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Evidence summaries

Low-Molecular-Weight Heparins Vs. Standard Heparin for Acute Ischaemic Stroke

Low molecular weight heparins, when started within 24-48 h of ischaemic stroke, are associated with a reduced risk of venous thromboembolism and no increased risk of bleeding compared with unfractionated heparin use. Level of evidence: "A"

A Cochrane review [Abstract] 1 included 9 trials involving 3 137 patients. Four trials compared a heparinoid (danaparoid), four trials compared a low-molecular-weight heparin (enoxaparin or certoparin), and one trial compared an unspecified low-molecular-weight heparin with standard unfractionated heparin. Allocation to a low-molecular-weight heparin or heparinoid was associated with a significant reduction in the odds of deep vein thrombosis (OR 0.55, 95% CI 0.44 to 0.70). 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 of low-molecular-weight heparins or heparinoids compared with standard unfractionated heparin. Insufficient information was available to assess effects on recurrent stroke or functional outcome.

A systematic review 2 including 3 RCTs (n=2 028) was abstracted in DARE. The studies compared low molecular weight heparins (LMWH, enoxaparin and certoparin) and unfractionated heparin (UFH) in the prevention of venous thromboembolism (VTE) in ischaemic stroke patients. Other endpoints were pulmonary embolism (PE), bleeding and mortality. Time from stroke to drug administration ranged from 24 to 48 hours. There was a significant reduction in risk of VTE with LMWH (OR 0.54, 95% CI 0.41 to 0.70) compared with UFH. Similar results were found when the analysis was restricted to proximal VTE only. LMWH use led to fewer PEs as well (OR 0.26; 95% CI 0.07 to 0.95). There were no significant differences between LMWH and UHF for intracerebral bleeding (OR 0.70, 95% CI 0.26 to 1.84), or for nonintracerebral major haemorrhage (OR 1.31, 95% CI 0.63 to 2.71). Mortality was reported both at the end of treatment (early) and after 90 days (late) with no difference in either measure between different heparin groups.

    References

    • Sandercock PA, Leong TS. Low-molecular-weight heparins or heparinoids versus standard unfractionated heparin for acute ischaemic stroke. Cochrane Database Syst Rev 2017;4():CD000119. [PubMed]
    • Shorr AF, Jackson WL, Sherner JH, Moores LK. Differences between low-molecular-weight and unfractionated heparin for venous thromboembolism prevention following ischemic stroke: a metaanalysis. Chest 2008 Jan;133(1):149-55. [PubMed] [DARE]

Primary/Secondary Keywords