Arterial Occlusion, Emergency Medicine

Basics

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 aneurysms or atherosclerotic lesions
- Emboli typically lodge where there is an acute narrowing of the artery
- 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.

Etiology

Embolus:
- Atrial fibrillation
- Myocardial infarction
- Valvular disease
- Endocarditis
- Atrial myxoma
- Aneurysm
- Atherosclerotic plaques
- Paradoxical embolus
  - Patent foramen ovale
Thrombosis
- Vascular grafts
- Atherosclerosis
- Thrombosis of an aneurysm
- Entrapment syndrome
- Blood clotting 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

Diagnosis

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)
- Polar (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
Muscle weakness
Skin color changes
Loss of pulse
Signs of chronic arterial insufficiency:
- Hair loss
- Atrophic skin
Ankle-brachial pressure index 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

Essential Workup

Elevation, cool compress or ice, or warm compress to the affected extremity is contraindicated. �

Diagnosis 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
- 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
Septic thrombophlebitis
Superficial thrombophlebitis
Trauma, peripheral vascular injuries

Treatment

Pre-Hospital

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
Heparin bolus followed by an infusion
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

Medication

Heparin: Weight-based protocol anticoagulation with typical 80 U/kg loading bolus; 18 U/kg/h IV

Follow-Up

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.

Additional Reading

Clair �D, Shah �S, Weber �J. Current state of diagnosis and management of critical limb ischemia. Curr Cardiol Rep. 2012;14(2):160-170.
Katzen �BT. Clinical diagnosis and prognosis of acute limb ischemia. Rev Cardiovasc Med. 2002;3(suppl 2):S2-S6.
Setacci �C, De Donato �G, Setacci �F, et al. Hybrid procedures for acute limb ischemia. J Cardiovasc Surg. 2012;53(1 suppl 1):133-143.
Van den Berg �JC. Thrombolysis for acute arterial occlusion. J Vasc Surg. 2010;52(2):512-515.

Codes

ICD9

444.9 Embolism and thrombosis of unspecified artery
444.21 Arterial embolism and thrombosis of upper extremity
444.22 Arterial embolism and thrombosis of lower extremity
415.19 Other pulmonary embolism and infarction

ICD10

I74.2 Embolism and thrombosis of arteries of the upper extremities
I74.3 Embolism and thrombosis of arteries of the lower extremities
I74.9 Embolism and thrombosis of unspecified artery
I26.99 Other pulmonary embolism without acute cor pulmonale

SNOMED

2929001 Occlusion of artery (disorder)
54687002 Arterial embolism (disorder)
195147006 Atrial thrombosis
59282003 Pulmonary embolism (disorder)
302300004 Femoral popliteal occlusion (disorder)
314188009 Femoral artery occlusion (disorder)
69357003 pulmonary thrombosis (disorder)

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