What are arterial leg ulcers?

Content:

• Cause and origin of arterial leg ulcers
• Investigation of arterial insufficiency – recording pressure at the ankle/in the arm
• Characteristics and appearance arterial ulcers
• Symptoms of arterial insufficiency and arterial leg ulcers

Cause and origin of an arterial ulcer

To understand the cause and origin of an arterial ulcer, it is important to make the correct diagnosis. In cases of an arterial leg ulcer, there is usually a history of arterial insufficiency, i.e. the arterial circulation having been interrupted. Problems with arterial vessels are associated with a narrowing of the arteries in the leg. The most common cause of narrowing is atherosclerosis or hardening of the arteries. Lifestyle and genetics, including factors such as diabetes, smoking, high blood pressure and high cholesterol, can contribute to the onset of atherosclerosis.

When this occurs in the lower extremities (the legs), the blood vessels can narrow, which restricts circulation. This prevents the arteries from functioning correctly, which is carrying oxygenated blood from the heart around the body, and leads to a lack of oxygen in the extremity.

In cases of arterial insufficiency, when the skin is not perfussed with enough oxygen, the skin becomes thin, fragile and sensitive, which increases the risk of ulcers developing. Poor circulation makes it difficult to form new tissue and new blood vessels, which can prevent an ulcer from healing. An ulcer that develops as a result of arterial insufficiency is defined as an arterial leg ulcer.

Investigation of arterial insufficiency – recording pressure at the ankle/in the arm

In cases when poor arterial circulation is suspected, a full holistic  examination should be conducted to establish the correct diagnosis and identify any underlying conditions. In order to ensure the correct treatment is provided, an ankle brachial pressure index (ABPI) test must always be performed.In order to ensure the correct treatment is provided, an ankle brachial pressure index (ABPI) test must always be performed.

This measures the systolic blood pressure in both arms followed by both ankles using a Doppler probe and a blood pressure cuff. The ankle pressure that produced the highest value is then divided by the arm pressure that produced the highest value, which results in the ABPI value.

Ankle pressure
_________ = ABPI
Arm pressure

There are reference values for ABPI, with values of less than 0.8 indicating vascular disease and poor circulation. The lower the value, the poorer the circulation, with values of less than 0.5 being considered indicative of severe arterial disease.

Nb. Smokers or patients with diabetes may record false high values during measurement of ankle pressure. This is because of stiff vessels that cannot be compressed by the blood pressure cuff. In such cases, the clinician should refer the patient for a toe pressure test, which is a more accurate test for determining the patient’s arterial circulation. A vascular surgeon and vascular nurse specialist should be consulted about further treatment if recorded values deteriorate. Having little or no flow of oxygenated blood to the area makes it difficult for the ulcer to heal. This may lead to a risk of amputation.

It is important that the ABPI test is not used as the sole investigative tool, but it should be interpreted alongside other examinations and patient assessments.