Acute Limb-Threatening Ischemia

Acute limb-threatening ischemia refers to the sudden occlusion of one or more arteries causing severe pain and placing the affected limb in jeopardy of dying. The cause is often sudden thrombosis (occlusion from blood clot formation) of a bypass graft, intravascular stent, or area of chronic stenosis (narrowing) from progressively worsening atherosclerotic (cholesterol) plaque within the peripheral arteries. Other possible causes are embolization and dissection.

Embolization is when thrombus (blood clot) or plaque from higher up in an artery or the heart breaks loose and lodges itself into an artery further downstream. Dissection is when the inner wall of an artery tears and blood flows between 2 layers of the artery wall in 2 lumens (channels) known as the ‘false’ lumen (newly created channel within the wall of the artery), and the ‘true’ lumen (the proper lumen that has always existed). The ‘false’ lumen can often cause collapse and occlusion of the ‘true’ lumen and thus lack of blood flow to the affected limb.

The arteries in the legs are most commonly affected. The symptoms that can occur include sudden and severe pain, coldness, numbness, loss of motor function, and blue/purple or white discoloration. Complications from acute limb-threatening ischemia include loss of motor and/or neurologic function, gangrene and infection, which can result in loss of toes or limbs.

Diagnosis of acute limb-threatening ischemia requires a thorough history and physical exam by a vascular surgeon, and an emergent computed tomography (CT) scan, magnetic resonance imaging (MRI) study, or arteriogram (injection of contrast dye into the arteries).

Treatment of acute limb-threatening ischemia requires an emergent procedure to restore blood flow to the affected limb. This may include a minimally invasive (endovascular) treatment with thrombolysis (removal of thrombus with medicine through a catheter), thrombectomy (mechanical disruption and removal of thrombus through a catheter), and possibly also balloon angioplasty and/or stenting of the affected artery(s). If the patient or circumstances do not allow for this technique, then it requires open surgical removal of the thrombus or embolus and subsequent endovascular or open surgical treatment of the cause.