Mitral valve asymmetry in healthy, pathological, and repaired cases

The entry of blood into the left ventricle is regulated by the two valve leaflets. Mitral valve prolapse is the primary cause of mitral regurgitation. Mitral valve repair is the gold standard therapeutic procedure for patients with degenerative mitral valve regurgitation and follows two fundamental principles: restoring a good coaptation surface of the flap and correcting annular dilation. This study presents a first step in the direction of addressing the influence of valve geometry on valve fluid dynamics and mitral regurgitation. To this end, it develops a systematic analysis to identify how the level of regurgitation and the efficiency of flow transit in the left ventricle depend on the degree of asymmetry of the leaflets. The analysis is performed starting from a mathematically designed mitral valve and then extended to the actual valves extracted from medical imaging. The specific objective is to evaluate the changes in mitral regurgitation associated with the symmetrical properties of the mitral valve. The broader aim is to begin building physics-based means for evaluating repair options and prosthetic design. Results showed that valve shape does not affect flow; sub-volumes are similar to inflow and vary to outflow due to the presence of false regurgitation under healthy/repaired conditions and regurgitation under pathological conditions affecting the amount of direct flow, delayed and finally the Stroke volume. The best valve asymmetry point was found to be 0.25, while the optimal range was between 0.4 and 0.2, giving an important suggestion to valve surgery.