Transapikalinės mitralinio vožtuvo korekcijos skaitinis modeliavimas

This dissertation presents the numerical modeling approach for the simulation of transapical mitral valve (MV) repair procedure. The main object of the research is the development of the finite element (FE) model of the MV with ruptured chordae tendineae and its application for modeling of MV repair with neochordae implantation through the transapical approach. The dissertation aims to develop and implement a numerical model of the MV for quantitative evaluation of transapical MV repair surgical procedure and its effect on post-operative MV function. The work presents five tasks. Firstly, studies describing computational models used for investigation of MV biomechanical functions and evaluation of novel MV repair surgical techniques are reviewed. Next, the modeling strategy for the numerical simulation of virtual transapical MV repair procedure is developed. Patient-specific echocardiographic image data are obtained for the reconstruction of MV geometry and creation of structural FE model with MV prolapse. Virtual repair using different neochordal lengths is performed and the systolic function of the MV model is simulated. Finally, the outcomes of virtual transapical MV repair are evaluated and the eligibility of numerical modeling strategy is considered. The present thesis consists of an introduction, three main chapters, general conclusions, references, a list of publications by the author on the topic of the dissertation and a summary in Lithuanian. The introduction presents the research problem, the relevance of the thesis, the object of the research, formulates the aim and the tasks of the work, describes the research methodology and scientific novelty, considers the practical significance of the results and the defensive statements. Chapter 1 discusses the problem of MV prolapse from both medical and mechanical point of view. In the medical part, the anatomy and physiology of the human heart are described and thorough analysis of the MV structure is presented. In the mechanical part, an overview of studies describing computational MV models is provided and the models analyzing different MV repair techniques are distinguished. Chapter 2 introduces the modeling strategy applied for virtual transapical MV repair and its mathematical formulation. Chapter 3 presents the systolic function simulations of virtual repair procedures using two sets of patient-specific data and evaluates the parameters calculated during these simulations before and after virtual repair. The results of this dissertation were published in 4 scientific papers: two articles in journals with impact factor indexed in Clarivate Analytics Web of Science database, one article in a journal indexed in other international databases and one paper in international conference proceedings. These results were presented at 7 international conferences.Dissertatio