Dynamic intra-vascular pressure harmonic analysis.
The postulate that dynamic intra vascular pressure is a function of positional wall properties has been difficult to verify due to non-linear viscoelastic influences in arteries. It was tested, in rabbit carotid artery in vitro segments using dynamic and static input. A Multifunction Pressure Generator (MPG, Millar Inc.) provide dynamic input of defined swept frequency (2-200 Hz) pressure superimposed on multiple levels of mean intraluminal pressure (IP). Bode plots were analyzed for natural frequency (omega n), gain (dB) and damping (zeta) of the IP/MPG transfer function. An increase in omega n (all zeta > 0.25) was found with increase in mean IP. An increase in segment Elastic modulus (Em) was found with increase in static force input. Relation between Em and omega n results was demonstrative of non-linear elasticity. Results supported the postulate and verified estimating vessel properties by harmonic analysis.
Stinnett
H
H
Department of Physiology, School of Medicine, University of North Dakota, Grand Forks 58202.
Wheeldon
J
J
Hennes
M
M
D000818:Animals; D001158:Arteries / Q000502:physiology*; D001696:Biomechanical Phenomena; D001794:Blood Pressure / Q000502:physiology*; D002339:Carotid Arteries / Q000502:physiology; D004548:Elasticity; D005583:Fourier Analysis; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D011817:Rabbits; D014783:Viscosity