Engineering Analysis of Minimally Invasive Mitral Valve Repair

Surgical treatment for severe functional MR often involves mitral annuloplasty to improve leaflet apposition and ultimately downsize the dilated mitral valve. However, the high rate of operative mortalities of up to 6 ~12% have limited the more expanded use of this procedure. Recently, minimally invasive percutaneous transvenous mitral annuloplasty (PTMA) approaches using entirely catheter-based methods have been developed to reduce procedural morbidity and mortality. One of the approaches is to utilize the proximal location of the coronary sinus (CS) to the mitral annulus (MA) to percutaneously deploy a PTMA device within CS vessel. When the device contracts, it indirectly reshapes the MA and decreases MR. Although the approach has been shown to be promising in several animal studies, device dysfunction and fatigue fracture have been reported in human clinical trials. In this research, integrated experimental and computational studies were performed to apply quantitative analysis to study the biomechanical tissue-stent interaction (TSI) between PTMA device and CS vessel. Both human and animal CS tissue properties were characterized experimentally and implemented into finite element (FE) simulation. Realistic patient-specific geometries of the CS vessel were obtained from clinical imaging data and reconstructed into three-dimensional (3D) FE model. By incorporating proper tissue material properties and realistic 3D patient-specific geometries, FE simulation of the device deployment into the vessel could be achieved to investigate TSI and the associated biomechanics involved in the system. Quantitative understanding of the biomechanics in PTMA intervention is clearly an enabling step for science-based design of the devices.