8.2 COMPARISON OF THREE DIFFERENT METHODS TO CALCULATE AORTIC PULSE WAVE VELOCITY (PWV) USING A 1D MODEL OF THE SYSTEMIC CIRCULATION

Abstract

Aortic pulse wave velocity (PWV) is a measure of the stiffness of the large arteries, and is often used as indicator of clinical cardiovascular risk. Yet, methodological issues still exist on how PWV should best be measured. We have used a 1D arterial network computer model of the systemic circulation to compare three different methods to determine aortic PWV: PWVcar-fem (∼ carotid-femoral PWV, the current clinical gold standard method), PWVATG (∼ PWV computed with a new device called Arteriograph, making use of only one brachial pressure recording) and PWVtheor (∼ theoretical PWV according to the Bramwell-Hill equation). Different model parameters such as arterial distensibility, terminal resistance (R), cardiac contractility (Emax) and duration of the heart cycle (HC) were varied to obtain in total 42 different simulations. We found a good correlation between PWVtheor and PWVcar-fem (R2=0.95) or PWVATG (R2=0.94) but the latter were systematically lower than PWVtheor (with 1.08±0.70m/s for PWVcar-fem and 2.17±0.42m/s for PWVATG respectively). For both methods, Bland-Altman plots showed that the underestimation increases for higher values of PWV (figure not shown). Comparing PWVcar-fem with PWVATG, both methods correlate well (R2=0.90), with PWVcar-fem being on average 1.09±0.48m/s higher than PWVATG. In conclusion, in our computer model study, both the carotid-femoral PWV and the Arteriograph method provide values that correlate well to aortic PWV, but the actual values are lower than the theoretical ones following from the Bramwell-Hill formula.