A 68-year-old woman presents with acute limb ischemia. On examination, the right leg is cold, white, and paralyzed with absent sensation. Onset is estimated at 4 hours. Doppler confirms absence of pedal signals. Embolectomy is performed. Intraoperatively, the clot shows a 'cast' of the femoral bifurcation with a characteristic pale appearance. What underlying cardiac condition most commonly causes this presentation?
- A Mitral valve prolapse
- B Atrial fibrillation with left atrial thrombus ✓
- C Aortic stenosis
- D Hypertrophic obstructive cardiomyopathy
Explanation
Acute embolic limb ischemia is most commonly caused by cardiac embolism, with atrial fibrillation (AF) accounting for 60–70% of cases. AF causes stasis in the left atrial appendage, promoting thrombus formation; embolization produces pale, firm, well-demarcated emboli that 'cast' the arterial bifurcation (commonly femoral or popliteal). The sudden onset, absence of prior claudication, and bilateral absence of AF-specific arterial disease distinguish embolism from in-situ thrombosis. Mitral valve prolapse and aortic stenosis can occasionally cause embolism but are far less common causes. HOCM does not typically cause arterial embolism.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.