What Is the Ankle Brachial Index?

The Ankle Brachial Index (ABI) is an important diagnostic tool for detecting peripheral arterial disease (PAD).

This noninvasive test measures the difference between blood pressure in your upper and lower limbs to check for reduced blood flow.

Healthcare providers calculate the ABI score by dividing the blood pressure reading in your ankle by the blood pressure reading in your arm. This ratio helps determine if your arteries are narrowed by atherosclerosis and PAD.

Indicators That an Ankle Brachial Index Test Might Be Needed

You may need an Ankle Brachial Index test if you are at an increased risk for PAD due to:

• Being over 70 years old
• Having diabetes
• Being a smoker
• Having built-up plaque in your coronary arteries

You may also need this test if you have PAD symptoms such as:

• Claudication (pain with movement)
• Slowed hair or nail growth on legs and feet
• Changes in skin color or texture on your legs.

However, many people develop PAD without experiencing any symptoms, making the ABI test essential for early PAD diagnosis. This helps prevent disease progression and identify your risk for future strokes or heart attacks. 

How Is the ABI Procedure Performed?

The Ankle Brachial Index is a quick, noninvasive procedure done right in our office. It uses inflatable cuffs similar to those used in a regular blood pressure test.

Before Testing

• Wear loose, comfortable clothing.
• Rest for at least ten minutes before the test.

During Testing

• Lie flat on your back.
• An inflatable cuff is placed just above your ankle, and an ultrasound probe is positioned above its artery to listen to blood flow.
• The cuff is inflated to stop blood flow and then deflated to measure systolic blood pressure.
• The process is repeated on both ankles and arms.

Once all four ankles and arms have been tested, the AB Index administrator divides the higher systolic blood pressure measured in each ankle by the higher of your two arm’s systolic blood pressures to determine your ankle arm index.

Interpreting ABI Results

Your ABI score helps determine whether you have PAD.

• Normal ankle brachial index: 1.0 to 1.4 (blood pressure in the ankle is higher than in the arm)
• ABI below 0.9 indicates PAD
• ABI below 0.5 suggests severe PAD

If your ABI score is lower than 0.9, it is time to explore minimally invasive PAD treatment.  

An ABI score alone cannot determine the severity of your atherosclerosis (arterial narrowing). Your doctor may order further testing to help determine the precise degree of PAD advancement, informing your treatment. Additional tests may include:

• Arterial ultrasound
• Computed Tomography (CT) scan
• Magnetic Resonance Angiography (MRA) scan.

Treatment Options

If you have PAD, request a consultation with the specialists at Georgia Endovascular. With decades of experience treating peripheral arterial disease using minimally invasive interventional radiology procedures, they can review your Ankle Brachial Index test results and recommend the best treatment for you.

Some individuals with PAD may be able to manage symptoms, delay disease progression, and preserve mobility by making simple lifestyle adjustments, like changes to your diet and exercise routine. However, patients with more severe disease, indicated by a lower Arterial Brachial Index, may require medical intervention. For those individuals, procedures such as angioplasty, atherectomy, and stenting can help reduce or eliminate painful PAD symptoms without the need for major surgery or overnight hospital stays.

We understand how PAD and its symptoms can affect your life. Our team specializes in effective PAD treatments and is ready to help you find relief and improve your quality of life.