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cardio.dvt.factor-v-leiden.v1PRODUCTION
cardio.dvt.factor-v-leiden.v1

Factor V Leiden thrombophilia DVT (heterozygous or homozygous)

cardiologyacuteadult
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Detailed

Factor V Leiden = G1691A → APC resistance phenotype; heterozygous ~5% European descent (3-8× VTE risk), homozygous ~0.02-0.06% (80× risk). Acute treatment same as parent; AC duration decision driven by zygosity + provoking factor + concurrent thrombophilia + bleed risk

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FVL phenotype framed

Patient inputs (11)

Factor V Leiden PCR for G1691A point mutation; result determines zygosity (heterozygous vs homozygous) which drives AC duration and pregnancy plan

Comprehensive thrombophilia panel: prothrombin G20210A, antiphospholipid antibodies (lupus anticoagulant + anti-cardiolipin + anti-β2-glycoprotein I, both ≥12 weeks apart), protein C, protein S, antithrombin; concurrent traits shift to indefinite AC and may change DOAC vs warfarin choice

Age at first VTE drives testing indication (ASH 2018: under 45 with unprovoked); younger patients also have more lifetime AC exposure if indefinite AC chosen

Female heterozygous FVL with OCP use has multiplicative risk; pregnancy planning is a major management decision point

First-degree relative with VTE under 50 strongly suggests heritable thrombophilia; informs first-degree relative screening counseling

Provoked (reversible) vs unprovoked drives AC duration even with FVL — provoked + heterozygous can stop at 3 mo if low-bleed-risk; unprovoked + heterozygous is debated

Cardinal symptom of proximal DVT

Initial confirmation of DVT location (proximal vs distal)

Baseline platelet for AC and HIT screen during heparin exposure

HAS-BLED + falls + GI bleed history drives indefinite-AC eligibility

eGFR for DOAC dosing

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Severity triggers (5)

5 need judgement
  • informationalsevereconcurrent_aps_triple_positive_discovered_during_workup
    Thrombophilia panel returns triple-positive antiphospholipid syndrome (lupus anticoagulant + anti-cardiolipin + anti-β2-glycoprotein I, confirmed at ≥12 weeks) on top of FVL — DOAC contraindicated, warfarin preferred
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverepregnancy_in_fvl_homozygous_or_heterozygous_with_prior_vte
    Pregnant patient with FVL homozygous OR heterozygous + prior VTE — high-risk pregnancy requiring antepartum + 6-week postpartum LMWH prophylaxis (or therapeutic if active DVT)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverehomozygous_fvl_with_first_unprovoked_vte_indefinite_AC_decision
    Homozygous FVL with first unprovoked DVT — strong indication for INDEFINITE AC (~80× lifetime VTE risk; recurrence rate ~5-10%/yr without AC)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereheterozygous_fvl_first_unprovoked_vte_individualized_indefinite_decision
    Heterozygous FVL with first unprovoked DVT — individualized indefinite vs 3-mo decision; ACCP 2021 leans indefinite if low bleed risk (HAS-BLED 0-1); HERDOO2 may help in women
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmildfirst_degree_relative_screening_counseling_pre_OCP_or_pre_pregnancy
    Proband with confirmed FVL has first-degree relative requesting OCP, planning pregnancy, or facing high-risk surgery — testing indication exists per ASH 2018 (result will change management)
    Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

