• Effects of sudden arterial occlusion depends on state of collateral supply
• Collateral supply in leg usually inadequate unless pre-existing occlusive disease

Aetiology of acute limb ischaemia

• Embolism
  • Left atrium in patients in atrial fibrillation
  • Mural thrombus after myocardial infarct
  • Prosthetic and diseases heart valves
  • Aneurysm or atheromatous stenosis
  • Tumour, foreign body, paradoxical

• Thrombosis
• Other
• Trauma
• Dissecting aneurysm
• Raynaud's Syndrome

Clinical features of limb ischaemia

• Clinical diagnosis depends on the 6 'p' s
  • Pain
  • Paraesthesia
  • Pallor
  • Pulselessness
  • Paralysis
  • Perishing with cold
• Fixed staining is a late sign
• Objective sensory loss requires urgent treatment
• Need to differentiate embolism from thrombosis
• Important clinical features include
  • Rapidity of onset of symptoms
  • Features of pre-existing chronic arterial disease
  • Potential source of embolus
  • State of pedal pulses in contralateral leg

Management of acute ischaemia

Initial

• Heparinise & analgesia
• Treat associated cardiac disease
• Treatment options are:
  • Embolic disease - embolectomy or intra-arterial thrombolysis
  • Thrombotic disease - intra-arterial thrombolysis / angioplasty or bypass surgery

Emergency embolectomy

• Can be performed under either general or local anaesthesia
• Display and control arteries with slings
• Transverse artereotomy performed over common femoral artery
• Fogarty balloon embolectomy catheters used to retrieve thrombus
• If embolectomy fails - on-table angiogram and consider
• Bypass graft or intraoperative thrombolysis

Picture provided by John Byrne, Albany Medical Centre, New York, USA

Intra-arterial thrombolysis

• Arteriogram and catheter advanced into thrombus
• Streptokinase 5000u/hr + heparin 250u/hr
• Alternative thrombolytic agents include urokinase or tissue plasminogen activator (tPA)
• Repeat arteriogram at 6 -12 hours
• Advance catheter and continue thrombolysis for 48 hours or until clot lysis

• Angioplasty of chronic arterial stenosis may be necessary

• Success 60-70% but needs careful case selection
• Not suitable if severe neuro-sensory deficit
• Thrombolysis can be accelerated by:
  • Pulse spray through multiple side hole catheter
  • Aspiration thrombectomy - debulking thrombus aspiration
  • High dose over shorter time
• Complications
• Mortality of 1-2%
• Bleeding - CVA, retroperitoneal

Bibliography

Beard J D  Gaines P A.  Management of the acutely ischaemic leg.  Curr Pract Surg 1995;  7:  123-130.

Beattie D K  Davies A H.  Management of the acutely ischaemic limb.  Br J Hosp Med 1996;  55:  204-208.

Earnshaw J J.  Thrombolysis in acute limb ischaemia.  Ann R Coll Surg Eng 1994;  76:  216-222.

Engledow A H.  Crinnion J N.  Acute lower limb ischaemia.  Hosp Med 2002;  63:  412-415

Golledge J  Galland R B.  Lower limb intra-arterial thrombolysis.  Postgrad Med J 1995;  71:  146-150.

Last updated: 05 January 2008

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