Atrial fibrillation — KFP-style written assessment

KFP 1 (10 marks)

A 72-year-old male teacher presents after two days of palpitations. ECG confirms atrial fibrillation at 118 beats per minute; blood pressure 138/84. He has treated hypertension and type 2 diabetes, walks daily, drinks four standard beers most nights, and his TSH is pending. ^[4]

1. Calculate his CHA2DS2-VASc score and state the anticoagulation recommendation with the treatment thresholds. (3) ^[4]
2. His wife read that "blood thinners cause bleeds". How do you use a HAS-BLED assessment correctly in this conversation? (3) ^[5]
3. Which DOAC will you start and at what dose? Give the trial evidence that supports the class choice over warfarin and over aspirin. (4) ^[8][1]

Model answers

1. Hypertension (1) + diabetes (1) + age 65–74 (1) = 3. Oral anticoagulation is recommended for men at 2 or more and women at 3 or more, considered at 1 and 2 respectively — he is clearly above threshold. The score's value lies in its low-risk floor: in derivation, low-score patients recorded no thromboembolic events at all. ^[4]
2. HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history, Labile INR, Elderly above 65, Drugs/alcohol) quantifies one-year major-bleeding risk and surfaces modifiable factors — his alcohol and blood pressure are both fixable. It informs monitoring intensity and counselling; it never overrides a stroke indication. Frame it as "we reduce what we can reduce, and we still protect you from stroke". ^[5]
3. Apixaban 5 mg twice daily (no dose-reduction criteria met). Class evidence: ARISTOTLE — apixaban superior to warfarin for stroke/systemic embolism (HR 0.79), less major bleeding (HR 0.69), lower mortality (HR 0.89); RE-LY and ROCKET-AF corroborate across agents; COMBINE AF patient-level meta-analysis confirms standard-dose DOACs safer and more effective than warfarin down to CrCl 25 mL/min, while reduced doses raise stroke and death without cutting bleeding. Aspirin has no role: BAFTA showed warfarin halved primary events versus aspirin even in the elderly. Also address his alcohol — each extra drink/day adds about 6% relative AF risk. ^[1][8][2]