Limb ischaemia can be divided into an acute and a chronic form. The diagnosis of acute ischaemia must be made promptly, and immediate revascularisation is necessary in most cases. Chronic critical limb ischaemia is the most severe form of peripheral arterial occlusive disease (PAOD). It is characterised by rest pain, or necrosis or gangrene.
Acute limb ischaemia ("acute limb ischemia", ALI) represents an acutely occurring hypoperfusion of the limb that is no more than 2 weeks old. It is usually caused by embolisation or local thrombosis on the basis of a pre-existing pathology such as PAOD.
Chronic limb ischaemia ("chronical limb ischemia", CLI) refers to rest pain or ischaemic skin lesions such as ulcers or gangrene (Fontaine stages III and IV or Rutherford categories 4–6). It is strongly associated with cerebrovascular and cardiovascular events. Chronicity is defined as symptoms persisting for more than 2 weeks.
TASC II criteria
The consensus document TASC II (Transatlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease) addresses aspects of revascularisation in PAOD [1]. According to the TASC criteria, therapeutic treatment options can be derived depending on the length of the local occlusion/stenosis. The length of the stenosis and its anatomical location determine the treatment: endovascular or open vascular surgery.