Cerebral microbleeds and the risk of intracerebral haemorrhage after thrombolysis for acute ischaemic stroke: systematic review and meta-analysis
- 1Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- 2Department of Stroke Medicine, Imperial College Healthcare, NHS Trust, London, UK
- 3Biomedical Research Centre, UCL, London, UK
- 4Education Unit, UCL Institute of Neurology, London, UK
- Correspondence to Dr David J Werring, Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Box 6, Queen Square, London WC1N 3BG, UK;
- Received 3 June 2012
- Revised 13 August 2012
- Accepted 28 August 2012
- Published Online First 28 September 2012
Background Intracerebral haemorrhage (ICH) remains the most devastating yet unpredictable complication of intravenous thrombolysis for acute ischaemic stroke. We performed a systematic review and meta-analysis, to assess whether the presence of cerebral microbleeds (CMBs) on prethrombolysis MRI scans is associated with an increased risk of ICH.
Methods We searched PubMed for studies assessing ICH risk in patients with acute ischaemic stroke treated with thrombolysis, in relation to the presence of pre-treatment CMBs.
Results We identified five studies including 790 patients and pooled data in a meta-analysis. The CMB (+) versus CMB (−) groups were not significantly different in age, gender or stroke severity. The overall prevalence of CMBs was 135/790 (17.1%). Amongst patients with CMBs, 10/135 (7.4%) experienced a symptomatic ICH after thrombolysis, compared to 29/655 (4.4%) patients without CMBs. The pooled relative risk of ICH was 1.90 (95% CI 0.92 to 3.93; p=0.082).
Conclusions The available evidence does not demonstrate a statistically significant increased risk of symptomatic ICH after thrombolysis for ischaemic stroke in patients with CMBs. However, in view of the methodological limitations of the studies included, the clinical relevance of any potential hazard associated with CMBs remains uncertain. Further studies are warranted to evaluate whether the risk of ICH might outweigh the benefit of thrombolysis, especially in patients with multiple lobar CMBs suggestive of cerebral amyloid angiopathy.
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