A model approach to in situ coronary autoregulation.
Pressure and flow waveforms were recorded at the entrance of the circumflex coronary artery in anaesthetized dogs during artificial constriction and release of the aorta which caused noticeable variations in the coronary perfusion pressure. The beat-to-beat mean diastolic flow resulting from the autoregulation of the coronary bed in response to the pressure changes was analysed on the basis of a simple model. Flow variations were interpreted as the result of an active mechanism, triggered by the pressure changes and affecting the elastic behaviour of the vessels. The timing and the main characteristics of this response mechanism, after constrictions of varying duration, were evaluated and are discussed. The predicted variations in vessel distensibility and cross-sectional area were compared with data quoted in the literature, showing that the results of this procedure are compatible with those of in vitro measurements on isolated microvessels.
Guiot
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Dip. Anatomia e Fisiologia Umana dell 'Universita' di Torino, Italia.
D000222:Adaptation, Physiological; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003326:Coronary Circulation / Q000502:physiology*; D004285:Dogs; D004548:Elasticity; D006439:Hemodynamics; D006706:Homeostasis / Q000502:physiology; D008955:Models, Cardiovascular; D014655:Vascular Resistance