Ankle-brachial indexes (ABIs)

What should you do?

CALCULATE the ankle-brachial indexes (ABIs) to estimate arterial occlusion. (Also known as the arm-to-ankle index, AAI)

When should you perform this assessment?

Calculate the ABI when the patient has peripheral arterial disease

Procedure

• The ABI is calculated by dividing the ankle systolic blood pressure by the brachial systolic blood pressure.

• With the patient in a supine position, take the brachial systolic blood pressure in both arms using Doppler sound

• Apply the blood pressure cuff above the ankle to measure the systolic blood pressure of the posterior tibialis or dorsalis pedis pulses using the Doppler

• Divide the posterior tibial or dorsalis pedis (ankle) systolic blood pressure by the brachial systolic blood pressure for each side.

Expected Findings

ABI greater than 1.0-1.4

Unexpected Findings: Peripheral artery disease (PAD)

The patient who has __ has impaired peripheral perfusion that is reflected in a lower systolic pressure in the leg than the arm, which reveals an ABI less than normal

Unexpected Findings: Narrowing of arteries

0.91–0.99 indicates some __ (borderline PAD)

Unexpected Findings: PAD

Less than 0.90 indicates __