Anticoagulation After Falls in a 90-Year-Old With Atrial Fibrillation
A 90-year-old man with permanent atrial fibrillation comes for follow-up. His CHA2DS2-VASc score is 6 (age, hypertension, diabetes, prior TIA, heart failure) and HAS-BLED is 3. He has fallen twice in the past year - once tripping on a rug, once from orthostatic dizziness - without fracture or head injury. He lives with his wife, walks with a walker, and his Montreal Cognitive Assessment score is 24. He takes aspirin 81 mg daily, metoprolol, furosemide, lisinopril, metformin, and atorvastatin. Blood pressure is 138/72 seated and 112/64 standing. Weight is 58 kg, creatinine 1.5 mg/dL, estimated creatinine clearance 28 mL/min. His daughter, a nurse, asks whether "blood thinners are worth it at his age." He says he wants "to avoid a big stroke" but is worried about bleeding and falling.
1. How do you weigh stroke and bleeding risk, and does fall risk alone justify withholding anticoagulation?
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His stroke risk is high: a CHA2DS2-VASc of 6 predicts roughly 7–10% annual stroke risk without anticoagulation, and a prior TIA marks him as particularly high risk. HAS-BLED of 3 should trigger correction of reversible factors, not withholding therapy; the score was designed to flag modifiable bleeding risks, not to be used as a reason to deny anticoagulation.
Fall risk alone is a weak justification. Modeling studies suggest a patient would need to fall hundreds of times per year for the subdural risk to outweigh the stroke benefit in a high-risk patient. His two falls were mechanical and orthostatic - the second is a target for intervention, not a contraindication.
The right frame is "how do I anticoagulate him as safely as possible," not "whether." Aspirin should be stopped: it adds bleeding risk without meaningful stroke protection in atrial fibrillation. His own stated goal - avoiding a large stroke - aligns with treatment, and that should guide the discussion with his daughter.
2. Which anticoagulant and dose would you choose, given his age, weight, and renal function?
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Apixaban is a reasonable choice. He meets all three dose-reduction criteria - age ≥80, weight ≤60 kg, and creatinine ≥1.5 mg/dL - so 2.5 mg twice daily is the correct reduced dose. Using 5 mg twice daily here would be an overdose by label.
Warfarin with a target INR of 2–3 remains an alternative if cost or access is an issue, but it requires monitoring and carries a higher risk of intracranial hemorrhage than apixaban.
Check renal function every 6–12 months and after any acute illness, because his creatinine clearance of 28 mL/min will drift during dehydration or infection. Counsel on missed doses (do not double), on drug interactions (avoid NSAIDs and strong CYP3A4/P-gp inhibitors), and on the need to seek urgent evaluation after any head strike even if he feels fine. Confirm he can obtain and afford the drug before prescribing it.
3. What would you do to reduce bleeding risk, and what if he falls again with a head strike?
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Mitigation is concrete: treat the orthostasis by reviewing furosemide and lisinopril dosing and timing, recheck standing blood pressure, address home hazards, provide physical therapy, correct vision, and avoid sedatives. Stop aspirin. Recheck hemoglobin periodically.
After a fall without head injury, continue the anticoagulant - do not stop it reflexively. After a fall with head strike, obtain an immediate noncontrast head CT regardless of symptoms, hold the next dose pending imaging, and reverse the anticoagulant if intracranial bleeding is found, using andexanet alfa or prothrombin complex concentrate per local protocol. A serious bleed does prompt a reassessment of the risk-benefit balance, but one uncomplicated fall does not.
Document his own decision, his daughter's concerns, and the reasoning, so that the next clinician - or the next hospitalization - does not silently stop the drug.