Key principles | Wounds Africa

Main principles for arterial (ischemic) ulcers

Keep dry eschar dry! Eschar is the hard dead tissue you often see on especially toes with arterial ulcers.

Don't debride dry necrosis until the circulation is improved. Obviously, in areas with limited resources without access to vascular surgery, the patient may never get significantly improved circulation. Also, then dry treatment may be the only treatment of choice!

If there is wet gangrene, you can debride - but do so very gently. Try not to disturb the surrounding tissue too much. Often it is wise to do a serial debridement - that is, careful debridement at each visit rather than trying to debride it all in one go!

As a rule of thumb, local anesthesia close to the ulcer should be avoided. This is especially true of toe ulcers. Giving a digital nerve block at the base of the toes can have catastrophic results on the remaining circulation of the toe. This is also true if you use local anesthesia without adrenaline. Obviously, local anesthesia with adrenaline should be avoided here. But also local anesthesia without adrenaline can cause a permanent decline in the remaining circulation. This can be caused by traumatic damage to the tiny blood vessels by the needle, but also the increase in tissue pressure from the injected fluid can cause irreversible damage to small blood vessels. If possible, use topical lidocaine gel or equivalent directly on the ulcer. If that is not sufficient, it is best to do a regional block- for example, an ankle block.

ALL patients with ischemic ulcers must be tested for diabetes as these two conditions often occur together, especially in elderly patients! Usually, an HbA1c test is sufficient to rule out diabetes.

Check also the patient's hemoglobin. An ischemic ulcer is hard to heal with a Hb <10g/dl and almost impossible to heal with a Hb <8 g/dl. In cases of anemia, try to find the cause and rectify this. If there is an iron deficiency, you obviously will need to provide iron supplementation. Remember that iron deficiencies often indicate another medical condition - in many cases, it is not a lack of iron in the nutrition but rather something that is depleting the iron levels in the body. Do whatever you can to improve the patient's hemoglobin levels. A normal hemoglobin level will to some degree, be able to compensate for at least moderate circulation problems.

Patients with arterial ulcers must stop smoking immediately. Smoking is the worst of all nicotine products, but all nicotine use leads to peripheral arterial constriction.

Patients with arterial ulcers should always be referred to a vascular specialist. Understandably this will, in many cases, not be a realistic option in Africa. In the chapter on the treatment of ischemic ulcers, we define some alternative options for situations where resources are limited.

Under ideal conditions, where all resources are available - patients with arterial ulcers need to undergo an angiogram using endovascular contrast to visualize the locations of the stenotic sections in the arteries. This can be done using conventional x-ray, but more commonly, a CT/MRI-angiogram is used in clinics today.

The primary method used today by vascular surgeons to improve arterial circulation in the lower extremities is PTA ( percutaneous transluminal angioplasty) which can be done in local anesthesia and is considered a minimally invasive procedure. In some cases, there may be use for conventional surgical methods like bypass surgery using synthetic grafts or, for example, a venous graft.

Many clinics don't offer vascular reconstructive procedures to patients who are unwilling to stop smoking. We agree with this policy - the patient needs to show some self-initiative before providing such a resource-demanding procedure. Also - the incidence of complications and the chance of new stenosis is much higher with smokers after such a procedure.

Figure 1 A typical arterial (ischemic) ulcer with characteristic, well-defined wound edges on the anterior side of the leg. These ulcers often have a "punched out" appearance.

Figure 2 An ischemic foot that looks like this can be saved if there is a possibility for quick vascular intervention. This demands a clinic that can perform an angiogram and a PTA or bypass surgery. If such a clinic is not a realistic option, your only choice is to wait and see.

What causes arterial ulcers?

Arterial ulcers arise when there is insufficient blood supply to the skin and subcutaneous layers. Note that arterial ulcers do not just appear out of nothing - that is, simply having inadequate arterial circulation alone does not usually give rise to an ulcer. In most cases, some sort of tissue trauma was the cause of skin breakdown. Often this is pressure or friction related to inadequate shoe wear, a seemingly insignificant bump to something hard like the edge of a bed, etc., or pressure to bony prominences when a patient is bed-ridden. It is possible to see skin breakdown in severe ischemia without any preceding trauma to the skin, but this is more rare.

Certain lifestyle factors and medical conditions have been associated with arterial ulcers. These include:

Diabetes
Smoking
High blood fats and cholesterol
High blood pressure
Renal insufficiency
Obesity
Rheumatoid arthritis
Clotting and circulation disorders
Other arterial diseases such as heart disease, cerebrovascular disease, and peripheral vascular disease.

What are the clinical features of arterial ulcers?

Located on the lower legs, dorsum of feet, and toes
A tendency to be painful, particularly at night
Well-defined borders are often described as having a "punched out appearance."
The wound bed is usually yellowish, light brown, or black in color
There is generally very little granulation tissue
Minimal bleeding when touched or debrided
Often little secretion
Not so typical to see puss in the ulcers as the circulation may be too poor to cause an adequate inflammatory (immune) response
Be aware that signs of infection ( redness, increased skin temperature) may be hard to spot because the local immune response is impaired due to inadequate circulation.
Cool, pale, or bluish surrounding skin which may appear shiny or dry
Faint or absent ankle pulses
Loss of leg hair

Arterial ulcers develop in the advanced stages of atherosclerosis. Arterial ulcers are common over the malleoli of the ankles, over the heel, or most common in the toes. These locations are areas with bony prominences and are prone to pressure. As a preventive measure, we must ensure that the patient has adequate shoewear or uses something that cushions the areas prone to pressure.

In many cases, it may be pretty apparent that the patient's ulcer is related to poor arterial circulation. However, sometimes the ulcer does not have the typical characteristics as in the list above, and here the patient history may give more clues to what we are dealing with. A tell-tale sign of decreased circulation is pain in the legs while walking, which causes the patient to stop and rest until the pain is gone. This phenomenon is known as intermittent claudication, Latin for "intermittent pain," and is due to insufficient oxygen supply to meet the muscles' needs while walking. The patient will often interpret this as cramps. Note that in patients with diabetes, there may be no pain at all due to the presence of neuropathy.

The prevalence of atherosclerosis is highest among diabetic patients. It is crucial that you screen every patient with arterial ulcers or gangrene for diabetes! The worst combination you can have is critical arterial circulation and blood sugar that is out of control at the same time.

In later stages of atherosclerosis, the patients usually develop pain in the leg/foot while resting. Typically the patient will say that the pain is at its strongest during the night. This is because the foot is elevated when lying in bed, which reduces blood circulation even more since gravity assists circulation less when the foot is lying flat. The patients will often say that the pain is less when lowering the leg. When the patient sleeps with one or both legs hanging out of the bed, there is no doubt that the arterial circulation is critically impaired. Many patients choose to sleep in a chair to cope with the pain. However, this habit will lead to edema, especially on the legs and feet ( known as ischemic edema). This can lead to a detrimental cycle - the edema in the tissue compresses the tiny arterioles even further, which can accelerate the ischemic process and cause even more pain.