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    Patent Pending

    HERDOO2 Rule for Discontinuing Anticoagulation in Unprovoked VTE

    Identifies low-risk women who can safely discontinue VTE treatment.
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    INSTRUCTIONS

    Use in women ≥18 years old with unprovoked VTE. Do not use in patients with any of the following at the time of VTE diagnosis: leg fracture, lower-extremity plaster cast, immobilization >3 days, general anesthesia <3 months before, or cancer diagnosis within 5 years.

    When to Use
    Why Use

    Women ≥18 years old with unprovoked VTE. Inclusion criteria in the original study:

    • Patients diagnosed 5–7 months before enrollment.
    • On heparin or low molecular weight heparin (LMWH) for ≥5 days and oral anticoagulation for 5–7 months after the event.
    • Without recurrent VTE during the treatment period.
    • Noncompressible segment on compression ultrasound of popliteal (or more proximal) leg vein, high-probability V/Q scan, or segmental (or larger) artery filling defect on spiral CT.

    Exclusion criteria:

    • Leg fracture.
    • Lower-extremity plaster cast.
    • Immobilization for >3 days.
    • General anesthetic <3 months before index event.
    • Cancer diagnosis within 5 years.

    Indefinite anticoagulation is burdensome and associated with bleeding risk. The HERDOO2 Rule can identify patients who have very low risk of recurrent VTE and can therefore safely stop anticoagulation in the short term.

    Result:

    Please fill out required fields.

    Next Steps
    Evidence
    Creator Insights

    Advice

    The benefits and known risks of discontinuing anticoagulation in those deemed low-risk should be discussed with the patient.

    Formula

    Addition of the selected points:

     

    0 points

    1 point

    Post-thrombotic signs*

    No

    Yes

    D-dimer level

    <250 µg/L

    ≥250 µg/L

    BMI, kg/m²

    <30

    ≥30

    Age, years

    <65

    ≥65

    *Hyperpigmentation, edema, or redness (either leg)

    HERDOO2 = Hyperpigmentation, Edema, or Redness; D-dimer, Obesity, Older age

    Facts & Figures

    Interpretation:

    HERDOO2

    Risk group

    Risk of recurrent major VTE*

    Recommendation

    0-1

    Low

    3.0%

    Can safely discontinue oral anticoagulation

    2-4

    Not low

    7.4%

    Continue oral anticoagulation

    *Proximal DVT and segmental or greater PE, % per 100 patient years.

    Dr. Marc A. Rodger

    About the Creator

    Marc A. Rodger, MD, FRCP(C), MSc, is a professor in the department of medicine at the University of Ottawa. He is the chief and chair of the division of hematology and the head of the thrombosis program. Dr. Rodger is also a senior scientist at the Ottawa Hospital Research Institute.

    To view Dr. Marc A. Rodger's publications, visit PubMed