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surgery.acute-limb-ischemia.core.v1

Acute Limb Ischemia

vascularacuteadultacuteinpatient
Start encounter →Print handoutPRODUCTION

Acute limb ischemia engine — Rutherford classification drives disposition. Rutherford III = primary amputation (DO NOT reperfuse necrotic muscle). 2024 ACC/AHA/SVS PAD Guideline (Gornik PMID 38752899) is current floor; supersedes 2016 AHA/ACC PAD. ESVS 2020 (Bjorck PMID 31899099) for European context. Workup workup.acute_limb_ischemia is registered in clinical-tools-registry. No engine-specific calculators — Rutherford is embedded in severity_triggers + risk_stratification rationale. All 7 PMIDs live-verified via PubMed MCP on 2026-05-26. All RxCUIs live-verified via RxNav forward + reverse on 2026-05-26.

Entry points (5)

  • symptom
    Six Ps — Pain, Pallor, Pulselessness, Paresthesia, Paralysis, Poikilothermia (2024 ACC/AHA/SVS PAD)
    six_ps_limb
  • symptom
    Sudden severe limb pain with cold/mottled extremity (ESVS 2020)
    sudden_limb_pain
  • history
    New AF / recent MI with mural thrombus / prosthetic graft / mechanical valve (2024 ACC/AHA/SVS PAD)
    recent_embolic_source
  • vital_abnormality
    Absent distal pulses with ABI <0.4 or non-recordable (ESVS 2020)
    absent_distal_pulses
  • imaging
    CTA showing acute arterial occlusion <14 days (2024 ACC/AHA/SVS PAD)
    cta_arterial_occlusion

Required inputs (14)

  • agerequired
    demographic • used at CONTEXT
    Older patients more likely embolic from AF; alters revasc choice (2024 ACC/AHA/SVS PAD)
  • onset_timerequired
    symptom • used at ENTRY
    Within 14 days defines ALI; <6h vs >6h alters reperfusion-injury risk (ESVS 2020)
  • sbprequired
    vital • used at RED_FLAGS
    Shock screens for systemic embolic shower / aortic occlusion (ESVS 2020)
  • hrrequired
    vital • used at CONTEXT
    New AF (tachy-irregular) is the dominant embolic source (2024 ACC/AHA/SVS PAD)
  • creatininerequired
    lab • used at INITIAL_WORKUP
    CTA contrast gating + heparin/lytic adjustment (2024 ACC/AHA/SVS PAD)
  • potassiumrequired
    lab • used at INITIAL_WORKUP
    Hyperkalemia from reperfusion / muscle necrosis (Rutherford III pre-revasc) (ESVS 2020)
  • lactaterequired
    lab • used at RED_FLAGS
    Ischemic muscle necrosis marker; elevated lactate + tense muscle = Rutherford III (ESVS 2020)
  • cpk
    lab • used at INITIAL_WORKUP
    CK >5000 suggests muscle necrosis; gates rhabdo / reperfusion injury management (ESVS 2020)
  • inrrequired
    lab • used at INITIAL_WORKUP
    Baseline coag before heparin; informs thrombolytic safety (2024 ACC/AHA/SVS PAD)
  • plateletsrequired
    lab • used at INITIAL_WORKUP
    Heparin / lytic contraindication threshold; HIT screen if heparin exposure (2024 ACC/AHA/SVS PAD)
  • cta_or_dsarequired
    imaging • used at INITIAL_WORKUP
    Defines anatomy + level of occlusion; DSA when CTA contraindicated (2024 ACC/AHA/SVS PAD)
  • afib_or_embolic_source
    history • used at CONTEXT
    Embolic vs thrombotic distinction alters revasc strategy (2024 ACC/AHA/SVS PAD)
  • prior_bypass_or_stent
    history • used at CONTEXT
    Graft thrombosis vs native artery occlusion (STILE) (Weaver/Comerota 1996)
  • recent_surgery_or_bleeding
    history • used at CONTEXT
    Thrombolytic absolute / relative contraindications (TOPAS) (Ouriel 1998)

