Most emboli result from a detached piece of thrombus, often originating from left ventricular thrombus after myocardial infarction or from atrial fibrillation. Other sources include atheroemboli from ruptured plaque, tumor, or foreign bodies such as venous or arterial catheters.
Acute arterial embolization usually occurs at branch points, due to the abrupt change in diameter, and results in distal tissue infarction. The most frequent site is the bifurcation of the common femoral artery (35%-50%). Patients generally present with some or all the “six Ps”: pain, pallor, pulselessness, paresthesias, poikilothermia, and paralysis. Predictors of ischemic insult degree include collateral circulation amount, vessel size, and embolus size. Patients with longstanding peripheral vascular disease often have a greater amount of collateral circulation and can tolerate an acute occlusion better than a patient with normal arteries.
Management and Disposition
Acute arterial embolus is a surgical emergency. Immediate initiation of IV heparin is indicated to prevent further clot propagation. Prompt consultation with a vascular surgeon is imperative, as the rate of limb salvage drastically decreases after 4 to 6 hours. In clear-cut cases, treatment is generally Fogarty catheter embolectomy without prior angiography. Preoperative angiography only prolongs ischemic time and decreases salvage. If it is difficult to distinguish between acute embolic occlusion and in situ thrombosis, preoperative angiography may be considered. Emergent surgical intervention may aggravate thrombosis for in situ thrombus formation.
Acute arterial embolus generally presents with sudden onset of severe pain. In contrast, in situ thrombosis tends to be more subacute.
Aortic dissection may mimic acute arterial embolus. Involvement of multiple sites suggests dissection.
Arterial Embolus. Note right foot pallor, consistent with an acute arterial embolus, in this case secondary to femoral artery occlusion. (Photo contributor: Lawrence B. Stack, MD.)
Arterial Embolus. Pallor in the right hand secondary to arterial embolus, likely from atrial fibrillation. (Photo contributor: Lawrence B. Stack, MD.)
Blue Toe Syndrome. Atherothrombotic microembolism, causing transient focal ischemia, occasionally with minor apparent tissue loss, but without diffuse forefoot ischemia. (Photo contributor: R. Jason Thurman, MD.)