Ankle-Brachial Index

Modern Heart and Vascular Institute

Cardiovascular Specialist & Board Certified Cardiologist located in Humble, TX, Katy, TX & Cleveland, TX

The ankle-brachial index (ABI) is a way to check blood pressure in the arms and legs. An ABI test is a valuable tool for measuring blood flow and diagnosing vascular conditions like peripheral artery disease.

cardiologist checking blood pressure

What Is an Ankle-Brachial Index Test?

An ankle-brachial index assessment is a noninvasive way to analyze how your blood flows through your limbs. This simple exam analyzes the blood pressure in your arms and ankles and compares the two measurements. Specifically, your ABI result is the systolic blood pressure of your ankles divided by the blood pressure in your arms. A low ABI score signifies poor blood flow in your arms and legs.

Doctors commonly use the ABI test to check for peripheral arterial disease (PAD). PAD is a common circulatory condition in which plaque collects in your arteries, reducing blood flow to your limbs. Insufficient blood flow can cause serious complications and increase your risk of heart attack or stroke. Your doctor may recommend an ABI test if you’re at risk or show PAD symptoms. The ankle-brachial index can also help doctors check PAD’s severity or monitor its progression over time.

How Is ABI Calculated?

The ankle-brachial index test is a straightforward process, similar to a standard blood pressure measurement. It is a noninvasive and painless exam that only takes a few minutes to complete. If you have a blood clot, your doctor might suggest a different test. Otherwise, there are no special preparations for an ABI test.

During the exam, you’ll lie down on a table. The technician will measure the blood pressure in both of your arms and ankles with an inflatable cuff. They’ll use a Doppler ultrasound device to hear blood flow in your arteries and take measurements. These readings will calculate your ABI.

Sometimes, you might need to take an exercise ABI test. A technician will take your blood pressure measurements before and immediately after you walk on a treadmill to examine your arteries during activity.

Ankle-Brachial Index Interpretation

Follow up with your doctor after the exam for your results. The number your doctor calculates will tell you more about your arteries’ condition:

  • Over 1.4: A result at or over this level means your arteries are too stiff to get a meaningful ABI reading. Your doctor will likely use a different exam.
  • 1.0-1.4: This is a normal ankle-brachial index measurement and suggests no blockage in your arteries.
  • .90-.99: Results within this range are considered acceptable but might mean you’re at borderline risk of developing PAD.
  • Below .90: An ABI measurement under .90 indicates significant blockage and moderate or severe PAD.

Depending on your measurement, your doctor may request additional testing or develop a treatment plan for peripheral artery disease. Common treatments include lifestyle changes or medications to help manage or slow your condition’s progression. Severe peripheral artery disease (results less than .50) may require surgery.

Consult With a Cardiologist Today

At Modern Heart and Vascular, you can consult with a cardiologist to determine if you need an ABI test or other cardiovascular exam. Contact us today to request an appointment.

This article does not provide medical advice. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. If you need cardiovascular care, please call us at 832-644-8930.