To develop an acutely ischemic limb, either thrombosis in situ or embolic obstruction must occur.
+You must start anticoagulant therapy in all patients who present with acute limb ischemia.
+90% of emboli causing acute lower extremity ischemia arise in the abdominal aorta.
+The most common site of an embolus of an upper extremity is the distal radial artery.
+The diagnosis of arterio-arterial emboli may be confused with a vasculitis.
Low cardiac output may result in acute extremity ischemia without initial thrombosis or embolus. The duration of symptoms is an important prognostic determinant. Limb salvage is poor if ischemic sensory-motor deficits have been present for more than 3 hours. Antithrombotic therapy is not indicated for the nonsalvageable or gangrenous limb. Up to 90% of peripheral emboli arise in the heart. The most common upper extremity vessel involved is the brachial artery. Aneurysms of the aorta or major vessels may dislodge arterio-arterial microemboli, resulting in muscle tenderness from infarcts, skin lesions, and gangrenous toes. Endocarditis and systemic vasculitis have a different distribution of lesions and physical signs.