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 — 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.
Diagnosis & workup
Diagnostics & workup: - Clinical diagnosis: 6 P's of acute limb ischemia — Pain, Pallor, Pulselessness, Paresthesia, Paralysis, Poikilothermia (cold) - Rutherford classification: I (viable, no sensory/motor loss), IIa (marginally threatened, salvageable with prompt treatment), IIb (immediately threatened, sensory loss + motor deficit), III (irreversible, anesthetic + paralyzed) - CT angiography: localize embolic occlusion, plan intervention, identify multilevel disease - Duplex ultrasound: if CTA unavailable, assess flow and localize occlusion - Echocardiography (TTE ± TEE): identify cardiac source — LA thrombus, LV thrombus, valvular vegetation, myxoma, PFO with right-to-left shunt - ECG and telemetry for AF detection - Labs: lactate (tissue ischemia), CK/myoglobin (muscle necrosis), potassium (hyperkalemia from reperfusion), creatinine, coagulation studies - Hypercoagulability workup if no clear cardiac source: antiphospholipid antibodies, lupus anticoagulant