Left heart simulator for evaluation of prosthetic heart valves: behavior of tricuspid bioprosthetic mitral valves during diastole

The purpose of this work was to know the characteristics of tricuspid bioprosthetic mitral valves in terms of velocity fields and valve aperture areas for some instants concerning the diastole. A left heart simulator was used as an in vitro platform for the bioprostheses. A particle image velocimetry (PIV) system was applied for characterizing instantaneous 2D-velocity fields within the left ventricular model (LVM), and also for detection of mitral bioprostheses aperture areas. The ventricular states were established for 60, 70 and 90 bpm (beats per minute) and a blood analog fluid based on glycerol was employed at 36.5±0.5ºC. Two mitral bioprostheses (nominal diameter of 27 and 31 mm) and an aortic bileaflet mechanical valve (27 mm diameter) were used. Instantaneous two-dimensional velocity fields at the upper part of the LVM, for two sections (in the middle of the LVM, and also in a section at 7 mm of distance from that) were obtained. Averaged velocity vector maps (N = 50) were calculated for some instants of interest. According to different heart rates, bioprostheses and sections within the LVM, the velocity fields were presented, as well the bioprostheses aperture areas. In conclusion, the experimental scope including different ventricular states showed how the inflow characteristics of the LVM change according to the chosen variables. This information will aid the validation of a numeric model for the LVM operation, which has been elaborated (some specific methods are presented in the Appendix).