Is anticoagulation contraindicated if the Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile International Normalized Ratio (INR), Elderly, Drugs/Alcohol Concomitantly (HAS-BLED) score is greater than the Congestive Heart Failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke/TIA/Thromboembolism (CHA2DS2-VASc) score?

Anticoagulation Decision-Making When HAS-BLED Score Exceeds CHA₂DS₂-VASc Score

A high HAS-BLED score exceeding the CHA₂DS₂-VASc score does not automatically contraindicate anticoagulation, but rather indicates the need for closer monitoring and correction of modifiable bleeding risk factors.

Understanding the Risk Scores

CHA₂DS₂-VASc Score

• Evaluates stroke risk in atrial fibrillation patients 1
• Maximum score of 9 points:
  • Congestive heart failure/LV dysfunction: 1 point
  • Hypertension: 1 point
  • Age ≥75 years: 2 points
  • Diabetes mellitus: 1 point
  • Stroke/TIA/thromboembolism: 2 points
  • Vascular disease: 1 point
  • Age 65-74 years: 1 point
  • Female sex: 1 point

HAS-BLED Score

• Assesses bleeding risk in patients with atrial fibrillation 2
• Maximum score of 9 points:
  • Hypertension (systolic BP >160 mmHg): 1 point
  • Abnormal renal/liver function: 1-2 points
  • Stroke: 1 point
  • Bleeding history or predisposition: 1 point
  • Labile INR: 1 point
  • Elderly (>65 years): 1 point
  • Drugs/alcohol concomitantly: 1-2 points

Clinical Decision Algorithm

1. Calculate both scores accurately

   • CHA₂DS₂-VASc for stroke risk assessment
   • HAS-BLED for bleeding risk assessment

2. Evaluate stroke risk based on CHA₂DS₂-VASc

   • Score 0: No antithrombotic therapy recommended 2
   • Score 1: Oral anticoagulation recommended (preferably over antiplatelet therapy) 2
   • Score ≥2: Oral anticoagulation definitely recommended 2

3. Assess bleeding risk with HAS-BLED

   • Score ≥3: Indicates high bleeding risk requiring caution and regular review 2
   • Important: A high HAS-BLED score should not automatically exclude patients from anticoagulation therapy 2

4. When HAS-BLED > CHA₂DS₂-VASc:

   • This does NOT automatically contraindicate anticoagulation
   • Instead, focus on correcting modifiable bleeding risk factors:
     • Control hypertension
     • Review medications that increase bleeding risk (NSAIDs, antiplatelet drugs)
     • Reduce alcohol consumption
     • Improve INR control if on warfarin
     • Address abnormal renal/liver function if possible

5. Monitor more closely:

   • Patients with HAS-BLED > CHA₂DS₂-VASc require more frequent follow-up
   • Regular review of anticoagulation is recommended 2

Evidence Supporting This Approach

The European Society of Cardiology guidelines explicitly state that the HAS-BLED score should be used to "identify modifiable bleeding risks that need to be addressed, but should not be used on its own to exclude patients from OAC therapy" 2. This is a Class IIa recommendation with Level A evidence.

Research has shown that stroke remains the predominant intracranial event regardless of CHA₂DS₂-VASc score or HAS-BLED score ≤4, even in patients on oral anticoagulation 3. The risk of intracranial bleeding only exceeds the risk of ischemic stroke with very high HAS-BLED scores (>4) 3.

A study from the Euro Heart Survey found that in 89% (CHADS₂/HAS-BLED) and 97% (CHA₂DS₂-VASc/HAS-BLED) of patients, the bleeding risk category was equal to or lower than their cardioembolic risk category 4. This suggests that for most patients, the stroke risk outweighs the bleeding risk.

Clinical Pearls and Pitfalls

• Common pitfall: Withholding anticoagulation solely based on a high HAS-BLED score. Instead, use the score to identify and address modifiable risk factors.

• Important consideration: The HAS-BLED score has better discriminatory performance for clinically relevant bleeding compared to CHADS₂ and CHA₂DS₂-VASc scores 5. Therefore, use the appropriate score for each risk assessment.

• Key point: Even patients with a HAS-BLED score ≥3 often benefit from anticoagulation if their CHA₂DS₂-VASc score indicates a significant stroke risk 2, 6.

• Practical approach: For patients with HAS-BLED > CHA₂DS₂-VASc, consider:

  • Using NOACs instead of warfarin when appropriate (lower risk of intracranial hemorrhage) 1
  • More frequent monitoring of renal function if using NOACs 1
  • Closer follow-up and regular reassessment of modifiable bleeding risk factors 2

In conclusion, the decision to anticoagulate should be based primarily on stroke risk (CHA₂DS₂-VASc), with the bleeding risk (HAS-BLED) guiding management strategies rather than serving as an absolute contraindication to therapy.