Arterial Occlusion, Acute

• • Sudden occlusion of previously patent artery supplying an extremity

  • Abrupt onset of ischemia: pain, coldness, numbness, motor weakness, absent pulses

  • Tissue viability determined by collaterals and surgical intervention

  • Line of demarcation occurs between viable and nonviable tissue

  • Caused by embolus, thrombosis, trauma, or dissection

Embolus

• • Heart source of embolus in 85%; higher risk in patients with atrial fibrillation, LV thrombus, mechanical valves; septic emboli from infective endocarditis

  • Aneurysms in aortofemoral or popliteal arteries can be the source of emboli

  • Cardiac tumors and paradoxic emboli (through patent foramen ovale) rarely source

  • Source is unknown in 5-10% of cases (cryptogenic)

Thrombosis

• • Sudden thrombosis in hypercoagulable states, patients with malignancy, or atherosclerotic vessel

  • May be difficult to distinguish thrombotic from embolic event

Trauma

• • Arterial damage by bone fracture or dislocation, penetrating injury, complication of catheterization or percutaneous transluminal angioplasty (PTA)

Dissection

• • Most common in thoracic aorta and propogates distally

  • May cause limb ischemia with iliofemoral involvement

Symptoms and Signs

• • 5 Ps: pain, pallor, pulselessness, paresthesias, paralysis

  • Sudden pain present in 80% indicates time of occlusion, may be absent with prompt onset of paresthesia/paralysis

  • Pallor followed by mottled cyanosis

  • Hyperesthesia followed by anesthesia; light touch lost, pressure, pain, and temperature often more preserved

  • Motor paralysis: impending gangrene

  • Symptoms > 12 h, unlikely salvageable

  • Tense swelling and acute tenderness of gastrocnemius denotes irreversible infarction

  • 4-6 hrs nerves and muscles ischemic; skin more resistant to ischemia

  • Level of demarcation varies with site of occlusion

  • Collateral flow may result in return of warmth and color of skin, lessening of sensory deficit with symptoms of chronic occlusion of artery

• • Consider both thrombosis and embolic events

  • Must evaluate for secondary tissue loss or compartment syndrome

• • Immediate administration of heparin

  • Arteriography may help differentiate thrombosis from embolus

Embolisms/Thrombosis

• • Immediate administration of heparin

  • Arteriography can help if no delay in treatment

Traumatic

• • Repair arterial injury in addition to other injuries

Surgery

Indications

• • Advanced, reversible ischemia

  • Fasciotomy often required with long ischemia time

  • Thrombolysis, surgical embolectomy (least delay in reestablishing flow)

  • Arterial reconstruction in thrombotic event with atherosclerosis (alternative to thrombolytic therapy)

Contraindications

• • Irreversible ischemia

Medications

• • Heparin

  • Thrombolytics

Complications

• • With reperfusion: Myoglobinuria, renal failure, hyperkalemia

Prognosis

• • Good if reestablish blood flow within 6 hours