Why is a patient with a history of stroke and reduced left ventricular function (ejection fraction 30-35%) prescribed Eliquis (apixaban), an anticoagulant, to manage the risk of recurrent stroke and deep vein thrombosis (DVT)?

Apixaban (Eliquis) for Stroke Prevention and DVT Risk Reduction in Patients with Reduced Ejection Fraction

Apixaban is recommended for patients with a history of stroke and reduced ejection fraction (30-35%) to prevent recurrent stroke and reduce DVT risk due to its superior safety profile and effectiveness compared to warfarin. 1

Mechanism and Indications

Apixaban is a direct factor Xa inhibitor that:

• Prevents formation of thrombin and subsequent clot development
• Reduces risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation 2
• Provides prophylaxis against deep vein thrombosis (DVT) and pulmonary embolism (PE) 2

Why Apixaban is Prescribed in This Clinical Scenario

Stroke Prevention

1. History of stroke: Previous stroke is a major risk factor for recurrent stroke, placing patients in a high-risk category requiring anticoagulation 3
2. Reduced ejection fraction (30-35%):
   • Low ejection fraction increases risk of left ventricular thrombus formation
   • Patients with severe left ventricular dysfunction (EF ≤35%) have higher risk of thromboembolism 3
   • Heart failure increases stroke risk, including recurrent stroke 3

DVT Prevention

1. Immobility risk: Patients with stroke history may have reduced mobility, increasing DVT risk
2. Hypercoagulable state: Both heart failure and history of stroke can create prothrombotic conditions
3. Proven efficacy: Apixaban has demonstrated effectiveness in preventing DVT in high-risk patients 2

Benefits of Apixaban Over Other Anticoagulants

1. Compared to warfarin:

   • 21% reduction in stroke or systemic embolism (1.27% vs 1.60% per year) 1, 4
   • 31% reduction in major bleeding risk (2.13% vs 3.09% per year) 1
   • 49% reduction in hemorrhagic stroke 1
   • 11% reduction in all-cause mortality 1, 4
   • No need for regular INR monitoring 1

2. Real-world effectiveness:

   • Similar effectiveness to warfarin in reducing stroke and thromboembolic events 5
   • Better safety profile compared to warfarin, dabigatran, and rivaroxaban 5
   • Lower risk of gastrointestinal bleeding compared to other oral anticoagulants 5

Dosing Considerations

• Standard dosing: 5 mg twice daily 1
• Reduced dosing (2.5 mg twice daily) if patient has at least two of:
  • Age ≥80 years
  • Body weight ≤60 kg
  • Serum creatinine ≥1.5 mg/dL 1

Timing of Initiation After Stroke

The American College of Chest Physicians recommends starting oral anticoagulation within 2 weeks of acute ischemic stroke, with specific timing based on stroke severity 1:

• TIA: 1 day (immediate)
• Mild stroke: >3 days post-stroke
• Moderate stroke: >6-8 days post-stroke
• Severe stroke: >12-14 days post-stroke

Important Monitoring Considerations

1. Renal function: Monitor at least annually, more frequently if impaired 1
2. Medication adherence: Critical due to short half-life of apixaban 1
3. Bleeding risk: Assess regularly, especially if combined with antiplatelet therapy
4. Brain imaging: Consider repeat imaging before initiating anticoagulation in moderate to severe strokes 1

Contraindications and Precautions

• Do not use in patients with:
  • Moderate to severe mitral stenosis
  • Mechanical heart valves 1
  • Severe renal impairment (creatinine clearance ≤30 mL/min) 1
  • History of hemorrhagic stroke (requires careful risk-benefit assessment) 1

Clinical Pearls and Pitfalls

1. Avoid combining anticoagulants with antiplatelets unless specifically indicated, as this significantly increases bleeding risk 1
2. Do not stop abruptly due to risk of rebound hypercoagulability
3. Patient education about medication adherence is crucial for effectiveness
4. Consider left atrial appendage closure in patients who have contraindications for lifelong anticoagulation 3
5. Early initiation of anticoagulation after TIA or small-to-medium sized stroke appears safe and may be beneficial 6

By following these evidence-based recommendations, patients with stroke history and reduced ejection fraction can receive optimal protection against both recurrent stroke and DVT with a favorable safety profile.