From the Guidelines
For a 37-year-old female with an unprovoked deep vein thrombosis (DVT) and no known medical conditions, I recommend a comprehensive workup to identify potential underlying causes, including a thrombophilia panel and age-appropriate cancer screening, and initiation of anticoagulation therapy with direct oral anticoagulants (DOACs) or low molecular weight heparin bridging to warfarin, with consideration for extended therapy depending on workup results and risk-benefit assessment, as suggested by the most recent guidelines 1, 2.
Initial Evaluation
Initial evaluation should include:
- Complete blood count
- Comprehensive metabolic panel
- Coagulation studies (PT, PTT, INR)
- D-dimer ### Thrombophilia Panel A thrombophilia panel should be ordered, including:
- Factor V Leiden mutation
- Prothrombin gene mutation
- Protein C and S deficiency
- Antithrombin III deficiency
- Antiphospholipid antibodies ### Cancer Screening Age-appropriate cancer screening is essential, including:
- Mammogram
- Pap smear
- Consideration of abdominal/pelvic imaging with CT or MRI to rule out occult malignancy ### Anticoagulation Therapy Anticoagulation therapy should be initiated immediately with either:
- Direct oral anticoagulants (DOACs) like rivaroxaban 15mg twice daily for 21 days followed by 20mg daily
- Low molecular weight heparin bridging to warfarin with a target INR of 2-3 Treatment should continue for at least 3-6 months, with consideration for extended therapy depending on workup results and risk-benefit assessment, as the risk of recurrent VTE is high in patients with unprovoked DVT 1.
Risk-Benefit Assessment
The decision to extend anticoagulation therapy should be based on a careful risk-benefit assessment, taking into account the patient's individual risk of recurrent VTE and bleeding, as well as their preferences and values, as suggested by the American Society of Hematology 2020 guidelines 1 and the Chest guideline and expert panel report 2.
From the FDA Drug Label
The efficacy profile of apixaban was generally consistent across subgroups of interest for this indication (e.g., age, gender, race, body weight, renal impairment). Approximately 90% of patients enrolled in AMPLIFY had an unprovoked DVT or PE at baseline. Patients who had been treated for DVT and/or PE for 6 to 12 months with anticoagulant therapy without having a recurrent event were randomized to treatment with apixaban 2. 5 mg orally twice daily, apixaban 5 mg orally twice daily, or placebo for 12 months.
The FDA drug label does not provide information on the appropriate workup for a 37-year-old female with unprovoked Deep Vein Thrombosis (DVT) who is medically free. The label discusses the efficacy and safety of apixaban for the treatment of DVT and PE, but does not address the diagnostic workup for these conditions.
From the Research
Appropriate Workup for Unprovoked DVT
The workup for a 37-year-old female with unprovoked Deep Vein Thrombosis (DVT) who is medically free involves several steps:
- A full coagulation workup, including Protein C, Protein S, and antiphospholipid antibody, as well as factor V and prothrombin gene mutation screen, as seen in a case report of a 43-year-old female with DVT 3
- Computed tomography (CT) angiography of the lungs to rule out major emboli, although it may not be able to rule out minor emboli 3
- D-dimer test to assess the risk of recurrence, with a positive result indicating a higher risk 4, 5, 6
- Consideration of the patient's medical history, including any previous episodes of DVT or pulmonary embolism, and any underlying conditions that may increase the risk of recurrence, such as cancer or thrombophilia 4, 5
Risk Factors for Recurrence
Several factors can increase the risk of recurrence in patients with unprovoked DVT, including:
- Male sex, with a higher risk of recurrence compared to females 5, 6
- Presentation as pulmonary embolism (PE), particularly if concomitant proximal DVT is present 5
- Positive d-dimer test after stopping anticoagulation, indicating a higher risk of recurrence 5, 6
- Antiphospholipid antibody, which can increase the risk of recurrence 3, 5
- Low risk of bleeding, which may favor indefinite anticoagulation 5
Anticoagulation Management
The management of anticoagulation in patients with unprovoked DVT involves several considerations:
- The duration of anticoagulation, with options ranging from 3-6 months to indefinite anticoagulation 4, 5
- The type of anticoagulant used, with options including low-dose oral Xa inhibitors, low-molecular-weight heparin, and warfarin 5
- The risk of bleeding, which must be balanced against the risk of recurrence 5
- Patient preference, which can play a role in decisions regarding anticoagulation management 5