What is the recommended anticoagulation therapy for a patient with a CHA2DS2-VASc (Cardiac failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke or transient ischemic attack, Vascular disease, Age 65-74 years, Sex category) score of 3?

Anticoagulation for CHA₂DS₂-VASc Score of 3

For a patient with atrial fibrillation and a CHA₂DS₂-VASc score of 3, oral anticoagulation with a direct oral anticoagulant (DOAC) is definitively recommended, as this score indicates high stroke risk requiring immediate anticoagulation therapy. 1

Risk Stratification

• A CHA₂DS₂-VASc score of 3 places the patient in the high-risk category for stroke, with an annual stroke rate exceeding 3% without anticoagulation 1
• Oral anticoagulation is a Class I, Level A recommendation for all patients with a CHA₂DS₂-VASc score ≥2 in men or ≥3 in women 1
• Atrial fibrillation increases stroke risk 5-fold, and these strokes carry greater disability, recurrence risk, and mortality compared to non-AF strokes 1, 2

First-Line Anticoagulant Selection

Direct oral anticoagulants (DOACs) are preferred over warfarin as first-line therapy 1:

DOAC Options (all Class I recommendations):

• Apixaban 1
• Dabigatran 1
• Rivaroxaban 1, 3
• Edoxaban 1

Rationale for DOAC Preference:

• DOACs demonstrate similar or superior efficacy to warfarin with significantly lower rates of hemorrhagic stroke 1, 2
• No requirement for INR monitoring 1
• More predictable pharmacodynamics with fewer drug-food interactions 2
• Lower major bleeding rates compared to warfarin in most trials 2

When Warfarin is Indicated Instead

Warfarin (target INR 2.0-3.0) is the required anticoagulant in these specific situations 1, 4:

• Moderate-to-severe mitral stenosis 1
• Mechanical prosthetic heart valves 1
• End-stage chronic kidney disease (CrCl <15 mL/min) or hemodialysis 1
• Severe renal impairment where DOACs lack evidence 1

Critical contraindication: Dabigatran must never be used with mechanical heart valves (Class III: Harm recommendation) 1

Bleeding Risk Assessment

Calculate HAS-BLED Score:

Award 1 point each for 1, 2:

• Hypertension (systolic BP >160 mmHg)
• Abnormal renal function (1 point) or liver function (1 point)
• Stroke history
• Bleeding history or predisposition
• Labile INR (if on warfarin)
• Elderly (age >65 years)
• Drugs (antiplatelet agents, NSAIDs) or alcohol (1 point each)

Interpretation:

• HAS-BLED ≥3 indicates high bleeding risk requiring closer monitoring and correction of modifiable factors 1, 2
• A high HAS-BLED score is NOT a contraindication to anticoagulation—it identifies patients needing more frequent follow-up 1, 5, 2
• Address modifiable bleeding risk factors: uncontrolled hypertension, excessive alcohol, concomitant antiplatelet therapy, NSAIDs 1

Renal Function Considerations

Assess creatinine clearance before initiating any anticoagulant and reassess at least annually 1:

• CrCl >50 mL/min: Standard DOAC dosing 3
• CrCl 30-50 mL/min: Reduced DOAC doses available; rivaroxaban 15 mg daily 3
• CrCl 15-30 mL/min: Limited DOAC data; consider warfarin 1
• CrCl <15 mL/min or dialysis: Warfarin only; DOACs contraindicated due to lack of evidence 1

Common Pitfalls to Avoid

• Never use aspirin or antiplatelet monotherapy as stroke prevention in AF—it is ineffective and still carries bleeding risk (Class III recommendation) 1, 5
• Never withhold anticoagulation solely because of elevated HAS-BLED score; instead, address modifiable bleeding factors and increase monitoring frequency 1, 5, 2
• Never combine oral anticoagulants with antiplatelet agents unless there is a separate indication (e.g., recent acute coronary syndrome or stent)—this significantly increases bleeding risk 1
• Never prescribe DOACs for mechanical valves or moderate-to-severe mitral stenosis 1, 5
• Never assume paroxysmal AF requires less aggressive anticoagulation than persistent or permanent AF—stroke risk is equivalent across all AF patterns 1

Practical Implementation

1. Confirm absence of absolute contraindications: active major bleeding, severe uncontrolled hypertension (>180/120 mmHg), recent intracranial hemorrhage 6
2. Check renal function to guide DOAC selection and dosing 1
3. Calculate HAS-BLED score to identify modifiable bleeding risk factors 1, 2
4. Select a DOAC as first-line therapy unless contraindications exist requiring warfarin 1
5. Schedule follow-up within 3 months initially, then at least annually to reassess renal function, bleeding risk, and medication adherence 1