II. Indications

  1. Assess a woman's risk of recurrent Venous Thromboembolism (VTE) after stopping Anticoagulation
  2. Assumes first unprovoked VTE in a woman over age 18 years old

III. Contraindications

  1. Male gender
    1. HERDOO2 was only developed to assess risk in women
    2. Male gender alone is a risk for recurrent VTE (RR 1.8 in unprovoked VTE)
      1. Douketis (2011) BMJ 342: d813 [PubMed]
  2. Identified Thromboembolism risk
    1. Leg Fracture or lower extremity plaster cast
    2. Immobilization >3 days
    3. General Anesthesia within last 3 months
    4. Cancer diagnosis within the last 5 years

IV. Criteria (Score 1 point for each positive)

  1. Positive D-Dimer
    1. D-Dimer >250 ng/ml D-Dimer Units (DDU) or
    2. D-Dimer >0.5 mcg/ml Fibrinogen Equivalent Units or (FEU)
  2. Body Mass Index (BMI) >=30 kg/m2
  3. Age >= 65 years old
  4. Post-Thrombotic Signs (e.g. edema, erythema, Hyperpigmentation)

V. Interpretation

  1. Score 0 to 1: Low Risk (3% recurrent major VTE Risk in 100 person years)
    1. May discontinue Anticoagulation after initial unprovoked VTE management
  2. Score 2 to 4: Higher Risk (7.4% recurrent major VTE Risk in 100 person years)
    1. Continue longterm Anticoagulation after initial unprovoked VTE management

VI. Resources

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