The PPG (photoplethysmography) Toe Pressure and the related Toe Brachial Index (TBI) are performed to assess the vascular condition of the foot by obtaining systolic pressures at the toe.

Toe pressures use an infrared PPG sensor to determine the small vessel vascular condition distal to the ankle. Toe pressures may be useful in cases of unsuspected vascular disease and in baseline diabetic foot assessment where falsely high ankle pressures can occur due to calcification.

Using a noninvasive vascular Doppler equipped with a Doppler probe and PPG sensor, systolic pressures are taken at both arms, using the same method as an Ankle Brachial Index.  Then, toe cuffs and PPG sensors are placed on the toes and the systolic toe pressures are taken by inflating the cuff past the point where waveform motion ceases, then slowly deflating the cuff until waveform motion returns.

The Toe Brachial Index is calculated by dividing the toe pressure by the highest arm pressure. A TBI of 0.7 or greater is generally considered normal.¹