Abstract 2264: Saddle-shaped Mitral Valve Annuloplasty Rings Provide Superior Annular Force Distribution
Introduction: New insight into the 3D dynamic behavior of the mitral valve has prompted a re-evaluation of annuloplasty ring designs. Force balance analysis indicates correlation between annulus forces and stresses in leaflets and chords. Improving this stress distribution will increase repair durability. The aim of this study was to determine the 3D force distribution in flat and saddle-shaped mitral annuloplasty rings.
Hypothesis: We assessed the hypothesis that saddle-shaped annuloplasty rings have superior systolic force distribution compared with a non-uniform force distribution in flat annuloplasty rings.
Methods: Fourteen animals were utilized in an acute porcine in vivo model. Mitral annulus 3D dynamic geometry was obtained with sonomicrometry prior to ring insertion. Strain gauges mounted on 8 dedicated D-shaped rigid flat and 6 saddle-shaped annuloplasty rings provided the force distribution perpendicular to the annulus plane (Fig⇓.).
Results: Average systolic annular height to commissural width ratio before ring implantation was 13.7 ± 1.4 % (n=14). Following ring implantation, the annulus was fixed (p<0.01). Force accumulation was seen at the anterior and commissural annular segments of the flat rings (Fig⇓.). In these segments, the difference between the two types of rings was statistically significant (p<0.05). The saddle shaped annuloplasty rings did not experience forces statistically significantly larger than zero in any annular segments (Fig⇓.).
Conclusions: Saddle shaped annuloplasty rings provide superior annular force distribution compared to flat rings. This may have important implications for annuloplasty ring selections.