What Is Critical Limb Ischemia?

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Critical limb ischemia (CLI) is a condition involving significantly reduced blood flow to the lower extremities. It affects 12% of the U.S. population. The cause of CLI is a severe blockage of the arteries from a condition called peripheral artery disease (PAD). In fact, CLI is considered the most severe form of PAD.

critical limb ischemia

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Critical Limb Ischemia Symptoms

The cardinal signs of CLI include severe pain in the feet and toes (even when at rest) as well as necrosis (death) of tissue. Other signs and symptoms may include:

  • Poor circulation in the lower extremities
  • Ulcers and wounds in the legs and feet that do not heal
  • Pain or numbness in the feet
  • Thickening of the toenails
  • Shiny, smooth, dry skin of the feet and legs
  • Diminished or absent pulses on the legs or feet
  • Gangrenous tissue of the feet or legs


Critical limb ischemia is considered the final stage of PAD, a chronic, progressive, thickening of the artery wall resulting from the build-up of plaque. The plaque occludes normal blood flow, resulting in a lack of proper oxygen in the tissues—also referred to as ischemia. PAD can reduce blood flow in the hands, legs, or feet. But CLI usually involves the legs and feet. 

Risk Factors

The risk factors that may cause a person to be more prone to getting CLI are the same as those for PAD, these include:

  • Smoking
  • Age
  • Diabetes
  • Obesity (or being overweight)
  • Sedentary lifestyle
  • High cholesterol levels
  • Hypertension (high blood pressure)
  • A family history of atherosclerosis


Diagnosis of CLI may involve one or more tests/assessments, including:

  • Audible presence of a bruit: This is a whooshing sound that's placed over the affected arteries in the legs, and a doctor will listen with a stethoscope.
  • Ankle-brachial index (ABI): The use of several blood pressure cuffs are positioned on the legs and arms at different levels. The blood pressure is then evaluated at each level to help assess blood flow in a specific area; this helps the diagnostician find the general area of an arterial blockage.
  • Doppler ultrasound: A type of ultrasound that creates a picture called a sonography to measure how strong the blood flow is through the vessels.
  • CT angiography: An advanced imaging technique that uses a contrast dye to view arteries and veins throughout the body. Three-dimensional images of the blood vessels are then created.
  • Magnetic resonance angiography (MR angiography): A type of MRI that is specifically focused on the blood vessels (including arteries). An MR angiogram is much less invasive—and less painful—than a traditional angiography, which requires the insertion of a catheter.
  • Angiogram: X-rays of the blood vessel—including the arteries—involving the insertion of a catheter that is threaded into the vessels to the area being studied. The use of contrast dyes helps the vessels show up better on the X-ray image.


Treatment for critical limb ischemia is aimed at restoring blood flow to the affected area. Treatment may include several different types of interventions, including:

Endovascular Procedures

There are several types of endovascular procedures to help improve blood flow to the artery.

What Is Endovascular Surgery?

Minimally invasive surgery involving the insertion of a catheter into the artery to access the diseased part of the blood vessel.

The type of procedure used depends on several factors, such as the severity and location of the blockage, as well as other factors. Some common types of endovascular surgery include:

  • Angioplasty: A very small balloon is inserted into the artery through a catheter. It is then inflated using saline solution, which sometimes helps to open the artery.
  • Stents: Metal mesh tubes are positioned in place where the artery is blocked. The stents serve as a support for the walls of the artery, keeping it open so that blood can flow through the blood vessel.
  • Atherectomy: A procedure aimed at removing the plaque from an artery, opening the blood vessel, and allowing for blood flow to resume. This is done by using a catheter with a rotating cutting blade. This procedure is an alternative to angioplasty.

Surgical Treatment

When endovascular surgery is not an option, due to arterial blockages not being favorable—such as those in an inaccessible location—surgical treatment may be performed.

Treatment of wounds and ulcers (to remove dead or infected tissue) may be needed.

Bypass surgery is usually the preferred type of open surgery for those who have had a failed endovascular procedure, or when endovascular procedures are not an option.


CIL is associated with a very high risk for cardiovascular events such as:

  • Heart attack
  • High mortality rate

A 2018 study revealed that within the first year of being diagnosed with CLI, 29% of the patients will either have a major amputation performed or they not survive.

The survival rate after multiple procedures (to establish revascularization) is on average only 3.5 years.

Studies show that intensive follow-up for those with atherosclerosis may lend itself to extending one's life expectancy.


There is a very high rate of depression and other psychological issues experienced by people with critical limb ischemia; there are many reasons for this, including:

  • The condition often interferes with a person’s ability to be active.
  • The condition may force a person to depend on others to meet their daily needs.
  • Most people with CLI cannot work.
  • CLI is a long-term condition, involving intensive medical treatment, surgery, long-term rehab, and multiple visits to outpatient medical facilities.

If you have critical limb ischemia, it’s important to empower yourself by getting educated. The more you get involved with your own treatment choices, the more empowered you will feel. Self-empowerment can help you cope with feelings of helplessness.

Some experts in the field recommend always getting a second or third opinion before having an amputation.

It’s also vital to reach out for help when you need it. Ask for support from friends and family members when possible. Getting involved in a support group for people with PAD and CIL can be a very effective tool in dealing with some of the depression and isolation that often comes along with the disease.

Ask for Help

If you are experiencing severe symptoms of depression, be sure to talk to your primary health care provider about getting a mental health consultation. 

A Word From Verywell

If you have been diagnosed with CIL, it's important to note that intensive long-term follow-up is an absolute necessity after treatment. Follow-up care includes rehabilitation to help you return to your maximal level of physical activity and independence. 

Although the statistics may look grim when it comes to the outcome of CLI, there is hope. Those who follow a strict regime of follow-up care—according to their doctors' instructions—are able to beat some of the odds, improving their prognosis and even extending their life expectancy after treatment. 

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  1. Davies MG. Critical limb ischemia: epidemiologyMethodist DeBakey Cardiovascular Journal. 2012;8(4):10-14. doi:10.14797%2Fmdcj-8-4-10

  2. UC Davis Health. Critical limb ischemia (CLI).

  3. University of Southern California Department of Surgery. Critical limb ischemia.

  4. Johns Hopkins Medicine. Magnetic resonance angiography (MRA).

  5. Teraa M, Conte MS, Moll FL, Verhaar MC. Critical limb ischemia: current trends and future directions. JAHA. 2016;5(2). doi:10.1161/JAHA.115.002938 

  6. Mustapha JA, Katzen BT, Neville RF, et al. Determinants of long‐term outcomes and costs in the management of critical limb ischemia: a population‐based cohort study. J Am Heart Assoc. 2018;7(16). doi:10.1161/JAHA.118.009724

  7. University Hospitals. A life-saving option for those facing limb amputation for PAD. Updated October 2, 2019.