From the Guidelines
Anticoagulation is essential for patients with embolic stroke caused by atrial fibrillation or other cardioembolic sources, with direct oral anticoagulants (DOACs) preferred over warfarin for non-valvular atrial fibrillation, as supported by the most recent guideline from the American Heart Association/American Stroke Association 1.
Key Considerations
- For long-term prevention, apixaban (5mg twice daily), rivaroxaban (20mg daily with food), dabigatran (150mg twice daily), or edoxaban (60mg daily) are recommended options, as they have been shown to be noninferior to warfarin in reducing thromboembolic risk and have a reduced bleeding risk 1.
- Warfarin (target INR 2-3) remains appropriate for mechanical heart valves or severe mitral stenosis, but should not be used in patients with moderately severe or greater mitral stenosis or a mechanical heart valve 1.
- Anticoagulation should generally begin 4-14 days after stroke, with timing based on stroke size and severity, and patients with large infarcts should undergo repeat brain imaging before starting anticoagulation to rule out hemorrhagic transformation.
Risk Stratification
- The CHADS2 score can be used to stratify patients with atrial fibrillation into low, moderate, and high risk of stroke, with those having a score of 2 or higher considered at high risk and recommended for anticoagulation 1.
- Patients with prior stroke or TIA are considered at high risk for recurrence and should be treated with anticoagulation unless contraindicated, as supported by the Stroke Prevention in Atrial Fibrillation (SPAF) study 1.
Bleeding Risk
- The risk of bleeding should be carefully considered when initiating anticoagulation, particularly in elderly patients, those with poorly controlled hypertension, and those taking concomitant aspirin or nonsteroidal anti-inflammatory drugs 1.
- The optimal target international normalized ratio (INR) for primary prevention of stroke in patients with nonvalvular atrial fibrillation appears to be 2.0 to 2.5, but a range of 2 to 3 is generally recommended for most atrial fibrillation patients 1.
From the FDA Drug Label
1.1 Reduction of Risk of Stroke and Systemic Embolism in Nonvalvular Atrial Fibrillation Apixaban tablets are indicated to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation.
The apixaban drug label directly supports the use of apixaban for the reduction of risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation 2.
- Indication: Reduction of risk of stroke and systemic embolism
- Patient population: Nonvalvular atrial fibrillation
- Key point: Apixaban is indicated to reduce the risk of stroke and systemic embolism in these patients.
From the Research
Anticoagulation for Embolic Stroke
- Anticoagulation therapy is crucial in preventing embolic stroke, particularly in patients with atrial fibrillation 3, 4, 5, 6, 7
- Non-vitamin K antagonist oral anticoagulants (NOACs) have been proven to be safer and equally effective compared to warfarin in stroke prevention for patients with nonvalvular atrial fibrillation 3, 4, 5, 6
- The choice of oral anticoagulant agent should be made by careful consideration of the benefit-to-risk ratio, taking into account the risk of bleeding and stroke 4, 5, 6
Embolic Stroke of Unknown Source
- Anticoagulation therapy may be beneficial in patients with embolic stroke of unknown source, particularly those with a high risk of cardioembolic stroke 7
- Direct-acting oral anticoagulants (DOACs) are not significantly more likely than aspirin to cause severe hemorrhage and may be a better option for patients with paradoxical embolism 7
- Patients in whom cardioembolic stroke is strongly suspected should probably be anticoagulated pending the results of investigations such as echocardiography and prolonged cardiac monitoring for atrial fibrillation 7
Treatment Options
- Apixaban has been shown to be effective in reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, with a lower risk of intracranial hemorrhage compared to warfarin 4, 6
- Dabigatran, rivaroxaban, and apixaban are currently approved for stroke and systemic embolism prevention in atrial fibrillation, with management of bleeding complications remaining an area of concern 5
- Colchicine treatment and factor XIa inhibition constitute novel pharmacologic approaches that might provide future treatment options in the secondary prevention of cardioembolic stroke attributable to atrial fibrillation 3