Photoplethysmography Assessments in Cardiovascular Disease

Peripheral vascular disease can lead to disabling claudication symptoms, critical limb ischaemia, gangrene, and even loss of life. The simple, non-invasive, and low-cost optical physiological measurement technique photoplethysmography (PPG) has the potential to screen for such disease. Traditionally, PPG measurements have been made at a single body site, at the finger or the toe, giving basic information about the peripheral circulation. We have also investigated the value of multi-channel PPG measurements for this clinical application, complemented by state-of-the-art pulse wave analysis techniques to extract diagnostic information from the different features of the pulse in health and disease. This article describes the principle of photoplethysmography, optical methods and instrumentation systems, computer-based pulse wave analysis, and in each case related to the clinical application of vascular disease detection.