Critical limb ischemia (CLI)

Critical limb ischemia (CLI) is a severe blockage in the arteries of the lower extremities, which markedly reduces blood-flow. It is a serious form of peripheral arterial disease, or PAD, but less common than claudication. PAD is caused by atherosclerosis, the hardening and narrowing of the arteries over time due to the buildup of fatty deposits called plaque.

CLI is a chronic condition that results in severe pain in the feet or toes, even while resting. Complications of poor circulation can include sores and wounds that won't heal in the legs and feet. Left untreated, the complications of CLI will result in amputation of the affected limb.

The most prominent features of critical limb ischemia are called ischemic rest pain — severe pain in the legs and feet while a person is not moving, or non-healing sores on the feet or legs. Other symptoms include:

• Pain or numbness in the feet
• Shiny, smooth, dry skin of the legs or feet
• Thickening of the toenails
• Absent or diminished pulse in the legs or feet
• Open sores, skin infections or ulcers that will not heal
• Dry gangrene (dry, black skin) of the legs or feet

Risk factors for chronic limb ischemia are the same as those for atherosclerosis -- hardening and narrowing of the arteries due to the build up of fatty deposits, called plaque. The following all contribute to this condition:

• Age
• Smoking
• Diabetes
• Overweight or obesity
• Sedentary lifestyle
• High cholesterol
• High blood pressure
• Family history of atherosclerosis or claudication

Your doctor may identify and locate the cause of blockages associated with critical limb ischemia (CLI) using one or more of the following methods:

• Auscultation: The presence of a bruit, or "whooshing" sound, in the arteries of the legs is confirmed using a stethoscope.
• Ankle-brachial index (ABI): The systolic blood pressure in the arm is divided by the systolic pressure at the ankle.
• Doppler Ultrasound: This form of ultrasound can measure the direction and velocity of blood-flow through the vessels.
• CT angiography: An advanced X-ray procedure that uses a computer to generate three-dimensional images.
• Magnetic resonance angiography (MR angiography): The patient is exposed to radiofrequency waves in a strong magnetic field. The energy that is released is measured by a computer and used to construct two- and three-dimensional images of the blood vessels.
• Angiogram: An X-ray study of the blood vessels is taken using contrast dyes.

Critical limb ischemia is a serious condition that requires immediate treatment to re-establish blood-flow to the affected area. The number one priority is to preserve the limb.

Endovascular treatments

Minimally invasive endovascular therapy is often an option in the care of CLI. The Vascular Center has the full complement of endovascular treatments available. The treatment recommended depends on the location and severity of the blockages. Most patients with CLI have multiple arterial blockages, including blockages of the arteries below the knee. In general, puncture of the groin, under local anesthesia, with insertion of a catheter into the artery in the groin will allow access to the diseased portion of the artery. Some of the endovascular procedures used to treat CLI include:

• Angioplasty: A tiny balloon is inserted through a puncture in the groin. The balloon is inflated one or more times, using a saline solution, to open the artery.
  • Cutting balloon: A balloon imbedded with micro-blades is used to dilate the diseased area. The blades cut the surface of the plaque, reducing the force necessary to dilate the vessel.
  • Cold balloon (CryoPlasty): Instead of using saline, the balloon is inflated using nitrous oxide. The gas freezes the plaque. The procedure is easier on the artery; the growth of the plaque is halted; and little scar tissue is generated.
• Stents: Metal mesh tubes that provide scaffolding are left in place after an artery has been opened using a balloon angioplasty.
  • Balloon-expanded: A balloon is use to expand the stent. These stents are stronger but less flexible.
  • Self-expanding: Compressed stents are delivered to the diseased site. They expand upon release. These stents are more flexible.
• Laser atherectomy: Small bits of plaque are vaporized by the tip of a laser probe.
• Directional atherectomy: A catheter with a rotating cutting blade is use to physically remove plaque from the artery, opening the flow channel.

Recovery from these procedures usually takes one or two days, and most of these procedures are done on an outpatient basis. Treatment includes management of the risk factors of atherosclerosis (see reducing risk factors).

Surgical treatments

Treatment of wounds or ulcers may require additional surgical procedures or other follow-up care. If the arterial blockages are not favorable for endovascular therapy, surgical treatment is often recommended. This typically involves bypass around the diseased segment with either a vein from the patient or a synthetic graft. Hospitalization after a bypass operation varies from a few days to more than a week. Recovery from surgery may take several weeks.