Ankle brachial index (ABI). Blood pressure cuffs are placed on both arms and ankles. Systolic blood pressures are measured at the brachial artery and dorsalis pedis artery with the assistance of an ultrasound Doppler. Two measurements are taken from each arm and leg and then recorded as an average. The ABI is then calculated when the systolic blood pressure in the ankle is divided by the systolic blood pressure in the arm (21).