Vascular Assessment in Patients With a Lower Limb Wound: A Correlational Study of Photoplethysmography and Laser Doppler Flowmetry Toe Pressure Techniques

Abstract

Background: Vascular assessment of the lower limbs is essential in patients with diabetes. In the presence of noncompressible arteries, the ankle brachial index (ABI) can either be inconclusive or provide false-positive results. Toe pressure measurement has been suggested as an alternative as a noninvasive method for detecting peripheral arterial disease (PAD). Toe pressure measurement can be performed either by photoplethysmography (PPG) or by Laser Doppler flowmetry (LDF). The aim of this study was to determine correlations between the two techniques in order to promote the use of PPG in clinical practice. Methods: This was a prospective correlational study of 108 consecutive recruited adult patients, with and without diabetes, with at least one lower limb wound from a University-affiliated hospital wound care clinic. Toe pressure measurements were both performed with PPG and LDF devices. Results: Mean toe pressure values for PPG and LDF were, respectively, 83.7 (SD 35.4) and 79.5 (SD 32.0) mmHg (with a paired t-test 3.969, P < 0.01). In patients with at least one lower limb wound, a strong linear relation was found between PPG and LDF toe pressure techniques with a Pearson’s r correlation coefficient of 0.920 ( P < 0.001). Conclusions: PPG and LDF toe pressure techniques are equivalent in patients with at least one lower limb wound, irrespective of the presence of diabetes. Therefore, in the presence of an ABI with inconclusive results, such as in a patient with noncompressible vessels, both toe pressure techniques can be used for assessing the vascular supply of the lower limb with a wound.

Non-invasive detection of early microvascular changes in juveniles with type 1 diabetes

“…Another tool used to assess the microcirculation in this study is photoplethysmography (PPG), which reflects the pulse waves in the arterioles and is widely used to evaluate blood circulation [ 28 , 39 , 40 ]. Research in diabetes considering PPG is promising [ 41 – 44 ]. However, according to the author’s knowledge, the only published work on assessing vascular flow using PPG in children with diabetes is a 1989 study conducted on a group of 42 patients with diabetes.…”

Screening for Peripheral Artery Disease Using an Automated Four-Limb Blood Pressure Monitor Equipped with Toe–Brachial Index Measurement

“…Since toe arteries are usually not affected by MAC, the measurement of systolic toe pressure helps overcome the limitations resulting from falsely elevated ankle pressure values due to mediasclerosis [20,21,24]. The two most common measurement methods of toe pressure, LD flowmetry and photophlethysmography, have been validated in some studies and are considered a reliable alternative for each other [26,[48][49][50][51][52].…”

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

“…32–35,37 Laser Doppler flowmetry and laser speckle imaging are emerging technologies with potential for assessing perfusion in limbs with wounds, but larger prospective studies are required for their validation as useful primary perfusion assessment tools. 63,64 Similarly, pedal acceleration time has been correlated with the ABI and clinical presentation of PAD, and improvement in the pedal acceleration time (180 ms) after revascularization in patients with CLTI has been associated with limb salvage in a single-center study. 65,66 Development of additional tools for perfusion assessment and prediction of wound-healing potential in the setting of CLTI is an area of ongoing investigation with new modalities, such as spatial frequency domain imaging, currently under investigation.…”