Author:
David W.Schoenfeld
Christie L.Fritz
Description
Immediate and severe compromise of the blood supply to a limb, threatening its viability, secondary to the sudden blockage of a peripheral artery
- Arterial embolization:
- Thrombus or plaque
- Originates from the heart (atrial fibrillation) aneurysms, atherosclerotic lesions or previous graft/stent sites
- Emboli typically lodge where there is an acute narrowing of the artery or branch site
- 75% of emboli involve an axial limb vasculature:
- Femoral 28%
- Arm 20%
- Aortoiliac 18%
- Popliteal 17%
- Visceral and other 9%
- Thrombosis
- Arterial dissection
- Trauma:
- Crush injuries
- Compression
- Arterial contusion and thrombosis
- Arterial transection
- Limb ischemia >6 hr usually results in functional impairment or limb loss:
- If acute on chronic, collateral circulation may preserve tissue beyond 6 hr
- Distal blood flow is entirely dependent on collateral circulation
- Thrombus extends proximally and distally as time goes on due to low flow
Etiology
- Embolus:
- Atrial fibrillation
- Myocardial infarction
- Valvular disease
- Endocarditis
- Atrial myxoma
- Aneurysm
- Atherosclerotic plaques
- Paradoxical embolus (venous thromboembolism entering arterial system through communication i.e., PFO)
- Thrombosis:
- Vascular grafts
- Atherosclerosis
- Thrombosis of an aneurysm
- Entrapment syndrome
- Hypercoagulable disorders
- Low flow state
- Heparin-induced thrombosis
- Arterial dissection
- Arterial injury:
- Intimal flap
- Dissection
- Pseudoaneurysms
- Iatrogenic:
- Catheterization
- Arteriography
- Balloon angioplasty
- Complication of arterial puncture
- Penetrating trauma:
- Gunshot, stab wounds, shotgun, shrapnel
- IV drug use
- Blunt trauma
- Joint displacement
- Fracture
- Compartment syndrome
Signs and Symptoms
- Sudden onset of a cold, painful leg
- The 6 Ps:
- Pain:
- Gradual, initially increasing in severity then decreasing with progressive sensory loss
- Distal progressing proximally
- Sudden onset with embolization
- Pallor
- Paresthesias
- Paralysis
- Pulseless (late finding)
- Poikilothermia (cold)
- Progressive peripheral nerve dysfunction:
- Early loss of proprioception and light touch
- Loss of sensation and weakness follows
- Blue toe syndrome:
- Development of blue or violaceous discoloration in one or more toes
- The affected digits are often painful
- The cyanosis initially blanches with pressure or leg elevation
- Signs of severe obstruction and poor prognosis
- Absent capillary flow
- Skin marbling
- Loss of distal pulses
- Paralysis
History
- Time of onset
- History of claudication or cramps:
- Reproducible discomfort of a defined group of muscles that is induced by exercise and relieved with rest
- Past medical history to identify risk factors for thrombosis or embolus
Physical Exam
- Sensory loss:
- Light touch, vibratory sense, 2 point discrimination and proprioception are lost first
- Muscle weakness
- Skin color changes
- Loss of pulse or diminished pulse
- Signs of chronic arterial insufficiency:
- Ankle-brachial pressure index (ABI) measurement
- Measure arm systolic pressure with the Doppler flowmeter for accuracy
- Record pressure in both arms and both tibial arteries at the ankle
- Ratio of systolic BP in the lower legs to the brachial pressure in the arm:
- Place cuff above malleoli to measure pressure in lower legs
- Use Doppler at posterior tibial or dorsalis pedis artery
- Chronic PVD <0.9
- Acute arterial occlusion <0.5
- Demarcation of the warm part of the extremity to the cold part to estimate level of the obstruction
- Doppler US examination of the extremity including above and below believed site of occlusion
Essential Workup
ALERT |
| Elevation, cool compress/ice, or warm compress to the affected extremity is contraindicated |
Diagnostic Tests & Interpretation
Lab
- Electrolytes/anion gap
- BUN
- Creatinine
- CBC
- Creatine phosphokinase
Imaging
