Is it appropriate to transition an elderly male patient with a history of breast cancer, chronic anemia, diabetes mellitus type 2 (DM-2), hyperlipidemia (HLD), meningioma, celiac artery stenosis, hypertension (HTN), and urinary retention, who was recently diagnosed with pulmonary embolism (PE) and deep vein thrombosis (DVT) and is currently on Lovenox (enoxaparin), to an oral anticoagulant such as Eliquis (apixaban) now that he is mobilizing with physical therapy (PT) and occupational therapy (OT)?

Transitioning to Oral Anticoagulation in an Elderly Patient with Cancer-Associated VTE

Yes, transitioning from Lovenox to apixaban is appropriate for this patient, and apixaban is the preferred oral anticoagulant choice given his cancer history, chronic anemia, and multiple comorbidities. 1

Rationale for Transition

For patients with cancer-associated thrombosis (CAT), oral factor Xa inhibitors including apixaban are now recommended over LMWH for treatment-phase therapy. 1 The 2021 CHEST guidelines provide a strong recommendation (moderate-certainty evidence) that apixaban, edoxaban, or rivaroxaban be used over LMWH in patients with acute VTE in the setting of cancer. 1

• The patient's mobilization status with PT/OT is appropriate for oral anticoagulation, as this indicates clinical stability and adequate functional capacity. 1
• The DVT appears provoked by IV placement (now removed), and the PE occurred in the context of recent hospitalization, making transition to oral therapy reasonable after initial parenteral treatment. 1

Why Apixaban is the Optimal Choice

Apixaban is specifically advantageous in this patient for several critical reasons:

• Lower GI bleeding risk: Among the oral factor Xa inhibitors, apixaban does not appear to be associated with higher risk of GI major bleeding compared to LMWH in patients with cancer-associated thrombosis, unlike rivaroxaban and edoxaban. 1 Given this patient's chronic anemia, minimizing bleeding risk is paramount for quality of life and avoiding transfusions.

• Renal safety profile: Apixaban has less renal excretion (approximately 27%) compared to other DOACs, making it safer in elderly patients who may have declining renal function. 1 This is particularly important given his diabetes, hypertension, and advanced age—all risk factors for renal impairment.

• No bridging required: Transition from Lovenox to apixaban requires no bridging therapy with heparin, simplifying the transition. 2 Simply discontinue Lovenox and begin apixaban at the usual time of the next scheduled Lovenox dose. 3

Dosing Considerations for This Elderly Patient

The appropriate apixaban dose requires assessment of specific criteria:

• Standard VTE treatment dose: 10 mg orally twice daily for 7 days, then 5 mg twice daily. 3

• Dose reduction criteria: Evaluate if the patient meets at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL. 2, 3 If two or more criteria are met, use 2.5 mg twice daily after the initial treatment phase.

• Renal function assessment is mandatory: Calculate creatinine clearance using the Cockcroft-Gault formula before initiating apixaban. 2 Apixaban can be used if CrCl >30 mL/min at the appropriate dose. 2 Given his diabetes and hypertension, renal function should be assessed at least annually and when clinically indicated. 2

Critical Safety Considerations

Several factors in this patient's profile require heightened vigilance:

• Chronic anemia: Monitor hemoglobin, hematocrit, and platelet count at least every 2-3 days for the first 14 days, then every 2 weeks thereafter. 1 This is particularly important given his baseline anemia and cancer history.

• Drug interactions: Review all medications for combined P-glycoprotein and strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir), which would require dose reduction. 3 Avoid concomitant use of other antiplatelet agents, NSAIDs, or SSRIs/SNRIs that increase bleeding risk. 3

• Celiac artery stenosis: This vascular pathology may indicate broader atherosclerotic disease, but does not contraindicate apixaban use. However, it underscores the importance of minimizing bleeding risk. 3

• Meningioma: While not an absolute contraindication, any intracranial pathology warrants careful consideration. Apixaban has significantly lower risk of intracranial hemorrhage compared to warfarin, making it preferable in this context. 2

Practical Transition Protocol

Execute the following steps for safe transition:

1. Baseline laboratory testing: Obtain CBC, comprehensive metabolic panel (including creatinine for CrCl calculation), hepatic function panel, aPTT, and PT/INR before initiating apixaban. 1

2. Timing of switch: Discontinue Lovenox and begin apixaban at the time the next dose of Lovenox would have been administered. 3 No overlap or bridging is required. 2

3. Initial dosing: Start apixaban 10 mg orally twice daily for 7 days, then reduce to 5 mg twice daily (or 2.5 mg twice daily if dose reduction criteria are met). 3

4. Patient education: Ensure the patient understands twice-daily dosing is critical for efficacy, as missed doses significantly impact anticoagulation. 2 If a dose is missed, take it as soon as possible on the same day but do not double the dose. 3

5. Administration considerations: For patients with swallowing difficulties (common in elderly patients), apixaban tablets may be crushed and suspended in water, D5W, or apple juice, or mixed with applesauce. 3

Duration of Anticoagulation

For this patient with provoked VTE (IV-related DVT) and cancer:

• The standard treatment phase is 3 months for provoked VTE. 1
• However, active cancer represents an ongoing risk factor that may warrant extended-phase therapy beyond 3 months. 1
• After completing at least 6 months of treatment, consider reduced-dose apixaban 2.5 mg twice daily for extended-phase therapy to reduce recurrence risk. 1, 3
• Reassess the risk-benefit ratio at 3 months, considering cancer status, bleeding risk, and functional status. 1

Common Pitfalls to Avoid

Do not make these errors:

• Assuming all DOACs are equivalent: Apixaban has distinct advantages in GI bleeding risk compared to rivaroxaban and edoxaban in cancer patients. 1
• Neglecting renal function monitoring: Elderly patients with diabetes and hypertension require periodic reassessment of renal function, as declining CrCl may necessitate dose adjustment or discontinuation. 1, 2
• Overlooking adherence: Without INR monitoring, adherence becomes critical. Establish a system for follow-up and medication reconciliation. 1
• Premature discontinuation: Stopping anticoagulation without adequate alternative coverage increases thrombotic risk significantly. 3 If apixaban must be discontinued for surgery or bleeding, have a clear plan for resumption or alternative anticoagulation. 3