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cardio.dvt.antiphospholipid-syndrome.v1

Antiphospholipid syndrome (APS) DVT — warfarin preferred, DOAC avoided

cardiologyacuteadultacuteinpatienttransitionoutpatient
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Phase E variant of cardio.dvt.core.v1 — narrowed to antiphospholipid syndrome (APS), the autoimmune thrombophilia defined by recurrent thrombosis (venous + arterial) + pregnancy morbidity + persistent aPL antibodies (lupus anticoagulant + anti-cardiolipin + anti-β2GPI). Sapporo/Sydney criteria require clinical event PLUS aPL persistence at ≥12 wk. Triple-positive (LA + aCL + anti-β2GPI all positive at medium-to-high titre) is highest recurrence risk. Inherits parent DVT diagnostic arc; SUBSTANTIALLY specializes long-term AC management. KEY DIFFERENCES FROM PARENT: WARFARIN is first-line (target INR 2-3 venous, 2.5-3.5 arterial/recurrent, 3-4 selected triple-positive). DOACs are INFERIOR per TRAPS (PMID 30196097 — rivaroxaban arm terminated for arterial harm in triple-positive APS), RAPS (PMID 27932287 — surrogate endpoint only), and ASTRO-APS (apixaban arm terminated for arterial harm). EULAR 2019 + ISTH 2020 advise DOAC avoidance. LMWH first-line in pregnancy (warfarin teratogenic). AC is LIFELONG after first event — no taper, no stop. Hydroxychloroquine adjunct in SLE-associated APS reduces recurrent thrombosis. Pregnancy: LMWH therapeutic + low-dose ASA antepartum + 6-wk postpartum. CATASTROPHIC APS (CAPS) — rare but life-threatening multi-organ thrombosis (≥3 organs ≤1 wk); ~37% mortality even with treatment; multi-modality required (anticoagulation + corticosteroids + plasma exchange + IVIG ± rituximab ± eculizumab) per CAPS Registry (Cervera). Manifest pointer reuses cardio.dvt.core.v1 manifest. Design-brief pointer reuses parent (APS-specific differences documented inline). EHR DOAC-avoidance flag is an operational safety requirement. Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute as APS DVT variant.

Entry points (5)

  • symptom
    Unilateral leg swelling/pain with prior APS diagnosis OR strong APS suspicion (recurrent VTE, arterial + venous events, pregnancy morbidity, autoimmune disease — particularly SLE)
    unilateral_leg_swelling_with_aps_history_or_features
  • history
    Unprovoked VTE in patient with ≥3 consecutive miscarriages <10 wk OR ≥1 fetal death ≥10 wk OR severe preeclampsia/placental insufficiency — Sapporo/Sydney pregnancy-morbidity criteria
    unprovoked_vte_with_recurrent_pregnancy_loss
  • history
    Patient with both prior arterial event (stroke, MI, TIA) AND venous event — APS until proven otherwise
    prior_arterial_and_venous_thrombosis
  • lab_abnormality
    Unexplained aPTT prolongation that does not correct with mixing study — lupus anticoagulant suspected
    prolonged_aptt_with_normal_inr
  • lab_abnormality
    Mild to moderate thrombocytopenia + recurrent thrombosis — APS-associated thrombocytopenia (paradoxical: low platelets, prothrombotic)
    thrombocytopenia_with_recurrent_thrombosis

Required inputs (14)

  • agerequired
    demographic • used at CONTEXT
    APS often presents in young adults (3rd-5th decade); pregnancy-morbidity criteria apply only to women of reproductive age
  • sexrequired
    demographic • used at CONTEXT
    Women with APS face pregnancy management decisions (LMWH + ASA antepartum; hydroxychloroquine adjunct); reproductive planning is central
  • prior_thrombosis_historyrequired
    history • used at CONTEXT
    Prior arterial or venous thrombosis defines APS clinical criterion; first vs recurrent affects intensity of AC (target INR 2-3 vs 2.5-3.5 vs 3-4 per phenotype)
  • pregnancy_morbidity_historyrequired
    history • used at CONTEXT
    ≥3 consecutive losses <10 wk, or ≥1 fetal death ≥10 wk, or severe preeclampsia/placental insufficiency — Sapporo/Sydney pregnancy criteria; informs reproductive plan
  • autoimmune_disease_historyrequired
    history • used at CONTEXT
    Secondary APS (most often associated with SLE, less commonly Sjögren / RA / scleroderma); affects multi-system surveillance
  • leg_swellingrequired
    symptom • used at ENTRY
    Cardinal symptom of proximal DVT
  • compression_usrequired
    imaging • used at INITIAL_WORKUP
    Initial confirmation of DVT location (proximal vs distal)
  • lupus_anticoagulantrequired
    lab • used at BRANCHING_WORKUP
    LA is most thrombosis-specific aPL; functional assay (DRVVT + confirm) — must be confirmed at ≥12 wk to satisfy Sapporo/Sydney; cannot reliably interpret on warfarin or full-dose DOAC (mixing study workaround)
  • anticardiolipin_igg_igmrequired
    lab • used at BRANCHING_WORKUP
    IgG and IgM medium-to-high titre (>40 GPL/MPL or >99th percentile) at ≥12 wk — Sapporo/Sydney lab criterion
  • anti_b2_glycoprotein_i_igg_igmrequired
    lab • used at BRANCHING_WORKUP
    IgG and IgM medium-to-high titre (>99th percentile) at ≥12 wk — Sapporo/Sydney lab criterion; "triple-positive" if all three classes (LA + aCL + anti-β2GPI) positive — highest recurrence risk
  • creatininerequired
    lab • used at TREATMENT
    eGFR for LMWH dosing; renal involvement (APS nephropathy) screen
  • cbcrequired
    lab • used at INITIAL_WORKUP
    Baseline platelet for AC and APS-associated thrombocytopenia screen
  • pt_inr_pttrequired
    lab • used at INITIAL_WORKUP
    Baseline coags; prolonged aPTT not correcting with mixing study supports LA; PT/INR baseline for warfarin titration
  • bleed_riskrequired
    history • used at RED_FLAGS
    HAS-BLED for AC bleed risk; lifelong AC mandates bleed-risk vigilance

