Influence of vascular smooth muscle activation on the aortic hydraulic filtering performance in conscious dogs

To evaluate arterial physiopathology, complete arterial wall mechanical characterization is necessary. In this study, parametric models were implemented to assess the arterial system dynamics based on instantaneous descending thoracic aortic pressure and diameter measurements. Stress-strain relationships in control state and during smooth muscle activation by continuous administration of phenylephrine were obtained. The linear autoregressive (AR), autoregressive-moving average (ARMA) models and the nonlinear truncated Volterra series and Bilineal models (BL) were fit to the input-output (stress-strain) data on eight chronically instrumented conscious dogs. Model residual variance was used as the primary intermodel comparison criterion. Results of experiments comparing the models performance are presented. Aortic hydraulic low pass filter was also evaluated, using the mean best fit order ARMA model over all the cases considered.