The influence of tricuspid annuloplasty prostheses on ovine annular geometry and kinematics.

BACKGROUND

Surgical repair of functional tricuspid regurgitation is centered on annular reduction with artificial rings; however, the precise effect of prosthesis implantation on annular geometry, dynamics, and strain is unknown.

METHODS

Forty healthy sheep had sonomicrometry crystals implanted around the tricuspid annulus and onto right ventricle free wall. Ten animals underwent tricuspid annuloplasty with a flexible Duran AnCore ring (Medtronic, Minneapolis, Minn) (28 ± 1 mm), 10 with Contour 3D rigid ring (Medtronic) (29 ± 1 mm), 10 with hybrid Tri-Ad Adams band (Medtronic) (28 ± 1 mm), and 10 had no prosthesis (control group). Pressure sensors were inserted in the left ventricle, right ventricle, and right atrium. Data were acquired with open chest after weaning off cardiopulmonary bypass and hemodynamic stabilization. Annular area, global and regional contraction, height, and strain were calculated based on cubic spline fits to crystal locations.

RESULTS

Tricuspid annular area contraction during the cardiac cycle was 11% ± 3% in the control group. The Contour 3D ring significantly impaired annular contraction (2% ± 1%) whereas the Duran AnCore ring and Tri-Ad Adams band (9% ± 3% and 8% ± 4%, respectively) permitted dynamic area change. Global perimeter reduction was 6% ± 1% in the control group and decreased in the Duran AnCore (3% ± 1%), Contour 3D (0.4% ± 0.2%), and Tri-Ad Adams (3% ± 1%) groups (all P values < .001 vs control). Annular height was 6.2 ± 2.0 mm in the control group, unchanged in the Contour 3D (4.9 ± 1.1 mm) but reduced in the Duran AnCore (3.1 ± 1.3 mm) and Tri-Ad Adams (3.1 ± 1.0 mm) groups (P < .001 Duran AnCore and Tri-Ad Adams vs control). Rings perturbed systolic global annular strain (control, 5.3% ± 1.8%; Duran AnCore, 2.3% ± 1.0%; Contour 3D, 0.6% ± 0.2%; and Tri-Ad Adams, -2.6% ± 0.7%) with Contour 3D inducing the biggest change (P < .05 vs other groups).

CONCLUSIONS

In healthy ovine hearts, flexible and hybrid rings better preserved annular dynamics and strain, whereas the rigid ring maintained 3-dimensional geometry. These data may aid the design of optimal tricuspid annular prostheses and improve durability of valve repair.