Wave reflection affects estimation of arterial compliance by first-order lumped model

The authors applied their modified T-tube model to estimate systemic arterial parameters from measurements of ascending aortic pressure and ascending and descending aortic flows in two anaesthetised dogs, under basal and vasoconstricted (methoxamine) conditions. After parameter estimation, the authors used their T-tube model to simulate pressure waves and their forward and reflected components at different sites along the proximal descending aorta. Then, the authors evaluated the effects of reflected waves on estimates of arterial compliance, C, determined by mono-exponential fit to diastolic decay of simulated pressure waves. They found that amplitude and timing of reflected waves affected the estimates of C. When reflected waves caused evident distortion in diastolic pressure decay, vasoconstrictor-induced changes in the estimates of C were opposite to reality as judged from comparison with direct estimates of local ascending aortic compliance.<>