Efficacy and safety of anticoagulants in the prevention of venous thromboembolism in patients with acute cerebral hemorrhage: a meta‐analysis of controlled studies

The role of anticoagulants for the prevention of venous thromboembolism in acute hemorrhagic stroke is uncertain. We performed an updated meta-analysis of studies to obtain the best estimates of the efficacy and safety of anticoagulants for the prevention of venous thromboembolism in patients with acute hemorrhagic stroke.Using electronic and manual searches of the literature, we identified randomized and non-randomized studies comparing anticoagulants (unfractionated heparin or low-molecular-weight heparin or heparinoids) with treatments other than anticoagulants (elastic stockings, intermittent pneumatic compression or placebo) in patients with acute hemorrhagic stroke. Study outcomes included symptomatic and asymptomatic deep venous thrombosis (DVT), symptomatic and asymptomatic pulmonary embolism (PE), any hematoma enlargement or death. Risk ratios (RRs) for individual outcomes were calculated for each study and data from all studies were pooled using the Mantel-Haenszel method.Four studies (two randomized) involving 1000 patients with acute hemorrhagic stroke met the criteria for inclusion in this meta-analysis. Compared with other treatments, anticoagulants were associated with a significant reduction in PE (1.7% vs. 2.9%; RR, 0.37; 95% CI, 0.17-0.80; P = 0.01), a DVT rate of 4.2% compared with 3.3% (RR, 0.77; 95% CI, 0.44-1.34; P = 0.36), an increase in any hematoma enlargement (8.0% vs. 4.0%; RR, 1.42; 95% CI, 0.57-3.53; P = 0.45), and a non-significant reduction in mortality (16.1% vs. 20.9%; RR, 0.76; 95% CI, 0.57-1.03; P = 0.07).Our findings indicate that in patients with hemorrhagic stroke, early anticoagulation is associated with a significant reduction in PE and a non-significant reduction in mortality, with the trade-off of a non-significant increase in hematoma enlargement. These results must be taken with caution and should encourage the assessment of the clinical benefit of antithrombotic prophylaxis in patients with cerebral bleeding by properly designed clinical trials.