Anticoagulation Therapy

Introduction to Anticoagulation

• Anticoagulation therapy is essential for preventing stroke or systemic embolism in patients with atrial fibrillation, with various options available including warfarin, apixaban, and rivaroxaban, as stated by the American Heart Association and the European Society of Cardiology [@A1@, 1, 2, 3, 4]

Efficacy and Safety of Apixaban

• Apixaban is superior to warfarin in preventing stroke or systemic embolism while causing less bleeding, with high-quality evidence, as demonstrated by the American College of Cardiology supported trial, ARISTOTLE 5, 6
• Apixaban reduces the risk of stroke or systemic embolism by 21%, all-cause mortality by 11%, and major bleeding by 31% compared to warfarin, as demonstrated in the following table:

5, 7, 8

• Apixaban has a greater reduction in major bleeding compared to warfarin among patients with moderate or severe renal impairment, as noted by the American Heart Association 5
• Underweight patients may have a higher bleeding risk with anticoagulants, according to the European Society of Cardiology Working Group on Thrombosis 9

Dosing and Monitoring of Apixaban

• The standard dose of apixaban is 5 mg twice daily, with a reduced dose of 2.5 mg twice daily for patients with at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL, as recommended by the American College of Cardiology 5, 6
• A dose reduction to 2.5 mg twice daily is recommended for patients with end-stage renal disease on hemodialysis who are either age ≥80 years or body weight ≤60 kg, as recommended by the American College of Cardiology 6
• For patients with severe renal impairment (CrCl 15-29 mL/min), the dose should be reduced to 2.5 mg twice daily, as recommended by the European Society of Cardiology and the American College of Cardiology 10
• Regular monitoring of renal function is essential for patients on apixaban, as stated by the American College of Cardiology and the European Society of Cardiology 7, 11, 2

Contraindications and Precautions

• Contraindications for direct oral anticoagulants (DOACs) in atrial fibrillation include mechanical heart valves, moderate-to-severe mitral stenosis, severe renal failure, and active major bleeding, as stated by the American Heart Association and American Stroke Association 2, 3, 4
• DOACs, including rivaroxaban, are not recommended for patients who are pregnant or breastfeeding, as stated by the American Heart Association and the European Society of Cardiology 12

Monitoring and Management

• No routine coagulation monitoring is required for rivaroxaban or apixaban, as stated by the American Heart Association and the European Society of Cardiology 13, 11, 2, 7
• Vitamin K antagonists (VKAs) require regular INR monitoring with target range 2.0-3.0, as recommended by the American Heart Association and the European Society of Cardiology 14, 15
• The European Society of Anaesthesiology recommends discontinuing apixaban and rivaroxaban 48 hours before elective surgery with significant bleeding risk, and resuming as soon as adequate hemostasis is achieved, typically 24-72 hours postoperatively, as supported by the American Society of Anesthesiologists and the Journal of the American College of Cardiology 16, 6, 17

Duration of Anticoagulation Therapy

• Extended therapy (no scheduled stop date) should be considered for unprovoked venous thromboembolism (VTE) with low or moderate bleeding risk, as recommended by the European Society of Cardiology and the American College of Cardiology 14
• For proximal DVT or pulmonary embolism (PE) provoked by surgery, 3 months of anticoagulation is recommended (Grade 1B evidence), and for proximal DVT or PE provoked by non-surgical transient risk factor, 3 months of anticoagulation is recommended (Grade 1B evidence) 14