What is Peripheral Vascular Disease?
What is a Vascular Ulcer and how do you treat it? Peripheral Vascular Disease is a combination of Peripheral Arterial Disease (PAD) and Peripheral Venous Disease.
PAD is more common in diabetes patients than PVD.
Peripheral Vascular Disease (PVD) occurs when blood vessels in the legs are narrowed, hardened or blocked by fatty deposits. Blood flow to your feet and legs decreases. If you have PVD, you have an increased risk for heart attack and stroke. It can occur in individuals without diabetes but is more common and more severe in people with diabetes. Why this is the case is not clear, but it is well established that smoking makes peripheral vascular disease much worse. A marked redness or loss of blood supply to an area is called ISCHAEMIA.
You can cut your chances of having those problems by taking special care of your blood vessels.
An estimated one out of every three people with diabetes over the age of 50 has this condition. However, many of those with warning signs don't realize that they have PAD and therefore don't get treatment.
Risk factors for Peripheral Vascular Disease (PVD)
Just having diabetes puts you at risk, but your risk is even greater if
- you smoke
- you have high blood pressure
- you have abnormal blood cholesterol levels
- you already have heart disease, or have had a heart attack or a stroke
- you are overweight
- you are not physically active
- you are over age 50
- you have a family history of heart disease, heart attacks, or strokes
Both big and small blood vessels can be affected by diabetes. In diabetic PAD it is blockage of the larger arteries in the thigh and leg which causes most of the clinical problems. Peripheral Arterial disease can affect both legs but is often more severe on one side (compared with peripheral neuropathy which affects both feet symmetrically).Often the very small arteries and capillaries in the feet are affected as well, which has negative implications for wound healing and other skin problems. Blood supply may not meet the demand of the small muscles in the foot resulting in aching/pain/cramps and eventually muscle weakness and atrophy.
Signs of PVD
Many people with diabetes and PAD do not have any symptoms. Some people may experience mild leg pain or trouble walking and believe that it's just a sign of getting older. Others may have the following symptoms:
- Leg pain, (mainly in the calf muscles and particularly when walking or exercising), which disappears after a few minutes of rest.
- Numbness, tingling, or coldness in the lower legs or feet.
- Sores or infections on your feet or legs that heal slowly.
If it is mild, peripheral vascular disease can be completely without symptoms. However, as blood supply becomes progressively inadequate, it can cause claudication, rest pain or vascular ulceration. It is therefore important not to get to this stage by refraining from smoking.
- Claudication is development of pain in the calf after walking for a distance or up an incline or stairs. As activity increases the demand for oxygen and nutrients for cells increases. Due to limitations in blood flow, when demand outstrips supply, pain results. The pain makes the person stop or slow down until blood flow is again adequate and the pain recedes. The distance a person can walk before such pain occurs is referred to as claudication distance. The leg and foot look and feel normal as long as the person is resting. As claudication distance becomes shorter and shorter, physical activities become more and more restricted. Cessation of smoking is most important before one gets to this stage. Regular exercise by walking through the pain threshold can sometimes increase the claudication distance. In many cases to relieve the symptom it is necessary to have either an angioplasty (an instrument is threaded down the artery to widen the blocked area) or by-pass surgery (a vein from other part of the body or an artificial tubing is used to by pass the blockage, allowing blood to flow through).
- Rest pain is pain in the foot even when not walking. Rest pain occurs because the supply of blood to the foot is so restricted that it can not even meet the demand of tissue at rest, for the basic of cell functions, oxygen supply and nutrition to keep cells alive. This is distressing and it is difficult to obtain respite. It is a more severe stage of peripheral vascular disease than claudication. The affected foot looks purplish in colour and feels cold to touch. The foot pulses are not palpable. Angioplasty and by-pass surgery are the only available treatment. Sometimes, amputation is required as the last resort to relieve pain
- The wounds of patients with severe arterial disease heal poorly because of inadequate blood supply. Therefore minor trauma or pressure often leads to ulceration. This is called a vascular ulcer (sometimes also known as arterial ulcer or ischaemic ulcer). It tends to be situated on the edge of the foot or toes because blood supply is the poorest at these sites. A typical arterial ulcer is shown below. In a purely ischaemic ulcer, nerve function is normal and sensation is intact, hence ischaemic ulcers are usually painful.
A typical ischaemic ulcer
Therefore, a typical ischaemic ulcer is:
- painful and often dry
- not surrounded by callus
- associated with absent or poor foot pulses
- associated with a foot that is cold to touch
- at the edge of the foot or toes
An ischaemic/arterial ulcer should not be confused with a venous ulcer which is due to varicose veins. Varicose ulcers are situated on the leg (rather than in the foot), associated with varicose veins and often accompanied by swelling and a brownish discoloration of the leg. A typical varicose ulcer is shown below.
