Ankle-brachial Index

How to Perform

With the patient resting supine for about 10 minutes, measure the systolic blood pressure in both arms and at both ankles using a blood-pressure cuff and handheld Doppler. In each arm, place the cuff around the upper arm and position the Doppler probe over the brachial artery. Inflate the cuff until the Doppler signal disappears, then slowly deflate it and record the pressure when the signal first returns.

At each ankle, place the cuff just above the malleoli. Locate the dorsalis pedis artery with the Doppler and measure its systolic pressure in the same way. Then locate the posterior tibial artery and measure its systolic pressure. Repeat on the opposite ankle.

For each leg, divide the higher of its dorsalis pedis and posterior tibial systolic pressures by the higher of the two arm systolic pressures to obtain the ankle-brachial index.

How to Interpret