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cardio.dvt.post-orthopedic-arthroplasty.v1

Post-orthopedic-arthroplasty DVT (post-THA/TKA/hip-fracture; ASA vs DOAC vs LMWH per AAOS 2025 + ACCP)

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Phase E variant of cardio.dvt.core.v1 — narrowed to post-major-orthopedic-arthroplasty (THA / TKA / hip-fracture surgery) DVT, the highest-VTE-risk surgical class. Inherits parent diagnostic arc + DOAC chronic regimen via routing; specializes for extended-prophylaxis framework (35 d hip / 12 d knee per AAOS 2025 + ACCP 2021) and tiered drug choice (ASA non-inferior to DOAC for standard-risk per EPCAT-II; DOAC or LMWH for high-risk + HFS). Manifest pointer reuses cardio.dvt.core.v1 manifest. Design-brief pointer reuses parent (post-arthroplasty-specific differences documented inline). Distinguishing features vs generic provoked DVT: Single well-defined surgical event with known peak-VTE-risk window (THA: 5-7 d post-op median DVT; risk extends ~35 d; TKA: 7-14 d, risk extends ~12-14 d). Extended prophylaxis is dominant management differentiator. Symptomatic vs surveillance-detected distinction matters: symptomatic proximal DVT requires treatment-dose AC × 3 mo; asymptomatic distal incidental DVT requires extended prophylactic-dose AC vs serial imaging per shared decision (post-op surveillance US is NOT recommended per AAOS 2025). HFS demands DOAC or LMWH (not ASA monotherapy). Pre-op LMWH considered if HFS surgery delayed >12 h per HIP-ATTACK (PMID 32325025). Neuraxial anaesthesia (spinal/epidural) demands strict ASRA 2018 timing — LMWH 12 h before block; rivaroxaban 22-26 h; epidural removal 12 h post LMWH. HIT 4T-score in heparin-exposed cohort (5-14 d into LMWH); switch to argatroban or fondaparinux if confirmed. EPCAT-II (PMID 29466159) — ASA 81 mg BID after 5-d rivaroxaban lead-in non-inferior for symptomatic VTE in standard-risk THA/TKA patients only. Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute as post-orthopedic-arthroplasty DVT variant.

Entry points (6)

  • symptom
    Unilateral lower-extremity swelling, calf pain, or whole-leg swelling within 4-6 weeks of THA / TKA / hip-fracture surgery — post-arthroplasty VTE pretest probability sharply elevated
    unilateral_le_swelling_post_arthroplasty
  • history
    Documented THA / TKA / hip-fracture-surgery within preceding 6 weeks — anchor the surgical provoking factor and prophylaxis history (regimen + adherence + duration completed)
    index_arthroplasty_within_6_weeks
  • symptom
    New pleuritic chest pain, dyspnea, syncope, hemoptysis, or unexplained tachycardia within 35 days of THA / hip-fracture surgery (12 days for TKA) — concurrent PE screen mandated; CTPA if Wells PE > 4 or PERC fail
    pleuritic_chest_pain_dyspnea_post_arthroplasty
  • imaging
    Incidental DVT identified on post-op CT (e.g., for fever workup or PE screen) in arthroplasty patient — confirm + manage per symptomatic vs surveillance distinction
    incidental_dvt_on_post_op_ct_scan
  • history
    New DVT despite documented compliance with prophylactic regimen (rivaroxaban 10 mg daily, ASA 81 mg BID, enoxaparin 40 mg daily, or apixaban 2.5 mg BID) — prophylaxis-failure scenario warrants escalation + thrombophilia consideration
    breakthrough_vte_during_active_prophylaxis
  • lab_abnormality
    Platelet drop >50% from baseline 5-14 days into LMWH prophylaxis — HIT 4Ts screen; affects AC choice and platelet transfusion threshold
    thrombocytopenia_with_recent_heparin_exposure_post_arthroplasty

Required inputs (11)

