When a patient reports leg cramps, pain while walking, cold feet, or a wound that is not healing, one of the first questions is whether enough blood is reaching the legs and feet.
A common test used to help answer that question is the ankle-brachial index, often shortened to ABI.
The ABI is a noninvasive test that can help healthcare providers evaluate patients for peripheral artery disease.
What Does an ABI Test Measure?
The test compares blood pressure measured at your ankle with blood pressure measured in your arm.
In healthy arteries, these pressures should have a predictable relationship. If pressure is significantly lower at the ankle, it can suggest that narrowing or blockage is reducing blood flow to the leg.
The test gives healthcare providers useful information without requiring surgery or an incision.
Why Would My Doctor Order an ABI?
ABI testing may be considered when someone experiences symptoms that could be related to poor circulation.
These include:
- Leg pain during walking
- Calf cramping
- Cold feet
- Numbness or weakness
- Reduced walking ability
- Non-healing foot wounds
- Resting foot pain
Testing may also be considered when a patient has significant risk factors for PAD.
What Happens During an ABI Test?
During a typical ABI test, you lie down while blood pressure cuffs are placed around your arms and ankles.
A healthcare professional measures the pressure in these areas, often using a handheld Doppler device to identify blood flow.
The measurements are then used to calculate your ankle-brachial index. The procedure is generally noninvasive and does not require anesthesia.
What Do ABI Results Mean?
Your healthcare provider interprets the result along with your symptoms, physical examination, and medical history.
An ABI of 0.90 or lower is generally considered abnormal and can support a diagnosis of PAD.
However, ABI testing does have limitations. For example, some patients have arteries that are difficult to compress, which can affect the accuracy of ankle pressure measurements. Additional tests may be needed when results do not match the patient’s symptoms or clinical picture.
What If My ABI Is Normal but My Legs Still Hurt?
A normal resting ABI does not always end the evaluation.
If symptoms consistently occur during walking, your healthcare provider may recommend an exercise ABI test. Blood pressure measurements can be repeated following treadmill walking to determine whether exercise reveals a circulation problem that was less obvious at rest.
Other tests may also be considered.
What Testing Can Come After an ABI?
Depending on your symptoms and results, your vascular specialist may recommend:
- Doppler ultrasound
- Duplex ultrasound
- Toe-brachial index testing
- CT angiography
- Magnetic resonance angiography
- Angiography
These tests can provide additional information about the location and severity of arterial narrowing.
Why Early PAD Detection Matters
Peripheral artery disease is more than a leg problem.
PAD is caused by atherosclerosis, the same disease process that can affect arteries elsewhere in the cardiovascular system.
Recognizing PAD allows patients and providers to address both leg symptoms and overall cardiovascular risk. Treatment may involve exercise, smoking cessation, management of cholesterol, blood pressure and diabetes, medication, and vascular procedures when appropriate.
Take the First Step Toward Understanding Your Circulation
If you experience recurring leg pain, cold feet, difficulty walking, or a wound that is not healing, a vascular assessment may provide important answers.
At Vascular Centers of America, evaluation for PAD begins with understanding your symptoms and determining which vascular tests are appropriate.
Contact Vascular Centers of America to learn more about PAD testing and the ankle-brachial index.