
Objective:
We performed a systematic review and meta-analysis to assess whether the presence of cerebral microbleeds (CMBs) on pretreatment MRI of patients with acute ischemic stroke treated with IV thrombolysis is associated with increased risk of symptomatic intracerebral hemorrhage (ICH) and poor functional outcome.
Methods:
We searched PubMed for relevant studies and calculated pooled odds ratios (OR) for symptomatic ICH and poor (i.e., modified Rankin Scale score >2) 3- to 6-month functional outcome using random effects models with DerSimonian-Laird weights among individuals with vs without CMBs.
Results:
Eight eligible studies including 2,601 stroke patients treated with IV thrombolysis were pooled in a meta-analysis. The cumulative CMBs prevalence was 24% (95% confidence interval [CI] 18%-30%). The pooled symptomatic ICH incidence was 5% (95% CI 4%-7%) among patients with CMBs and 3% (95% CI 2%-5%) in patients without CMBs. CMB presence was associated with higher risk of symptomatic ICH compared to patients without CMBs (OR 2.18; 95% CI 1.12-4.22; p = 0.021). Four studies (n = 1,665) reported data on 3- to 6-month poststroke functional outcome. The pooled incidence of poor functional outcome was 52% (95% CI 45%-59%) in patients with CMBs vs 41% (95% CI 35%-46%) in those without CMBs. Meta-analysis of these studies demonstrated OR for CMBs presence and adverse outcome to be 1.58 (95% CI 1.18-2.14; p = 0.002).
Conclusions:
CMBs are associated with greater symptomatic ICH risk and poor functional outcome in ischemic stroke patients undergoing thrombolytic therapy. In the absence of adjusted analyses and randomized evidence, this risk seems acceptable and should probably not discourage recanalization therapies in this patient population (Level B recommendation: nonrandomized Class IIa evidence).
Insights
Cerebral microbleeds (CMBs) increase symptomatic intracranial hemorrhage (ICH) and poor outcomes in acute ischemic stroke patients receiving IV thrombolysis. However, this risk appears acceptable and should not deter thrombolytic therapy.
Area of Science:
- Neurology
- Radiology
- Cardiovascular Research
Background:
- Cerebral microbleeds (CMBs) are common findings on MRI in patients with acute ischemic stroke.
- The clinical significance of CMBs in patients treated with intravenous thrombolysis remains debated.
Purpose of the Study:
- To systematically review and meta-analyze the association between pretreatment CMBs and the risk of symptomatic intracranial hemorrhage (ICH).
- To assess the impact of CMBs on functional outcomes in acute ischemic stroke patients receiving IV thrombolysis.
Main Methods:
- A systematic literature search was conducted on PubMed.
- Pooled odds ratios (OR) for symptomatic ICH and poor functional outcome (modified Rankin Scale score >2) were calculated using random-effects models.
- Eight studies with 2,601 patients were included in the meta-analysis.
Main Results:
- The prevalence of CMBs was 24%.
- CMB presence was associated with a significantly higher risk of symptomatic ICH (OR 2.18; p = 0.021).
- Patients with CMBs had a higher incidence of poor functional outcome at 3-6 months (OR 1.58; p = 0.002).
Conclusions:
- CMBs are linked to increased risks of symptomatic ICH and poor functional outcomes in stroke patients treated with thrombolysis.
- Despite the increased risks, the evidence suggests that CMBs should not contraindicate thrombolytic therapy in acute ischemic stroke.
