INDICATIONS FOR ABI

ABI stands for Ankle-brachial index test. It is a way to check for peripheral artery disease (PAD). Peripheral artery disease is also known as peripheral vascular disease, it is a circulatory condition in which narrowed blood vessels reduce blood flow to the limbs. Studies show that PAD affects about 10 percent of people over the age of 55. The disease is a sign of fatty deposits and calcium building up in the walls of the arteries (atherosclerosis). It can cause leg pain when walking and increases the risk of heart attack and stroke.
The ankle-brachial index test compares the blood pressure measured at the person’s ankle with the blood pressure measured at their arm. A low ankle-brachial index number can indicate narrowing or blockage of the arteries in the person’s legs. In preparation for the procedure, the person will be asked to rest for 5 to 30 minutes before the test. For the test, the person is asked to lie on a table on their back, and a technician measures their blood pressure in both arms and both ankles, using an inflatable cuff and a hand-held ultrasound device that is pressed on the skin. The device uses sound waves to produce images and allows the person’s pulse to be heard in their ankle arteries after the cuff is deflated.
A person may also have anti-brachial index test done before or immediately after walking on a treadmill. An exercise ankle-brachial index test can assess the severity of the narrowed arteries during walking.
The doctor uses the blood pressure measurements from the arms and ankles to calculate a person’s ankle-brachial index. And based on the number the doctor calculates, the ankle-brachial index may show that the person has either of the following: No blockage (1.0 to 1.4)—an ankle-brachial index in this range suggests that the person probably doesn’t have PAD. However, if the person has symptoms of PAD, the doctor might still proceed to perform an exercise ankle-brachial index test; Borderline blockage (0.91 to 0.99)—an ankle-brachial index number in this range indicates that a person has borderline PAD and the doctor might recommend an exercise ankle-brachial index test; PAD (less than 0.90)—an ankle-brachial index number in this range is considered abnormal and indicates a diagnosis of PAD. The doctor may recommend further testing such as ultrasound or angiography, to view the arteries in the legs.
Depending on the severity of a person’s blockage, the doctor may recommend lifestyle changes, medication, or surgery to treat PAD.
The ankle-brachial index test has also been found to predict cardiovascular events such as heart attack and stroke.
Before performing ankle-brachial index test, it is important to obtain a thorough history and physical. An indication is a valid reason to use a certain test, medicine, procedure, or surgery and there can be more than one indication to use a procedure or medication. Accordingly, the indications for ankle-brachial index test are:

1. Intermittent claudication: Claudication or intermittent claudication is pain a person feels when their leg muscles don’t get enough blood while they exercise. It is a sign of atherosclerosis, which means plaque has built up in the arteries in the legs and is causing blockages, making it harder for blood to get through. It can be a serious health risk, if it is present in the legs, it can also be present in the heart.
   Symptoms of claudication are cramping, numbness, pain, tingling and weakness. These symptoms are usually felt in the legs, from the feet up to the buttocks. They get better or go away when the person stops moving. Other symptoms may include an aching or burning feeling, blotchy or shiny skin on the leg or foot, cold feet, foot sores, hair loss on the leg, impotence in men, weak arms or legs. Over time, the person might feel pain in their legs even when they are not exercising, cuts and sores might not heal like they should if the person has PAD and if they become infected, the person might get gangrene which could result in them losing a leg.
   The most common cause of claudication is PAD. Other conditions that can cause it include a bulging artery in the belly or leg, damaged nerves, and narrowed spinal canal. Men over the age of 55 and women over the age of 60 are at a higher risk of getting claudication. In addition, being overweight or obese, lack of regular exercise, having diabetes, high blood pressure or high cholesterol, having a family history of claudication or certain kinds of heart disease such as atherosclerosis, and smoking, also place a person at higher risk of getting claudication.
   In diagnosing claudication, the doctor will ask about the person’s symptoms, lifestyle, and family history, and proceed to carry out certain tests top of which is the ankle-brachial index test.
2. Over 70 years of age: Studies show that people aged 70 years or older are at a higher risk of developing Lower extremity arterial disease (LEAD). The ankle-brachial index test is considered as a valid and reliable test especially for individuals who have atypical symptoms or are asymptomatic. This is because the test has high sensitivity and specificity and its accuracy in the diagnosis of LEAD has been well established.
3. Over 50 years of age with a history of tobacco use or diabetes: Studies show that persons aged 50 through 69 years that have a history of tobacco use or diabetes are at a higher risk of developing LEAD. Risk factors for LEAD include advanced age, tobacco use, diabetes, among others.
4. Vascular disease: This covers a wide range of arterial and venous problems including stroke, abdominal aortic aneurysm and PAD, as well as acute and chronic venous disease. Vascular risk factor assessment is necessary for people over the age of 40. The ankle-brachial index test is used as a screening tool to detect asymptomatic arterial disease in the legs to prevent progression to claudication or limb ischemia, and to detect individuals at high risk of cardiovascular events.