Peripheral Arterial Aneurysms
Peripheral arterial aneurysms are abnormal dilations of the peripheral arteries caused by weakening of the arterial wall (see also Overview of Aortic Aneurysms).
About 70% of peripheral arterial aneurysms are popliteal aneurysms; 20% are iliofemoral aneurysms. Aneurysms at these locations frequently accompany abdominal aortic aneurysms, and > 50% are bilateral. Rupture is relatively infrequent, but these aneurysms may lead to thromboembolism. They occur in men much more often than women (> 20:1); mean age at presentation is 65. Aneurysms in arm arteries are relatively rare; they may cause limb ischemia, distal embolism, and stroke.
Infectious (mycotic) aneurysms may occur in any artery but are most common in the femoral. They are usually due to salmonellae, staphylococci, or Treponema pallidum (which causes syphilitic aneurysm).
Common causes include atherosclerosis, popliteal artery entrapment, and septic emboli (which cause mycotic aneurysms).
Peripheral arterial aneurysms are usually asymptomatic at the time of detection. Thrombosis or embolism (or rarely, aneurysm rupture) causes extremities to be painful, cold, pale, paresthetic, or pulseless. Infectious aneurysms may cause local pain, fever, malaise, and weight loss.
Diagnosis is by ultrasonography, magnetic resonance angiography, or CT. Popliteal aneurysms may be suspected when physical examination detects an enlarged, pulsatile artery; the diagnosis is confirmed by imaging tests.
Risk of rupture of extremity aneurysms is low (< 5% for popliteal and 1 to 14% for iliofemoral aneurysms). For leg artery aneurysms, surgical repair is therefore often elective. It is indicated when the arteries are twice normal size or when the patient is symptomatic. However, surgical repair is indicated for all arm artery aneurysms because serious complications (eg, thromboembolism) are a greater risk. The affected segment of artery is excised and replaced with a graft. Limb salvage rate after surgical repair is 90 to 98% for asymptomatic patients and 70 to 80% for symptomatic patients.
In certain patients, an endovascular-covered stent graft is another option for repair.