Acute Limb Ischaemia
RCEM Learning Acute limb Ischaemia
ESVS 2020 Clinical Practice Guidelines on the Management of Acute Limb Ischaemia
2024 ACC/AHA Guideline for the Management of Lower Extremity Peripheral Arterial Disease
Minor changes and restructuring to the ‘Definition’ and ‘Clinical Features’ sections have been made.
Date: 13/11/25
A minor correction has been made. The article previously stated that ‘paraesthesia is often the first clinical feature of acute limb ischaemia’. This has now been corrected to: ‘Pain is typically the first and most common presenting feature of acute limb ischaemia.’ Paraesthesia is the earliest neurological deficit and indicates nerve ischaemia, making it a later and more concerning finding.
Date: 30/11/25
Disclaimer:
- The author would like to clarify that NICE CKS has a page on acute limb ischaemia, but it does not include any specific information on investigation, diagnosis and management. There are no dedicated NICE or UK organisation guidelines on acute limb ischaemia.
- Therefore, RCEM, ESVS and ACC/AHA guidelines were used to write this article.
Background Information
Definition
Acute limb ischaemia refers to a sudden decrease in limb perfusion (onset <2 weeks) that threatens limb viability
Aetiology
Two main causes of acute limb ischaemia: [Ref]
- Thrombosis (from atherosclerotic plaque rupture in underlying PAD) – 80-85%
- Embolism (most common from AF)
Clinical Features
Acute limb ischaemia often presents as acute-on-chronic limb ischaemia. Where patients with a history of PAD (e.g. intermittent claudication / resting leg pain + cardiovascular risk factors) suddenly progress into acute limb ischaemia (e.g. claudication → constant severe pain, or worsening resting pain)
6Ps of acute limb ischaemia: (the development of all 6 Ps in clinical practice is rare) [Ref]
- Pain – the earliest and most common symptom
- Pallor
- Perishingly cold
- Pulselessness
- Late findings (objective neurological deficit → indicate nerve ischaemia)
- Paraesthesia
- Paralysis – latest and poor prognosis (indicates irreversible ischemia)
Embolic vs thrombotic acute limb ischaemia:
- Embolic
- Acute onset
- Normal vascular examination on the unaffected leg
- Distinct demarcation between areas of perfusion and ischaemia
- Thrombotic
- Gradual onset
- Background of PAD (e.g. claudication, resting pain)
- Abnormal vascular examination on the unaffected leg
Assessment and Management
Step 1 – Initial Management
Immediate management in ALL patients with suspected acute limb ischaemia:
- IV unfractionated heparin (most important initial management – to prevent thrombus propagation and distal emboliation)
- Oxygen and IV fluids
- Analgesics (IV opioids often 1st line) (NSAIDs should be avoided)
- Refer all patients to vascular surgery
Immediate anticoagulation with IV heparin should NOT be delayed for diagnostic imaging or extended physical examination (including hand-held Doppler assessment).
Step 2 – Assessment and Definitive Management
Perform ALL the following to work out the Rutherford class
- Clinical examination
- Hand-held Doppler
Definitive management depends on the Rutherford class:
| Rutherford Class | Features | Definitive Management |
|---|---|---|
| I (viable) |
|
|
| IIa (marginally threatened) |
|
|
| IIb (immediately threatened) |
|
|
| III (irreversible) (non-viable limb) |
|
|
Revascularisation Options
Endovascular revascularisation (generally 1st line):
- Catheter-directed thrombolysis
- Mechanical / aspiration thrombectomy
- Balloon angioplasty and stenting
Open (surgical) revascularisation:
- Thrombo-embolectomy – generally 1st line for embolic occlusion
- Surgical bypass – usually for acute on chronic ischaemia
Many factors influence the option of revascularisation, including patient-specific factors (time to presentation, severity, anatomy and clot burden, patient comorbidities) and available resources.
For students, it is more important to be aware of the available options over the specific evidence and recommendations.
References