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

BACKGROUND: Low molecular weight heparins and heparinoids may be associated with lower risks of haemorrhage and more powerful antithrombotic effects than standard unfractionated heparin. OBJECTIVES: The 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. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register and MedStrategy (1995). We also contacted pharmaceutical companies. Date of most recent search: April 1999. 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 RESULTS: Five trials involving 705 people were included. Four trials compared a heparinoid (danaparoid), and one compared a low molecular weight heparin (enoxaparin), with standard unfractionated heparin. Overall, 55/414 (13%) of the patients allocated danaparoid or enoxaparin had deep vein thrombosis compared with 65/291 (22%) of those allocated unfractionated heparin. This reduction was significant (odds ratio 0.52, 95% confidence interval 0.56 - 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 in survivors. REVIEWER'S CONCLUSIONS: Low molecular weight heparin or heparinoid appear 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 effect on other important outcomes, including death and intracranial haemorrhage.