How long should a 75-year-old male with a history of two DVTs in the popliteal vein post-knee replacement be on Eliquis (apixaban) for the second DVT?

Duration of Anticoagulation for Recurrent DVT Post-Knee Replacement

For a 75-year-old male with a second DVT in the popliteal vein following knee replacement, extended anticoagulation therapy with apixaban (Eliquis) is strongly recommended, with indefinite treatment being the appropriate approach.

Assessment of Recurrent DVT

This patient presents with several important factors that guide treatment decisions:

• Second episode of DVT (recurrent VTE)
• Previous DVT in same location (popliteal vein)
• Both episodes occurred post-knee replacement
• Advanced age (75 years)
• First episode was treated with 3 months of apixaban with resolution

Treatment Recommendation

Duration of Therapy

• Extended anticoagulation therapy (indefinite treatment) is strongly recommended for this patient with a second unprovoked DVT 1, 2
• The American College of Chest Physicians (ACCP) guidelines specifically recommend extended anticoagulant therapy over 3 months of therapy in patients with a second unprovoked VTE who have a low bleeding risk (Grade 1B recommendation) 1
• Even for patients with moderate bleeding risk, extended anticoagulation is suggested (Grade 2B recommendation) 1

Dosing for Extended Therapy

• After completing initial treatment (first 6 months), the recommended regimen for indefinite treatment is reduced-dose apixaban 2.5 mg twice daily 2, 3
• This dosing is supported by the AMPLIFY-EXT trial, which demonstrated that apixaban 2.5 mg twice daily was superior to placebo in preventing recurrent VTE without significantly increasing bleeding risk 3

Risk Assessment

Recurrence Risk

• The annual risk of recurrence for patients with a second unprovoked DVT is approximately 12% if anticoagulation is stopped 2
• This high recurrence risk strongly justifies extended therapy

Bleeding Risk Considerations

• If this patient has a high bleeding risk, the recommendation would be modified, potentially limiting treatment to 3 months 1
• However, given the second episode of DVT, extended therapy would still be suggested even with moderate bleeding risk 1

Monitoring and Follow-up

• All patients on extended anticoagulation therapy should have treatment reassessed at least annually 2
• Regular monitoring should include:
  • Assessment of bleeding risk factors
  • Renal function monitoring
  • Evaluation for signs of bleeding complications
  • Assessment of medication adherence

Common Pitfalls to Avoid

1. Inadequate treatment duration: Treating for only 3 months after a second DVT significantly increases recurrence risk
2. Failure to transition to appropriate maintenance dose: For extended therapy, reduced-dose apixaban (2.5 mg twice daily) is appropriate after initial treatment period 2, 3
3. Overlooking periodic reassessment: Extended therapy requires ongoing evaluation of risk-benefit ratio 1
4. Misclassifying the type of DVT: This represents a second unprovoked DVT, which carries different recommendations than a provoked event 1

Evidence Summary

The recommendation for extended therapy is based on high-quality evidence showing that:

• Extended anticoagulation with apixaban reduces the risk of recurrent VTE by approximately 80% compared to placebo 3
• The reduced dose of apixaban (2.5 mg twice daily) maintains efficacy while minimizing bleeding risk in long-term therapy 3, 4
• For patients with a second unprovoked VTE, the risk of recurrence substantially outweighs bleeding risk in most patients 1, 5