CO-25: Evaluation of different methods for determining the time delay of the arterial pulse wave: application to the pOpmetre®

Abstract

Background Pulse Wave Velocity (PWV), an index of arterial stiffness, can be measured using different approaches by determining the time taken for the arterial pulse to propagate from one site to another. Here we used two different aspects to assess the PWV; the standard method Carotid-Femoral (CF) Sphygmocor (AtCor Medical – Australia) and the pOpmetre ® (Axelife SAS – France) which uses the Finger to Toe (FT) approach, The aim of this study was to evaluate the agreement between FT-PWV and CF-PWV and to assess the robustness of the foot wave detection method used by pOpmetre ® . Methods We measured 150 subjects (24 healthy normotensives and 126 hypertensive patients). In each patient, the CF and FT PWV were measured twice, and if their difference was greater than 0,5 m/s, a third measure was performed, the mean (or median if triplicate) was used. In-house software (MatLab; Mathworks) was used to calculate the propagation time from pOp-metre ® waveforms for 65 subjects using four methods, namely: maximum of second derivative (used by pOpmetre ® ), intersecting tangents, 10% threshold and the cross correlation method. Results 87 men and 63 women aged 58 ±18 years and 59±17 years respectively. Using built in algorithms, the comparisons of the PWVs and transit times showed a good agreement between the two methods. FT-PWV correlated with CF-PWV (r 2 =0.51; p 2 =0.62; p 2 =0.56; p 2 =0.61; p 2 =0.37, 10%, r 2 =0.35, cross-correlations, r 2 =0.22). Conclusions This study showed that pOpmetre ® measurements well correlated with the gold standard method and the wave foot detection algorithm used by pOpmetre ® gave the best correlation comparing to other algorithms. The FT-PWV technique has correct agreement with the reference technique, however further studies are needed to validate FT-PWV method in larger populations. Compared to CF-PWV, FT-PWV is faster, simpler to perform and importantly, more acceptable to patients.