What is an ankle-brachial index?
The ankle-brachial index (ABI) is a non-invasive test to diagnose peripheral artery disease (PAD). The ABI provides valuable information, indicating:
- The severity of PAD, although it does not pinpoint the definite location of blocked or narrowed blood vessels.
- Whether your arms and legs are receiving sufficient oxygen
- The extent of vascular damage following trauma
- The risk of cardiovascular-related mortality. Even in the absence of symptoms, PAD signifies an elevated risk of death from cardiovascular causes.
Detecting PAD in its early stages enables individuals to implement lifestyle changes and seek treatment that may mitigate the risk of cardiovascular conditions.
What is peripheral artery disease (PAD)?
Peripheral artery disease (PAD) is a medical condition characterized by insufficient blood flow to the legs and several other body parts, which occurs due to the blockage or narrowing of blood vessels caused by atherosclerosis. PAD raises the likelihood of experiencing stroke, transient ischemic attack, heart attack, and other cardiovascular complications.
What are the benefits of the ankle-brachial index test?
The ankle-brachial index test is the preferred method for screening and diagnosing peripheral artery disease (PAD) in at-risk individuals because it is easy, quick (about 10-20 minutes), cost-effective, and non-invasive.
Who needs to undergo an ankle-brachial index test?
- People older than 65.
- Diabetes over 50 years old.
- Individuals with hypertension, hyperlipidemia, or a family history of heart disease.
- People with a history of tobacco use.
The test is not suitable for those who have deep vein thrombosis and severe leg pain.
What are the steps of the ankle-brachial index test?
Before the procedure
- Refrain from exercising an hour before the test.
- Avoid smoking and alcoholic and caffeinated beverages on the day of the test.
- Inform your doctor if you have had procedures to increase blood circulation in the legs.
During the procedure
You will lie supine with arms and ankles at heart level. Your doctor will check your blood pressure over the brachial artery on both arms and the dorsalis pedis or posterior tibial artery in your ankle on both legs. Your doctor will calculate your ankle-brachial index by dividing the systolic ankle blood pressure by systolic arm blood pressure to yield your ABI index.
After the procedure
You can resume your daily activities immediately.
What can an ankle-brachial index tell?
Depending on the result of the calculation, your ankle-brachial index may indicate:
- 1.0-1.4 No blockage: Low probability of peripheral artery disease (PAD). However, if you exhibit PAD symptoms, an exercise ankle-brachial index test might be recommended.
- 0.90-0.99 Borderline blockage: An ankle-brachial index in this range indicates borderline PAD. Further assessment, such as an exercise ankle-brachial index test, may be advisable.
- Lower than 0.90 PAD: Additional tests, like ultrasound or angiography, may be conducted to visualize the arteries in your legs.
For individuals with uncontrolled diabetes or those with significantly blocked arteries, a blood pressure reading at the big toe (toe-brachial index) may be necessary to confirm the test result.
What does a low ankle-brachial index mean?
If your ABI is ≤ 0.9, you have PAD. You are at higher risk of developing stroke, heart attack, kidney disease, and hypertension. If you exhibit symptoms of peripheral artery disease (PAD), but your ankle-brachial index (ABI) is slightly below the normal range, a repeat ABI test after you walk on a treadmill is recommended. If your ABI decreases by 20% or more after the exercise ankle-brachial index test, this signifies abnormalities.
What does a high ankle-brachial index mean?
The ankle-brachial index (ABI) exceeding 1.4 may indicate arterial hardening in the lower limbs, often associated with advanced age or diabetes. Individuals with ankle-brachial indices surpassing 1.4 face double the risk of cardiovascular death.
What are the treatments for severe arterial blockage?
The usual treatments include medications, lifestyle modification, angioplasty, and surgery.
Note from MedPark’s Doctors
An ankle-brachial index test offers a swift, simple, painless procedure to ascertain the presence of peripheral artery disease (PAD). ABI is a non-invasive test requiring no needle sticks, cuts, or anesthesia. Early detection of PAD can provide timely treatments to improve the patient’s quality of life.
