Acute Limb Ischaemia
Sudden occlusion of a previously patent limb artery by embolus or in-situ thrombosis, cutting off perfusion so abruptly that irreversible muscle and nerve damage begins within hours, a surgical emergency defined by the six Ps.
First principles
Acute ischaemia is a sudden loss of the collateral safety net
In chronic peripheral arterial disease, atherosclerosis narrows an artery slowly, giving the circulation time to grow collateral vessels that partly compensate. In acute limb ischaemia (an embolus lodging at an arterial bifurcation, or thrombosis occluding an already-diseased segment, stent or bypass graft), there is no time for collaterals to develop, so distal perfusion falls abruptly and profoundly. The same degree of arterial occlusion is therefore far more dangerous acutely than it would be if it had developed gradually.
Educational content pending clinical review. Not medical advice.