Ankle Brachial Index (ABI): A Useful Diagnostic Tool for PAD

Peripheral artery disease (PAD) is both common and dangerous.  Yet, it is widely overlooked.  Many patients are unaware of the disease and the risk factors such as diabetes, high blood pressure, and high cholesterol, or the potential consequences such as limb amputation, stroke, and heart attack.  Fortunately, in the case of PAD, a little bit of knowledge can go a long way.  Once a patient understands that they may be at risk for developing the condition, they can pursue the appropriate tests to detect and monitor their arterial health.  In many cases, a test as simple as an ankle brachial index (ABI) can make a big difference in patient outlook.

What is an Ankle Brachial Index?

An ABI is a quick, non-invasive test used to detect the potential presence of PAD.  In the majority of cases, PAD affects the legs, quietly narrowing the arteries and rarely causing symptoms.  An ABI can give physicians quick insight into how well blood is flowing throughout the legs and if a potential blockage may be present. 

An ABI is conducted with the use of a blood pressure cuff on both the arms and ankles, and comparative readings are provided in order to determine if blood flow may be inhibited in one or both legs.

Interpreting an Ankle Brachial Index Reading

Results from these tests are obtained by dividing the systolic (top number) blood pressure readings in the ankles by those in the arms.  The following chart, highlights the potential range of results:

Interpreting ABI Test Results
Ankle Pressure/Brachial Pressure =	ABI
More than 1.3	Arterial calcification
1.0	Normal
0.9 — 1.0	Normal – minimal disease
.50 — .90	Single level disease(minimal -moderate claudication)
.30 — .50	Multiple level disease(severe claudication -rest pain)
Less than .30	Severe occlusive disease(rest pain/gangrene)

Based on the results of an ABI test, physicians can determine the best next steps.  More testing may be required to find a definitive diagnosis, or depending on the severity of PAD, recommendations may be made for medications, lifestyle changes, or minimally-invasive interventional procedures such as balloon angioplasty, stenting, or atherectomy.  Even if the results indicate no blockage at all, monitoring may still be recommended based on your personal risk factors.

If you are concerned about your risk for PAD, contact Cardiovascular Institute of the South.  As industry leaders in cardiovascular care, we are home to many skilled physicians who are experts in the treatment of PAD and the prevention of amputations.  Contact us to learn more or request an appointment at a CIS location nearest you.