Vascular Wall Stiffness Indices Detection Using an Accelerometer-Based System

Abstract

The measure of arterial stiffness is significant for the diagnosis of the cardiovascular health. A prototype accelerometer- based system for vascular stiffness indices detection is proposed and experimentally validated. The developed accelerometer-based system could continuously capture the accelerations related to the displacement of the carotid arterial walls. The measured accelerometric waveforms are recorded by a data acquisition card for signal processing and analysis in real-time. The recorded accelerometric signals from the carotid skin surface are double- integrated and calibrated linearly using our clinically validated ARTSENS® (ARTerial Stiffness Evaluation for Noninvasive Screening) device to estimate the subject-specific one-time calibration coefficients. The acquired accelerometric signal with these calibration coefficients was used to estimate the diameter parameters such as arterial distension ($\Delta \textbf{D}$), end-diastolic diameter ($\textbf{D}_{\mathbf {d}}$), and systolic diameter ($\textbf{D}_{\mathbf {s}}$). 12 subjects (7 males, 5 females, age $=25.42\pm 2.5$ years) with no prior history of cardiovascular diseases were enrolled for the in-vivo validation study. The accelerometer-based system could capture continuous distension waveforms for all the recruited subjects. Arterial stiffness indices such as stiffness index (β), arterial compliance (AC) and Peterson's elastic modulus ($\textbf{E}_{\mathbf {p}}$) were calculated using the obtained diameter parameters from the accelerometer-based system. The correlation ($\textbf{R}^{\mathbf {2}}$) for β, AC and $\textbf{E}_{\mathbf {p}}$ observed between ARTSENS reference device and accelerometric system were 0.93, 0.95 and 0.94 respectively. Bland-Altman plots of β, AC, and $E_{\mathbf {p} }$ of ARTSENS reference device and the accelerometric system shows a small mean bias of 0.07, -0.001 and 0.81 respectively. The preliminary results suggest the potential of the accelerometer- based system for vascular wall stiffness indices detection.