Aneurysms, Peripheral

• • True aneurysms: Involves all 3 layers of vessel wall

  • False aneurysm (pseudoaneurysm): Disruption of artery causing contained hematoma confined by fibrous capsule

Lower Extremity

• • 70% of peripheral aneurysms are of popliteal artery; femoral artery next most common site

  • Persistence of sciatic artery

  • -Rare anomaly

    -Large embryonic sciatic artery (originates from internal iliac artery) communicates directly with popliteal artery;

    -Propensity for aneurismal degeneration

Upper Extremity

• • Subclavian artery aneurysms: Rare

  • -Several causes: Pseudoaneurysms from drug addict injections increasing, poststenotic dilation from patient with cervical rib or thoracic outlet syndrome, congenital variant with aberrant artery arising from proximal descending thoracic aorta (Kommerell's diverticulum)

  • Radial artery pseudoaneurysms: Increased as a result of increased radial artery catheters, occasionally infected

Epidemiology

• • 0.5-6% incidence of pseudoaneurysm of femoral artery after puncture

  • Popliteal aneurysms bilateral in 50%

  • 33% of patients with popliteal aneurysm have AAA

Symptoms and Signs

• • Usually minimal until progressive thrombosis, stenosis occurs

  • Femoral: Throbbing mass in groin often present

  • Popliteal: Usually asymptomatic

  • -First symptom often acute ischemia

    -Thrombosis, peripheral embolization cause acute ischemia

    -Occlusion may occur from fragmentation of mural thrombus

    -Thrombus may occlude lumen of aneurysm or embolize

    -Can progress rapidly to gangrene

    -Recurrent embolization presents with sudden ischemia of toe or foot with gradual resolution

    -Popliteal aneurysms rarely cause symptoms from compression of vein or tibial nerve

    -Palpation suggests diagnosis

  • Persistent sciatic artery aneurysms: Painful, pulsatile buttock mass

  • Subclavian: Emboli to fingers, dysphagia lusoria (difficulty swallowing)

Imaging Findings

• • US confirms size, diagnosis, flow

  • Arteriography advised before operation

• • Evaluate for multiple sites of aneurysm

  • Evaluate for distal ischemia or embolus

• • US confirms diagnosis

  • Arteriography may not demonstrate aneurysm but is advised before operative repair to define distal arteries

• • Immediate operation or thrombolytic therapy indicated when pregangrenous

  • Femoral pseudoaneurysm treated with US-guided compression

Surgery

• • Femoral artery: Replace diseased segment

  • Popliteal artery: Exclude and bypass with saphenous vein

  • Sciatic nerve: Exclude aneurysm and bypass with saphenous vein

  • Subclavian: Resect first rib or cervical rib, divide scalenus anterior, replace aneurysm with graft

  • Radial pseudoaneurysm

  • -Normal Allen test, excise and ligate

    -Abnormal Allen test, reconstruct artery

Indications

• • Pregangreneous ischemia

  • Recurrent peripheral embolization

  • Symptomatic aneurysm

  • Asymptomatic aneurysm 3 × normal diameter

Medications

• • Thrombolytics for occluded popliteal aneurysms should be considered

Prognosis

• • Depends on outflow tract

  • Late graft failures less common than operations done for peripheral vascular occlusive disease

References