P120: A Model-Based Study on The Evolution of Blood Pressure During Ageing

Abstract

Background

Hypertension being a major risk factor of cardiovascular mortality, there is a pressing need to understand the ageing mechanisms that lead to the continuous increase of pulse pressure and systolic blood pressure over time. Alterations in both forward and backward waves with age have been widely recognized as key features affecting the development of hypertension, with investigators, however, not reaching a consensus on the relative importance of each wave component (1,2).

Objective

The aim of the current investigation was to examine the wave profile over time after developing an age-adapted, mathematical, one-dimensional model of the cardiovascular system.

Methods

Our state-of-the-art 1-D model (3,4) was extended to include turbulence and inertial effects of the flow exiting the left ventricle. Literature data on the age-associated changes in arterial stiffness, peripheral resistance and cardiac contractility were gathered and used as an input for the simulation.

Results

The predicted evolution of pressure and augmentation index with age followed accurately the curves obtained in a number of large-scale clinical studies. Analysis of the relative contribution of the forward and backward wave components showed that the forward wave becomes the major determinant of the increase in central and peripheral SBP and PP with advancing age.

Conclusions

The 1-D model of the ageing tree and heart captures faithfully and with great accuracy the central pressure evolution with ageing. The stiffening of the proximal aorta and the resulting augmentation of the forward pressure wave is the major contributor of the systolic pressure augmentation with age.