Pre-treatment cerebral microbleeds and intracranial hemorrhage in patients with ischemic stroke receiving endovascular therapy: a systematic review and meta-analysis

Background and purpose Predicting the risk of intracranial hemorrhage (ICH) is an important aspect for improving the efficacy and safety of endovascular therapy (EVT). We intended to perform a systematic review and meta-analysis to show whether pre-treatment cerebral microbleeds (CMBs) were associated with an increased incidence of ICH in patients with ischemic stroke receiving EVT. Methods We searched PubMed, EMBASE, Web of Science and Cochrane Library from their dates of inception to December 18, 2018, and also manually searched reference lists of relevant articles. Cumulative prevalence of CMBs and ICH was calculated. Relative risk and 95% confidence interval (CI) were calculated for the incidence of ICH in patients with CMBs versus those without after EVT. Results Four studies involving 598 patients were included. The pooled prevalence of CMBs was 18% (95% CI 15-21%) and the pooled prevalence of >= 5 CMBs was 1% (95% CI 0-2%). The pooled incidence of ICH was 29% (95% CI 8-49%) in all patients, 25% (95% CI 5-45%) in those with CMBs and 29% (95% CI 8-50%) in those without CMBs. The pooled relative risk of ICH was 0.90 (95% CI 0.65-1.25, P = 0.528; I-2 = 0%, P = 0.949) in patients with CMBs versus those without CMBs. Conclusions There is no evidence that pre-treatment CMBs were associated with an increased incidence of ICH in patients with ischemic stroke receiving EVT.