Arterial and left-ventricular ageing strongly affects morbidity and mortality. It is characterized by stiffening, dilation and lengthening of large arteries, microcirculation changes, and alteration of heart contracting capacity and timing. The scientific community is debating the evaluation, impact, and interaction among these fundamental processes. As fluid dynamics play a key-role, our aim is to use a physically-based model of the heart-arterial tree hemodynamics to investigate quantitatively these processes.

Our multi-scale mathematical model considers lumped descriptions of left ventricle, aortic valve dynamics and microcirculatory distal volumes, and the 1D characterization of large-to-medium arteries. Notice that model has been validated in patient-specific settings against a population of six healthy young men. In the present work, starting from parameters statistically representing a healthy young man, the ageing of both heart and arterial tree is simulated by changing the diameter, length, wall thickness and mechanical properties of large arteries, and the left-ventricular force of contraction and its activation time.

Once the main features of the ageing heart-arterial interaction are simulated, our efforts are focused to reproduce the isolated systolic hypertension (ISH) coherently with the most advanced literature data about this pathology. With the aim to elucidate the links between ISH and “healthy” ageing, the key-role of aortic stiffening and remodeling as well as the consequent early-return of reflected pressure wave and the different ventricular ejection pattern are investigated and discussed, paying attention to the physical process identification and understanding.