What is an Ankle-Brachial Index?
The ankle-brachial index, or ABI, is a non-invasive test that uses inflatable cuffs to gauge blood flow in the leg, foot, and toe arteries. The ABI is calculated by dividing the ankle’s blood pressure to that of the arm’s brachial artery. If the resulting ratio is less than 0.9, it could indicate peripheral artery disease (PAD) in the patient’s legs.
PAD occurs when a buildup of plaque deposits in the coronary artery causes the blood vessels to narrow or block entirely. PAD can cause severe leg pain and increase the patient’s risk of heart attack and stroke.
Your doctor may recommend an ABI test if you exhibit the following risk factors associated with PAD:
- High blood pressure
- High cholesterol
- History of tobacco use
What Happens During an Ankle-Brachial Index?
During the procedure, you will be asked to lie down on the exam table while blood pressure cuffs are placed on your arms and legs. You will then remain still and breathe normally, while the ABI test analyzes your blood flow. The whole process usually lasts about 20 minutes or less.
After the procedure, your doctor will give you the ABI test results and discuss the appropriate next steps. The results of your test will fall into one of the following categories:
- ABI of 1.0 or greater. This range indicates no blockage. Your blood flow is in a normal range.
- ABI of 0.5-0.9. This range indicates mild to moderate blockage. Your doctor may prescribe medication or refer you to a vascular specialist for follow up treatment.
- ABI of less than 0.5. This range indicates blockage and the presence of PAD. Additional measures will be determined by your doctor and referred specialist.
A simple exam can help you stay mobile longer and reduce your risk of heart attack or stroke. Talk to your doctor about the ankle-brachial index exam or other non-invasive screening options available through Baptist Health.