Understanding Critical Limb Ischemia

Written by
Michael Cumming, MD, MBA

Critical Limb Ischemia (CLI) is a severe blockage of the arteries which markedly reduces blood flow to feet. It causes skin ulcers, sores, or gangrene. The pain caused by CLI can wake up an individual at night. This is called  "rest pain" and often requires hanging the leg over the bed or getting up to walk.

CLI is a very severe condition of peripheral artery disease (PAD) and needs immediate comprehensive treatment by a vascular specialist. This condition will not improve on its own.


Critical limb ischemia is the advanced stage of peripheral artery disease (PAD), which results from a progressive thickening of an arteries lining (caused by a buildup of plaque). This buildup of plaque, also known as atherosclerosis, narrows or blocks blood flow, reducing circulation of blood to the legs, feet, or hands. The risk factors for critical limb ischemia include:

  • Age (Men over 60 and women after menopause)
  • Smoking
  • Diabetes
  • Overweight or obesity
  • Sedentary lifestyle
  • High cholesterol
  • High blood pressure
  • Family history of vascular disease

Warning Signs

You may have critical limb ischemia if you have any of the following symptoms:

  • Severe pain or numbness in the legs and feet while not moving known as rest pain
  • A noticeable decrease in the temperature of your lower leg or foot compared to the rest of your body
  • Toe or foot sores, infections or ulcers that will not heal or heal very slowly
  • Gangrene
  • Shiny, smooth, dry skin in the legs or feet
  • Thickening of the toenails
  • Absent or diminished pulse in the legs or feet

Treatment & Prevention

Critical limb ischemia is a serious condition that requires immediate treatment to re-establish blood flow to the affected area or areas. Most patients with CLI have multiple arterial blockages. Treatment for CLI can be quite complex and individualized, but the overall goal should always be to reduce the pain and improve blood flow to save the leg. The number one priority is to preserve the limb. Treatments for CLI include the following:


Several medications may be prescribed to prevent further progression of the disease and to reduce the effect of contributing factors such as high blood pressure, high cholesterol and diabetes, and most certainly to reduce the pain. Medications that prevent clotting or fight infections may also be prescribed.

Endovascular Treatments

These treatments are the least invasive and involve inserting a catheter into the artery in the groin to allow access to the diseased portion of the artery. Angioplasty may be done to open blockages by using small balloons introduced with a catheter into an artery. The balloon is inflated and, as it inflates, it stretches and opens the artery for improved blood flow. A metallic device called a “stent” can then be inserted to maintain the expanded the artery, thereby improving blood flow to the limb. Other treatments include laser atherectomy, where small bits of plaque are vaporized by the tip of a laser probe, and directional atherectomy, in which a catheter with a rotating cutting blade is used to physically remove plaque from the artery.

Bypass Surgery

If the arterial blockages are not favorable for endovascular therapy, surgery is often recommended. This involves removing or bypassing the arterial disease with either a vein from the patient or a synthetic graft. In a few cases, the surgeon may cut open the artery and scrape out the plaque keeping the artery usable.


The last recourse would be amputation of a toe, part of the foot, or leg. Amputation occurs in about 25% of all CLI patients.

Since treatment depends on the severity of the disease and many individual parameters, it is essential that someone with ulcers, or pain in the legs or feet when walking or at rest, see a vascular specialist as soon as possible. The earlier a diagnosis can be made, the earlier treatment can be started with less serious consequence.

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