Low-molecular-weight heparins or heparinoids versus standard unfractionated heparin for acute ischaemic stroke.

backgroundLow-molecular-weight heparins and heparinoids are anticoagulants that may be associated with lower risks of haemorrhage and more powerful antithrombotic (anti-clotting) effects than standard unfractionated heparin.

objectivesThe objective of this review was to compare the effects of low-molecular-weight heparins or heparinoids with those of unfractionated heparin in people with acute, confirmed or presumed, ischaemic stroke (sudden blockage of an artery carrying blood to the brain). SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register (last searched November 2003). In addition we searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), MEDLINE (1966 to October 2003) and EMBASE (1980 to October 2003). For previous versions of this review we searched MedStrategy (1995) and also contacted pharmaceutical companies. SELECTION CRITERIA: Randomised trials comparing heparinoids or low-molecular-weight heparins with standard unfractionated heparin in people with acute ischaemic stroke. Only trials where treatment was started within 14 days of stroke onset were included. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies for inclusion, assessed trial quality and extracted the data. MAIN

resultsSix trials involving 740 people were included. Four trials compared a heparinoid (danaparoid), one trial compared a low-molecular-weight heparin (enoxaparin), and one trial compared an unspecified low-molecular-weight heparin with standard unfractionated heparin. Allocation a to low-molecular-weight heparin or heparinoid was associated with a significant reduction in the odds of deep vein thrombosis (Peto odds ratio 0.52, 95% confidence interval 0.56 to 0.79). However, the number of more major events (pulmonary embolism, death, intra-cranial or extra-cranial haemorrhage) was too small to provide a reliable estimate of more important benefits and risks. No information was reported for recurrent stroke or functional outcome. AUTHORS'

conclusionsTreatment with a low-molecular-weight heparin or heparinoid after acute ischaemic stroke appears to decrease the occurrence of deep vein thrombosis compared to standard unfractionated heparin, but there are too few data to provide reliable information on their effects on other important outcomes, including death and intracranial haemorrhage.