Should I initiate enoxaparin (low molecular weight heparin) for a patient with acute ischemic stroke to prevent Deep Vein Thrombosis (DVT)?

From the Guidelines

Enoxaparin should be initiated for patients with acute ischemic stroke who have reduced mobility to prevent DVT, as long as there are no contraindications such as active bleeding, severe thrombocytopenia, or recent intracranial hemorrhage. The standard dosing is enoxaparin 40 mg subcutaneously once daily, typically started within 24-48 hours after stroke onset when intracranial hemorrhage has been ruled out 1. This prophylaxis should continue throughout the period of reduced mobility, often for the duration of hospitalization.

Key Considerations

• Ensure the patient has no contraindications to anticoagulation before initiating enoxaparin
• For patients who have received thrombolytic therapy (tPA), it's prudent to delay enoxaparin for 24 hours after tPA administration
• Mechanical prophylaxis with intermittent pneumatic compression devices should be used initially for these patients or for those with contraindications to anticoagulation
• The recommendation for DVT prophylaxis is based on the significantly increased risk of venous thromboembolism in stroke patients due to immobility, with studies showing that appropriate prophylaxis reduces this risk by approximately 50% without significantly increasing bleeding complications when properly timed 1.

Evidence-Based Recommendations

• Low-molecular-weight heparin (i.e., enoxaparin) should be considered for patients with acute ischemic stroke at high risk of venous thromboembolism; or unfractionated heparin for patients with renal failure 1
• Prophylactic-dose subcutaneous heparin (unfractionated heparin [UFH] or low-molecular-weight heparin [LMWH]) or intermittent pneumatic compression devices are recommended over no prophylaxis for patients with acute ischemic stroke and restricted mobility 1
• The use of anti-embolism stockings alone for post-stroke venous thromboembolism prophylaxis is not recommended 1

From the Research

Enoxaparin for Acute Ischemic Stroke to Prevent DVT

• The use of enoxaparin for preventing Deep Vein Thrombosis (DVT) in patients with acute ischemic stroke has been studied in several clinical trials 2, 3, 4.
• A study published in the Lancet in 2007 found that enoxaparin reduced the risk of venous thromboembolism by 43% compared to unfractionated heparin in patients with acute ischemic stroke 2.
• Another study published in Acta neurologica Scandinavica in 2002 found that enoxaparin was as safe and effective as unfractionated heparin in preventing thromboembolic events in patients with acute ischemic stroke 3.
• A subanalysis of the PREVAIL study published in Stroke in 2009 found that enoxaparin was not associated with poorer long-term neurological outcomes or increased rates of symptomatic intracranial hemorrhage compared to unfractionated heparin 4.

Comparison with Unfractionated Heparin

• A study published in the Journal of thrombosis and thrombolysis in 2023 found that unfractionated heparin was associated with a higher rate of mortality compared to enoxaparin in patients admitted to the intensive care unit 5.
• However, the use of heparin in acute ischemic stroke is still considered on a case-by-case basis, and there is no consensus as to the appropriate timing of anticoagulation or for which ischemic stroke subtypes heparin may be beneficial 6.

Clinical Implications

• The clinical benefits associated with the use of enoxaparin for venous thromboembolism prophylaxis in patients with acute ischemic stroke are not associated with poorer long-term neurological outcomes or increased rates of symptomatic intracranial hemorrhage compared to unfractionated heparin 4.
• Enoxaparin may be preferable to unfractionated heparin for venous thromboembolism prophylaxis in patients with acute ischemic stroke due to its better clinical benefits to risk ratio and convenience of once daily administration 2.