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Non-valvular atrial fibrillation — MSRA MCQ

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Hardall topics relevant for this examNon-valvular atrial fibrillationMSRA

An 82-year-old woman is reviewed after a 12-lead ECG confirms non-valvular atrial fibrillation. She has treated hypertension and no previous stroke, TIA, heart failure, diabetes or vascular disease. Her weight is 58 kg. Serum creatinine is 121 micromol/L and eGFR is 39 mL/min/1.73 m²; these values are stable. Liver function and full blood count are normal. She has no active bleeding, recent peptic ulceration, falls causing injury, mechanical valve, mitral stenosis, or interacting medicines. Her CHA₂DS₂-VASc score is 4. Following discussion of treatment options, she chooses apixaban for stroke prevention. What is the most appropriate regimen to start?

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

Reveal the answer and explanation

Correct answer: B — Start apixaban 2.5 mg orally twice daily

Explanation lettering: C = shown as A · D = shown as B · E = shown as C · B = shown as D · A = shown as E

This patient requires stroke prevention: her CHA₂DS₂-VASc score is 4 (age 75 years or over scores 2, hypertension scores 1, and female sex scores 1). NICE recommends offering a direct-acting oral anticoagulant to people with atrial fibrillation and a CHA₂DS₂-VASc score of 2 or more, unless it is unsuitable. For non-valvular atrial fibrillation, apixaban is normally prescribed at 5 mg twice daily. However, the licensed dose is reduced to 2.5 mg twice daily when at least two of three criteria are present: age 80 years or over, body weight 60 kg or less, and serum creatinine 133 micromol/L or more. She meets two criteria: age 82 years and weight 58 kg. Her creatinine is below 133 micromol/L, but this does not negate dose reduction because only two of the three criteria are needed. Her eGFR is not itself the dose-reduction criterion in this setting. A is overdosing for her licensed dose-reduction criteria. B is not a licensed apixaban regimen for atrial fibrillation. C is inadequate for stroke prevention in atrial fibrillation. E would be appropriate if a DOAC were contraindicated, not tolerated or unsuitable, but none of these apply and she has chosen apixaban.

Reference: NICE NG196: Atrial fibrillation: diagnosis and management — Stroke prevention (Updated March 2025) — https://www.nice.org.uk/guidance/NG196/chapter/recommendations Eliquis 5 mg film-coated tablets — Summary of Product Characteristics, section 4.2 (Last updated 08 January 2024) — https://www.medicines.org.uk/emc/product/2878/smpc