Numerical modeling of left ventricular hypertrophy with aortic stenosis and systemic hypertension

It has been reported that 30-40 % of patients with aortic stenosis are hypertensive. In such patients, the left ventricle faces a double (i.e. valvular and vascular) pressure overload what results in subsequent wall volume hypertrophy. From a clinical standpoint, it is difficult to separate the respective contributions of aortic stenosis and hypertension to left ventricular burden and patient's symptoms and thus to predict whether valve replacement would be beneficial. The objective of this theoretical study was therefore to investigate the relative effects of valvular and vascular afterloads on left ventricular hypertrophy. We used a ventricular-valvular-vascular mathematical model in combination with the Arts' model describing the myofiber stress. Left ventricular wall volume was computed for different aortic blood pressure levels and different degrees of aortic stenosis severity. Our simulations suggest that, in patients with aortic stenosis, the presence of concomitant systemic hypertension has a major influence on the development of left ventricular hypertrophy. These results also suggest that mild-moderate aortic stenosis has a less pronounced impact on left ventricular wall volume when compared to hypertension. On the other hand, when the aortic stenosis is severe, wall volume increases exponentially with increasing aortic stenosis severity and the impact of aortic stenosis on left ventricular hypertrophy becomes highly significant.