One of the most common ways to diagnose peripheral artery disease (PAD) and help measure vascular health is with an ankle brachial index (ABI) test. If you’re wondering what an ankle brachial index test is, it’s a test that measures the blood flow in your arms and legs.
The blood pressure in your ankle is divided by the blood pressure in your arm to get your ankle brachial index.
A low ankle-brachial index number can indicate that there is a blockage in an artery, preventing the proper nutrients from reaching the rest of your body. A low ABI test number also tells the doctor that your risk of circulatory issues has increased, and that you should be monitored more regularly. This doesn’t mean your arteries are completely blocked, but there is evidence of narrowing, which needs to be treated in order to avoid any future health conditions. Your legs need open arteries so that blood can flow freely, transporting nutrients and oxygen to your limbs.
If you suspect that you need an ABI test, we offer this quick, minimally invasive procedure at USA Vascular Centers.
How is an Ankle Brachial Index Test Done?
On the day of your ABI test, you’ll want to avoid drinking caffeine or exercising less than an hour beforehand. Wear loose-fitting, comfortable clothing that’s easy to relax in. Your doctor will have you lie on your back for 10 minutes before the test begins.
Using a handheld Doppler, a device that uses sound waves to estimate the speed of blood flow through your vascular system, as well as a blood pressure cuff, your doctor will calculate the systolic blood pressure in your upper arm. Your systolic blood pressure measures the force your heart applies to the walls of your arteries with every beat.
Your doctor will place the Doppler over the brachial artery and inflate and deflate the cuff, similar to a regular blood pressure test. They will take the numbers down and record what comes up on their monitor. Your doctor will measure the waveforms your pressure makes on the Doppler screen. Your doctor will then take your pulse at various intervals, most likely between each reading.
This process will be repeated on your other arm, and then on both ankles to measure the blood pressure and flow in the major arteries of the foot.
ABI Test Results
After measuring the systolic pressure in your arm and ankle, the doctor will divide the number from your ankle by the number from your arm.
The resulting number is your ankle brachial index. Here’s what the numbers mean:
- Above 1.4: Suggests calcification and hardening
- 1.0 – 1.4: Normal
- 0.9 – 1.0: Borderline
- 0.8 – 0.9: Some arterial disease
- 0.5 – 0.8: Moderate arterial disease
- Less than 0.5: Severe arterial disease
If your ankle brachial index is above 1.4 or between 0.9 and 0.5 or lower, your doctor may recommend treatment. Numbers above 1.4 indicate that you may need a toe brachial index test, or TBI, to get the most accurate diagnosis.
Next Steps After Ankle Brachial Index Test
Depending on the ABI test results, your vascular specialist may guide you toward making important lifestyle changes, such as modifying your diet, starting an exercise routine, or quitting smoking.
They may also prescribe medication to help lower your blood pressure or cholesterol, prevent blood clots from developing, or help manage diabetes.
An angioplasty may be needed to help determine whether any arteries are narrowed, signaling atherosclerosis as a result of plaque buildup, which is a major symptom of PAD.
If you do have PAD, your doctor may recommend a minimally invasive treatment to help ease the symptoms of PAD. Our specialists at USA Vascular offer minimally invasive procedures to help treat peripheral artery disease, including:
- Angioplasty, a treatment that involves inserting a balloon-tipped catheter into your blood vessels before inflating the balloon to open narrowed arteries.
- Stent placement, wherein your specialist places a mesh stent inside the narrowed blood vessel to help it stay open.
- Atherectomy, a procedure in which your doctor removes the plaque in affected blood vessels.
Schedule an Appointment with USA Vascular Centers
If you wish to get an ABI test or have already received results from a test and need to speak with a vascular specialist, our trusted experts at USA Vascular Centers can help. Schedule a consultation with one of our vascular specialists online or call us at 888-773-2193 today.
Medically Reviewed by:
Dr. Aaron Shiloh, M.D., FSIR
Dr. Aaron Shiloh is a board-certified interventional radiologist with decades of experience performing minimally invasive treatment for PAD and other vascular conditions. Dr. Shiloh was awarded a fellowship from the Society of Interventional Radiology, a prestigious distinction that only the top 10% of doctors in his field have earned.