Characterizing the Effect of Hold-Down Pressure for Local and Regional Stiffness Markers

Vascular aging occurs due to pathologies and old age. Early detection of stiffness markers and arterial geometry parameters in the carotid artery serves as an essential indicator for the progression of vascular aging. The assessment of stiffness markers is typically conducted using ultrasound and tonometer-based devices. However, both types of devices present challenges, requiring skilled operators and exhibiting variability in results due to different hold-down pressures when different operators are involved. In this study, we aim to quantify the impact of hold-down pressure on diameter-based measurements and evaluate its effects on local and regional stiffness markers. To carry out this investigation, we utilized ARTSENS Plus device along with a multi-modal probe comprising an ultrasound transducer and a tonometer. A-mode ultrasound scanning was performed on the left common carotid artery of each participant, tonometer indicated the applied hold-down pressure on the participant's skin. Four trials were conducted at hold-down pressure levels of 50, 100, 150, and 200 mmHg, and RF echo frames were recorded. ARTSENS Plus signal processing algorithms were applied to obtain the recorded frames' carotid diameter and pressure, central pressure, and local and regional stiffness. The beat-to-beat repeatability of diameter values was examined, and the coefficient of variation was calculated to assess the consistency of the measurements. The system's signal-to-noise ratio exceeded 25 dB. The results section delves into the impact of hold-down pressure on diameter, carotid pressure, and stiffness markers, providing insights into the variables influencing the reliability of the measurements in this cardiovascular assessment. From all the results and observations optimal hold-down pressure can be slightly higher than diastolic pressure.