New Approach to Measuring the Ankle and Toe Brachial Indices as New Markers for Early Detection of Lower Extremity Peripheral Artery Disease

Abstract

Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and is associated with an increased risk of coronary heart disease, stroke, and leg amputation. The first-line method for diagnosis of PAD is the Ankle Brachial Index (ABI), which is the ratio of ankle to brachial higher systolic pressure measured in ankles and arms. The Toe Brachial Index (TBI), which is the ratio of the toe systolic pressure to brachial higher systolic pressure measured in both arms, is considered to be an alternative to the ABI in screening for PAD. The ABI and TBI are measured on the right and left side, and the lower of these numbers is the patient's overall ABI and TBI. Clinical studies and metaanalysis reviews have shown that the conventional ABI measurement, which uses a cuff, and handheld sphygmomanometer and continuous-wave Doppler tracings, provides an acceptable-to-high specificity level but low sensitivity when compared with vascular color Doppler ultrasound, and/or angiography methods. Another study has shown that the TBI measurement has greater sensitivity but lower specificity than the ABI when compared with vascular color Doppler ultrasound diagnostic based on waveforms. The aim of this clinical study was to evaluate the specificity and sensitivity of the VasoPad System comparing its results to the vascular color doppler ultrasound waveforms. Materials and Methods: The VasoPad System is an automated device using the pulse wave method to measure the arms and ankles dorsalis and tibial posterior artery blood pressures, the photoplethysmography second derivative (PTGSD) to estimate the toe systolic pressure, a patented photoplethysmography (PTG) index marker and volume plethysmography via cuffs during deflation. Vascular Color Doppler ultrasound can diagnose stenosis How to cite this paper: Gandhi, P.G. and Kamble, P.