Figure 3.

The upper part gives a schematic representation of the BP curve on the right, and the forward and reflected wave on the left. In the lower part, the BP curve is represented in younger (on the left) and in older (on the right) subjects. Augmentation index (AIx) is the ratio between: 1) the difference between peak SBP and the shoulder of the ascending part of the BP curve, and 2) pulse pressure. AIx, measured in %, represents the supplementary increase in SBP due to wave reflections. This hemodynamic profile is observed in the elderly, not in young people. MAP is mean arterial pressure, corresponding to the steady pressure necessary to a continuous cardiac pump.