Exploring hemolysis due to paravalvular leakage in artificial heart valves

Abstract

Artificial heart valves require a surgical suture to keep them in place. These sutures can become infected or degrade over time, which can give rise to the phenomenon of paravalvular leakage. The defect compromising flow occurs due to a gap or channel between the rim of the valve and the heart wall. Regurgitation through the separation subjects blood cells to flow conditions and stresses outside of their normal operating conditions and can cause hemolysis. This study on paravalvular leakage of a bileaflet mitral valve prosthesis builds on previous computational work done to develop a model for hemolysis pertinent to turbulent flow. A three-dimensional model of the left atrium was used to calculate the amount of hemolysis caused by paravalvular leakage. This three-dimensional model was examined using computational fluid dynamics, in which the Kolmogorov Length Scale of the eddies involved was calculated, and the technique of eddy analysis was used to determine how much hemolysis occurs. The vast majority of the damage is found to be caused by the channel which allows paravalvular leakage, and not the flow within the atrium itself, though the amount of hemolysis predicted is lower than expected from its medical relevancy, leading to the assumption that the geometry in question needs to be altered for future work.