Stress phase angle depicts differences in arterial stiffness: phantom and in vivo study

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Biophysics

Background:

• Endothelial cells (ECs) respond to wall shear stress (WSS) and circumferential strain (CS).
• The stress phase angle (SPA) between WSS and CS is hypothesized to influence atherosclerosis.
• Lack of tools to measure WSS and CS simultaneously has limited experimental validation.

Purpose of the Study:

• To develop and utilize a non-invasive ultrasonic method to measure SPA.
• To experimentally evaluate the role of SPA in predicting early atherosclerosis.
• To investigate the relationship between arterial stiffness and SPA.

Main Methods:

• A non-invasive ultrasonic biomechanics technique was employed.
• Experiments were conducted using silicon and PVA-c phantoms of varying stiffness.
• In vivo studies were performed on healthy and atherosclerotic rat models.

Main Results:

• SPA was found to be highly negative in stiffer arteries in phantom studies.
• In rats, the atherosclerotic model group exhibited the most negative SPA.
• Healthy control rats showed the least negative SPA, while drug-treated rats had intermediate values.

Conclusions:

• Highly negative SPA is a prominent mechanical feature associated with atherosclerotic disease.
• This study provides experimental evidence supporting the hypothesis that SPA contributes to atherogenesis.
• The developed ultrasonic method offers a promising tool for assessing vascular biomechanics and predicting atherosclerosis.