Use of anticoagulant in prevention of stroke
Atrial fibrillation
  • For patients with atrial fibrillation, Warfarin reduces stroke by 68%
  • Annual stroke rate reduced from 4.5%  to 1.4% per year
  • There is a tendency for cardioembolic stroke to undergo hemorrhagic transformation
  • Best time to start Warfarin after stroke is not clear
  • For large stroke, consider delay anticoagulation for 2 days to 2 weeks
  • Except: high risk cardiac lesion, such as
    • mechanical heart valve
    • established intracardiac thrombus
    • atrial fibrillation w mitral stenosis or congestive heart failure
  • Aim for INR between 2 and 3
  • Patients under 60 year old with lone atrial fibrillation without other stroke risk factor do not need Warfarin
Treatment Guideline
  • The recommendations are primarily based on
    • patient age
    • presence or absence of a history of cardiovascular risk factors
      • TIA/stroke, hypertension, heart failure, diabetes mellitus, clinical coronary artery disease, echocardiographic findings of left atrial enlargement or left ventricular dysfunction
  • In the absence of a medical contraindication to anticoagulation
    • Age > 75 years: warfarin
    • Age 65 - 75 years with risk factor: warfarin; 
    • Age 65 - 75 years without risk factor: warfarin or aspirin
    • Age < 65 years with risk factor: warfarin
    • Age < 65 years without risk factor: aspirin or observe.
Side effect of Warfarin treatment
  • Risk of intracranial hemorrhage  (pooled analysis)
    • 0.3% vs 0.1% per year in control group
  • Risk of intracranial hemorrhage for patient >75 year old
    • 1.8% per year
    • Risk of hemorrhage may increase with INR > 3  
Further Reading