Mitral valves: a computational framework

The mitral valve (MV) is one of the four heart valves which locates in between the left atrium and left ventricle and regulates the unidirectional blood flow and normal functioning of the heart during cardiac cycles. Alternation of any component of the MV apparatus will typically lead to abnormal MV function. Currently, 40,000 patients in the United States receive MV repair or replacement annually according to the American Heart Association. Clinically, this can be achieved iteratively by surgical repair that reinstates normal annular geometry (size and shape) and restores mobile leaflet tissue, resulting in reduced annular and chordae force distribution. High-fidelity computer simulations provide a means to connect the cellular function with the organ-level MV tissue mechanical responses, and to help the design of optimal MV repair strategies. As in many physiological systems, one can approach heart valve biomechanics from using multiscale modeling (MSM) methodologies, since mechanical stimuli occur and have biological impact at the organ, tissue, and cellular levels. Yet, MSM approaches of heart valves are scarce, largely due to the major difficulties in adapting conventional methods to the areas where we simply do not have requisite data. There also remains both theoretical and computational challenges to applying traditional MSM techniques to heart valves. Moreover, existing physiologically realistic computational models of heart valve function make many assumptions, such as a simplified microstructural and anatomical representation of the MV apparatus, and thorough validations with in-vitro or in-vivo data are still limited. In the following, we present the details of the state of the art of mitral valve modeling techniques, with an emphasis on what is known and investigated at various length scales