Biomechanical investigation of tricuspid valve dynamics and the effect of annuloplasty techniques during acute right-ventricle pressure overload

Objective Current surgical strategy for functional tricuspid regurgitation comprises annular reduction annuloplasty. The substantial recurrence rate points to incomplete understanding of tricuspid valve(TV)-right ventricle(RV) relationship during pathological loading. This study aims to quantify TV dynamics during progressive right-ventricle pressure(RVP) overload, comparing suture-based, rigid ring- and flexible band-annuloplasty. Methods In a porcine model, TV-RV geometry was quantified by digital sonomicrometry. Beating-heart TV repair with partial suture-based Kay-annuloplasty(N=9), rigid 3D-ring annuloplasty(N=10) and flexible band annuloplasty(N=8) was performed and compared with a control-group(N=10). Data was collected during baseline and acute RVP-overload by pulmonary artery banding. Results All annuloplasty techniques showed significant annular reduction (P<0.05) with restricted antero-septal and septo-lateral displacement, compared to controls. The Band-group showed greater antero-lateral displacement but lower antero-septal displacement than the Kay-group. In controls, RVP-increase induced tensile strain in the antero-septal to mid-anterior and mid-posterior to postero-septal regions, which was effectively reduced after annuloplasty. Leaflet dynamics did not differ between groups during RVP-increase. Annuloplasty resulted in less septal and posterior leaflet retraction during RVP overload-related radial RV dilation compared to controls. Conclusions All annuloplasty techniques provide adequate annular stabilization but with different effects on annular geometry and strain distribution. Despite effective annular stabilization, leaflet dynamics were not improved during RVP-overload. However, annuloplasty prevented increased septal and posterior leaflet retraction during acute radial RV dilation.