Acute limb ischemiaMANAGEMENT

CARDIOVASCULAR PRESENTATIONS · 12 SECTIONS

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474 items

☷ Legend

01Approach to the Critical Patient/attcp65

Time critical priorities

›Acute limb ischemia priorities

›Limb threat categorization

›Viable limb category I

›Threatened limb category IIa

›Threatened limb category IIb

›Irreversible ischemia category III

›Time last known normal perfusion

›Symptom onset within 14 days

›Sudden onset minutes to hours

›Progressive onset hours to days

›Vascular surgery and interventional activation

›Category IIb immediate threatened limb

›Category III irreversible limb

Immediate stabilization

›Resuscitation basics

›Airway and breathing concerns

›Aspiration risk with altered mental status

›Supplemental oxygen for hypoxemia

›Circulation and access

›Two large bore IV lines

›Cardiac monitor

›12 lead ECG for atrial fibrillation or ischemia

›Analgesia and limb protection

›Opioid analgesia for severe ischemic pain

›Limb at rest

›Limb in neutral or dependent position

›Avoid elevation

›Avoid external heat or cold

Immediate medical therapy

›Anticoagulation on diagnosis

›Unfractionated heparin systemic anticoagulation

›Contraindications checklist

›Active major bleeding

›Recent intracranial hemorrhage

›Severe uncontrolled coagulopathy

›Dosing strategy

›Bolus 80 units per kg IV

›Infusion 18 units per kg per hour IV

›Alternative no bolus strategy for high bleeding risk

›Monitoring targets

›aPTT per institutional heparin nomogram

›Anti Xa per institutional protocol

Limb viability triggers

›Escalation triggers

›Threatened limb physiology

›Rest pain

›Sensory loss

›Motor weakness

›Absent arterial Doppler signal

›Irreversible ischemia physiology

›Profound anesthesia

›Paralysis

›Rigor

›Mottling fixed discoloration

›Absent arterial and venous Doppler signals

Pitfalls and safety

›High risk pitfalls

›Normal proximal pulses with distal occlusion

›Popliteal or tibial occlusion

›Embolus to distal vessels

›Neurologic mimic

›Acute stroke with limb weakness

›Spinal cord compression

›Overreliance on pain as ischemia marker

›Diabetic neuropathy

›Sedation and altered sensorium

›Missed compartment syndrome after reperfusion

›Increasing pain out of proportion

›Pain with passive stretch

02History/hx45

Symptom pattern and timeline

›Presentation features

›Six Ps pattern

›Pain

›Pallor

›Pulselessness

›Paresthesia

›Paralysis

›Poikilothermia

›Onset characteristics

›Sudden onset severe pain

›Progressive pain and numbness

›Minimal pain with advanced neuropathy

›Prior limb symptoms

›Claudication history

›Chronic rest pain

›Prior ulcers or gangrene

Etiology clues

›Embolic source clues

›Atrial fibrillation history

›Anticoagulation adherence

›Recent interruption

›Recent myocardial infarction

›Valvular disease or endocarditis features

›Thrombotic source clues

›Known peripheral artery disease

›Prior bypass graft

›Prior stent

›Known aneurysm

›Iatrogenic or trauma clues

›Recent arterial access

›Vascular surgery or catheter procedure

›Penetrating or blunt extremity trauma

Bleeding and thrombolysis risk

›Thrombolysis contraindication screen

›Prior intracranial hemorrhage

›Known intracranial neoplasm or AVM

›Ischemic stroke timing

›Recent major surgery timing

›Recent GI bleeding timing

›Severe uncontrolled hypertension

Medication and comorbidity context

›Baseline risks

›Antiplatelet therapy

›Anticoagulant therapy

›Statin therapy

›Smoking status

›Diabetes status

›Chronic kidney disease status

03Physical Exam/exam42

Vascular focused exam

›Perfusion assessment

›Skin temperature gradient

›Cool distal limb

›Contralateral comparison

›Skin color

›Pallor with elevation

›Cyanosis

›Mottling pattern

›Capillary refill

›Delayed refill

›Absent refill

›Pulse and Doppler assessment

›Palpable pulses

›Femoral

›Popliteal

›Dorsalis pedis

›Posterior tibial

›Handheld Doppler signals

›Arterial signal present

›Venous signal present

›Arterial signal absent

›Venous signal absent

