Ankle-brachial index test (ABI)
This test is done by measuring blood pressure at the ankle and in the arm while a person is at rest. Measurements are usually repeated at both sites after 5 minutes of walking on a treadmill.
The ankle-brachial index (ABI) result is used to predict the severity of peripheral arterial disease (PAD), which is plaque buildup in the arteries. A slight drop in your ABI with exercise means that you probably have PAD. This drop may be important because PAD can be linked to a higher risk of heart attack or stroke.
Why It Is Done
This test is done to screen for peripheral arterial disease of the legs. It is also used to see how well a treatment is working (such as medical treatment, an exercise program, angioplasty, or surgery). It will also differentiate arterial disease from vein problems like varicose veins.
The ABI results can help diagnose peripheral arterial disease (PAD). A lower ABI means you might have PAD. A slight drop in the ABI with exercise, even if you have a normal ABI at rest, means that you probably have PAD.
A normal resting ankle-brachial index is 0.9 to 1.3. This means that your blood pressure at your ankle is the same or greater than the pressure at your arm, and suggests that you do not have significant narrowing or blockage of blood flow.
A resting ankle-brachial index of less than 0.9 is abnormal. If the ABI is:
0.41 to 0.9, you likely have mild to moderate peripheral arterial disease.
0.4 or below, you likely have severe peripheral arterial disease.
What To Think About
You may experience leg pain during the treadmill portion of the test if you have peripheral arterial disease (PAD).
Undiagnosed arterial disease in the arms can cause inaccurate test results.
Blood pressure readings may not be accurate when the blood vessel being measured is hardened by calcium (calcified). Arteries may calcify more than usual if you have diabetes or kidney problems (renal insufficiency).
A very abnormal ABI test result may require more testing to determine the location and severity of PAD that might be present.
The ABI test is one of the most important tests in cardiovascular medicine. Patients with PAD are at a high risk of heart attack and stroke. The majority of top cardiologists best practice is to perform baseline ABI testing in all heart disease patients.
For further information please contact Cardiac Center of Texas at 972-529-6939 or send us a question through the patient portal under the Patients tab at the top of the page. Thank you for visiting CardiacCenterOfTexas.com.