A typical varicose ulcer
- you have had a foot ulcer before
- you have poor circulation in the feet when your doctor tested it
- you have misshaped feet e.g.: clawed toes or bunions
- you have claudication or rest pain
- you do not follow advice to protect your feet with good footwear and hygiene
- Remove the precipitating cause
- Replace shoes that are too tight
- Clean and dress the wound with non-caustic materials. In contrast to the treatment of neuropathic ulcers, do not debride aggressively. In the presence of vascular disease debridement could make the ulcer worse.
- Taking antibiotics if the ulcer is infected. Remember that signs of infection such as local redness, heat and swelling are often masked by vascular disease.
- Rest the feet as much as possible because this helps to minimize trauma to the ulcer. Walking is not a good exercise for someone who has a vascular ulcer (or someone at great risk of developing one).
Foot examination - Checking your risk of developing a diabetic foot ulcer
If a person already has a diabetic foot ulcer, the danger is clearly there (although sometimes both the patient and the doctor can be fooled because there is no pain). The need for treatment of the ulcer by a multi-disciplinary approach involving doctors, podiatrists and nurses is also well established. It is a different type of challenge to identify the patients before they have actually developed an ulcer so that they can receive appropriate footcare education.
Who is at risk of developing a diabetic foot ulcer?
The most important aspect of grading diabetic neuropathy from foot ulceration point of view is to assess the degree of loss of sensation in the feet. Podiatrists employ tests such as feeling the pain of a pin prick, the touch of cotton wool, the vibration of a tuning fork, testing vibration sensation with a biothesiometer, and testing touch pressure sensation with a monofilament.
Other tests can also be used to diagnosis PVD:
- Angiogram/Doppler: a test in which dye is injected into the blood vessels using a catheter and X rays are taken to show whether arteries are narrowed or blocked
- Ultrasound: a test using sound waves to produce sounds and images of the blood flow through vessels on a viewing screen.
- MRI (magnetic resonance imaging): a test using special scanning techniques to detect blockages within blood vessels
Please note the presence or absence of pain is not a major factor in determining the risk of arterial ulceration.
How to tell if the peripheral vascular disease is severe enough to predispose to foot ulceration?
If a person has claudication or rest pain (especially the latter), there is sufficiently severe peripheral vascular disease to predispose to vascular ulceration.
If a person has no claudication or rest pain, then one relies on physical examination and, if necessary, investigations to determine the risk .Very often there is no history of claudication pain purely because the person is not physically active. They may never walk more than a few meters and certainly not at speed for any number of reasons.
Looking at the feet to see if they are purplish in colour and feeling them to see if they are cold gives an important clue that the circulation may be impaired.
In most cases, looking at the feet and palpating the foot pulses are all that is required to assess the risk of vascular ulceration. When the foot pulses are very weak or not palpable, then it is necessary to carry out "non-invasive vascular tests" to assess the risk.
This is most easily done by measuring what is called the Ankle Brachial Index. It is as easy as having blood pressure checked although a simple hand held Doppler machine is required for this. This test compares the blood pressure in your ankle to the blood pressure in your arm. If the blood pressure in the lower part of your leg is considerably lower than the pressure in your arm, you may have PAD.
Foot Structure that increases risk for ulceration.
Like any other part of the body, our feet can have some minor variations in shape from one to another. Poor foot mechanics and resultant foot function and muscle imbalance can exacerbate the effects of PVD or peripheral neuropathy.
- Clawed toes can occur as a result of imbalance of the muscles in the feet due to diabetic neuropathy. This increases pressure at the tip of the toes. With the presence of neuropathy, these sites become ulcer prone.
- Rocker bottom deformity occurs due to Charcot's joint which is a complication of diabetic neuropathy
- Toe nails can become infected, thickened and deformed
How is PAD treated?
People with PAD are at very high risk for heart attacks and stroke; therefore, it is very important that cardiovascular risk factors are managed. The following issues are important: get help to quit smoking, aim to keep blood sugar levels reduced and stable, blood pressure management, and cholesterol control.
Studies have found that exercise, such as walking, can be used both to treat PVD and to prevent it. Medications may help relieve symptoms.
In some cases, surgical procedures are used to treat PAD:
- Angioplasty, also called balloon angioplasty: a procedure in which a small tube with a balloon attached is inserted and threaded into an artery; then the balloon is inflated, opening the narrowed artery. A wire tube, called a stent, may be left in place to help keep the artery open.
- Artery bypass graft: a procedure in which a blood vessel is taken from another part of the body and is attached to bypass a blocked artery.