The ankle brachial index screening test is done to predict peripheral arterial disease and gauge its severity. To conduct this test, blood pressure is measured at both the arm and the ankle. This test is performed twice: first when the patient is at complete rest, and second immediately after the patient has walked on a treadmill for at least five minutes.
If your blood pressure is normal while lying down, but decreases slightly after walking on the treadmill, there is probably a high likelihood of peripheral arterial disease. The ankle brachial test is often performed as a screening test for coronary heart disease and for predicting the likelihood of a heart attack or a stroke. This is because peripheral arterial disease is often linked to an increased risk of developing a heart condition.
The test is typically conducted to check the legs of a patient for the presence of peripheral arterial disease. However, it is also often used to check the efficacy of a treatment program such as angioplasty, exercise, change in diet, or surgery. A lower ankle brachial index means that you may have developed peripheral arterial disease. The normal ankle brachial index at rest is 1-1.1. This means that the blood pressure at the ankle should either be the same as or greater than that taken at the arm. However, if the ankle brachial index is lower than this, it means that there is a blockage of blood flow or that the arteries have narrowed significantly.
There are risks associated with the different slabs of the ankle brachial index. If the index is less than 0.95, it is an indication of significant narrowing of the blood vessels present in the leg. If the index is less than 0.8, it is highly likely that you will experience pain in your foot, your leg, or your buttocks even after a brief period of activity or during an exercise.
If the index turns out to be less than 0.4, you could probably experience pain and symptoms even when your body is at rest. Index values lower than 0.25 indicate the possibility of severe complications, and severe peripheral arterial disease which could eventually cost you a limb. If you are suffering from peripheral arterial disease, you will most likely experience pain in your leg immediately after walking on the treadmill.
Sometimes, the blood pressure readings may not be accurate. This happens if the blood vessels have been hardened due to calcification.