  • agerequired
    demographic • used at CONTEXT
    Older arthroplasty patients (peak elective THA/TKA 65-75 yr) have additive VTE + bleed risk; falls + frailty influence drug choice + duration
  • sexrequired
    demographic • used at CONTEXT
    Female + post-arthroplasty + OCP / HRT compounds risk (most should hold ≥4 wk pre-op per AAOS); pregnancy in arthroplasty cohort rare but possible (revision arthroplasty in young women)
  • arthroplasty_type_and_daterequired
    history • used at ENTRY
    THA + hip-fracture surgery → 35-day extended prophylaxis window; TKA → 12-day prophylaxis window; revision arthroplasty often reverts to higher-risk THA/TKA-like prophylaxis; date anchors days-post-op for risk-window staging
  • prophylaxis_regimen_and_adherencerequired
    history • used at CONTEXT
    Document specific prophylactic agent (ASA, rivaroxaban, apixaban, enoxaparin, dabigatran, warfarin), dose, start date, planned duration, and patient-reported adherence; breakthrough on documented adherence flags prophylaxis failure + thrombophilia consideration
  • additive_vte_risk_factorsrequired
    history • used at CONTEXT
    Prior VTE, active cancer, BMI >40, known thrombophilia, hip-fracture surgery (vs elective THA/TKA), prolonged immobility, age >75 — these shift away from ASA monotherapy toward DOAC or LMWH
  • leg_swellingrequired
    symptom • used at ENTRY
    Cardinal symptom of proximal DVT; ipsilateral post-op swelling makes physical-exam alone unreliable; ALWAYS confirm with US not just calf-circumference
  • compression_usrequired
    imaging • used at INITIAL_WORKUP
    Diagnostic anchor — femoral + popliteal compression; whole-leg US preferred given post-op patient may have proximal extension; D-dimer often baseline-elevated post-surgery (less useful as rule-out)
  • cbcrequired
    lab • used at INITIAL_WORKUP
    Baseline platelet for AC bleed risk; HIT screen if heparin exposure + platelet drop >50% from baseline at 5-14 d (4T score); post-op anaemia common — informs AC bleed-risk weighting
  • creatininerequired
    lab • used at TREATMENT
    eGFR for DOAC dosing (apixaban: ≥2 of age ≥80, weight ≤60 kg, Cr ≥1.5 → 2.5 mg BID; rivaroxaban CrCl <30 caution); LMWH dose-reduction at CrCl <30; informs UFH preference if CrCl <15
  • bleed_riskrequired
    history • used at RED_FLAGS
    HAS-BLED + post-op surgical bleed risk + falls history + neuraxial-anaesthesia timing per ASRA 2018 — drives AC eligibility, mechanical-only prophylaxis decision, and timing of AC initiation post-op (typically 12-24 h after haemostasis)
  • neuraxial_anaesthesia_status_and_epidural_catheter_timing
    history • used at TREATMENT
    Spinal / epidural anaesthesia with indwelling catheter mandates strict AC timing per ASRA 2018 — LMWH 12 h before block; rivaroxaban 22-26 h before block; epidural removal coordinated 12 h after last LMWH dose; prevents spinal hematoma

12-phase flow (11)

