A 72-year-old woman with a 3-year history of paroxysmal atrial fibrillation presents for routine follow-up. She is currently on metoprolol 50 mg twice daily for rate control and aspirin 75 mg daily. She denies recent palpitations or syncope. Her CHA₂DS₂-VASc score is calculated as 4 (age 72, hypertension, diabetes). What is the most appropriate anticoagulation strategy?

Explanation

## Risk Stratification & CHA₂DS₂-VASc Score **Key Point:** The CHA₂DS₂-VASc score stratifies stroke risk in AF. A score ≥2 in women (or ≥1 in men) mandates anticoagulation. | Component | Points | |-----------|--------| | **C** — Congestive heart failure | 1 | | **H** — Hypertension | 1 | | **A₂** — Age ≥75 years | 2 | | **D** — Diabetes mellitus | 1 | | **S₂** — Prior stroke/TIA/thromboembolism | 2 | | **V** — Vascular disease (MI, PAD, aortic plaque) | 1 | | **A** — Age 65–74 years | 1 | | **Sc** — Sex category (female) | 1 | This patient scores **4 points** (age 65–74: 1, female: 1, hypertension: 1, diabetes: 1), which is **high risk** for stroke. ## Anticoagulation Indication **High-Yield:** Current guidelines (ESC 2019, ACC/AHA 2019) recommend **anticoagulation for all patients with AF and CHA₂DS₂-VASc ≥2 in women or ≥1 in men**, regardless of AF pattern (paroxysmal, persistent, permanent). **Clinical Pearl:** Aspirin monotherapy is **NO LONGER recommended** for stroke prevention in AF, even in low-risk patients. It is inferior to anticoagulation and should be reserved for patients with absolute contraindications. ## DOAC vs. Warfarin | Feature | DOAC | Warfarin | |---------|------|----------| | **Onset** | Rapid (hours) | Slow (days) | | **INR monitoring** | Not required | Required | | **Drug interactions** | Fewer | Many | | **Reversibility** | Partial (idarucizumab for dabigatran) | Complete (vitamin K, FFP) | | **First-line status** | **Yes** (preferred) | Second-line | | **Renal clearance** | Variable (dabigatran 80%) | Hepatic | **Mnemonic for DOAC selection — ACED:** - **A**pixaban (dose: 5 mg BD or 2.5 mg BD if ≥2 criteria: age ≥60, weight ≤60 kg, Cr ≥1.5) - **C**arixa (edoxaban) — not widely used in India - **E**doxaban (dose: 60 mg OD or 30 mg OD if CrCl 15–50 or weight ≤60 kg) - **D**abigatran (dose: 110 mg or 150 mg BD) **Why DOAC over warfarin in this patient?** 1. No need for INR monitoring (better compliance) 2. Faster onset 3. Fewer drug interactions 4. Non-inferior or superior efficacy to warfarin in AF [cite:ESC Guidelines on Atrial Fibrillation 2019; Harrison 21e Ch 226]