Acute limb ischaemia

Acute limb and/or digital ischaemia (ALI, acute limb ischaemia) is a global healthcare problem that is associated with high morbidity and mortality. It is caused by occlusion of a native artery, vascular bypass graft, or angioplasty site/stent due to embolization or thrombosis, or occlusion of digital micro-vessels due to vasospasm or thrombosis. The culprit risk factor for embolic ALI is most often cardiogenic associated with atrial fibrillation. Other risk factors for ALI include smoking, hypertension, raised cholesterol and diabetes. ALI is diagnosed clinically by identifying the classical ‘6 Ps’: Pain, Pallor, Pulselessness, Perishing cold, Paraesthesia, and Powerlessness. Rutherford's classification is used to grade the severity of ALI, and helps the clinician ascertain whether the limb is viable (I), marginally threatened (IIa), immediately threatened (IIb), or non-salvageable (III). Immediate management of ALI involves analgesia, supplemental oxygen, intravenous fluids, intravenous heparin, and arranging for an urgent CT angiogram. Definitive revascularization options include open surgery, endovascular procedures, or a combined ‘hybrid’ surgical and radiological approach. If a limb, or digit, is non-salvageable primary amputation may be indicated. Dependent upon the severity of ischaemia and on patient fitness, the most appropriate management strategy may instead be conservative, including palliation. Whatever the management approach decided upon, the patient (and ideally their family and/or carers) should be appropriately counselled and given a realistic picture of their options, including doing nothing, with their associated risks and benefits.