Acute occlusive disease

Question 1

Define acute limb ischaemia?

Answer 1

Acutely developed limb ischaemia.

Differs from critical limb ischaemia which is a chronic process.

Question 2

Describe the aetiology of acute limb ischaemia?

Answer 2

Thrombotic occlusion of a pre-existing stenotic arterial segment.

Embolic occlusion of a pre-existing stenotic arterial segment.

Compartment syndrome: this occurs when perfusion pressure falls below tissue pressure in a closed anatomical space.

Traumatic: Crush injuries, # with arterial damage or iatrogenic most commonly tourniquets to prevent exsanguination.

Question 3

Describe how acute limb ischaemia is classified?

Answer 3

Acute or acute on chronic.

Incomplete occlusion aka limb not imminently threatened.

Complete occlusion limb is imminently threatened.

Irreversible the limb is non viable.

Question 4

Describe the symptoms of acute limb ischaemia?

Answer 4

6 P’s

• Painful
• Pulseless
• Pale
• Perishingly cold
• Paraesthesiae and paralysis: this indicates complete occlusion the limb is imminently threatened.

Question 5

In a patient with a complete occlusion how long before the leg will be non viable?

Answer 5

Clearly variance between patients but general rule is 6 hours.

Question 6

Describe the management of acute limb iscahemia?

Answer 6

If no contraindication give IV heparin as it limits progression of a thrombus and protects any collateral circulation.

Check for compartment syndorme, and perform a fasciotomy if so.

If occlusion is complete straight to theatre if incomplete perform CT angiography.

Embolic occlusion:

• Embolectomy 1st line (via catheter).
• If embolus has lodged in an area in which there is longstanding stenosis may need to perform a by pass. (OR if embolectomy fails)
• Incomplete: Inter-arterial thrombolysis

Thrombotic occlusion:

• Incomplete: Intra-arterial thrombolysis
• Limb threatening: Bypass graft or angioplasty

Irreversible ischaemia:

• Amputation

Post op: IV heparin

Long term: Aspirin +/- Warfarin if indicated (AF?)

Question 7

Describe the prognosis of acute limb ischaemia?

Answer 7

Surgical treatment of acute limb ischaemia has a 30-day mortality rate of 15-25%, mainly because of related complications.

Thrombosis or embolism is not infrequently a pre-terminal event in patients dying from other causes.

Question 8

What are some of the complications of acute limb ischaemia?

Answer 8

Reperfusion injury:

• Neutrophils migrate into the reperfused area causing damage.
• Can cause limb swelling causing compartment syndrome.
• Leakage from damaged cells can cause an acidosis and a hyperkalemia.

Chronic pain syndrome:

• Due to nn damage.

Question 9

Describe the symptoms of acute venous occlusion?

Answer 9

Aka venous gangrene

• Presents with very swollen legs
• Full superficial veins
• May not palpate pulses due to oedema
• Gangrene present

Can be differentiated as should still have normal waveforms and ABPI on doppler.

Question 10

Describe the management of acute venous occlusion?

Answer 10

• Elevation
• Heparinisation
• Thrombolysis
• Treatment of the underlying cause usually a pelvic or abddominal malignancy

Question 11

Describe the management of non iatrogenic arterial trauma?

Answer 11

Resus 1st: replace blood loss and apply pressure to reduce bleeding. *

Angiogram and theatre to bypass or graft the aa.

*note application of a torniquet will often result in amputation therefore should only be done if a patient is at risk of exangiunating.