Assessment of the Variability of an Echo-Doppler Method for Measurement of Aortic Pulse Wave Velocity

Background

Pulse wave velocity (PWV) is an indirect measure of elastic arterial stiffness. Although various methods have been established to measure PWV, the Echo-Doppler method for measuring thoracic aortic PWV (a-PWV) is a highly available and cost-effective technique within the cardiology clinic. The purpose of this study was to assess the variability of a-PWV using the Echo-Doppler method and identify the optimal number of measurements providing the least variability of a-PWV in paediatric patients and healthy controls.

Methods

Eighteen patients with a dilated proximal aorta and 21 healthy controls with a normal-sized proximal aorta (10-18 years) were evaluated. Imaging was performed in 4 studies across 2 visits. Variability comparisons were performed for short-term, medium-term, intra-reviewer, inter-reviewer, and inter-sonographer variability and analysed via intraclass correlation coefficient (ICC) and Bland-Altman plots.

Results

The ICCs were highest for 10 beats. The combined group ICCs for the variability comparisons for 10 beats were short-term (0.743), medium-term (0.723) intra-reviewer (0.978), inter-reviewer (0.729), and inter-sonographer (0.823). Bland-Altman plots showed good agreement for all variability comparisons.

Conclusions

This study has established that the measurement over 10 beats produces the lowest variability and is recommended when assessing a-PWV in both patients with a dilated proximal aorta and controls. Further, reproducibility remains high, even when accounting for sources of measurement variation, such as differences between sonographers, reviewers, and study visits.