  1. 1FRAME
    Post-orthopedic-arthroplasty DVT = highest-VTE-risk surgical class with extended prophylaxis (35 d hip / 12 d knee per AAOS 2025 + ACCP 2021) and tiered drug choice (ASA non-inferior to DOAC for standard-risk per EPCAT-II; DOAC or LMWH for high-risk; LMWH for hip-fracture surgery). Treatment of established post-op DVT follows standard provoked-VTE 3-mo arc but distinguishes symptomatic vs surveillance-detected presentations
    inputs: arthroplasty_type_and_date, leg_swelling
    advance: Post-arthroplasty DVT framed
  2. 2ENTRY
    Wells DVT score (post-op +1 immobility); compression US (D-dimer often baseline-elevated post-op so go straight to imaging if symptomatic); document index arthroplasty type + date + prophylaxis regimen + adherence; PE screen for respiratory symptoms
    inputs: age, arthroplasty_type_and_date
    advance: Pretest probability + arthroplasty context documented
  3. 3CONTEXT
    Prophylaxis regimen used (ASA vs rivaroxaban vs apixaban vs enoxaparin vs dabigatran vs warfarin) + dose + adherence + duration completed vs remaining; additive VTE risk factors (prior VTE, cancer, BMI >40, thrombophilia, HFS); bleed-risk profile (post-op surgical bleed risk, falls, neuraxial catheter status); revision vs primary arthroplasty
    inputs: sex, prophylaxis_regimen_and_adherence, additive_vte_risk_factors
    advance: Prophylaxis history + additive risk profile complete
  4. 4RED_FLAGS
    Concurrent PE (pleuritic pain, dyspnea, hypoxia, tachycardia) — CTPA if Wells PE > 4 or PERC fail; phlegmasia cerulea dolens (cyanosis, severe pain, arterial compromise) requires emergent CDT; post-op haematoma or active surgical bleed contraindicating AC → mechanical-only prophylaxis (IPC); HIT 4Ts screen if heparin exposure + platelet drop; spinal hematoma if neuraxial catheter + recent AC (sudden back pain + neurologic deficit)
    inputs: bleed_risk
    actions: pe_full, le_edema
    advance: PE + limb-threatening + bleed-risk + HIT + spinal-hematoma features screened
  5. 5INITIAL_WORKUP
    Compression US (whole-leg preferred); CBC + BMP + INR/PTT + ABG if hypoxia; CXR if respiratory symptoms; troponin + BNP if PE confirmed for risk-stratification; HIT 4T-score + serotonin-release assay if HIT suspected
    inputs: compression_us, cbc, creatinine
    actions: panel.cardiac, panel.renal, panel.coag, panel.abg
    advance: Imaging confirms DVT + bleed-risk + renal status documented
  6. 6BRANCHING_WORKUP
    CTPA or VQ if PE suspicion; echo for RV strain if intermediate-high PE; thrombophilia workup ONLY if breakthrough VTE on documented prophylaxis adherence, young (<45) primary arthroplasty patient, strong family history, recurrent unprovoked, or unusual site — post-arthroplasty alone is NOT a thrombophilia testing indication per ASH 2018 (PMID 30482764)
    advance: Branching workup decisions documented
  7. 7RISK_STRATIFICATION
    Wells DVT (treatment confirmation); HAS-BLED for AC bleed-risk; eGFR for DOAC; recurrence risk LOW after 3-mo treatment-dose AC for symptomatic post-op DVT (provoked, reversible substrate); HIGHER if breakthrough on prophylaxis (escalate intensity + revisit thrombophilia)
    inputs: bleed_risk
    actions: calc.ckd_epi_2021
    advance: Treatment-dose AC duration plan documented (typically 3 mo for symptomatic post-op DVT)
  8. 8TREATMENT
    Symptomatic post-op DVT: TREATMENT-DOSE AC — apixaban 10 mg BID × 7 d → 5 mg BID × 3 mo; OR rivaroxaban 15 mg BID × 21 d → 20 mg daily × 3 mo; OR enoxaparin 1 mg/kg SC BID bridge to warfarin; STOP at 3 mo (provoked, reversible). For DISTAL incidental asymptomatic DVT in arthroplasty patient: extended prophylactic-dose AC (rivaroxaban 10 mg daily continued, apixaban 2.5 mg BID continued) vs serial imaging × 2 wk per shared decision. Coordinate AC initiation with neuraxial catheter status per ASRA 2018
    inputs: creatinine, bleed_risk
    advance: AC initiated per symptomatic vs surveillance distinction; neuraxial timing coordinated
  9. 9DISPOSITION
    Outpatient management standard for symptomatic uncomplicated proximal DVT (Hestia / sPESI low if PE absent); admit if phlegmasia, concurrent PE intermediate-high risk, severe pain, post-op bleed, or social barriers to outpatient AC + LMWH self-injection
    advance: Disposition documented
  10. 10MONITORING
    Symptom resolution at 2 weeks; PTS Villalta at 3/6/12 mo; bleed surveillance during AC; compression stocking 30-40 mmHg if symptomatic for PTS prevention; orthopedic surgeon coordination for prosthesis-site exam; physical therapy reactivation timeline; substrate-reversibility marker (ambulatory at 6 wk for hip; 4-6 wk for knee)
    actions: panel.cardiac
    advance: Monitoring + substrate-reversibility schedule documented
  11. 11FOLLOWUP
    STOP AC at 3 mo for provoked-by-reversed-factor presentation per ACCP 2021; 6-wk orthopedic follow-up confirms substrate reversal (ambulatory, prosthesis healed); future arthroplasty (contralateral or revision) requires the same extended-prophylaxis cycle; reinforce future-surgical-prophylaxis awareness; cardiac rehab if HFS in elderly patient
    advance: AC stop date + future-surgical-prophylaxis plan documented