In-Silico assessment of aortic valve function and mechanics under hypertension

Area of Science:

• Cardiovascular Mechanics
• Biomedical Engineering
• Pathophysiology of Valve Disease

Background:

• Calcific aortic valve disease (CAVD) is the most prevalent heart valve disorder.
• Hypertension is a significant risk factor for CAVD, but underlying mechanisms remain unclear.
• Aortic valve (AV) tissue is sensitive to mechanical forces, suggesting a role for hypertension-induced stress.

Purpose of the Study:

• To investigate the impact of normotensive, pre-hypertensive, and hypertensive conditions on AV function and mechanics.
• To test the hypothesis that hypertension induces mechanical stress states conducive to CAVD.
• To utilize fluid-structure interaction modeling to compare AV behavior across different blood pressure levels.

Main Methods:

• Fluid-structure interaction modeling was employed in an idealized aortic root geometry.
• Arbitrary Lagrangian-Eulerian approach computed AV flow and leaflet dynamics.
• Analysis focused on fluid wall shear stress (fWSS) and leaflet mechanics (coaptation angle, tensile stretch) under varying pressure conditions.

Main Results:

• Hypertensive conditions increased flow vorticity and reduced leaflet coaptation angle in a pressure-dependent manner.
• Elevated pressures led to increased fluid wall shear stress (fWSS) on leaflets, with varied regional alterations.
• Hypertension increased leaflet tensile stretch, particularly on the left- and non-coronary leaflets.

Conclusions:

• Hypertension induces complex fluid and structural stress alterations in AV leaflets.
• Findings support a mechanical etiology for CAVD in hypertensive individuals.
• This mechano-etiology may explain the high prevalence of CAVD in patients with hypertension.