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Atrial fibrillation stroke prevention — USMLE Step 3 MCQ

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ModerateAmbulatory Medicine / Primary CareAtrial fibrillation stroke preventionUSMLE Step 3

A 63-year-old man with persistent atrial fibrillation comes for routine follow-up. He has hypertension and diabetes but no prior stroke. He takes metoprolol and lisinopril. Blood pressure is 128/76 mm Hg, creatinine is 1.0 mg/dL, and liver tests are normal. He asks whether aspirin is enough to prevent stroke. Which of the following is the most appropriate next step in management?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Start oral anticoagulation

His CHA2DS2-VASc score is elevated, so oral anticoagulation is indicated for stroke prevention. Aspirin is not adequate stroke prevention for atrial fibrillation in this risk category.

Reference: 2023 ACC/AHA/ACCP/HRS Atrial Fibrillation Guideline