Arterial Stiffness and Dialysis Calcium Concentration

Figure 5

Contour of digital volume pulse. The digital volume pulse provides a dicrotic signal. The first peak is the incident pulse wave generated from the heart while the second peak is generated from the reflection of incidental wave from the reflection site of the lower part of the body. The peak-to-peak time (PPT) represents the transit time between the incidental and reflective waves. Since the travel distance of the reflective wave is proportional to the height (h) of the subject, a stiffness index (SI) can be calculated by dividing height by the PPT. The ratio of the height of the reflective wave (b) to the incidental wave (a) is used as the reflective index (RI).