Pulse wave velocity in veins (vPWV) has recently been reconsidered as a potential index of vascular filling, which may be valuable in the clinic for fluid therapy. The measurement requires that an exogenous pressure pulse is generated in the venous blood stream by external pneumatic compression. To obtain optimal measure repeatability, the compression is delivered synchronously with the heart and respiratory activity. We present a portable prototype for the assessment of vPWV based on the PC board Raspberry Pi and equipped with an A/D board. It acquires respiratory and ECG signals, and the Doppler shift from the ultrasound monitoring of blood velocity from the relevant vein, drives the pneumatic cuff inflation, and returns multiple measurements of vPWV. The device was tested on four healthy volunteers (2 males, 2 females, age $33\pm 13$ years), subjected to the passive leg raising (PLR) manoeuvre simulating a transient increase in blood volume. Measurement of vPWV in the basilic vein exhibited a low coefficient of variation ($3.6\pm 1.1\%$), a significant increase during PLR in all subjects, which is consistent with previous findings. This device allows for carrying out investigations in hospital wards on different patient populations as necessary to assess the actual clinical potential of vPWV.

Local carotid pulse wave velocity (cPWV), a hemodynamic variable related to arterial stiffness, is a recognized risk indicator for cardiovascular disease. Yet, current methods for its estimation pose challenges, requiring multiple simultaneous local measurements, as is the case for the established Bramwell-Hill (BH) method, or relying on assumptions that may not universally apply, as for single-measurement loop-based methods. This study introduces a novel, non-invasive, single-measurement method for estimating local cPWV. The proposed method relies solely on morphological indices derived from the carotid velocity waveform, measured via pulsed wave Doppler (pw-D) ultrasound. A multivariate regression (MVR) model relating eight such indices to cPWV was trained on a large available virtual cohort (N=5,160), previously generated via one-dimensional hemodynamic modeling. The MVR model was then tested on a clinical dataset of 27 cardiac surgery patients, showing moderate but significant correlation with the reference Bramwell-Hill method (r=0.54, p<0.01), and Bland-Altman values falling within clinically acceptable thresholds (mean difference 0.16 m/s, limits of agreement ±1.98 m/s). The proposed method outperformed the alternative pressure-less flow-area loop (QA-loop) method, which compared poorly to reference BH values (r=0.47, p<0.05, mean difference 0.72 m/s, and limits of agreement ±5.41 m/s). Furthermore, the proposed method showed the lowest intra-subject coefficient of variation (median 2.4%, interquartile range (IQR) 0-4.2%), and measurement-related uncertainty (median 0.11 m/s, IQR 0.07-0.23 m/s) among the three compared methods.