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Acute Limb Ischaemia

RCEM Learning Acute limb Ischaemia ESVS 2020 Clinical Practice Guidelines on the Management of Acute Limb Ischaemia The author would like to clarify that author NICE CKS has a page on acute limb ischaemia, it does not include any specific recommendations on the investigation, diagnosis and management. Therefore, recommendations from the RCEM and ESVS are used.

Background Information

The following terms are commonly misused, they are not interchangeable.   
Peripheral arterial disease Presence of atherosclerotic obstruction in the peripheral arteries of the lower limb.
Can be asymptomatic or symptomatic.
Chronic limb ischaemia Symptomatic presentation of peripheral arterial disease.
Can present as different severity:
  • Asymptomatic
  • Intermittent claudication
  • Chronic limb-threatening ischaemia (old term: critical limb ischaemia)
Acute limb ischaemia Sudden (signs and symptoms develop over <2 weeks) decrease in limb perfusion that threatens limb viability.

Two main causes of acute limb ischaemia:
  • Thrombosis from atherosclerotic plaque rupture (80-85%)
  • Embolisation 
Features that suggestive of embolic vs thrombotic acute limb ischaemia:
  • Embolic
    • Acute onset
    • Normal vascular examination on the other leg
    • Distinct demarcation between areas of perfusion and ischaemia
  • Thrombotic
    • Gradual onset
    • Background of worsening claudication / resting pain
    • Abnormal vascular examination on the other leg

6Ps: (the development of all 6 Ps in clinical practice is rare)
  • Paraesthesia – often 1st sign
  • Pain 
  • Pallor 
  • Perishingly cold 
  • Pulselessness – unreliable
  • Paralysis – late and poor prognosis (indicates irreversible ischemia)

Acute limb ischaemia often presents as acute on chronic limb ischaemia. Where they have a history of intermittent claudication and risk factors who suddenly develop features of acute limb ischaemia.

Guidelines

RCEM states ‘choice of imaging is likely to depend on the local resources available’
The ESVS (European Society of Vascular Surgeon) 2020 Guidelines made the following recommendations:
1st line: CTA (computed tomography angiography)
2nd line:
  • Duplex US
  • Contrast-enhanced MRA

All patients:
  • Oxygen and IV fluids
  • Analgesics 
  • IV unfractionated heparin
Refer to vascular surgery.

Definitive management depends on Rutherford’s Classifications. The following table is summarises selected points from the ESVS guidelines.
Rutherford Class Features Definitive Management  
I (viable) No sensory loss
No motor deficit
Audible Doppler		 IV unfractionated heparin
 
IIa (marginal threatened) Mild sensory loss
No moto deficit
Audible arterial Doppler		 Urgent revascularisation (1st line: endovascular)
IIb (immediately threatened) Sensory loss
Mild motor deficit
Inaudible arterial Doppler		 Urgent revascularisation (open or endovascular)
III (irreversible) Sensory loss
Paralysis
Inaudible Doppler		 Amputation

If there are any features of a threatened limb (i.e. sensory loss / motor deficit / inaudible Doppler signal) → urgent revascularisation is required.


Open techniques:
  • Thrombo-embolectomy: usually for embolic occlusion
  • Surgical bypass: usually for acute on chronic ischaemia
Endovascular techniques:
  • Percutaneous catheter-directed thrombolysis
  • Percutaneous mechanical thrombectomy
  • Aspiration thrombectomy
  • Balloon angioplasty and stenting

Multiple factors influence the option of revascularisation, including patient-specific factors (time to presentation, severity, anatomy and clot burden, patient comorbidities) and available resources.
For non-specialists, it is more important to be aware of the available options over the specific evidence and recommendations.

References

Author: Olga
Editor:
Reviewer: