Assessment of New Deep Vein Thrombosis

Clinical Probability Assessment

• The American Heart Association recommends using the Wells Score to stratify pretest probability before or immediately after diagnosis confirmation, which includes factors such as active cancer, paralysis, paresis, or recent plaster immobilization, recently bedridden, localized tenderness along deep venous system, entire leg swollen, calf swelling, pitting edema, collateral superficial veins, and previously documented DVT, with a score ≥2 indicating high probability and <2 indicating low probability 1, 3

Baseline Laboratory Testing

• The American College of Cardiology recommends obtaining complete blood count with platelet count, PT, aPTT, liver function tests, and kidney function tests as part of initial diagnostic workup, with kidney function being critical for LMWH and DOAC dosing decisions 2, 4

Complete Imaging Assessment

• The American Heart Association recommends complete duplex ultrasound as the preferred imaging modality, including compression of deep veins from inguinal ligament to ankle, spectral Doppler waveforms, popliteal spectral Doppler, and color Doppler images throughout, and evaluating symptomatic areas for superficial venous thrombosis or alternative pathology 1

Assessment for Pulmonary Embolism

• The Mayo Clinic recommends considering evaluating for concurrent PE if the patient has any respiratory symptoms, using clinical probability assessment combined with D-dimer if PE unlikely, or proceeding directly to CT pulmonary angiography if PE likely 4, 5

Provoked vs Unprovoked Classification

• The American College of Chest Physicians recommends determining if the DVT is provoked or unprovoked, as this impacts duration of anticoagulation, with provoked DVT including recent surgery, trauma, immobilization, pregnancy, estrogen therapy, and unprovoked DVT requiring longer anticoagulation 1, 4

Cancer Screening Considerations

• The American Heart Association recommends assessing for occult malignancy through age-appropriate cancer screening in patients with unprovoked DVT, as active cancer is present in approximately 10% of patients with unprovoked VTE, and cancer patients require different anticoagulation strategies 1, 2

Common Pitfalls to Avoid

• The American College of Cardiology recommends not relying on clinical examination alone, not accepting limited proximal-only ultrasound, not forgetting to assess renal function before selecting anticoagulation, and not overlooking bilateral symptoms, considering alternative diagnoses like heart failure, venous insufficiency, or lymphedema 1, 2, 4