Cardiovascular diseases (CVDs) are the no: 1 cause of death in the world and now 1 in 5 heart attack patients are younger than 40 years of age. The carotid artery (central artery) gradually stiffens over time as a result of daily stress brought on by routine and high-pressure lifestyles which is a strong indicator of CVDs. To address the lack of technology for continuous measurement of carotid arterial stiffness, we have developed a wearable accelerometer system.

In this seminar, we will cover the state-of-the-art methods for ambulatory arterial stiffness evaluation, the research gaps, and the instrumentation challenges. We will show mathematically how pulse pressure (ΔP), peak distention (ΔD), and arterial stiffness indices (Ep, β, AC) are related to the novel APG-derived markers. Interestingly, we will show how both pressure and displacement information can be obtained from a single accelerometer attached to the neck. We will discuss the wearable neckband design as well as the hardware and software development of the wearable accelerometer device for real-time acquisition of acceleration plethysmogram (APG) at the carotid artery site. We will also show the performance of the wireless system in terms of hours of continuous operation and the reliability of APG signals in terms of SNR and coefficient of variation (CoV). We will present the results of an in-vitro study to understand the influence of hold-down pressure on APG signal which aided in the wearable neckband design. We will also present results from an in-vivo verification study to verify and support the novel APG-derived marker for arterial stiffness evaluation. Our results showed that the novel APG-derived marker could estimate arterial stiffness index (Ep) with a correlation of r = 0.76. We will also show the magnitude response of different novel APG-derived markers towards change in carotid arterial stiffness and compare it with the magnitude response of the arterial stiffness indices obtained from the reference device.

Further research would include the verification of the novel APG-derived markers on middle and old-age populations.