Objectives: To define the effects of annuloplasty rings (ARs) on the dynamic motion of anterior mitral leaflet (AML) and posterior mitral leaflet (PML). Methods: Fifty-eight adult, Dorsett-hybrid, male sheep (49±5kg) had radiopaque markers inserted: eight around the mitral annulus, four along the central meridian (from edge to annulus) of the AML (#A1-#A4) and one on the PML edge (#P1). True-sized Edwards Cosgrove (COS, n=12), St Jude RSAR (St. Jude Medical, St. Paul, MN, USA) (n=12), Carpentier-Edwards Physio (PHYSIO, n=12), Edwards IMR ETlogix (ETL, n=10) or Edwards GeoForm (GEO, n=12) ARs were implanted in a releasable fashion. Under acute open-chest conditions, 4D marker coordinates were obtained using biplane videofluoroscopy with the respective AR inserted (COS, RSAR, PHYSIO, ETL and GEO) and after release (COS-Control, RSAR-Control, PHYSIO-Control, ETL-Control and GEO-Control). AML and PML excursions were calculated as the difference between minimum and maximum angles between the central mitral annular septal-lateral chord and the AML edge markers (α1exc-α4exc) and PML edge marker (β1exc) during the cardiac cycle. Results: Relative to Control, (1) RSAR, PHYSIO, ETL and GEO increased excursion of the AML annular (α4exc: 13±6° vs 16±7°*, 16±7° vs 23±10°*, 12±4° vs 18±9°*, 15±1° vs 20±9°*, respectively) and belly region (α2exc: 41±10° vs 45±10°*, 42±8° vs 45±6°, n.s., 33±13° vs 42±14°*, 39±6° vs 44±6°*, respectively, α3exc: 24±9° vs 29±11°*, 28±10° vs 33±10°*, 16±9° vs 21±12°*, 25±7° vs 29±9°*, respectively), but not of the AML edge (α1exc: 42±8° vs 44±8°, 43±8° vs 41±6°, 42±11 vs 46±10°, 39±9° vs 38±8°, respectively, all n.s.). COS did not affect AML excursion (α1exc: 40±8° vs 37±8°, α2exc: 43±9° vs 41±9°, α3exc: 27±11° vs 27±10°, α4exc: 18±8° vs 17±7°, all n.s.). (2) PML excursion (β1exc) was reduced with GEO (53±5° vs 43±6°*), but unchanged with COS, RSAR, PHYSIO or ETL (53±13° vs 52±15°, 50±13° vs 49±10°, 55±5° vs 55±7°, 52±8° vs 58±6°, respectively, all n.s); *=p<0.05. Conclusions: RSAR, PHYSIO, ETL and GEO rings, but not COS, increase AML excursion of the AML annular and belly region, suggesting higher anterior mitral leaflet bending stresses with rigid rings, which potentially could be deleterious with respect to repair durability. The decreased PML excursion observed with GEO could impair left ventricular filling. Clinical studies are needed to validate these findings in patients. © 2010 European Association for Cardio-Thoracic Surgery.
Bothe, W., Kvitting, J. P. E., Swanson, J. C., Göktepe, S., Vo, K. N., Ingels, N. B., & Miller, D. C. (2010). How do annuloplasty rings affect mitral leaflet dynamic motion? European Journal of Cardio-Thoracic Surgery, 38(3), 340–349. https://doi.org/10.1016/j.ejcts.2010.02.011