Factor V Leiden thrombophilia — acute + extended-phase AC tailored to zygosity, provoking factor, and concurrent thrombophilia (ACCP 2021; ASH 2020; TRAPS 2018)
axis: factor_v_leiden_phenotype_anticoagulation
Selected axis "Factor V Leiden thrombophilia — acute + extended-phase AC tailored to zygosity, provoking factor, and concurrent thrombophilia (ACCP 2021; ASH 2020; TRAPS 2018)" by default fallback (first axis)
  • apixaban
    first line
    doac_factor_xa_direct
    10 mg BID × 7 d → 5 mg BID full-dose; 2.5 mg BID extended-phase after first 6 mo if continuing indefinite • PO • BID × ≥3 months minimum, indefinite if homozygous/unprovoked/concurrent thrombophilia
    triggers: fvl_with_acute_dvt, no_active_bleed, no_triple_positive_aps, egfr_above_25
    AMPLIFY (Agnelli NEJM 2013 PMID 23808982) — apixaban first-line; AMPLIFY-EXT (Agnelli NEJM 2013 PMID 23216615) — 2.5 mg BID extended-phase preserves efficacy with lower bleed; FVL subgroup analyses show DOAC efficacy preserved
    rxcui 1364430
  • rivaroxaban
    first line
    doac_factor_xa_direct
    15 mg BID × 21 d → 20 mg daily; 10 mg daily extended-phase after first 6 mo if continuing indefinite • PO • BID then daily ≥3 months, indefinite per criteria
    triggers: fvl_with_acute_dvt, no_active_bleed, no_triple_positive_aps, egfr_above_30
    EINSTEIN-DVT (Bauersachs NEJM 2010 PMID 21128814); EINSTEIN-CHOICE (Weitz NEJM 2017 PMID 28316279) — 10 mg daily extended-phase non-inferior to 20 mg with less bleed
    rxcui 1114195
  • edoxaban
    first line
    doac_factor_xa_direct
    60 mg PO daily (30 mg if CrCl 15-50, weight ≤60 kg, or with strong P-gp inhibitor) after 5-10 d LMWH bridge • PO • daily × ≥3 months, indefinite per criteria
    triggers: post_lmwh_bridge, doac_alternative
    Hokusai-VTE (Büller NEJM 2013 PMID 23991958) — non-inferior to warfarin after LMWH lead-in
    rxcui 1599538
  • warfarin
    first line
    vitamin_k_antagonist
    5 mg daily; INR target 2-3 (target 3 if triple-positive APS per ISTH) • PO • daily ≥3 months, indefinite per criteria
    triggers: concurrent_aps_triple_positive, severe_renal_impairment_doac_unsafe, patient_preference
    TRAPS (Pengo Blood 2018 PMID 30002145) — warfarin > rivaroxaban in triple-positive APS; ISTH 2020 — DOACs avoided in triple-positive APS
    rxcui 11289
  • enoxaparin
    first line
    lmwh
    1 mg/kg SC BID; reduce to 1 mg/kg daily if CrCl <30 • SC • BID
    triggers: pregnancy, aps_workup_pending, planned_invasive_procedure, doac_contraindicated
    ASH 2020 (PMID 33007077); ASH 2018 pregnancy (PMID 30482767) — LMWH first-line in pregnancy and as bridge during workup; safer if concurrent APS suspected pre-confirmation
    rxcui 67108
  • heparin
    first line
    unfractionated_heparin
    80 U/kg bolus + 18 U/kg/h targeting aPTT 1.5-2.5× • IV • continuous
    triggers: acute_severe_renal_impairment, peri_procedural_bridge, pe_with_hemodynamic_instability
    Reversibility for acute peri-procedural management (ACCP 2021)
    rxcui 235473
  • aspirin
    comorbidity specific
    antiplatelet_cox1
    81 mg daily as adjunct or as fallback if AC discontinued in low-risk extended phase • PO • daily
    triggers: AC_discontinued_with_residual_risk_extended_phase, patient_declines_long_term_AC
    WARFASA (Becattini NEJM 2012 PMID 22621626) + ASPIRE (Brighton NEJM 2012 PMID 23121403) — ASA modest VTE recurrence reduction (~30%) post-AC; inferior to extended-phase DOAC but option if patient refuses AC
    rxcui 243670

outpatient playbook — drug actions (3)

  1. 1. maintenance apixaban
    rxcui 1364430
    apixaban 2.5 mg BID extended-reduced OR 5 mg BID full • PO • BID
    trigger: Per 3-mo decision
    AMPLIFY / AMPLIFY-EXT
  2. 2. switch to LMWH if pregnancy planned or confirmed
    rxcui 67108
    enoxaparin therapeutic 1 mg/kg BID antepartum + 6 weeks postpartum if homozygous or prior VTE • SC • BID
    trigger: Pregnancy
    ASH 2018 pregnancy PMID 30482767; RCOG 2015
  3. 3. ASA fallback if AC discontinued and patient still wants some protection
    rxcui 243670
    aspirin 81 mg daily • PO • daily
    trigger: AC stopped, residual risk concern
    WARFASA + ASPIRE — modest recurrence reduction (~30%); inferior to DOAC extended-phase

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Unilateral leg swelling or proven DVT in patient with strong family history of VTE (first-degree relative under 50) — pretest probability for heritable thrombophilia including FVL is elevated; First VTE under age 45 with no provoking factor — ASH 2018 indication to consider heritable thrombophilia testing including FVL PCR; Recurrent VTE with minor or no provoking factors — strong indication for thrombophilia evaluation and likely indefinite AC.

