Endo-MASS: Multi-signal Acquisition System and Software for non-invasive assessment of endothelial function

Endothelial dysfunction (ED) is a reliable biomarker for cardiovascular diseases and thus has significant potential as a screening tool. However, non-invasive methods for measuring endothelial function have a high degree of variability. Triangulation of observations from multiple indicators can mitigate this problem. This work presents Endo-MASS, a modular device capable of simultaneously acquiring multiple biosignals, including photoplethysmography (PPG), impedance plethysmography (IPG), peripheral arterial tonometry (PAT), and temperature. Concurrent measurements are obtained from all four modalities at an adequate sampling rate to measure transient changes in vascular function during reactive hyperemia of the forearm. We confirm that Endo-MASS could differentiate healthy and impaired endothelial function from data collected from a cohort of subjects. Hence the design and implementation of device serve as a foundation for using multiple modalities to improve ED diagnosis, and for research of novel markers of ED such as bioimpedance.