Worldwide, at least 200 million people are affected by peripheral vascular diseases (PVDs), including peripheral arterial disease (PAD), chronic venous insufficiency (CVI) and deep vein thrombosis (DVT). These diseases have considerable socioeconomic impacts due to their high prevalence, cost of investigation, treatment and their effects on quality of life. PVDs are often undiagnosed with up to 60% of patients with PVD remaining asymptomatic. Early diagnosis is essential for effective treatment and reducing socioeconomic costs, particularly in patients with diabetes where early endovascular treatment can prevent lower extremity amputation. However, available diagnostic methods simply do not meet the needs of clinicians. For example, duplex ultrasound or plethysmography are time-consuming methods, costly and require access to highly trained clinicians. Due to the cost and time requirements of such methods, they are often reserved for symptomatic patients. On the other hand, the Ankle Brachial Index (ABI) test is cheap but has poor sensitivity for those patients with diabetes and the elderly, both growing high-risk populations. There is an urgent need for new diagnostic tools to enable earlier intervention. Researchers at the MARCS Institute have developed a novel hemodynamic monitor platform named HeMo, specifically for the assessment of peripheral blood flow in the leg. This development aimed to provide a fast and low-cost diagnosis of both peripheral arterial disease and chronic venous insufficiency. This work first provides a comprehensive literature review of the existing non-invasive diagnostic devices developed since 1677 to highlight the need of development of a new blood monitoring tool. Second, it presents the simplified circuit of the HeMo device and provides series of pilot experiments with HeMo demonstrating its potential for diagnosis of both peripheral arterial disease and chronic venous insufficiency. Third, it presents a quantitative characterisation of the electrical behaviour of the electro-resistive band sensors with the development of an expansion/contraction simulator rig and using spectral analysis. The characterisation of the electro-resistive band was essential to understand the nonlinear electrical behaviour of such sensors and would be of interest for other users and uses of the electro-resistive band sensors. However, in another perspective this sinusoidal linear stretching movement and the presented method shows an example for the application of the presented rig, highlighting that the same technique could be used for characterisation of similar stretchable sensors. Fourth, it shows data from a healthy population, assessing the performance of HeMo compared to light reflection rheography (LRR sensor-VasoScreen 5000) for the assessment of venous function. Fifth, it presents human study data where the performance of HeMo is compared to photoplethysmography (PPG sensor-VasoScreen 5000) for the evaluation of the arterial function. Overall, the presented work here, steps toward development of the final version of a novel hemodynamic monitoring device, and its validation
