Pressure-Less Local Pulse Wave Speed Estimation in the Carotid Artery Using Ultrasound-Based Velocity Waveform Indices

The local carotid pulse wave speed, a hemodynamic variable related to arterial stiffness, serves as an indicator of generalized cardiovascular risk, yet current methods for estimating it pose challenges, requiring multiple simultaneous local measurements, or relying on assumptions that may not universally apply. This study introduces a novel, non-invasive, single-measurement method for estimating local carotid pulse wave speed. The proposed method relies solely on morphological indices derived from the carotid velocity waveform, measured via pulsed wave spectral Doppler ultrasound. A multivariate regression model relating eight such indices to carotid pulse wave speed was trained on a large virtual cohort (N=5,160), previously generated via one-dimensional hemodynamic modeling. The model was then tested on a clinical dataset of 10 patients and showed promising results, with the proposed method showing moderate but significant correlation (r=0.56, p=0.0006) with the 'gold standard' Bramwell-Hill method, and Bland-Altman values falling within clinically acceptable thresholds (mean difference 0.86 m/s, limits of agreement ± 2.71 m/s). While further validation on a larger and more diverse dataset is warranted to conclusively establish the method's clinical validity, this approach demonstrates potential for the introduction of carotid pulse wave velocity assessment in routine clinical examinations, due to the practical advantage of requiring only a single ultrasound measurement.