[Blood pressure and arterial stiffness. A comparison of two devices for measuring augmentationindex and pulse wave...

Augmentationindex (AIx) and Pulse Wave Velocity (PWV) give much more information on the function of the arterial tree than that obtained by blood pressure recordings. The rediscovered value of arterial stiffness measured by means of AIx or PWV is now proven as an independent cardiovascular risk factor and helps to differentiate patients at risk and their cardiovascular treatment offer. In the last decade, the methods to measure and to calculate AIx and PWV have become increasingly simple. But as the different methods use different strategies for measuring and calculating these parameters, the results concerning the same term vary, depending on the device used. We undertook nearly simultaneous recordings of AIx in 400 and of PWV in 100 treated hypertensive patients with the very new TensioClinic device developed by M. Illyés, and compared those data with measurements obtained by the SphygmoCor device. The absolute values of m (mean) and SD (standard deviation) of AIx were when TensioClinic was used m: -6.2 % +/- SD:37.9 % and by SphygmoCor m: 26,2 % +/- SD: 11,8 %. The differences were caused by the different methods. As both devices measure the same quality of vascular function, the results correlate closely with a correlation coefficient r = 0.77. In PWV the results of Aortic PWV measured by TensioClinic were m: 9.1 +/- SD: 1.8m/sec and of brachial PWV measured by SphygmoCor: 8.4 +/- SD: 1.5 m/sec. As in AIx, these results were also different, but in contrast to AIx they did not correlate (r = -0.04) because PWV depend on the artery and its physical characteristics, and we