In atrial fibrillation with a valvular lesion, what is the preferred anticoagulation strategy?

• A. Aspirin
• B. Warfarin
• C. Rivaroxaban
• D. Dabigatran

Answer: (B)

In atrial fibrillation with a valvular lesion, the anticoagulation approach relies on evidence that vitamin K antagonists provide reliable stroke prevention in the setting of valve disease. Warfarin is preferred because it has long‑standing data showing reduced embolic risk when a structural valve abnormality or prosthetic valve is present, and because the direct oral anticoagulants have not proven safe or effective in this scenario. Trials and guidelines limit DOACs like rivaroxaban and dabigatran for valvular AF, especially with mechanical valves or significant rheumatic valvular disease, due to higher rates of thromboembolism or bleeding. Aspirin alone does not offer the level of protection needed in AF with valvular disease. Therefore warfarin with an appropriate INR target is the recommended strategy (with higher targets for certain mechanical valves, and around 2.0–3.0 for most valvular AF).