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Critical Limb Ischemia

CLI is the most severe form of peripheral artery disease, usually in the foot or leg, that can lead to severe pain, skin ulcers, gangrene, and even amputation.


What is critical limb ischemia?

Peripheral artery disease involves the build-up of plaque in the arteries of the trunk, arms, or legs. This plaque can eventually slow the flow of blood and thus oxygen to the affected part, causing pain, weakness, or other complications and leading to more serious conditions. Approximately 10% of patients with peripheral artery disease develop critical limb ischemia.

Critical Limb Ischemia is the most severe form of peripheral artery disease, usually occurring in the feet or leg.

It is a difficult condition to treat, because it is often made worse by other conditions—such as diabetes or heart failure—which contribute to the reduced flow of blood to the feet and legs.


What are the symptoms of critical limb ischemia?

Typical symptoms include:

  • severe pain in the toes, feet, or legs—even when resting
  • shiny, smooth skin on the feet or legs
  • thickening toenails
  • open sores, skin infections, or ulcers that do not heal
  • gangrene, usually in the toes
  • diminished pulse in the feet or legs

Critical limb ischemia can have a major impact on patient quality of life. Clinicians and researchers are thus looking for better, less invasive treatment options to improve function, reduce pain, and avoid amputations.


How is it diagnosed?

Various tests may be used to diagnose CLI, such as:

  • Tests to check the pulse and blood flow in the affected limbs – including an Ankle-Brachial Index (ABI), which compares blood pressure in the arms with that in the legs to see how well blood is flowing; a TBI or Toe Brachial Index measures the blood pressure in the toes
  • Imaging – such as magnetic resonance imaging (MRI) and computed tomography (CT scan) to look for blockages in the arteries of the legs and feet
  • Blood tests – to check for diabetes and high cholesterol

What causes critical limb ischemia?

CLI and peripheral artery disease are caused by a build-up of plaque in the arteries. This plaque consists of fat, cholesterol, calcium, and fibrous substances in the blood.

Blockages in the arteries appears to stem from damage to the walls of the arteries in the heart, which may be due to a combination of:

  • High blood pressure
  • High LDL (“bad”) cholesterol
  • Low HDL (“good”) cholesterol
  • Smoking
  • Diabetes or insulin resistance
  • Obesity
  • Sedentary lifestyle
  • Inflammation

CLI usually develops gradually over time in patients with a combination of conditions, especially diabetes and heart failure, that reduce blood flow to the feet and legs.

How is CLI treated?

Treatment usually aims to reduce pain, allow skin to heal, and improve limb function—which may include a combination of:

  • Medication – to reduce blood cholesterol or high blood pressure, prevent blood clots, or treat pain.
  • Angioplasty and stent placement – inserting a catheter into the blocked artery and inflating a balloon to press the plaque against the artery wall to improve blood flow; a stent (wire mesh tube) may be place to keep the artery open
  • Atherectomy – inserting a catheter into the blocked artery and using a special device, such as Cardio Flow’s FreedomFlow® device, to remove the blockage; it may be used prior to angioplasty and stenting if the plaque is especially hard to compress
  • Bypass surgery – using a blood vessel from another part of the body to re-route or bypass the blockage
  • Amputation – if blood flow cannot be restored, amputation may be necessary

How many people are affected by CLI?

Peripheral artery disease is common in the United States, affecting some 8-10 million Americans, but only 10% of those will develop critical limb ischemia. Because CLI patients are often hospitalized—often for bypass surgery or amputation—the condition has a serious impact on their quality of life and is costly for healthcare systems as well.

Joseph Karam and Elliot J. Stephenson, “Critical Limb Ischemia: Diagnosis and Current Management,” Journal of the Minneapolis Heart Institute Foundation, Fall/Winter 2017, accessed online 1202.20.
Luigi Uccioli, et. al., “Critical Limb Ischemia: Current Challenges and Future Prospects,” Vascular Health Risk Magazine, April 2018, 14: 63-74, accessed online 12.02.20
Scott Kinlay, “Management of Critical Limb Ischemia,” Circulation: Cardiovascular Interventions, February 2016, 9(2), accessed online 01.12.21.

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