What anticoagulant to start for a patient with a CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke or transient ischemic attack, Vascular disease, Age 65-74 years, Sex category) score of 2?

Anticoagulation for CHA₂DS₂-VASc Score of 2

Start a Direct Oral Anticoagulant (DOAC) as first-line therapy—specifically apixaban, rivaroxaban, dabigatran, or edoxaban—over warfarin for stroke prevention in atrial fibrillation with a CHA₂DS₂-VASc score of 2. 1

Risk Justification

• A CHA₂DS₂-VASc score of 2 corresponds to an annual stroke risk of approximately 2.2% without anticoagulation, which clearly exceeds the 1% threshold that justifies oral anticoagulation therapy 1
• Oral anticoagulation is definitively recommended for all patients with a CHA₂DS₂-VASc score ≥2, regardless of whether the atrial fibrillation pattern is paroxysmal, persistent, or permanent 1
• This recommendation applies to males with a score of ≥2 and females with a score of ≥3 (since female sex alone contributes 1 point) 1

Preferred Anticoagulant Selection

First-Line: Direct Oral Anticoagulants (DOACs)

DOACs are superior to warfarin and should be prescribed as first-line therapy 2, 1:

• Apixaban 5 mg twice daily (or 2.5 mg twice daily if patient has ≥2 of: age ≥80 years, weight ≤60 kg, or serum creatinine ≥1.5 mg/dL) 3
• Rivaroxaban 20 mg once daily with evening meal (or 15 mg once daily if CrCl 30-50 mL/min) 4
• Dabigatran (dosing per product labeling) 1
• Edoxaban (dosing per product labeling) 1

Rationale for DOAC Preference

• DOACs have been demonstrated to be at least non-inferior and in some trials superior to warfarin for preventing stroke and systemic embolism 1
• DOACs carry lower risks of serious bleeding, particularly hemorrhagic stroke, compared to warfarin 2, 1
• DOACs have predictable pharmacodynamics and do not require routine coagulation monitoring, unlike warfarin 2
• Apixaban specifically demonstrated superiority to warfarin in the ARISTOTLE trial, with a 21% relative risk reduction in stroke/systemic embolism (HR 0.79,95% CI 0.66-0.95, p=0.01) and significantly fewer major bleeds 3

Alternative: Warfarin

Use warfarin (target INR 2.0-3.0) only if DOACs are contraindicated, not tolerated, or in specific clinical scenarios 1:

• Severe renal impairment (CrCl <15 mL/min) or hemodialysis 1
• Moderate-to-severe mitral stenosis 2, 1
• Mechanical prosthetic heart valves 2, 1
• Patient preference or cost considerations with adequate monitoring infrastructure 2

Warfarin Management Requirements

• Monitor INR at least weekly during initiation and monthly when stable 1
• Target time in therapeutic range (TTR) ≥65%, ideally ≥70% 2
• If considering warfarin, calculate SAMe-TT₂R₂ score: if >2, strongly favor DOAC over warfarin due to predicted poor INR control 2

Bleeding Risk Assessment

Calculate HAS-BLED score before initiating anticoagulation, but do not withhold therapy based on elevated bleeding risk alone 2, 1:

• HAS-BLED components: Hypertension, Abnormal renal/liver function, Stroke history, Bleeding history, Labile INR, Elderly (>65), Drugs/alcohol 2
• A HAS-BLED score ≥3 identifies patients requiring more frequent monitoring and modification of bleeding risk factors, but is NOT a contraindication to anticoagulation 2, 1
• Address modifiable bleeding risk factors: uncontrolled hypertension, concomitant antiplatelet/NSAID use, excessive alcohol intake 2

Critical Implementation Steps

1. Assess renal function before initiating DOACs and reassess at least annually 1
2. Do not use antiplatelet therapy (aspirin or clopidogrel) as an alternative to anticoagulation for stroke prevention—it is ineffective and still carries bleeding risk 2, 1
3. Ensure patient does not have mechanical heart valves or moderate-to-severe mitral stenosis before prescribing DOACs 2, 1

Common Pitfalls to Avoid

• Do not withhold anticoagulation solely based on fall risk—a patient would need to fall approximately 300 times per year for intracranial hemorrhage risk to outweigh stroke prevention benefit 5
• Do not count female sex alone (CHA₂DS₂-VASc score of 1 in women) as justifying anticoagulation—this represents truly low risk 2, 1
• Do not use aspirin monotherapy—warfarin reduces stroke risk by two-thirds compared to no therapy, while aspirin is far less effective 2
• Do not prescribe standard DOAC doses in severe renal impairment without appropriate dose adjustment or consideration of warfarin 1, 4