Print this topic

HealthInfo Waitaha Canterbury

Critical limb ischaemia

Toto rawaka-kore ki ngā pepeke tinana

Critical limb ischaemia (isc-ee-mi-a) is a lack of blood supply to parts of your arm or leg. It develops over time, unlike acute limb ischaemia, which happens suddenly.

Critical limb ischaemia is caused by peripheral vascular disease. It means that your arm or leg doesn't get enough oxygen. When body tissues do not get enough blood supply, the tissue dies. This shows as dry, black skin and is called gangrene.

The symptoms of critical limb ischaemia include severe pain, even when at rest, and ulcers or sores.

Critical limb ischaemia doesn't get better by itself. It's a serious condition and needs to be treated by a vascular specialist (a surgical doctor who specialises in blood vessels).

Reducing the risk of critical limb ischaemia

You cannot control all risk factors, but lifestyle changes can help you lower some risks. This means:

Diagnosing critical limb ischaemia

Your doctor will examine you and ask you questions about your health and about your family's health. They may arrange tests like an ankle-brachial pressure index, a doppler ultrasound or an angiogram.

Doppler ultrasound looks at the blood flow through your arteries and veins. A doppler ultrasound produces images of the blood flow as well as recording the sound of the blood flowing.

An angiogram is used to see the inside of your blood vessels and organs. A special dye is injected into a vein. Then a scanner is used to look at the blood flow through your arteries and show any narrowing or blockages.

Treating critical limb ischaemia

Treatment options include walking exercise, medication and surgery.

Walking exercise

Walking exercise can be as good for critical limb ischaemia as surgery. As well as helping you keep active, walking helps small new blood vessels grow that improve the blood flow in your legs.

You should walk for at least one hour, three times a week. Within the hour, you can stop and rest as often as you need to. If you get a pain in your leg while walking, stop and rest until it goes away.

If you feel embarrassed stopping and starting while walking on the street, you could try walking in a shopping mall.

Taking medication

You're likely to be prescribed a statin cholesterol medicine (even if you do not have high cholesterol) and an anti-clotting medicine like low-dose aspirin or clopidogrel to help prevent blood clots from forming.

If you have high blood pressure or diabetes, it's very important to control these well. You'll be prescribed medication to control these conditions.


The main aim of surgery is to save your limb. If the blockage cannot be treated with angioplasty, then arterial bypass surgery is needed.

If it is not possible to unblock the artery and increase the blood supply, the affected body part (toe, finger, foot or leg) has to be surgically removed (amputated).

Written by HealthInfo clinical advisers. Last reviewed August 2022.


Page reference: 404539

Review key: HIBLV-403653