Occlusive Disease: Limb Arteries

Key Features

Essentials of Diagnosis

• Sudden pain in an extremity with absent extremity pulses

• Neurologic dysfunction (eg, numbness, weakness, or complete paralysis)

• Loss of light touch sensation requires revascularization within 3 hours for limb viability

General Considerations

• May be due to an embolus or to thrombosis of a diseased atherosclerotic segment

• Destinations of emboli from the heart

  • Lower extremities (50%)

  • Cerebrovascular circulation (20%)

  • Upper extremities and mesenteric and renal circulation (30%)

• Emboli from arterial sources, such as arterial ulcerations or calcified excrescences, are usually small and go to the distal arterial tree (toes)

• Causes of the thrombus

  • Atrial fibrillation (most common)

  • Valvular disease

  • Thrombus formation on the ventricular surface of a large anterior myocardial infarct

• Patients with primary thrombosis have a history of claudication

• If stenosis developed over time, collateral blood vessels develop and resulting occlusion may only cause a minimal increase in symptoms

Clinical Findings

Symptoms and Signs

• Sudden onset of extremity pain, with loss or reduction in pulses

• Neurologic dysfunction (eg, numbness or paralysis)

• With popliteal occlusion, only the foot may be affected

• With proximal occlusions, the whole leg may be affected

• Signs of severe arterial ischemia

  • Pallor

  • Coolness of the extremity

  • Mottling

Differential Diagnosis

• Deep venous thrombosis

• Cerebrovascular accident

Diagnosis

Laboratory Findings

• Blood work may show myoglobin and a metabolic acidosis

Imaging Studies

• May be helpful in expediting revascularization procedure by

  • Identifying exact areas of occlusion

  • Delineating distal vessel patency

• May show an abrupt cutoff of contrast with embolic occlusion

• Doppler examination of the distal vessels demonstrates little or no flow

• When possible, should be done in the operating room because obtaining angiography, MRA, or CTA may delay revascularization and jeopardize the viability of the extremity

• However, in cases with only modest symptoms and where light touch of the extremity is maintained, imaging may be helpful in planning the revascularization procedure

Diagnostic Procedures

• Doppler examination shows little or no flow in the distal vessels

Treatment

Medications

• Unfractionated heparin

  • Start as soon as the diagnosis is made

  • Dose: 5000–10,000 units intravenously followed by a heparin infusion to maintain the aPTT in therapeutic range (60–85 seconds)

  • Helps prevent propagation of the clot

  • May also help relieve associated spasm of the vessels

Surgery

• General anesthesia is usually indicated

• Local anesthesia may be used in extremely high-risk patients if the exploration is limited to the common femoral artery

• Revascularization

  • Required in all cases ...