Pulse Wave Acceleration—A Novel Biophysical Parameter

Pulse wave propagation through blood vessels is affected by many biophysical parameters that change with aging. The aim of this study was to investigate both theoretically and experimentally how the pulse wave velocity changes in the vertical position and to introduce a new parameter in biophysics: pulse wave acceleration (PWA). Using a biophysical model of the cardiovascular system, placed in horizontal and vertical positions, pressure waveforms were measured along the arterial tree at several sites at different diastolic pressures and pump frequencies. Blood flow waveforms on the carotid and femoral arteries in the supine and standing positions were measured on the subjects. The results showed that the pulse pressure wave accelerates in the direction of gravity and decelerates in the opposite direction both in the model and in humans. A new biophysical parameter, PWA, was defined, and the experimental results are in agreement with the mathematical model. Due to the acceleration of the pulse wave, the reflected wave in the standing position arrives earlier in systole and contributes to the increase in pressure. This emerging biophysical parameter may contribute to a better understanding of the phenomenon of wave propagation of blood through blood vessels.