Merck Manual

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Peripheral Arterial Aneurysms


Koon K. Teo

, MBBCh, PhD, McMaster University

Reviewed/Revised Jul 2023

Peripheral arterial aneurysms are abnormal dilations of the peripheral arteries caused by weakening of the arterial wall.

About 70% of peripheral arterial aneurysms are popliteal aneurysms; 20% are iliofemoral aneurysms. Aneurysms at these locations frequently accompany abdominal aortic aneurysms Abdominal Aortic Aneurysms (AAA) Abdominal aortic diameter ≥ 3 cm typically constitutes an abdominal aortic aneurysm. The cause is multifactorial, but atherosclerosis is often involved. Most aneurysms grow slowly (~10%/year)... read more Abdominal Aortic Aneurysms (AAA) , and > 50% are bilateral. Rupture is relatively infrequent, but these aneurysms may lead to thromboembolism with acute distal arterial occlusion Acute Peripheral Arterial Occlusion Peripheral arteries may be acutely occluded by a thrombus, an embolus, aortic dissection, or acute compartment syndrome. Acute peripheral arterial occlusion may result from: Rupture and thrombosis... read more Acute Peripheral Arterial Occlusion . Peripheral arterial aneurysms occur in men much more often than in women (> 20:1); mean age at presentation is 65 years. Aneurysms in arteries supplying the arm are relatively rare; they may cause limb ischemia, distal embolism, and, when extending to the aortic arch, stroke Overview of Stroke Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be Ischemic (80%), typically resulting... read more Overview of Stroke .

Infectious (mycotic) aneurysms may occur in any artery but are most common in the femoral artery. They are usually due to salmonellae, staphylococci, or Treponema pallidum, which causes syphilitic 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, and/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 but increases with increasing diameter above 2 cm. 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 stent graft is another option for repair.

Key Points

  • Peripheral arterial aneurysms occur mainly in men; the most common location is the popliteal artery.

  • Complications are rare and include rupture and thromboembolism.

  • Treat lower extremity aneurysms if patients are symptomatic or if the artery is twice normal size; all upper extremity aneurysms should be treated because of the higher risk of serious complications (eg, stroke when the aneurysm extends to the aortic arch).

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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