Pathophysiology
Clinical meaning
Peripheral arterial embolism occurs when thrombus or other material from a proximal source lodges in a distal artery, causing acute limb ischemia. The most common source is cardiac (80-90%): left atrial thrombus in AF, LV mural thrombus post-MI, valvular vegetations (endocarditis), prosthetic valve thrombus, or cardiac tumors (atrial myxoma). Non-cardiac sources include aortic atherosclerotic plaque, aortic aneurysm mural thrombus, paradoxical embolism through PFO, and iatrogenic (catheter-related). The embolus typically lodges at arterial bifurcations where vessel diameter suddenly decreases โ most commonly the femoral bifurcation (35%), followed by iliac (18%), aortic bifurcation ('saddle embolus', 14%), and popliteal (11%). Ischemia duration determines tissue viability: skeletal muscle tolerates ~6 hours of warm ischemia before irreversible damage. Reperfusion injury after prolonged ischemia can cause compartment syndrome, myoglobinuria, hyperkalemia, and metabolic acidosis.