Key points

• Acute limb ischaemia (ALI) is associated with significant mortality and morbidity

• Clinical assessment is paramount for planning management

• All cases of ALI should be assessed by a vascular specialist

• All cases should be started on intravenous heparin as soon as possible to prevention extension of thrombus

• Surgery is preferred with severe ALI as time is of the essence

• Thrombolysis is associated with a lower mortality rate but higher failure rates

• Surgery is more durable but is associated with a higher mortality rate

• If compartment syndrome likely or suspected a fasciotomy is required

Definition

Acute limb ischaemia (ALI) can be defined as a sudden compromise of the blood supply to a limb, threatening its viability. Symptoms are usually of less than 2 weeks in duration. The lower limbs are more commonly affected than the upper limbs.

Background

Patients with ALI present depending on the severity of their symptoms. In patients with acute arterial occlusions and no collaterals symptom onset is immediate and severe. This scenario is seen in patients with embolic occlusions, trauma, thrombosed aneurysms and occluded grafts. If the acute event occurs with a background of an artery or a graft narrowing/occluding over a period of time then usually there are developed collaterals. In these patients the symptoms are often not as severe.

After 3–6 hours of severe ischaemia muscle and nerve undergo irreversible changes. Ischaemia of the limb for greater than 6 hours usually results in functional impairment or limb loss.