Mitral valve plastic surgery with an autopericardial stripe: finite element modeling

Currently, one of the methods of treatment of ischemic mitral insufficiency, leading to blood regurgitation, is annuloplasty surgery. In medical practice, MitraClip procedures and the installation of various types of rings have become widespread, ensuring reliability, biocompatibility and high manufacturability of the operation. In this paper, a modified annuloplasty using a pericardial strip is considered. A common problem of performing such operations is predicting their results depending on the correction parameters. Finite element modeling is used to solve this problem. As part of the study, a finite element model of the mitral valve was developed in the environment of the LS-DYNA software product, which allows for imitation of plastic surgery with a pericardial strip. The model is constructed using shell elements and includes valve flaps, a fibrous ring and chords. The change in the tension forces of the chords and the dilation of the fibrous ring are carried out respectively by the imposition of kinematic and force boundary conditions, which persist even after the plastic surgery. The pericardial strip, sewn to the back of the fibrous ring, is modeled by elements of a flexible thread with the possibility of pre-tensioning. The mechanical properties of the pericardium used in computer modeling were obtained from the results of tensile testing of samples. The results of a computational experiment of the effect of the pericardial strip plasty procedure on the restoration of valve leaf co-optation in the presence of dilation of the posterior part of the fibrous ring are presented. After correction according to the diagnostic data of a particular patient, the model can be used to select the necessary strip sizes during mitral valve repair surgery.