Influence of Annular Dynamics and Material Behavior in Finite Element Analysis of Barlow's Mitral Valve Disease

Barlow's disease affects the entire mitral valve apparatus, by altering several of the fundamental mechanisms in the mitral valve which ensures unidirectional blood flow between the left atrium and the left ventricle. In this paper, a finite element model of a patient diagnosed with Barlow's disease with patient-specific geometry and boundary conditions is presented. The geometry and boundary conditions are extracted from the echocardiographic assessment of the patient prior to surgery. Material properties representing myxomatous, healthy human and animal mitral valves are implemented and computed response are compared with each other and the echocardiographic images of the patient. This study shows that the annular dilation observed in Barlow's patients controls several aspects of the mitral valve behavior during ventricular systole. The coaptation of the leaflets is observed to be highly dependent on annular dilation, and the coaptation area reduces rapidly at the onset of mitral regurgitation. Furthermore, the leaflet material implementation is important to predict lack of closure in the FE model correctly. It was observed that using healthy human material parameters in the Barlow's diseased FE geometry gave severe lack of closure from the onset of mitral regurgitation, while myxomatous material properties showed a more physiological leakage.