ABSTRACT
INTRODUCTION: The level of smooth muscle activation or `tone' (VSMT) can be defined as an intrinsic spontaneous level of vasoconstriction that may change in response to biomechanical stimuli such as flow, pressure, hormonal stimuli, neural stimuli, and drugs. Arteries can actively modify arterial pressure pulse wave velocity (PWV) by changing smooth muscle tone and diameter with little change in the mean arterial blood pressure. OBJECTIVE: To evaluate the influence of aortic VSMT in terms of beat to beat PWV variations. METHODS: Aortic pressure-diameter (P-D) relationships were invasively evaluated in five conscious animals. An `incremental' PWV was directly derived from the P-D loops, both in purely elastic conditions as well as in the presence of VSMT. RESULTS: Beat to beat PWV waveform variations showed different behavior, where mean PWV values were higher when VSMT was included in the P-D evaluation. CONCLUSION: Changes in incremental beat to beat PWV could be attributed to the influence of VSMT.
Subject(s)
Blood Pressure , Muscle, Smooth, Vascular , Pulse Wave Analysis , Animals , Aorta , Arteries , Blood Flow Velocity , PulseABSTRACT
INTRODUCTION: The interest on computational simulations of biomedical models has increased in the last years. Nevertheless, the viscous properties of vessel all are usually neglected. MATERIALS AND METHODS: A 1D model of blood flow and its interaction with the arterial wall was implemented. Non-viscous modeling and the addition of a wall-viscosity term were considered. The goodness of fit in each case was evaluated. RESULTS: Simulated radial blood pressure was generated using central blood pressure as the input of the proposed 1D tapered model. Results obtained showed an improvement as a consequence of introducing wall viscosity into the model calculations. DISCUSSION: The effect of viscoelasticity has a great significance in the implementation of computational models, since a better fit between simulated and experimental data is achieved.