12-phase flow (12)

  1. 1FRAME
    Confirm ALI scope (<14d) — chronic limb-threatening ischemia routes to CLTI engine (2024 ACC/AHA/SVS PAD)
    inputs: onset_time
    advance: symptom onset <14 days documented
  2. 2ENTRY
    Recognize Six Ps + acute onset; embolic source screen (2024 ACC/AHA/SVS PAD)
    inputs: age, afib_or_embolic_source
    advance: one entry trigger present
  3. 3CONTEXT
    Embolic vs thrombotic clinical context; anticoag history; bleeding risk (2024 ACC/AHA/SVS PAD)
    inputs: sbp, hr, afib_or_embolic_source, prior_bypass_or_stent, recent_surgery_or_bleeding
    advance: context captured
  4. 4RED_FLAGS
    Rutherford IIb (motor deficit) or III (paralysis + sensory loss + tense muscle, doppler-silent) — STAT vascular surgery / IR; hyperK from necrotic muscle pre-reperfusion (ESVS 2020)
    inputs: sbp, lactate, potassium
    actions: workup.acute_limb_ischemia
    advance: Rutherford category assigned
  5. 5INITIAL_WORKUP
    IV heparin bolus + infusion BEFORE imaging; CTA both legs + pelvis + abdomen; BMP / CBC / coags / lactate / CK / type & screen (2024 ACC/AHA/SVS PAD)
    inputs: creatinine, potassium, inr, platelets, cta_or_dsa, cpk
    actions: panel.renal, panel.cbc, panel.coag, workup.acute_limb_ischemia
    advance: heparin running + CTA obtained
  6. 6BRANCHING_WORKUP
    Embolic vs thrombotic anatomy on imaging; ECG / TTE if embolic to find source; HIT screen if heparin exposure last 14d (2024 ACC/AHA/SVS PAD)
    inputs: cta_or_dsa
    actions: panel.cardiac
    advance: mechanism characterized + source workup launched
  7. 7DIFFERENTIAL
    Distinguish ALI vs acute-on-chronic CLTI vs phlegmasia cerulea dolens (DVT) vs compartment syndrome vs acute aortic occlusion (saddle embolus) (ESVS 2020)
    advance: differential resolved
  8. 8RISK_STRATIFICATION
    Rutherford I (viable) / IIa (marginally threatened) / IIb (immediately threatened, motor deficit, salvage limited) / III (irreversible) drives urgency (Rutherford 1997)
    inputs: lactate, cpk
    advance: Rutherford category drives revasc timing
  9. 9TREATMENT
    IV UFH first (load 80 U/kg, infusion 18 U/kg/h, aPTT 1.5-2.5x); Rutherford I/IIa -> catheter-directed thrombolysis (CDT) or percutaneous mechanical thrombectomy (PMT); Rutherford IIb -> surgical embolectomy / bypass + likely fasciotomy; Rutherford III -> primary amputation (NOT reperfusion) (2024 ACC/AHA/SVS PAD / ESVS 2020)
    inputs: creatinine, platelets, inr
    advance: revasc strategy executed or amputation planned
  10. 10DISPOSITION
    ICU post-revasc for reperfusion monitoring; OR/IR for Rutherford IIb-III emergent; ward for Rutherford I (heparin + CDT) (ESVS 2020)
    inputs: sbp, potassium
    advance: destination + procedure timing locked
  11. 11MONITORING
    Serial compartment exam (fasciotomy threshold delta-P <30); CK / K / Cr / lactate q4-6h x 24h post-revasc; urine output + dipstick for myoglobinuria; aPTT q6h on heparin (ESVS 2020)
    inputs: potassium, creatinine, cpk
    actions: panel.renal
    advance: reperfusion injury controlled
  12. 12FOLLOWUP
    Long-term anticoagulation (DOAC or warfarin) if embolic source; antiplatelet + high-intensity statin if thrombotic; smoking cessation; vascular medicine follow-up; ABI / duplex at 1 month (2024 ACC/AHA/SVS PAD)
    advance: secondary prevention plan in place