Diagnosis

Acute extremity ischemia

Etiology

Cause [iom][ghw][nvp]

• Embolization (30%) from proximal artery or heart with atrial fibrillation, myocardial infarction, valvular disease, septic embolization

• Trauma (5%): knee dislocation, long-bone fracture, penetrating trauma, iatrogenic (catheter)

• Thrombosis: Atherosclerosis (40%), stenosis, aneurysm (5%), postoperative bypass graft thrombosis (20%)

• Upper extremity: vasospasm, arteritis, subclavian steal syndrome, septic embolization

Pathophysiology

1. Sudden Arterial Occlusion

2. Impaired Blood Flow

3. Metabolic Imbalance: anaerobic metabolism --> lactic acid --> metabolic waste -->

4. Inflammatory response --> Tissue damage

5. Eventual necrosis (gangrene)

6. Reperfusion injury: swelling, severe pain and hyperesthesia [ghw]

Risk factors [vic]

• Age

• Smoking

• Diabetes

• Obesity

• Sedentary lifestyle

• Family history of vascular disease

• High cholesterol

• High blood pressure

Epidemiology

Incidence per 100.000 [zfb][esh][iom][nb9][nvp][vic]

Approach

• Clinical diagnosis: [ghw]

  • the “6 Ps”: pain, pallor, paralysis, pulse deficit, paresthesia and poikilothermia

  • Rutherford classification for acute limb ischemia: [kig]

    1. I. Viable:

       Sensory Loss: No. Weakness: No. Arterial signal: Yes. Venous signal: Yes.

    2. IIa. Marginally Threatened - Salvageable if promptly treated

       Sensory Loss: Minimal. Weakness: No. Arterial signal: No. Venous signal: Yes.

    3. IIb. Immediately Threatened - Salvageable with immediate revascularization

       Sensory Loss: Some. Weakness: Some. Arterial signal: No. Venous signal: Yes.

    4. III. Irreversible - Major tissue loss or permanent nerve damage

       Sensory Loss: Yes. Weakness: Yes. Arterial signal: No. Venous signal: No.

• Blood test

• Blood gas

• Ankle-brachial index

• CT angiography

• MR angiography

Treatment

The therapeutic strategy will depend on: type of occlusion (thrombus or embolus), location, type of conduit (artery of graft), Rutherford class, duration of ischemia, comorbidities and therapy-related risks and outcomes [ghw]

1. Endovascular techniques: [ghw][nvp]

   • Percutaneous catheter-directed thrombolysis

   • Percutaneous thromboaspiration with or without thrombolytic therapy

   • Percutaneous mechanical thrombectomy

2. Open surgery:

   • Thromboembolectomy with a balloon catheter (Fogarty) [iom]

   • Bypass surgery

   • Endarterectomy and patch angioplasty

   • Amputation

3. Postprocedural pharmacotherapy: [ghw]

   • Vasodilators if there is evidence of vasospasm

   • Cardiac thromboembolism --> Anticoagulation: warfarin, dabigatran, apixaban, rivaroxaban

   • Atherosclerotic thrombosis or after stent --> statin and anti-platelet therapy (aspirin and clopidogrel)

Differential diagnoses

Aortic dissection, Cellulitis, Compartment syndrome, Deep venous thrombosis, Erysipelas, Gout, Necrotizing fasciitis, Shock, Spinal disc herniation, Spinal stenosis, Thromboangiitis obliterans, Trauma