Pulse wave velocity measurement by cross-correlation of Doppler velocity signals. Application to elderly volunteers during training.

Pulse wave velocity (PWV) measurement is widely used for the indirect assessment of arterial wall distensibility. In order to improve its measurement technique, we built a system performing the calculation of the cross-correlation function of Doppler velocity signals. In 12 normal subjects and 10 patients, the mean difference between duplicate measurements was 0.7 +/- 7.8% (NS). We tested this technique in 15 elderly volunteers before and after a three months training period. Brachial and tibial systolic blood pressure decreased respectively from 18.1 +/- 2.2 kPa to 16.7 +/- 1.9 kPa (p = 0.008) and from 21.1 +/- 3.4 kPa to 18.4 +/- 2.5 kPa (p = 0.003), while lower limb PWV decreased from 8.96 +/- 1.26 to 7.92 +/- 1.22 m.s-1 (p = 0.016). Therefore, automatic PWV measurement using the cross-correlation technique allows to demonstrate training induced changes in PWV, although concomitant changes in blood pressure must be considered in their interpretation.