What Is Critical Limb Ischemia (CLI) vs. Acute Limb Ischemia?

Reviewed on 11/19/2021

Critical limb ischemia is an advanced form of peripheral arterial disease (PAD) affecting blood flow in the extremities, while acute limb ischemia is a sudden and rapid decrease in, or loss of, lower limb blood flow.
Critical limb ischemia is an advanced form of peripheral arterial disease (PAD) affecting blood flow in the extremities, while acute limb ischemia is a sudden and rapid decrease in, or loss of, lower limb blood flow.

Limb ischemia is a severe blockage in the arteries of the lower extremities, which significantly reduces blood flow. 

  • Critical limb ischemia is a chronic condition that is an advanced form of peripheral arterial disease (PAD), a condition that affects blood vessels in the extremities
  • Acute limb ischemia is a sudden and rapid decrease in, or loss of, lower limb blood flow

What Are Symptoms of Critical Limb Ischemia and Acute Limb Ischemia?

Symptoms of critical limb ischemia include:

  • Severe pain in the legs and feet while a person is not moving (called ischemic rest pain)
  • Open sores, skin infections, or ulcers on the feet and legs that will not heal
  • Numbness in the feet
  • Shiny, smooth, dry skin of the legs or feet
  • Thickening of the toenails
  • Diminished or absent pulse in the legs or feet
  • Dry gangrene (dry, black skin) of the legs or feet

Symptoms of acute limb ischemia are often referred to as the “six Ps” and include: 

  • Pain that is located in the extremity and gradually increases in severity, but may eventually decrease due to progressive ischemic sensory loss
  • Pallor: pale or mottled skin 
  • Poikilothermia: cool skin
  • Pulselessness: diminished or absent pulse
  • Paresthesia: numbness and tingling
  • Paralysis

What Causes Critical Limb Ischemia and Acute Limb Ischemia?

Critical limb ischemia is an advanced stage of peripheral arterial disease (PAD), which is caused by the hardening and narrowing of the arteries over time due to the buildup of fatty deposits called plaque (by atherosclerosis).

Risk factors for chronic limb ischemia are the same as those for atherosclerosis, including:

Causes of acute limb ischemia include: 

How Are Critical Limb Ischemia and Acute Limb Ischemia Diagnosed?

Critical limb ischemia and acute limb ischemia are diagnosed with a patient history and physical examination. The blockages associated with limb ischemia are located using one or more of the following methods:

What Is the Treatment for Critical Limb Ischemia and Acute Limb Ischemia?

Immediate treatment is needed for severe critical or acute limb ischemia to re-establish blood flow to the affected area and to preserve the limb.

Treatments for chronic limb ischemia include:

  • Angioplasty
    • A tiny balloon is inserted through a puncture in the groin and is inflated using a saline solution, to open the artery
      • Cutting balloon: The balloon is imbedded with micro-blades that cut the surface of the plaque, reducing the force necessary to dilate the vessel
      • Cold balloon (CryoPlasty): The balloon is inflated using nitrous oxide which freezes the plaque
  • Stents
    • Metal mesh tubes are used to provide scaffolding after an artery has been opened using a balloon angioplasty
      • Balloon-expanded: A balloon is use to expand the stent
      • Self-expanding: Compressed stents expand upon release
  • Laser atherectomy: the tip of a laser probe is used to vaporize small bits of plaque 
  • Directional atherectomy: A catheter with a rotating cutting blade physically removes plaque from the artery, opening the flow channel
  • Surgical treatments
    • Wounds or ulcers may require surgical procedures or other follow-up care
    • Surgical treatment may be recommended if endovascular therapy is not beneficial for the arterial blockages 
    • Often involves bypass around the diseased segment with either a vein from the patient or a synthetic graft

Treatments for acute limb ischemia include: 

  • Intravenous (IV) injection of unfractionated heparin 
  • Surgical treatment 
  • Thromboembolectomy
  • Bypass surgery
  • Endovascular treatment 
  • Catheter-directed thrombolysis (CDT)
  • Percutaneous thrombus aspiration
  • Stent placement
  • Hybrid treatment that combines both therapies

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Reviewed on 11/19/2021
References
Image Source: iStock Images

https://health.ucdavis.edu/vascular/diseases/cli.html

https://www.uptodate.com/contents/clinical-features-and-diagnosis-of-acute-lower-extremity-ischemia#H403210236

https://www.uptodate.com/contents/clinical-features-and-diagnosis-of-acute-lower-extremity-ischemia#H3813423469

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326052/