12-phase flow (11)

  1. 1FRAME
    APS = autoimmune thrombophilia with recurrent thrombosis (venous + arterial) + pregnancy morbidity + persistent aPL; warfarin preferred (target INR 2-3 venous, 2.5-3.5 arterial/recurrent, 3-4 some triple-positive); DOAC INFERIOR (TRAPS terminated for harm); lifelong AC; CAPS = catastrophic multi-organ phenotype
    inputs: leg_swelling
    advance: APS phenotype framed
  2. 2ENTRY
    Wells DVT score + compression US; document prior thrombosis (arterial + venous), pregnancy morbidity, autoimmune disease; Sapporo/Sydney clinical criterion screen
    inputs: age, sex, prior_thrombosis_history
    advance: pretest probability + APS clinical criterion documented
  3. 3CONTEXT
    Detailed pregnancy-morbidity history; autoimmune (SLE primarily) co-disease; medication review (estrogens, OCP — must hold); current AC and prior bleed events; reproductive plans
    inputs: pregnancy_morbidity_history, autoimmune_disease_history
    advance: context complete
  4. 4RED_FLAGS
    Catastrophic APS (multi-organ thrombosis ≥3 organs ≤1 week — life-threatening); concurrent PE; phlegmasia; APS-associated thrombocytopenia (paradoxical); valvular Libman-Sacks endocarditis; APS nephropathy; DOAC inadvertently started (must transition to warfarin)
    inputs: bleed_risk
    actions: pe_full, thrombocytopenia
    advance: critical features screened
  5. 5INITIAL_WORKUP
    Compression US (proximal vs distal); CBC + BMP + PT/PTT; D-dimer if borderline pretest probability; baseline coags before AC; troponin + BNP if PE suspected
    inputs: compression_us, cbc, pt_inr_ptt, creatinine
    actions: panel.cardiac, panel.renal, panel.coag
    advance: imaging confirms DVT + baseline labs available
  6. 6BRANCHING_WORKUP
    aPL panel: LA (DRVVT + confirm) + aCL IgG/IgM + anti-β2GPI IgG/IgM. Timing matters — DOAC and direct thrombin inhibitors interfere with LA (mixing-study workarounds exist; some centres draw before AC). Must repeat aPL at ≥12 wk to satisfy Sapporo/Sydney persistence requirement; document triple-positive phenotype if present (highest recurrence)
    inputs: lupus_anticoagulant, anticardiolipin_igg_igm, anti_b2_glycoprotein_i_igg_igm
    advance: aPL profile + triple-positive status documented
  7. 7RISK_STRATIFICATION
    Wells DVT, HAS-BLED, eGFR; Caprini if surgical context; integrate phenotype: first venous APS = warfarin INR 2-3 lifelong; recurrent or arterial = INR 2.5-3.5 lifelong; some triple-positive = INR 3-4; CAPS = ICU multi-modality
    inputs: bleed_risk
    actions: calc.wells_dvt, calc.has_bled
    advance: AC intensity + duration plan documented (lifelong)
  8. 8TREATMENT
    Acute: LMWH (enoxaparin 1 mg/kg SC BID) + bridge to warfarin (5 mg PO daily, target INR per phenotype). DO NOT use DOAC (TRAPS; ASTRO-APS — terminated for harm). LMWH alone if pregnant (warfarin teratogenic). Add ASA 81 mg if arterial APS or recurrent. Consider hydroxychloroquine adjunct in SLE-associated APS
    inputs: creatinine, bleed_risk
    advance: LMWH + warfarin bridge initiated and DOAC ruled out; reproductive plan addressed
  9. 9DISPOSITION
    Outpatient for uncomplicated proximal DVT with reliable INR follow-up; admit if CAPS suspected, concurrent PE intermediate-high risk, phlegmasia, social barriers, or new APS diagnosis needing inpatient bridge
    advance: disposition documented
  10. 10MONITORING
    INR weekly during warfarin titration → q2-4 wk maintenance; CBC + creatinine quarterly; bleed surveillance; PTS Villalta at 3/6/12 mo; annual reassessment confirms lifelong AC continuation; SLE/autoimmune surveillance if secondary APS
    actions: panel.cardiac, panel.coag
    advance: monitoring schedule documented
  11. 11FOLLOWUP
    Hematology + rheumatology co-management; reproductive planning for women (LMWH + low-dose ASA antepartum + 6-wk postpartum; hydroxychloroquine adjunct); estrogen avoidance lifelong; cardiovascular risk modification; APS patient card for emergency providers; no DOAC prescription warning in EHR
    advance: lifelong AC + reproductive plan + interdisciplinary follow-up + EHR DOAC-avoidance flag documented