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Factor V Leiden thrombophilia DVT (heterozygous or homozygous)** (cardio.dvt.factor-v-leiden.v1).
Scope: Factor V Leiden = G1691A → APC resistance phenotype; heterozygous ~5% European descent (3-8× VTE risk), homozygous ~0.02-0.06% (80× risk). Acute treatment same as parent; AC duration decision driven by zygosity + provoking factor + concurrent thrombophilia + bleed risk

No severity triggers fired against current inputs.

Plan

Regimen axis: **Factor V Leiden thrombophilia — acute + extended-phase AC tailored to zygosity, provoking factor, and concurrent thrombophilia (ACCP 2021; ASH 2020; TRAPS 2018)**.
1. apixaban 10 mg BID × 7 d → 5 mg BID full-dose; 2.5 mg BID extended-phase after first 6 mo if continuing indefinite PO BID × ≥3 months minimum, indefinite if homozygous/unprovoked/concurrent thrombophilia (doac_factor_xa_direct, first line) — AMPLIFY (Agnelli NEJM 2013 PMID 23808982) — apixaban first-line; AMPLIFY-EXT (Agnelli NEJM 2013 PMID 23216615) — 2.5 mg BID extended-phase preserves efficacy with lower bleed; FVL subgroup analyses show DOAC efficacy preserved
2. rivaroxaban 15 mg BID × 21 d → 20 mg daily; 10 mg daily extended-phase after first 6 mo if continuing indefinite PO BID then daily ≥3 months, indefinite per criteria (doac_factor_xa_direct, first line) — EINSTEIN-DVT (Bauersachs NEJM 2010 PMID 21128814); EINSTEIN-CHOICE (Weitz NEJM 2017 PMID 28316279) — 10 mg daily extended-phase non-inferior to 20 mg with less bleed
3. edoxaban 60 mg PO daily (30 mg if CrCl 15-50, weight ≤60 kg, or with strong P-gp inhibitor) after 5-10 d LMWH bridge PO daily × ≥3 months, indefinite per criteria (doac_factor_xa_direct, first line) — Hokusai-VTE (Büller NEJM 2013 PMID 23991958) — non-inferior to warfarin after LMWH lead-in
4. warfarin 5 mg daily; INR target 2-3 (target 3 if triple-positive APS per ISTH) PO daily ≥3 months, indefinite per criteria (vitamin_k_antagonist, first line) — TRAPS (Pengo Blood 2018 PMID 30002145) — warfarin > rivaroxaban in triple-positive APS; ISTH 2020 — DOACs avoided in triple-positive APS
5. enoxaparin 1 mg/kg SC BID; reduce to 1 mg/kg daily if CrCl <30 SC BID (lmwh, first line) — ASH 2020 (PMID 33007077); ASH 2018 pregnancy (PMID 30482767) — LMWH first-line in pregnancy and as bridge during workup; safer if concurrent APS suspected pre-confirmation
6. heparin 80 U/kg bolus + 18 U/kg/h targeting aPTT 1.5-2.5× IV continuous (unfractionated_heparin, first line) — Reversibility for acute peri-procedural management (ACCP 2021)
7. aspirin 81 mg daily as adjunct or as fallback if AC discontinued in low-risk extended phase PO daily (antiplatelet_cox1, comorbidity specific) — WARFASA (Becattini NEJM 2012 PMID 22621626) + ASPIRE (Brighton NEJM 2012 PMID 23121403) — ASA modest VTE recurrence reduction (~30%) post-AC; inferior to extended-phase DOAC but option if patient refuses AC

Setting playbook (outpatient) — Long-term management: indefinite AC for indicated patients with annual reassessment; family screening; reproductive planning; genetic counseling; PTS surveillance
8. maintenance apixaban apixaban 2.5 mg BID extended-reduced OR 5 mg BID full PO BID — Per 3-mo decision (AMPLIFY / AMPLIFY-EXT)
9. switch to LMWH if pregnancy planned or confirmed enoxaparin therapeutic 1 mg/kg BID antepartum + 6 weeks postpartum if homozygous or prior VTE SC BID — Pregnancy (ASH 2018 pregnancy PMID 30482767; RCOG 2015)
10. ASA fallback if AC discontinued and patient still wants some protection aspirin 81 mg daily PO daily — AC stopped, residual risk concern (WARFASA + ASPIRE — modest recurrence reduction (~30%); inferior to DOAC extended-phase)

Non-pharmacologic actions:
- Compression stocking 30-40 mmHg if PTS symptoms
- OCP avoidance lifelong if FVL heterozygous or homozygous with VTE history
- Pre-procedure AC management plan documented
- Patient carries thrombophilia card

