Why is heparin (unfractionated heparin or low molecular weight heparin) administered 3 days after a hemorrhagic stroke?

Timing of Heparin Administration After Hemorrhagic Stroke

Heparin (unfractionated or low molecular weight) is typically administered 3 days after hemorrhagic stroke to prevent venous thromboembolism (VTE) while allowing sufficient time for hematoma stabilization to minimize the risk of hematoma expansion. 1

Risk of VTE in Hemorrhagic Stroke Patients

• Patients with hemorrhagic stroke are at high risk for developing VTE due to immobility, especially those unable to move one or both lower limbs, unable to mobilize independently, with previous history of VTE, dehydration, or comorbidities such as cancer 1
• Immobilized stroke patients have significantly increased risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) if prophylaxis is not provided 2

Timing of Heparin Administration

• After documentation of cessation of bleeding, low-dose subcutaneous low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) may be considered for VTE prevention in patients with lack of mobility after 1 to 4 days from onset 1
• Specifically for intracerebral hemorrhage, pharmacological VTE prophylaxis may be initiated after 48 hours post-stroke onset after careful risk assessment and following repeat brain imaging that demonstrates stability of the hematoma 1
• The 3-day waiting period represents a clinical consensus balancing the risk of hematoma expansion (highest in the first 24-48 hours) against the increasing risk of VTE with prolonged immobility 3, 2

Evidence Supporting This Approach

• Research has shown that low-dose LMWH treatment after 48 hours of stroke in ICH patients is not associated with increased hematoma growth and should be used for DVT and PE prophylaxis 3
• In a prospective randomized study of ICH patients, no hematoma enlargement was observed at 72 hours, 7 days, and 21 days after starting LMWH at the 48-hour mark 3

Mechanical vs. Pharmacological Prophylaxis

• Patients with ICH should have intermittent pneumatic compression (IPC) for prevention of VTE beginning the day of hospital admission 1
• IPC should be applied within the first 24 hours after admission and continued until the patient becomes independently mobile, is discharged, develops adverse effects, or reaches 30 days (whichever comes first) 1
• Graduated compression stockings are not beneficial to reduce DVT or improve outcome 1
• For high-risk patients, a combination of mechanical and pharmacological prophylaxis may provide optimal protection once the hematoma has stabilized 4

Recommended Prophylactic Regimens

• Prophylactic-dose UFH is defined as 10,000 to 15,000 units/day 1
• Prophylactic-dose LMWH is defined as 3,000 to 6,000 International Units/day (e.g., enoxaparin 40 mg subcutaneously once daily) 1, 4
• LMWH is generally preferred over UFH except in patients with renal failure 1
• Compared with UFH, LMWH results in fewer symptomatic DVTs and pulmonary emboli per 1,000 treated patients 1

Duration of Prophylaxis

• Pharmacological VTE prophylaxis should be continued throughout the hospital stay or until the patient regains mobility 4
• For stroke patients admitted to hospital and remaining immobile for longer than 30 days, ongoing VTE prophylaxis is recommended 1

Important Considerations and Precautions

• Early mobilization and adequate hydration should be encouraged for all acute stroke patients to help prevent VTE 1
• Repeat brain imaging to confirm hematoma stability before initiating pharmacological prophylaxis is essential 1
• For patients with systemic or intracranial hemorrhage, mechanical prophylaxis should be used initially until pharmacological prophylaxis can be safely initiated 1
• For patients with symptomatic DVT or PE, systemic anticoagulation or IVC filter placement is probably indicated, with the decision between these options taking into account time from hemorrhage onset, hematoma stability, cause of hemorrhage, and overall patient condition 1