Neuromuscular assessment

›Ischemic nerve injury

›Sensory loss distribution

›Toes only

›Foot dorsum plantar

›Proximal progression

›Motor deficit

›Toe movement weakness

›Ankle dorsiflexion weakness

›Foot drop

›Paralysis

Red flags and complications

›Compartment syndrome screen

›Pain out of proportion

›Pain with passive stretch

›Tense compartments

›Paresthesia progression

›Systemic instability

›Hypotension

›Tachycardia

›Fever

›Sepsis physiology

04Differential Diagnosis/ddx24

Limb threatening vascular differentials

›Vascular occlusive causes

›Acute arterial embolism ICD-10 I74.3

›Cardioembolic atrial fibrillation

›Left ventricular thrombus

›Acute thrombosis on chronic PAD ICD-10 I74.3

›In situ thrombosis at stenosis

›Stent thrombosis

›Acute bypass graft occlusion ICD-10 T82.868A

›Graft thrombosis

›Anastomotic stenosis

›Aortic or peripheral dissection ICD-10 I71 series

›Iliac dissection

›Femoral dissection

Non occlusive ischemia and mimics

›Flow limiting non occlusive states

›Shock related low flow ischemia

›Severe heart failure low output

›Vasopressor related ischemia

›Mimics

›Acute deep vein thrombosis ICD-10 I82

›Phlegmasia cerulea dolens

›Acute compartment syndrome ICD-10 T79.A

›Acute neuropathy or radiculopathy

›Cellulitis with pain and swelling

›Frostbite and cold injury

05Laboratory Tests/lt28

Baseline labs for intervention readiness

›Pre procedure lab set

›Complete blood count

›Hemoglobin baseline for bleeding risk

›Platelet count for thrombolysis eligibility

›Electrolytes and renal function

›Creatinine for contrast risk

›Potassium baseline for reperfusion monitoring

›Coagulation studies

›INR baseline

›aPTT baseline

›Fibrinogen baseline if thrombolysis planned

Ischemia severity and reperfusion risk

›Muscle injury markers

›Creatine kinase

›Elevated CK suggesting myonecrosis

›Rising CK after reperfusion

›Lactate

›Elevated lactate with severe ischemia or shock

›Acid base and potassium monitoring

›Venous blood gas

›Metabolic acidosis with severe ischemia

›Potassium repeat testing

›Hyperkalemia after reperfusion

Etiology evaluation labs

›Cardioembolic and systemic clues

›Troponin for myocardial infarction suspicion

›Blood cultures if endocarditis concern

›Hypercoagulability selective testing

›Antiphospholipid antibodies for unexplained arterial thrombosis

›Myeloproliferative markers when clinically indicated

06Diagnostic Tests/dt61

Scoring Systems

›Limb viability classification

›Rutherford acute limb ischemia categories

›Category I viable

›No sensory loss

›No motor deficit

›Arterial Doppler audible

›Venous Doppler audible

›Category IIa marginally threatened

›Minimal sensory loss toes

›No motor deficit

›Arterial Doppler inaudible

›Venous Doppler audible

›Category IIb immediately threatened

›Sensory loss beyond toes

›Mild to moderate motor deficit

›Arterial Doppler inaudible

›Venous Doppler audible

›Category III irreversible

›Profound anesthesia

›Paralysis

›Arterial Doppler inaudible

›Venous Doppler inaudible

MRI

›MR angiography

›Indications

›Contrast allergy limiting CTA

›Need for detailed runoff mapping

›Limitations

›Time delay in threatened limb

›MRI incompatible devices

›Interpretation focus

›Level of occlusion

›Collateral flow

›Runoff vessel patency

›CT angiography with runoff

›Indications

›Threatened limb with unclear level of occlusion

›Suspected proximal aortoiliac disease

›Suspected aneurysm thromboembolism

›Imaging pearls

›Embolus pattern abrupt cutoff without calcified disease

›Thrombosis pattern long segment disease with calcification

›Safety considerations

›Contrast nephropathy risk

›Contrast allergy premedication strategy

Ultrasound

›Duplex ultrasound

›Indications

›Rapid bedside localization

›Alternative when CTA unavailable

›Findings

›Absent flow signal distal to occlusion

›High velocity jet at stenosis

›Thrombus visualization in aneurysm or graft

›Limitations

›Operator dependence

›Difficult visualization with obesity or edema

›Bedside Doppler

›Arterial signal assessment

