Secondary disorders of arteries or arterioles

**Definition:** Embolic occlusion of distal small arteries and arterioles by cholesterol crystals released from atherosclerotic plaque in larger more central arteries. The resultant microvascular ischaemia is accompanied by an inflammatory response to the presence of cholesterol crystals. This may occur spontaneously or as a complication of angiography or vascular surgery. Organs most commonly affected include the skin, kidneys, gastrointestinal tract, and brain. Cutaneous manifestations, present in the majority of cases, include livedo reticularis and focal ischaemic necrosis and ulceration; these are commonly associated with acute kidney injury.