What is the next step in managing a patient with a persistent blood clot in the right femoral superficial vein who has been on Eliquis (apixaban) for 3 years?

Management of Persistent Femoral Vein Thrombosis After 3 Years of Apixaban

Continue apixaban indefinitely without a scheduled stop date, as this represents an unprovoked deep vein thrombosis requiring extended-phase anticoagulation, and reassess the decision annually based on bleeding risk and patient preference. 1

Critical Clarification: This is a Deep Vein Thrombosis

The "superficial femoral vein" is a deep vein, not a superficial vein—this is a dangerous misnomer that has led to fatal errors in clinical practice. 2 The femoral vein (also called the superficial femoral vein) is part of the deep venous system, and thrombosis here is potentially life-threatening and requires full anticoagulation. 2

Duration of Anticoagulation for This Patient

This patient requires extended-phase anticoagulation (no scheduled stop date) because:

• The patient has completed the initial 3-month treatment phase and now requires assessment for extended therapy 1
• The persistence of thrombus after 3 years of anticoagulation suggests this is an unprovoked VTE (no transient risk factor identified) 1
• For unprovoked proximal DVT with low or moderate bleeding risk, the 2021 CHEST guidelines strongly recommend offering extended-phase anticoagulation with a DOAC 1
• The 2016 CHEST guidelines suggest extended anticoagulant therapy over stopping at 3 months for first unprovoked proximal DVT in patients with low or moderate bleeding risk 1

Assess Bleeding Risk to Guide Decision

Evaluate the patient's bleeding risk using the following framework: 1

• Low bleeding risk: Age <65 years, no prior bleeding, no comorbidities increasing bleeding risk, good medication adherence 1
• Moderate bleeding risk: Age 65-75 years, controlled hypertension, diabetes, or one risk factor for bleeding 1
• High bleeding risk: Age >75 years, prior major bleeding, thrombocytopenia, renal failure (CrCl <30 mL/min), liver disease, concurrent antiplatelet therapy, falls risk, or poor medication adherence 1

If low or moderate bleeding risk: Continue extended anticoagulation indefinitely 1

If high bleeding risk: The recommendation becomes weaker, but extended therapy may still be suggested over stopping, with more frequent reassessment 1

Optimize the Anticoagulation Regimen

Consider dose reduction for extended-phase therapy:

• The 2021 CHEST guidelines suggest using reduced-dose apixaban (2.5 mg twice daily) over full-dose apixaban (5 mg twice daily) for extended-phase anticoagulation 1
• Reduced-dose apixaban maintains efficacy for VTE prevention while potentially reducing bleeding risk during long-term therapy 1
• This dose reduction is specifically for the extended phase after completing initial 3-6 months of full-dose therapy 1

Continue the same anticoagulant (apixaban) rather than switching:

• The 2016 CHEST guidelines suggest no need to change the choice of anticoagulant after the first 3 months 1
• Apixaban has proven efficacy and safety for extended VTE treatment 3, 4

Investigate Why the Thrombus Persists

The persistence of thrombus after 3 years warrants additional evaluation: 1

• Confirm medication adherence: Verify the patient has been taking apixaban consistently at the prescribed dose 1
• Check for drug interactions: Review all medications for P-gp and CYP3A4 inhibitors/inducers that could affect apixaban levels 5
• Assess for underlying thrombophilia: Consider testing for antiphospholipid syndrome, factor V Leiden, prothrombin gene mutation, or other hypercoagulable states 1
• Screen for occult malignancy: Persistent or recurrent VTE despite anticoagulation may indicate underlying cancer 1
• Evaluate for May-Thurner syndrome: Anatomic compression of the left iliac vein can cause persistent femoral vein thrombosis 2

Note: The presence of residual thrombus itself is not necessarily an indication to change therapy, as many patients have persistent thrombus on imaging despite adequate anticoagulation and no recurrent events. 6

Annual Reassessment Protocol

Reassess the decision to continue anticoagulation at least annually: 1

• Re-evaluate bleeding risk (has it increased with age, new medications, or comorbidities?) 1
• Assess for any bleeding events on therapy 1
• Confirm ongoing patient preference for continued anticoagulation 1
• Consider D-dimer testing 1 month after stopping anticoagulation if considering discontinuation (elevated D-dimer suggests higher recurrence risk) 1
• Document the shared decision-making discussion in the medical record 1

Common Pitfalls to Avoid

Do not stop anticoagulation simply because the thrombus is still visible on imaging - residual thrombus is common and does not indicate treatment failure if the patient has had no recurrent events. 6

Do not confuse the "superficial femoral vein" with a superficial vein - this is a deep vein requiring full anticoagulation, and misinterpretation has led to fatal pulmonary emboli. 2

Do not switch to aspirin alone - aspirin is much less effective than anticoagulation for preventing recurrent VTE and should only be considered if the patient refuses anticoagulation or has prohibitive bleeding risk. 1

Do not use standard coagulation tests (PT, aPTT) to monitor apixaban - these tests are insensitive to apixaban levels and should not guide dosing decisions. 7

Do not abruptly discontinue apixaban without bridging to alternative anticoagulation - premature discontinuation increases stroke and thrombosis risk. 5