Modeling of the hemodynamics in the feet of patients with peripheral artery disease

Abstract

To simulate the hemodynamic effects in the feet in response to a thigh cuff occlusion, we have developed a multi-compartmental model in which the circulatory system for the leg is represented by its electrical equivalents. Dynamic vascular optical tomographic imaging data previously obtained from 20 patients with peripheral artery disease (PAD) and 20 healthy subjects is used to test the model. Analyzing the clinical data with the support of the model yields diagnostic specificity and sensitivity in the 90-95% range, significantly higher than previously reported.

Dynamic vascular optical spectroscopy for monitoring peripheral arterial disease patients undergoing a surgical intervention

“…For the analysis of the data collected before and after the intervention, the parameters considered were: Rise Time (RT), defined as the time needed for the signal to pass from 10% to 90% of its maximum value; Plateau Time (PT), defined as the time after the signal surpasses 90% of its maximum value during the cuff inflation until the cuff is deflated and the signal drops lower than 90% of its maximum value; and Signal Percent Change (SPC), defined as the percentage change of the signal peak respect to its baseline value. We found in previous publications (Hielscher, et al, 2019;Marone, et al, 2019;Maheshwari, et al, 2022) that those parameters hold the most significant information on the healthiness of the vascular system under the probe location. Note that the three parameters RT, PT and SPC cannot be collected during the intervention.…”

“…To address some of these shortcomings, we propose in this paper the use of dynamic vascular optical spectroscopy (DVOS). DVOS is a non-invasive technique that has shown promising results in monitoring PAD (Hielscher, et al, 2019;Marone, et al, 2019;Maheshwari, et al, 2022). DVOS measures transmitted and reflected light intensities and can monitor variations of the hemoglobin distribution in different parts of the lower leg and foot.…”

Postintervention monitoring of peripheral arterial disease wound healing using dynamic vascular optical spectroscopy

“…Each of the DVOS source–detector pairs tracks changes in absorbed light and reports readings in real time as voltage measurements that are plotted on the MATLAB GUI. In a previous publications, we showed how the raw data collected by the DVOS are input to a diffusion-theory-based PDE-constrained multispectral reconstruction algorithm to extract relevant variables related to blood perfusion in the lower extremity arteries 19 , 23 . These include the time it takes for blood to accumulate (trise) and the maximum total hemoglobin (HbTmax) concentration in the artery [Fig.…”

“…There is a need for a technology that can predict wound healing outcomes as soon as possible after an intervention and with high accuracy across patient demographics. In a previous clinical pilot study, our group showed that near-infrared optical imaging has the potential to diagnose PAD in diabetic and nondiabetic patients due to differences in the hemodynamic responses of healthy versus PAD subjects to pressure cuff inflation 19 . Therefore, we hypothesize that an optical method could monitor changes in wound healing dynamics within a PAD patient cohort.…”

“…In a previous clinical pilot study, our group showed that near-infrared optical imaging has the potential to diagnose PAD in diabetic and nondiabetic patients due to differences in the hemodynamic responses of healthy versus PAD subjects to pressure cuff inflation. 19 Therefore, we hypothesize that an optical method could monitor changes in wound healing dynamics within a PAD patient cohort. In this paper, we introduce a noninvasive, nonionizing, portable instrument—the dynamic vascular optical spectroscopy system (DVOS)—as a potential way to address the existing limitations with current monitoring techniques and aid in early prognoses of chronic wound healing.…”