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cardio.dvt.travel-related.v1

Travel-associated DVT (long-haul flight or train >4 h)

cardiologyacuteadultacuteinpatienttransitionoutpatient
Start encounter →Print handoutPRODUCTION

Phase E variant of cardio.dvt.core.v1 — narrowed to travel-associated VTE (long-haul flight or train travel >4 h). Inherits diagnostic arc and DOAC chronic regimen from parent via routing; specializes for the provoked-by-reversible-factor phenotype with explicit 3-mo AC stop point and structured future-travel prevention plan. Manifest pointer reuses cardio.dvt.core.v1 manifest. Design-brief pointer reuses parent (travel-specific differences documented inline). Distinguishing features vs generic provoked DVT: explicit travel exposure window (peak risk first 2 weeks; tail to 4 weeks); 3-mo AC then STOP per ACCP 2021 strong recommendation; future-flight prevention plan: graduated stockings 15-30 mmHg below knee + hydration + walking for everyone; LMWH single 40 mg dose 2-4 h pre-flight for high-risk patients (prior VTE, active cancer, known thrombophilia + planned >4 h flight); ASA explicitly NOT recommended (Cochrane / WRIGHT 2007 / Watson + Baglin 2011). Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute as travel-associated DVT variant.

Entry points (4)

  • symptom
    Unilateral leg swelling, calf pain, or whole-leg swelling within hours to ~4 weeks of long-haul travel >4 h (flight or train) — pretest probability for travel-associated DVT
    unilateral_leg_swelling_post_long_haul_travel
  • history
    Documented flight or continuous transport >4 h within the prior 4 weeks (peak risk window per LONFLIT) — anchor the provoking factor
    long_haul_travel_within_4_weeks
  • symptom
    New pleuritic chest pain, dyspnea, syncope, or hemoptysis within 4 weeks of long-haul travel — concurrent PE screen indicated (PERC fail in this context; CTPA if Wells > 4)
    pleuritic_chest_pain_or_dyspnea_post_travel
  • imaging
    Compression US showing proximal DVT in patient with recent travel history — confirm and treat as provoked VTE
    us_proximal_dvt_with_travel_history

Required inputs (10)

  • agerequired
    demographic • used at CONTEXT
    Risk increases with age >60; travel-associated VTE in younger patients should prompt thrombophilia screen (especially if family history positive)
  • sexrequired
    demographic • used at CONTEXT
    Female + OCP / hormone use compounds risk; pregnancy / postpartum is a separate pathway (cardio.dvt.pregnancy.v1)
  • travel_duration_and_typerequired
    history • used at ENTRY
    Document hours airborne or in continuous transport; >4 h is threshold; >8 h is high; multiple legs within same trip aggregate risk
  • additive_risk_factorsrequired
    history • used at CONTEXT
    Prior VTE, OCP / HRT, active malignancy, obesity BMI ≥30, recent surgery / trauma, varicose veins, known thrombophilia — drives baseline risk band and prevention plan for future travel
  • leg_swellingrequired
    symptom • used at ENTRY
    Unilateral leg swelling is the cardinal symptom; bilateral suggests systemic etiology (HF, cirrhosis, nephrotic) and lowers DVT probability
  • compression_usrequired
    imaging • used at INITIAL_WORKUP
    Initial confirmation of DVT (proximal vs distal); femoral + popliteal compression test
  • d_dimerrequired
    lab • used at INITIAL_WORKUP
    Age-adjusted D-dimer (cutoff = age × 10 ng/mL FEU if >50) rules out DVT in low-intermediate Wells
  • creatininerequired
    lab • used at TREATMENT
    eGFR for DOAC dosing — apixaban dose-reduction criteria, rivaroxaban CrCl <30 caution
  • cbcrequired
    lab • used at INITIAL_WORKUP
    Baseline Hgb + platelet for AC bleed risk; isolated thrombocytopenia after travel + recent illness can be coincident, screen if abnormal
  • bleed_riskrequired
    history • used at RED_FLAGS
    HAS-BLED + recent surgery + falls history determines AC eligibility and choice

