Peripheral Artery Aneurysms

Essentials of Diagnosis

• Widened, prominent pulses

• Acute leg or foot pain and paresthesias with loss of distal pulses

• High association of popliteal aneurysms with abdominal aortic aneurysms

General Considerations

• Peripheral artery aneurysms are silent until critically symptomatic (like aortic aneurysms)

• Presenting manifestations are due to peripheral embolization and thrombosis (unlike aortic aneurysms)

• Popliteal aneurysms

  • Account for 70% of peripheral arterial aneurysms

  • May embolize repetitively over time and occlude distal arteries

  • Ischemia does not occur until a final embolus occludes flow because of the redundant parallel arterial supply to the foot

• Primary femoral artery aneurysms

  • Much less common

  • However, pseudoaneurysms of the femoral artery following arterial punctures for arteriography and cardiac catheterization occur with an incidence ranging from 0.05% to 6%

• Popliteal aneurysms

  • Often undetected by patient and clinician

  • Patient may be aware of a pulsatile mass when the aneurysm is in the groin

• Peripheral aneurysms

  • May produce symptoms by compressing the local vein or nerve (rarely)

  • First symptom may be due to ischemia of acute arterial occlusion

  • Symptoms range from sudden-onset pain and paralysis to short-distance claudication that slowly lessens as collateral circulation develops

  • Symptoms from recurrent embolization to the leg are often transient

  • Sudden ischemia may appear in a toe or part of the foot, followed by slow resolution

  • Onset of recurrent episodes of pain in the foot, particularly if accompanied by cyanosis, suggests embolization and requires investigation of the heart and proximal arterial tree

• Palpation of a pulsatile aneurysm in the contralateral popliteal space may aid in diagnosis of thrombosis of popliteal aneurysms

• Ultrasonography

  • For patients in whom there is a prominent or easily felt pulse (popliteal pulses are usually somewhat difficult to palpate in normal individuals)

  • Abdominal ultrasonography for patients with popliteal aneurysms to determine whether an abdominal aortic aneurysm is also present

  • Duplex color ultrasound is the most efficient to

    • Confirm the diagnosis of peripheral aneurysm

    • Measure its size and configuration

    • Demonstrate mural thrombus

• Magnetic resonance angiography or computed tomographic angiography is required to define the aneurysm and local arterial anatomy for reconstruction

• Arteriography is not recommended because mural thrombus reduces the apparent diameter of the lumen on angiography

• Surgery indications

  • To prevent limb loss from thrombosis or embolization

  • An aneurysm is associated with any peripheral embolization

  • Aneurysm is > 2 cm

  • Mural thrombus is present

  • Acute ischemia caused by acute embolization or thrombus

• Bypass is generally performed

• Endovascular exclusion of the aneurysm can be done but is reserved for high-risk patients

• Intra-arterial thrombolysis may be done in the setting of acute ischemia, if examination (light touch) remains intact, suggesting that immediate surgery is not imperative

• Acute pseudoaneurysms of the femoral artery due to arterial punctures can be successfully treated using ultrasound-guided compression

• Open surgery with prosthetic interposition grafting is preferred for primary aneurysms of the femoral artery

Prognosis

• If left untreated, approximately one-third of patients will require an amputation

• Long-term patency of bypass grafts for femoral and popliteal aneurysms is generally excellent, but depends on the adequacy of the outflow tract

• Late graft occlusion is less common than in similar surgeries for occlusive disease

• Approximately 50% of patients with popliteal aneurysms have an aneurysmal abdominal aorta

When to Refer

• Patient has symptoms of ischemia

• Patient has a peripheral arterial aneurysm measuring 2 cm or has ultrasound evidence of thrombus within the aneurysm