A 65-year-old man with persistent atrial fibrillation (>12 months), LVEF 55%, CHA₂DS₂-VASc score of 3 is on warfarin (INR 2.5). He now requires anticoagulation optimisation. A direct oral anticoagulant (DOAC) is preferred over warfarin in AF because of:
- A Superior efficacy and safety with a fixed dose, no routine monitoring required, and reduced intracranial haemorrhage risk (RE-LY, ROCKET-AF, ARISTOTLE trials) ✓
- B Better efficacy in mechanical valve disease
- C Safer in severe renal impairment (eGFR <15)
- D Approved and superior for AF with mitral stenosis
Correct answer: A. Superior efficacy and safety with a fixed dose, no routine monitoring required, and reduced intracranial haemorrhage risk (RE-LY, ROCKET-AF, ARISTOTLE trials)
Explanation
DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) have been proven non-inferior or superior to warfarin for stroke prevention in non-valvular AF with consistent reduction in intracranial hemorrhage (by ~50%) across the pivotal trials: RE-LY (dabigatran), ROCKET-AF (rivaroxaban), ARISTOTLE (apixaban), and ENGAGE-AF (edoxaban). They require no INR monitoring and have fewer drug interactions. DOACs are contraindicated with mechanical valves (dabigatran worsened outcomes in RE-ALIGN trial) and with rheumatic mitral stenosis.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.