What is the appropriate workup for Deep Vein Thrombosis (DVT)?

From the Guidelines

The workup for deep vein thrombosis (DVT) should begin with a comprehensive medical history and physical examination, followed by imaging with venous ultrasound, as recommended by the NCCN guidelines 1. The initial evaluation should include a clinical suspicion of DVT, which can be assessed by symptoms such as swelling of the unilateral extremity, heaviness in the extremity, pain in the extremity, unexplained persistent calf cramping, swelling in the face, neck, or supraclavicular space, or catheter dysfunction if a catheter is present. Some key points to consider in the workup of DVT include:

• Clinical suspicion of DVT: assess for symptoms such as swelling, heaviness, pain, or cramping in the affected limb
• Imaging: venous ultrasound is the recommended initial imaging modality, with consideration of additional imaging such as CT venogram or magnetic resonance venogram if initial results are inconclusive
• Laboratory tests: CBC with platelet count, PT, aPTT, and liver and kidney function tests should be performed as part of the initial evaluation
• Anticoagulation therapy: should be initiated promptly in patients with confirmed DVT, with options including direct oral anticoagulants or traditional therapy with low molecular weight heparin bridged to warfarin. The NCCN guidelines recommend a minimum anticoagulation duration of 3 months, with consideration of extended anticoagulation in patients with active cancer, ongoing cancer treatment, unprovoked DVT, or persistent thrombosis 1. In cases with high suspicion of DVT and no contraindications, consider initiating early anticoagulation while awaiting imaging results, as recommended by the NCCN guidelines 1.

From the Research

DVT Workup

• The approach for diagnosing deep vein thrombosis (DVT) involves clinical features and probability assessment guiding further diagnostic tests 2.
• D-dimer testing is used as a screening test, while duplex ultrasound remains the primary confirmatory test 2, 3.
• Computed tomography and magnetic resonance imaging are used in select patient populations, such as when ultrasound results are equivocal or in patients suspected of central venous DVT 2.

Diagnostic Tests

• The pre-test probability of DVT can be assessed using a clinical decision rule that stratifies DVT into "unlikely" or "likely" 3.
• If DVT is "unlikely", a D-dimer test is recommended, and if the result is normal, DVT can be excluded 3.
• If DVT is "likely", compression ultrasound is recommended 3.
• The sensitivity and specificity of D-dimer testing can vary, with a high negative predictive value but low positive predictive value 4, 5.

Imaging Techniques

• Duplex ultrasound is a safe and effective method for the exclusion and diagnosis of DVT 6.
• Complete compression ultrasonography can be used to assess the thrombotic burden and diagnose acute symptomatic DVT of the lower limbs 4.
• Colour Doppler sonography can be used as the primary diagnostic technique, with a negative D-dimer assay helping to reduce the imaging workload 5.

Treatment and Management

• Anticoagulation is indicated to control symptoms, prevent progression, and reduce the risk of post-thrombotic syndrome and pulmonary embolism 3.
• Direct oral anticoagulants (DOACs) are the preferred treatment for DVT, but may require dose reduction or avoidance in patients with renal dysfunction or pregnancy 3.
• Thrombophilia testing may be recommended for patients with a family history of DVT or other risk factors 6.