Hip fracture surgery in a patient on apixaban with renal impairment
An 84-year-old woman, 58 kg, falls and sustains a displaced left femoral neck fracture. She takes apixaban 5 mg twice daily for atrial fibrillation, last dose 20 hours ago, and aspirin 75 mg daily. Her eGFR is 42 mL/min/1.73 m². Haemoglobin is 108 g/L, platelets 190 × 10^9/L, INR 1.1 and APTT 31 s. Blood pressure is 148/82 mmHg and heart rate 92/min. She has mild cognitive impairment but can consent with family support. The orthopaedic team wants a spinal anaesthetic within 6 hours because of pressure on theatre lists. The anaesthetist is concerned about neuraxial haematoma. A fascia iliaca block is planned for analgesia.
1. Using the pharmacology of apixaban, calculate when neuraxial anaesthesia could safely be performed and what additional tests might help.
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Apixaban has a terminal half-life of about 12 hours in patients with normal renal function, but renal impairment prolongs this. With an eGFR of 42 mL/min/1.73 m², a half-life of roughly 17–20 hours is realistic. Five half-lives would therefore be 85–100 hours, and ESRA guidance recommends stopping apixaban for at least 72 hours before neuraxial anaesthesia in patients with normal renal function, with a longer interval when renal impairment is present. The last dose was only 20 hours ago, so a spinal anaesthetic is not safe on pharmacological grounds. A calibrated anti-Xa assay specific for apixaban could be measured; a level below about 30 ng/mL is generally considered safe for neuraxial procedures, but this assay is not universally available and uncertainty remains. Aspirin alone is not a contraindication to neuraxial anaesthesia according to ESRA, but it does not offset the apixaban effect. I would therefore recommend general anaesthesia or delaying surgery, and I would document the reasoning clearly. The urgency of hip fracture surgery must be balanced against the catastrophic risk of spinal haematoma.
2. Compare general anaesthesia, spinal anaesthesia and peripheral nerve blockade for this patient, with reference to mortality and complications.
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The REGAIN trial showed no significant difference in mortality between spinal and general anaesthesia for hip fracture surgery, so the choice should be individualised. Spinal anaesthesia can provide excellent operating conditions and may reduce some postoperative respiratory complications, but it causes sympathectomy and hypotension, which is poorly tolerated in an elderly patient with atrial fibrillation and possible aortic stenosis. General anaesthesia allows controlled ventilation and haemodynamic support but carries risks of delirium, airway complications and postoperative cognitive dysfunction, although the evidence for a causal link is weak. A fascia iliaca block provides effective analgesia, reduces opioid requirements and can be performed despite anticoagulation because it is a peripheral block in a compressible site, although the apixaban level still needs consideration. For this patient, I would use a fascia iliaca block for analgesia and general anaesthesia with invasive blood pressure monitoring, careful fluid management and vasopressor support. If surgery could be delayed safely, a spinal anaesthetic might become an option after the apixaban has cleared, but the mortality difference is not a reason to wait.
3. If surgery cannot be delayed and neuraxial anaesthesia is strongly preferred, what reversal strategy would you use and what are the limitations?
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Reversal options for apixaban include andexanet alfa, a recombinant modified factor Xa decoy, or four-factor prothrombin complex concentrate at about 50 IU/kg. Andexanet alfa is not widely available, is expensive and carries thrombotic risk; PCC is more available but its efficacy in reversing apixaban is partial and not fully validated for neuraxial procedures. More importantly, current guidance does not recommend reversing an anticoagulant solely to permit neuraxial anaesthesia. After reversal, the anticoagulant effect may rebound, and the safe interval before neuraxial puncture is uncertain. There are case reports of neuraxial anaesthesia after reversal, but the evidence is weak. I would therefore treat general anaesthesia as the safer default and reserve reversal for life-threatening bleeding or urgent surgery where neuraxial is not the issue. If reversal were nevertheless chosen, I would involve haematology, document the off-label nature of the decision, check a calibrated anti-Xa level if available, and monitor closely for haematoma. The risk of an epidural haematoma with permanent paraplegia is catastrophic, so the threshold for proceeding must be very high.