A lumped hydrodynamic model to assess ageing and hypertension effects on the aortic stiffness

A Windkessel model is used to evaluate and separate the effects of ageing from those of hypertension on the aortic flow and pressure waveforms. The ageing- and hypertension-induced changes in the blood flow and pressure behaviour are simulated by using clinical data concerning the dependence of the Young modulus and aortic input impedance on age. The simulated pressure and flow waveforms show a typical steepening due to the ageing process. Using the model outcomes, we separate the effect of arterial tissue ageing from the effect of hypertension (here intended as a generic increase in mean blood pressure). The age-dependent component results to be more important than the pressure-dependent one especially in young and middle-aged individuals. However, the relative importance of the hypertension-driven term increases for the elderly, and reaching a value of the order of 20% becomes relevant. All the obtained results agree well with the qualitative expected behaviour.