12-phase flow (11)

  1. 1FRAME
    Travel-associated DVT = provoked VTE with a major reversible transient risk factor (immobility >4 h); 3-mo AC sufficient (ACCP 2021); future-flight prevention is the differentiator. Route to cardio.dvt.core.v1 for diagnostic arc + DOAC chronic regimen
    inputs: leg_swelling
    advance: travel-associated DVT framed
  2. 2ENTRY
    Wells DVT score + age-adjusted D-dimer; compression US if Wells ≥2 or D-dimer positive; explicitly anchor travel duration and timing relative to symptom onset (peak risk first 2 weeks; tail to 4 weeks)
    inputs: travel_duration_and_type, age
    advance: pretest probability + travel exposure documented
  3. 3CONTEXT
    OCP / HRT, malignancy, pregnancy, prior VTE, obesity BMI, recent surgery, varicose veins, known thrombophilia — determines baseline-risk band for future travel prevention plan; family hx for unmasking heritable thrombophilia if young or recurrent
    inputs: sex, additive_risk_factors
    advance: context complete
  4. 4RED_FLAGS
    Concurrent PE (pleuritic pain, dyspnea, syncope, hypoxia, tachycardia) — CTPA if Wells > 4 or PERC fail; phlegmasia (cyanosis + severe pain) requires emergent CDT; absolute AC contraindication (active bleed, recent ICH)
    inputs: bleed_risk
    actions: pe_full, le_edema
    advance: PE + limb-threatening features screened
  5. 5INITIAL_WORKUP
    Compression US (femoral + popliteal); CBC + BMP + INR/PTT; CXR if respiratory symptoms; troponin + BNP if PE confirmed for risk-stratification
    inputs: compression_us, d_dimer, cbc, creatinine
    actions: panel.cardiac, panel.renal
    advance: imaging confirms DVT
  6. 6BRANCHING_WORKUP
    CTPA if PE suspicion; thrombophilia workup ONLY if young (<45), strong family history, recurrent unprovoked, or unusual site — travel-associated alone is NOT an indication for thrombophilia testing per ASH 2018 (PMID 30482764). Most travel-related DVT in low-additive-risk adults requires no further workup
    advance: branching workup decision documented
  7. 7RISK_STRATIFICATION
    Wells DVT, HAS-BLED, eGFR for DOAC; CHADS-VTE not applicable; recurrence risk LOW after 3-mo AC because reversible provoking factor (annualised recurrence ~3% vs ~10% unprovoked per Iorio meta)
    inputs: bleed_risk
    actions: calc.wells_dvt, calc.has_bled
    advance: AC duration plan documented as 3 months
  8. 8TREATMENT
    Acute AC: DOAC first-line — apixaban 10 mg BID × 7 d → 5 mg BID × 3 mo OR rivaroxaban 15 mg BID × 21 d → 20 mg daily × 3 mo; alternatives: enoxaparin 1 mg/kg SC BID × 5–10 d bridge to warfarin, edoxaban 60 mg daily after 5–10 d LMWH bridge; STOP at 3 mo (provoked, reversible)
    inputs: creatinine, bleed_risk
    advance: AC initiated and 3-mo plan documented
  9. 9DISPOSITION
    Outpatient management standard for low-risk DVT (Hestia / sPESI low if PE absent); admit if phlegmasia, concurrent PE high-risk, severe pain, or social barriers to outpatient AC
    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
    actions: panel.cardiac
    advance: monitoring schedule documented
  11. 11FOLLOWUP
    Stop AC at 3 mo with symptom + reassessment visit; structured future-travel prevention plan: stockings 15–30 mmHg + hydration + walking for everyone; LMWH single dose pre-flight if high-risk (prior VTE, active cancer, known thrombophilia + planned >4 h flight); reinforce that ASA is NOT recommended for travel VTE prevention (Cochrane / WRIGHT 2007)
    advance: AC stop date + future-travel prevention plan documented