MDCalc

HERDOO2 Rule for Discontinuing Anticoagulation in Unprovoked VTE

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

Use in women ≥18 years old with a first unprovoked proximal DVT or segmental or more proximal PE who have completed initial anticoagulation treatment.

Do not use in individuals 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 the index event, cancer diagnosis within 5 years, or known thrombophilia.

The rule is not recommended if utilizing a D-dimer assay other than VIDAS® D-dimer, bioMérieux.

Post-thrombotic signs

Hyperpigmentation, edema, or redness (either leg)

D-dimer level

BMI, kg/m²
Age, years

Result:

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Advice

  • The benefits and risks of discontinuing anticoagulation in those deemed low-risk should be discussed with the patient as part of shared decision-making.

  • In the REVERSE II validation study (n=2,785), low-risk women (score 0-1) who stopped anticoagulation had a recurrence rate of 3.0% per patient-year (95% CI 1.8-4.8%), meeting the ISTH threshold of <5%/year.

  • ~50% of women are classified as low-risk and may safely discontinue anticoagulation.

  • Long-term follow-up (mean 5 years) showed low-risk women maintained low recurrence at 1.1% per year.

Management

HERDOO2 Score

Risk Group

Recommended Approach

0-1

Low risk

  • Anticoagulation may be safely discontinued after completing 5-10 months of treatment; recurrence rate ~3.0%/year.

  • Counsel on symptoms of recurrent VTE and instruct to seek care promptly if symptoms develop.

≥2

High risk

  • Continuation of anticoagulation recommended; expected recurrence rate ~8%/year if anticoagulation is stopped; individualized decision with the patient.

  • Refer to current ACCP or ASH guidelines for guidance on long-term anticoagulant choice (DOAC preferred over VKA in most patients) and duration.

  • Discuss extended-phase options, including reduced-dose DOACs, which may improve the risk-benefit balance.

  • Consider hematology referral for complex cases.

  • For women ≥50 years with non-estrogen-related events, recurrence risk may exceed 5%/year despite a low score; consider extended anticoagulation.

  • Estrogen-containing medications should not be resumed in women who stop anticoagulation; this was a protocol exclusion in the validation study, and reintroduction substantially increases VTE risk.

  • Assess bleeding risk using validated tools (e.g., HAS-BLED).

Critical Actions

  • Do not apply this rule to men.

  • Only use the VIDAS D-dimer assay at the ≥250µg/L FEU cut-point.

  • Screen for high-risk thrombophilia before applying the rule.

  • Do not use in patients with active or recent malignancy.

  • Counsel about estrogen explicitly before discontinuing anticoagulation.

  • Exercise additional caution in postmenopausal women scoring 0-1.

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