›Monophasic signal

›No signal

›Venous signal assessment

›Present venous signal supporting salvageability

07Disposition/dispo31

Level of care and destination

›Disposition pathways

›Category I viable limb

›Urgent vascular consultation

›Imaging guided planning

›Admission for intervention planning

›Category IIa threatened limb

›Emergent revascularization pathway

›Interventional suite or operating room

›Continuous heparin infusion

›Category IIb threatened limb

›Immediate revascularization

›Direct to operating room or endovascular thrombectomy

›Avoid delays for extensive imaging when clinical localization clear

›Category III irreversible limb

›Primary amputation pathway

›Avoid revascularization of nonviable tissue

Transfer criteria

›Transfer triggers

›No on site vascular surgery or endovascular capability

›Threatened limb category IIa or IIb

›Hemodynamic instability requiring ICU

›Need for complex revascularization or bypass

›Transfer essentials

›Heparin infusion continuity

›Limb protection

›Copies of imaging

›Time of symptom onset documentation

Post revascularization monitoring

›Monitoring needs

›ICU for high reperfusion risk

›Serial neurovascular checks

›Compartment syndrome surveillance

›Electrolyte monitoring for hyperkalemia

08Treatment/t74

Anticoagulation

›Systemic anticoagulation regimen

›Unfractionated heparin

›Initiate unless contraindicated

›ACC AHA 2024 Class 1 recommendation

›Level of evidence C-EO

›Standard dosing

›Bolus 80 units per kg IV

›Maximum bolus per institutional protocol

›Infusion 18 units per kg per hour IV

›Titration per aPTT nomogram

›Monitoring and safety

›Platelet count trend for HIT

›Overt bleeding surveillance

›Alternative anticoagulation

›Direct thrombin inhibitor for suspected HIT

›Argatroban infusion per institutional protocol

›Bivalirudin infusion per institutional protocol

Analgesia and supportive care

›Supportive measures

›Analgesia strategy

›Fentanyl IV 25 to 50 micrograms

›Repeat every 5 to 10 minutes to effect

›Hydromorphone IV 0.2 to 0.5 mg

›Repeat every 10 to 15 minutes to effect

›Nausea prophylaxis

›Ondansetron IV 4 mg

›Repeat every 8 hours as needed

›Fluids and perfusion

›Isotonic crystalloid for hypovolemia

›Avoid hypotension to support collateral flow

Revascularization strategies

›Revascularization for salvageable limb

›Endovascular options

›Catheter directed thrombolysis

›Alteplase infusion 0.5 to 1 mg per hour intra arterial

›Maximum total dose per institutional protocol

›Fibrinogen monitoring per protocol

›Adjunctive angioplasty or stenting after lysis

›ACC AHA 2024 Class 2a usefulness

›Level of evidence C-EO

›Mechanical thrombectomy

›Aspirational thrombectomy

›Rheolytic thrombectomy

›Combined thrombectomy and limited lysis strategy

›Surgical options

›Open embolectomy

›Fogarty catheter embolectomy for embolus

›Completion angiography when available

›Surgical thrombectomy and endarterectomy

›Thrombosis on chronic stenosis

›Bypass surgery

›Inflow correction aortoiliac

›Outflow bypass femoropopliteal or tibial

›Guideline indication

›ACC AHA 2024 revascularization for salvageable limb

›Class 1 indication

›Level of evidence A

Fasciotomy and reperfusion injury

›Reperfusion injury mitigation

›Compartment syndrome response

›Fasciotomy after revascularization when compartment syndrome present

›ACC AHA 2024 Class 1 recommendation

›Level of evidence C-EO

›Prophylactic fasciotomy for threatened limb IIa or IIb when high risk

›ACC AHA 2024 Class 2a recommendation

›Level of evidence B-NR

›Metabolic monitoring

›Potassium and acid base checks after reperfusion

›CK trend for rhabdomyolysis

Amputation pathway

›Non salvageable limb management

›Avoid revascularization of nonviable tissue

›ACC AHA 2024 Class 3 harm

›Level of evidence C-EO

›Primary amputation planning

›Pain control

›Infection control if gangrene

›Rehabilitation planning

09Special Populations/sp30

Pregnancy

›Pregnancy considerations

›Maternal fetal risk balance

›Maternal limb salvage as priority