- The utility of imaging in the ED is limited as most of the decision making is based on the clinical presentation
- Duplex US
- Provides a “roadmap” of stenosis of the arteries of the lower extremities
- CT angiography
- With multidetectors, performance is similar to angiography
- Like angiography it requires IV contrast bolus and exposure to radiation
- MRI
- Viable alternative to angiography
- Noninvasive
- Does not required contrast material
- Angiography
Classification
- Class 1: Viable
- Pain but no paralysis or sensory loss
- Audible Doppler signals
- Needs attention, not in immediate danger
- Class 2: Threatened but salvageable
- 2A: Some sensory loss, no paralysis: No immediate threat
- 2B: Sensory and motor loss: Needs immediate treatment
- Class 3: Irreversible/nonviable:
- Sensory loss, paralysis, absent capillary flow, skin marbling, absent arterial Doppler flow
- Will require amputation
Differential Diagnosis
- Lumbar spine disorders
- Back pain, mechanical
- Decreased cardiac output owing to advanced atherosclerotic disease
- Frostbite
- Peripheral neuropathy
- Aneurysm, abdominal
- Ankle injury, soft tissue
- Deep venous thrombosis/phlegmasia
- Chronic Limb Ischemia
- Septic thrombophlebitis
- Superficial thrombophlebitis
- Trauma, peripheral vascular injuries
Prehospital
- Early recognition and rapid transport to an emergency department
- Place the limb in a dependent position
- Keeping the limb warm
- Oxygen by nasal cannula
- Aspirin
ED Treatment/Procedures
- Prompt consultation with vascular surgeon:
- Catheter based thrombolysis, traditional thrombolysis and thrombectomy/open embolectomy are treatment options
- Heparin bolus followed by an infusion
- IV fluids
- Class 1: Viable:
- Most often due to thrombosis
- Intra-arterial thrombolytic agents versus surgical revascularization or endovascular repair depending on viability of limb
- Class 2: Threatened but salvageable
- Immediate surgical revascularization
- Embolectomy if indicated
- Angiography and oral anticoagulation post op
- Class 3: Nonviable
- Prompt amputation
- Clinical assessment, imaging usually not required
- Pain control
- Prepare for metabolic derangements from ischemia and reperfusion (hyperkalemia, rhabdomyolysis, academia)
Medication
Heparin: Weight-based protocol anticoagulation with typical 80 units/kg loading bolus; 18 units/kg/hr IV
Disposition
Admission Criteria
All patients with clinical diagnosis of acute arterial occlusion or (ABI <0.5) should be admitted after an emergency consultation with a vascular surgeon
Discharge Criteria
- Patients with chronic occlusive disease, resolved pain, and stable ABI measurements
- No other acute medical issues (e.g., new atrial fibrillation)
- Vascular surgical follow-up can be ensured
- Patients should be instructed to return for any recurrent or progressive symptoms
Issues for Referral
- PVD patents in which illness is not severe or acute as to require inpatient treatment may be discharged with appropriate follow-up with a vascular surgeon
- Potential effects of various activities and medications on the course of their illness should be discussed
- Education on smoking cessation, temperature extremes, and vasoconstricting medications should be considered
- AboyansV, RiccoJ, BartelinkMEL, et al. 2017 ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, in collaboration with the European Society for Vascular Surgery (ESVS) . Euro Heart J. 2018;39:763-821.
- ClairD, ShahS, WeberJ. Current state of diagnosis and management of critical limb ischemia . Curr Cardiol Rep. 2012;14(2):160-170.
- CreagerMA, KaufmanMD, ConteMS. Acute limb ischemia . NEJM. 2012;366:2198-2206.
- Gerhard-HermanMD, GornikHL, BarrettC, et al. 2016 AHA/ACC Guideline on the Management of Patients with Lower Extremity Peripheral Artery Disease: Executive summary . Circulation. 2016;135:e726-e779.
See Also (Topic, Algorithm, Electronic Media Element)
Peripheral Vascular Disease