An Image-Free Ultrasound-Based Approach for Combined Assessment of Local and Regional Arterial Stiffness in Humans

Arterial stiffness is a cardinal marker of vascular aging, representing the cumulative impact of mechanical and biological stressors on the vessel wall resulting from aging and various cardiovascular risk factors, which lead to alterations in the material properties and wall mechanics of both central and peripheral arteries. Arterial stiffness has been identified as an independent predictor of cardiovascular morbidity and mortality. Based on whether the stiffness assessment is performed at a specific anatomical location or across a segment of the arterial tree, arterial stiffness measurements are broadly categorized as local and regional assessments. Local measurement involves quantifying arterial wall properties, including compliance, distensibility, or elastic modulus, while regional assessment is based on measuring the velocity of pulse wave propagation along an arterial segment. Here, we present a validated, image-free, ultrasound-based approach capable of simultaneously assessing both local and regional arterial stiffness in humans. The technique involves insonating the common carotid artery using a single-element piezoelectric ultrasound probe and real-time tracking of echoes originating from the arterial walls to capture the carotid artery distension waveform. Local measures of arterial stiffness are derived from distension data and carotid blood pressure. An oscillometric cuff applied to the thigh is used to simultaneously acquire the femoral pulse waveform and compute carotid-femoral pulse wave velocity by determining pulse travel times to the carotid and femoral sites, along with surface-measured arterial path lengths.