When to administer heparin (anticoagulant) in acute Cerebrovascular Accident (CVA)?

From the Guidelines

Heparin should be administered immediately in acute Cerebrovascular Accident (CVA) due to cerebral venous sinus thrombosis, regardless of the presence of hemorrhagic conversion, as it is associated with a reduced risk of death and dependency 1. When considering the administration of heparin in acute CVA, it is crucial to differentiate between various types of strokes, as the management and treatment protocols vary significantly.

Key Considerations

• The use of anticoagulation with heparin or low molecular weight heparin (LMWH) is recommended in the setting of cerebral venous sinus thrombosis (CVT), as evidenced by a Cochrane meta-analysis showing a pooled relative risk of death of 0.33 and death or dependency of 0.46 1.
• For patients with CVT, early anticoagulation is often considered as both treatment and early secondary prophylaxis, with studies suggesting that dose-adjusted unfractionated heparin (UFH) or LMWH can improve outcomes 1.
• The duration of anticoagulation therapy in patients with CVT is not well-established, but it is reasonable to follow guidelines set for patients with extracerebral deep vein thrombosis (DVT), which includes anticoagulation treatment for 3 months for first-time DVT in patients with transient risk factors and at least 3 months for an unprovoked first-time DVT 1.

Administration and Monitoring

• When used, unfractionated heparin is typically administered as an IV bolus followed by continuous infusion, adjusted to maintain aPTT at 1.5-2.5 times normal.
• Low molecular weight heparin (LMWH) may be an alternative, with dosing such as enoxaparin 1 mg/kg twice daily.
• It is essential to monitor patients closely for signs of bleeding or thrombosis, as heparin therapy carries significant risks that must be weighed against its benefits.

Special Considerations

• Heparin should be avoided in hemorrhagic strokes and used cautiously in large ischemic strokes due to the risk of hemorrhagic transformation.
• The decision to administer heparin in acute CVA should be made on a case-by-case basis, taking into account the specific type of stroke, the presence of hemorrhagic conversion, and the patient's individual risk factors and medical history.

From the Research

Administration of Heparin in Acute CVA

The administration of heparin in acute Cerebrovascular Accident (CVA) is a complex issue, with various studies providing conflicting evidence.

• The current consensus is that anticoagulation therapy has no role acutely in the management of ischemic stroke, although there is still debate for specific conditions, such as cerebral venous thrombosis and cervical dissection 2.
• Anticoagulation is used in the prevention of venous thromboembolic events, but the balance between preventing symptomatic pulmonary embolism and causing symptomatic intracerebral hemorrhage is a concern 2.
• The use of heparin, low-molecular-weight heparins (LMWHs), and heparinoids in acute ischemic stroke has been studied, but the results are variable, and their value in recurrent stroke prevention and treatment remains unsettled 3.

Specific Conditions for Heparin Administration

Certain subpopulations of ischemic stroke patients may derive benefit from heparin when given acutely, including:

• Patients with symptomatic large artery stenosis >70 % 4
• Patients with non-occlusive intraluminal thrombus 4
• Patients with high-risk cardiac conditions, including left ventricular thrombus, left ventricular assist devices, and mechanical heart valves 4
• Patients with atrial fibrillation or acute myocardial infarction and large mural thrombi 5

Timing and Dosage of Heparin Administration

The timing and dosage of heparin administration in acute CVA are not well established, and more trials are needed to test heparins in patients with defined stroke subtypes and occlusive vascular lesions 6.

• Heparins should not be indiscriminately given to all patients with acute ischemic stroke 6.
• The efficacy of heparins has not been adequately tested in patients with defined stroke subtypes and occlusive vascular lesions 6.
• Unfractionated intravenous heparin should not be used routinely in acute ischemic stroke, but it may be considered in select stroke groups at high risk for early recurrent ischemic events 5.