AVOID / contraindication checks:
- Doac_avoid_active_bleeding (FDA labels)
- Apixaban_avoid_egfr_below_15 (FDA label)
- Rivaroxaban_avoid_egfr_below_30 (FDA label)
- Doac_avoid_triple_positive_aps_use_warfarin (TRAPS 2018; ISTH 2020)
- Warfarin_avoid_pregnancy_use_lmwh (ASH 2018 pregnancy)
- Thrombophilia_panel_timing_dependent_on_AC_send_before_AC_or_off_2wk (Middeldorp 2012)
- Decision:fvl_homozygous_indefinite_AC (ASH 2018)
- Decision:fvl_heterozygous_with_first_unprovoked_vte_individualized_lean_indefinite_if_low_bleed_risk (ACCP 2021)
- Decision:fvl_heterozygous_provoked_3mo_AC_then_stop (ACCP 2021)
- Decision:family_screening_only_if_result_will_change_management (ASH 2018 / ACMG)
- Decision:pregnancy_heterozygous_FVL_alone_no_routine_LMWH_unless_prior_VTE (ASH 2018 / RCOG 2015)
- Decision:pregnancy_homozygous_FVL_antepartum_LMWH_plus_6wk_postpartum (ASH 2018 / RCOG 2015)

Monitoring

Regimen monitoring:
- cbc creatinine at 4 weeks then quarterly during indefinite AC (FDA labels)
- pts villalta at 3 6 12mo (Kahn Lancet 2014)
- annual AC continuation decision with HASBLED reassessment (ACCP 2021)
- inr weekly during warfarin titration then q4 6 weeks (ACCP 2021)
- pre OCP FVL PCR for first degree relatives with strong family hx (ASH 2018)
- pre pregnancy LMWH dose planning if homozygous or prior VTE (ASH 2018 pregnancy)

Setting (outpatient) monitoring:
- Annual labs + clinical reassessment
- Annual PTS Villalta
- Annual HAS-BLED

Follow-up plan: Genetic counseling for proband; first-degree relative screening discussion (ACMG / ASH 2018 — test only if result will change management, e.g. pre-OCP, pre-pregnancy, pre-high-risk-surgery); pregnancy planning for women (LMWH if homozygous or prior VTE); OCP discontinuation; address modifiable risk factors lifetime
- Close-out criterion: genetic counseling + reproductive plan + family screening pathway documented

Monitoring phase: CBC + creatinine at 4 weeks then quarterly during indefinite AC; bleed surveillance; PTS Villalta at 3/6/12 mo; re-evaluate AC continuation annually for indefinite patients (HAS-BLED can rise with age and creates a stop trigger)

Disposition

Current setting: outpatient — Long-term management: indefinite AC for indicated patients with annual reassessment; family screening; reproductive planning; genetic counseling; PTS surveillance

Disposition criteria:
- Indefinite annual follow-up; cross-reference with chronic-AC clinic

Escalation triggers (move to higher acuity):
- New VTE despite AC → reassess adherence + AC adequacy + consider switch (DOAC → warfarin if APS+)
- Pregnancy → switch to LMWH
- Major bleed → reverse, hold, reassess indefinite indication

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [SEVERE] Thrombophilia panel returns triple-positive antiphospholipid syndrome (lupus anticoagulant + anti-cardiolipin + anti-β2-glycoprotein I, confirmed at ≥12 weeks) on top of FVL — DOAC contraindicated, warfarin preferred
- [SEVERE] Pregnant patient with FVL homozygous OR heterozygous + prior VTE — high-risk pregnancy requiring antepartum + 6-week postpartum LMWH prophylaxis (or therapeutic if active DVT)
- [SEVERE] Homozygous FVL with first unprovoked DVT — strong indication for INDEFINITE AC (~80× lifetime VTE risk; recurrence rate ~5-10%/yr without AC)

Citations

- ACCP/CHEST 2021 (Stevens) + ASH 2018 thrombophilia testing + ASH 2020 VTE Treatment + ASH 2018 VTE in Pregnancy [PMID:34352295](https://pubmed.ncbi.nlm.nih.gov/34352295/)
- Cited evidence (PMID 30482764) [PMID:30482764](https://pubmed.ncbi.nlm.nih.gov/30482764/)
- Cited evidence (PMID 33007077) [PMID:33007077](https://pubmed.ncbi.nlm.nih.gov/33007077/)
- Cited evidence (PMID 30482767) [PMID:30482767](https://pubmed.ncbi.nlm.nih.gov/30482767/)
- Cited evidence (PMID 30002145) [PMID:30002145](https://pubmed.ncbi.nlm.nih.gov/30002145/)

Last reconciled with current guidelines: 2026-05-15.
References