II. Indications
- Assess a woman's risk of recurrent Venous Thromboembolism (VTE) after stopping Anticoagulation
- Assumes first unprovoked VTE in a woman over age 18 years old
III. Contraindications
- Male gender
- HERDOO2 was only developed to assess risk in women
- Male gender alone is a risk for recurrent VTE (RR 1.8 in unprovoked VTE)
- Identified Thromboembolism risk
- Leg Fracture or lower extremity plaster cast
- Immobilization >3 days
- General Anesthesia within last 3 months
- Cancer diagnosis within the last 5 years
IV. Criteria (Score 1 point for each positive)
- Positive D-Dimer
- D-Dimer >250 ng/ml D-Dimer Units (DDU) or
- D-Dimer >0.5 mcg/ml Fibrinogen Equivalent Units or (FEU)
- Body Mass Index (BMI) >=30 kg/m2
- Age >= 65 years old
- Post-Thrombotic Signs (e.g. edema, erythema, Hyperpigmentation)
V. Interpretation
- Score 0 to 1: Low Risk (3% recurrent major VTE Risk in 100 person years)
- May discontinue Anticoagulation after initial unprovoked VTE management
- Score 2 to 4: Higher Risk (7.4% recurrent major VTE Risk in 100 person years)
- Continue longterm Anticoagulation after initial unprovoked VTE management
VI. Resources
- HERDOO2 Rule for Discontinuing Anticoagulation in Unprovoked VTE (MDCalc)