›Obstetric consultation early

›Anticoagulation choices

›Unfractionated heparin preferred for rapid reversibility

›Avoid warfarin in pregnancy

›LMWH as alternative when stable and appropriate

›Imaging strategy

›Duplex ultrasound first line when feasible

›CTA when limb threatened and rapid localization needed

Geriatric

›Older adult considerations

›High prevalence of atrial fibrillation embolus

›ECG and rhythm monitoring importance

›High bleeding risk with thrombolysis

›Individualized lysis decision

›Frailty and function

›Pre event ambulatory status

›Shared decision making for amputation vs salvage

Pediatrics

›Pediatric considerations

›Common etiologies

›Iatrogenic arterial line thrombosis

›Congenital heart disease embolus

›Trauma related occlusion

›Anticoagulation dosing

›Weight based unfractionated heparin per pediatric protocol

›Anti Xa monitoring preference in pediatrics

›Specialist involvement

›Pediatric vascular surgery

›Pediatric hematology for thrombophilia evaluation

10Background/b38

Epidemiology

›Epidemiology overview

›Incidence range

›3 to 14 per 100000 person years reported in historical cohorts

›Higher incidence in adults older than 80 years

›Clinical significance

›Limb loss risk without timely revascularization

›High short term cardiovascular event risk

Pathophysiology

›Mechanisms of acute limb ischemia

›Embolism

›Sudden arterial occlusion in previously normal vessel

›Limited collateral development

›Thrombosis

›Acute thrombosis on chronic stenosis

›Collateral flow partially protective

›Graft or stent thrombosis

›Flow limiting outflow disease

›Intimal hyperplasia and stenosis

›Reperfusion injury

›Compartment syndrome

›Hyperkalemia

›Metabolic acidosis

›Myoglobin mediated kidney injury

Therapeutic Considerations

›Therapy rationale

›Immediate heparin benefits

›Prevent thrombus propagation

›Reduce distal microembolization

›Bridge to definitive revascularization

›Revascularization strategy selection

›Rutherford category driven urgency

›Embolus favoring embolectomy

›Thrombosis favoring endovascular plus lesion treatment

›Thrombolysis tradeoffs

›Better for distal and multilevel thrombus

›Bleeding risk increased

›Time to effect may be limiting in IIb

›Fasciotomy role

›Prevent irreversible neuromuscular damage from compartment syndrome

›Prevent amputation from reperfusion sequelae

11Patient Discharge Instructions/pdi24

Copy discharge instructions

›Discharge instructions for post ALI care

›Medication adherence

›Anticoagulant exactly as prescribed

›Antiplatelet exactly as prescribed

›Statin exactly as prescribed

›Wound and limb care

›Keep incisions clean and dry

›Daily foot and skin checks

›Avoid cold exposure to the limb

›Activity guidance

›Gradual walking program per vascular team

›Avoid prolonged immobility

›Return to ED now symptoms

›New severe limb pain

›New numbness or weakness

›New color change pale blue or black

›Cold limb compared with other side

›Bleeding that does not stop

›Chest pain or shortness of breath

›Fainting or new neurologic symptoms

›Follow up

›Vascular surgery follow up date and location

›Anticoagulation clinic follow up if applicable

›Cardiology follow up for embolic source evaluation

12References/r12

Clinical guidelines and key sources

›Guideline references

›2024 ACC AHA multisociety guideline for lower extremity peripheral artery disease

›Anticoagulation for ALI with unfractionated heparin Class 1 Level C-EO

›Revascularization for salvageable ALI Class 1 Level A

›Fasciotomy for compartment syndrome after revascularization Class 1 Level C-EO

›ESVS 2020 clinical practice guidelines on management of acute limb ischaemia

›Incidence estimates and epidemiology

›Etiology classification embolus thrombosis graft occlusion

›Review overview of Rutherford classification in peripheral artery disease

›Rutherford category definitions

›Thrombosis Canada peripheral arterial disease clinical guide

›Emergent heparin use in suspected ALI

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.