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PPG Toe Pressures & Toe Brachial Index (TBI)

The PPG (photoplethysmography) Toe Pressure and 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.

PPG probes are available for Koven's Bidop® 3, Smartdop™ 45, and Smartdop™ XT Vascular Dopplers.

The Toe Brachial Index Exam

A Toe Brachial Index study is performed by placing the patient in a supine position and wrapping pressure cuffs around both arms digit cuffs around the base of the toe on each foot.

Using a noninvasive ultrasound vascular Doppler, pressures are taken at both arms by inflating the pressure cuffs past the point where Doppler sounds cease, then slowly deflating the cuffs until Doppler sounds return.

After taking the sytolic pressure at both arms, a PPG sensor is affixed to the base of the patient's toe and the toe systolic pressure is taken by inflating the toe cuff past the point where waveform motion ceases, then slowly deflating the cuff until waveform motion returns.

Interpreting the Results of an Toe Brachial Index (TBI)

The TBI is calculated by dividing the toe pressure by the highest arm pressure.

When calculating the TBI ratio use the highest arm pressure to rule out subclavean steal syndrome.

¹ Greater than 0.7 = Normal
  Less than or equal to 0.7 = Abnormal

² A toe pressure of greater than 30 mmHg may be an indicator of healing potential in foot ulcers

A PPG waveform that does not have swift recovery may indicate poor perfusion ¹Creager MA, et al. (2011). 2012 ACCF/AHA/ACR/SCAI/SIR/STS/SVM/SVN/SVS Key Data Elements and Definitions for Peripheral Atherosclerotic Vascular Disease: A Report of the American College of Cardiology Foundation/American Heart AssociationTask Force on Clinical Data Standards (Writing Committee to Develop Clinical Data Standards for Peripheral Atherosclerotic Vascular Disease). Circulation 2012, 125:395-467. Retrieved December 5, 2011 from

²Zierlier RE, Sumner DS. Physiologic Assessment of Peripheral Arterial Occlusive Disease. Vasc Surg 4th Edition 1:65-117 WB Saunders Co., PA, USA, 1995

Bidop is a registered trademark ® of Koven Technology, Inc. St. Louis, MO
Smartdop is a trademark of Koven Technology Canada Inc., Winnipeg, Manitoba

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