Atrial Fibrillation-Borderline Risk — ABIM Board MCQ

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HardCardiologyAtrial Fibrillation-Borderline RiskABIM Board

A 49-year-old man with newly diagnosed atrial fibrillation and a CHA₂DS₂-VASc score of 1 (hypertension only, no other thromboembolic risk factors) seeks advice about stroke prevention. Which approach is most appropriate?

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Correct answer: A — No antithrombotic therapy is reasonable

In a 49-year-old male with new AF and CHA₂DS₂-VASc score of 1 (hypertension only), no routine antithrombotic therapy is most appropriate. Stroke risk in this cohort is approximately 1.3% annually, below the threshold where anticoagulation is favorable. The 2023 ACC/AHA guideline recommends anticoagulation for men with CHA₂DS₂-VASc ≥2. Aspirin is not supported for AF stroke prevention and does not reduce thromboembolism as effectively as anticoagulants. Warfarin and DOACs are overtreatment at this risk level. Left atrial appendage occlusion is an invasive intervention for patients with anticoagulation contraindications, not primary stroke prevention in low-risk patients. Individualized shared decision-making should address the patient's absolute risk, preferences, and any modifiable risk factors (e.g., blood pressure control).

Reference: Young Male Patients with Atrial Fibrillation and CHA₂DS₂-VASc Score of 1 May Not Need Anticoagulants: A Nationwide Population-Based Study, PMID PMC4795759 (2016); 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation, JACC 2024;83:e115–e218, https://pubmed.ncbi.nlm.nih.gov/38043043/