How to assess pulse wave velocity during transthoracic echocardiography? Comparison of femoral, carotid and radial time to flow
Authors: Mozdzan M , Mozdzan M , Balcerak M , Pawlos A , Gorzelak-Pabis P , Witowska A , Staciwa M , Broncel M , Broncel M , Wierzbowska-Drabik K 
Published: January 2025

Abstract

Background
Pulse Wave Velocity (PWV) is a key parameter for arterial stiffness assessment, which provides significant prognostic information in a wide range of patients. However, the access to the dedicated devices, additional time and logistics needed during the separate study limit significantly the feasibility of this important variable.

Purpose
Our aim was to elaborate the simplest and timesaving method for routine TTE assessment, noninvasive and in maximal way patient and user friendly. We tested pulsed wave velocity calculation with TTE (ePWV) which however includes the measurement of the distance between carotid and femoral artery and its simplification by using as a proxy time to the onset of blood flow in femoral artery (TF) with possible indexing to patient’s height for further standardization and inter-patient comparisons. In the second step we compared the utility of time to flow measured with linear probe in radial artery (TR) which my further simplify the procedure by easier access to radial artery.

Methods
We included 56 patients with wide age-range from 20 to 94 years(mean age 55 years; 65% female), who underwent TTE with Doppler examination of flow in left and right carotid (TC), femoral(TF) and radial arteries (TR) using respectively cardiac probe for carotid and femoral (for simplification and minimizing the time of the examination) and linear probe for radial arteries. Pulsed wave Doppler spectra were registered and times from R wave of ECG to onset of flow were measured as well as the distance between respective points of measurements. ePWV was calculated as the distance divided by estimated pulse wave transit time, see Figure 1.

Results
We found very good to good significant correlations, with p&lt;0.0001, between parameters measured in respective left and right arteries (with r= 0.92 for femorals, 0.82 for carotids and 0.73 for radials respectively). Similarly, median times to flow did not differ significantly between left and right-sided arteries although numerically the right-sided values were a few miliseconds longer e.g. 139 (118-154) vs 133 (116 – 155) ms in respective femorals, p=ns.
Calculated ePWV correlated significantly with time to flow in femoral artery (TF), underscoring its potential as a fast proxy parameter, r= -0.67, p&lt;0.0001.
Moreover, TF correlated well with TC, age and intima media thickness (IMT), whereas TR did not show significant relationships with those parameters, see Figure 2, compare left and right panels.

Conclusions
The assessment of ePWV by TTE is safe, fast and feasible with the possibility of further simplification while using time to flow in left or right femoral artery (TF). However analogous parameter obtained from radial artery did not show correlations neither with age nor with IMT as exponents of cardiovascular burden so could not be use in place of femoral examination.
Time to flow measurements.
Comparison of TF and TR correlations.