A Novel Technology for Detection of Peripheral Artery Stenosis and Quantification of Stenosis Severity, Based on the Analysis of Tissue Perfusion Dynamics. Theoretical and Clinical Studies

Background: Peripheral Artery Disease (PAD) is associated with high morbidity and mortality and affects over 200 million people worldwide. There is an unmet need to create a practical and sensitive noninvasive modality to screen the population, and for early detection of restenosis after revascularization when rapid intervention is critical. We have hypothesized that arterial stenosis induces an adaptive control response of the microcirculation and produces pathognomonic changes in the perfusion dynamics, and especially affects the initial slow-phase of the perfusion wave.

Methods: The clinical study is running in Hadassah Medical Center. We measured the perfusion dynamics from the calf of PAD patients (n=18) using impedance plethysmography (IPG), before and after revascularization. A unique algorithm was developed to extract the cardiac associated signals from the respiration-modulated signal and to segment the various phases.

Results: Arterial stenosis yielded pathognomonic changes in the perfusion dynamics that were not described before, as the prolongation of the slow-phase duration (SPd). The utility of the SPd was validated in two ways: (1) Prolongation of the SPd appeared only in patients with proximal arterial stenosis but not in patients with distal stenosis (2) Successful revascularization (evaluated by Duplex Ultrasound) significantly shortened the SPd form 103±35 ms to 35±18 ms, p=0.0015.

Conclusions: A novel modality for analyzing the perfusion dynamic was developed. The utility of identifying the slow-phase for the detection of proximal arterial stenosis was validated in PAD patients. The modality may assist in early detection of stenosis/restenosis, patient surveillance, and decision making.