The objective of the research work was to develop devices and algorithm for synchronous recording of pulse waves and ECG for measuring the delay time of pulse waves in the branches of various arteries relative to the R wave on an ECG, and to carry out computer simulation of the pulse wave propagation process to determine the dependence of the pulse wave propagation velocity on branching and other hemodynamic and morphological parameters of blood vessels. Material and methods. The study was conducted in 74 healthy subjects aged 18-23 years. The propagation time of the pulse wave by the arterial branches of the vessels of the common carotid, internal, external carotid and radial arteries was measured. The time was calculated by the delay of the beginning of the pulse wave relative to the tip of the R wave on the ECG. Vascular pulsations were recorded using mechanical sensitive and photosensitive sensors, which signals were amplified, digitized, recorded and analyzed using original computer soft wares. Computer simulation of the propagation of pulse waves along the wall of an “equivalent” vessel corresponding to the branching of several arterial vessels was carried out. Results. The velocity of propagation of a pulse wave along the branches of small arterial vessels was lower than its value for larger main arteries. The simulation results confirmed that the propagation velocity of a pulse wave can significantly slow down its movement along branched arterial vessels, which differ in the mechanical properties of the main arteries. Conclusion. The data obtained indicate that the developed devices and measurement algorithms make it possible to register pulse waves of various small arteries and obtain reproducible indices of the delay time of the pulse wave relative to the R wave on the ECG. The time and velocity of the pulse wave propagation depends on the length of the studied vessels, the mechanical properties of the walls of the vessels, which follows from the comparison of the obtained data with the morphological features of the structure of vascular networks. Simulation results for an “equivalent” vessel show that one of the possible causes of a lower pulse wave propagation velocity in small vessels is lower mechanical properties of the branches of small vessels compared with those of larger arteries. However, the identification of the nature of these dependencies and their connection with stiffness of the walls of small vessels requires further study.
Quantification of arterial wall inhomogeneity size, distribution, and modulus contrast using FSI numerical pulse wave propagation
