Go back

INDEX

    Deep Vein Thrombosis – Diagnosis

    Cardiovascular, Hematological / Oncological

    Last Reviewed on Nov 23, 2020
    Read Disclaimer
    By Nazde Edeer

    Context

    • Deep vein thrombosis (DVT) is common, with over 45,000 cases diagnosed in Canada each year.
    • Complications can include pulmonary embolism (PE) and post-thrombotic syndrome.
    • Risk factors for development of a DVT are closely related to Virchow’s triad (venous stasis, vascular injury and hypercoagulability) including recent surgery, immobilization, malignancy, trauma, pregnancy, estrogen use, and varicose veins.
    • Patients may present with calf pain or cramping, warmth, erythema and edema to a unilateral limb, primarily the lower limb.
    • 4-10% of DVT’s involve upper extremity:
      • 80% of these are secondary:
        • Pacemaker or Central Venous Catheters (including peripherally inserted central catheters (PICC line).
        • Anatomical: cervical rib; hypertrophy of scalenus muscle.
        • Trauma: clavicle fracture.
      • Paget-Schroetter syndrome:
        • Venous thrombosis of the subclavian vein in thoracic inlet syndrome.
        • Typically, young athletes.
        • Sports like baseball, swimming, or tennis.
      • Cancer
        • Pancoast tumor.
    • Diagnosis of DVT requires determining the pre-test probability of DVT either through clinical gestalt (depends on clinical experience) or better to use a clinical tool, such as the Well’s Score followed by D-dimer/ultrasound as indicated.

    Diagnostic Process

    • Thrombosis Canada recommends patients presenting with suspected DVT should be risk stratified. The most commonly used tool is the Well’s Score for DVT.

    • Wells Score > 2: DVT Likely
      • Perform Venous Compression Ultrasound (CUS) of the extremity
        • CUS is positive, initiate appropriate treatment for DVT.
        • CUS is negative, recommend performing a D-Dimer:
          • D-Dimer is negative, DVT can be ruled out.
          • D-Dimer is positive, repeat CUS in one week.
    •  Wells Score < 2: DVT Unlikely 
      • Perform a D-Dimer:
        • D-Dimer is negative, a DVT can be ruled out.
        • D-Dimer is positive, perform a CUS.
          • If the CUS is positive, a diagnosis of DVT can be made.
          • If the CUS is negative, DVT can be ruled out.
    • D-Dimer
      • D-Dimer is a marker of fibrin clot breakdown.
      • It is a highly sensitive (up to 90%) but non-specific test.
      • D-dimer can be elevated in many other conditions including:
        • Inflammatory diseases.
        • Infection.
        • Malignancy.
        • Advanced age – the use of an age-adjusted D-dimer cutoff has not been well validated for excluding DVT (unlike for PE). As such, its use for DVT diagnosis is not routinely recommended at this time by Thrombosis Canada.
        • Pregnancy.
        • Trauma.
        • Surgery.
      • In contrast to PE, there is no evidence to suggest that an age-adjusted D-dimer cutoff should be used to exclude DVT.
      • A D-dimer less than a fixed cut-off, in combination with validated clinical prediction rules (Wells score) can be used to rule out DVT in patients where DVT is deemed unlikely.

    CLICK TO ENLARGE

    Source: Diagnostic strategy adapted from Thrombosis Canada Deep Vein Thrombosis Diagnosis guideline.

    Quality Of Evidence?

    Justification

    This diagnostic strategy has been approved and developed by Thrombosis Canada.

    High

    Related Information

    Reference List

    Relevant Resources

    RELEVANT CLINICAL RESOURCES

    View all Resources

    RELEVANT VIDEO

    00:00

    Arterial Line or Central Venous Pressure (CVP) Monitoring

    View all Videos

    COMMENTS (0)

    Add public comment…