Suture tie-down forces and cyclic contractile forces after an undersized tricuspid annuloplasty using a 3-dimensional rigid ring in an ovine model

Abstract

OBJECTIVES This study was conducted to measure suture tie-down forces and evaluate cyclic contractile forces (CCFs) in beating hearts after undersized 3-dimensional (3D) rigid-ring tricuspid valve annuloplasty (TAP). METHODS Eight force transducers were attached to the 3D rigid TAP ring. Segments 1 to 8 were attached from the mid-septal to anterior-septal commissural area in a counterclockwise order. Two-sizes-down ring TAPs were performed in 6 sheep. Tie-down forces and CCF were recorded and analysed at the 8 annular segments and at 3 levels of peak right ventricular pressure (RVP: 30, 50 and 70 mmHg). RESULTS The overall average tie-down forces and CCF were 4.34 ± 2.26 newtons (N) and 0.23 ± 0.09 N, respectively. The CCF at an RVP of 30 mmHg were higher at 3 commissural areas (segments 3, 5 and 8) than at the other segments. The increases in the CCF following changes in the RVP were statistically significant only at the 3 commissural areas (P = 0.012). However, mean CCFs remained low at all annular positions (ranges of average CCF = 0.06–0.46 N). CONCLUSIONS The risk of suture dehiscence after down-sized 3D rigid-ring TAP might be minimal because the absolute forces remained low in all annular positions even in the condition of high RVP. However, careful suturing in the septal annular area and commissures is necessary to prevent an annular tear during a down-sized 3D rigid-ring TAP.

Suture tie-down forces and cyclic contractile forces after undersized tricuspid annuloplasty using a Tri-Ad Adams tricuspid annuloplasty ring in an ovine model

“…Contrary to a previous study showing significantly higher CCFs in the septal annular area [0.34 (SD: 0.22) N at RVP of 70 mmHg] after TAP using a 3D rigid ring, CCFs in the flexible septal band of the 3D hybrid band remained low [0.19 (SD: 0.14) N at RVP of 70 mmHg]. As in a previous study [ 14 ], the CCFs were the lowest in the posterior annular area. However, unlike the previous study, CCFs of the septal annular area were not statistically different from those of other areas, and there was no tendency of increasing CCFs towards the anterior end of the ring, indicating the favourable effect of the hybrid band in the septal and anterior parts (Fig.…”

“…In the present study, downsized ring annuloplasty was performed using a hybrid band with a wide open anteroseptal aspect to reduce the risk of potential conduction problems, flexible ends for preserving annular movement and a semi-rigid mid-portion for stabilizing the right ventricular (RV) free wall annular aspect [ 10 , 15 ]. The average suture tie-down force of 4.42 (SD: 2.32) N was not lower than the value reported by a previous study using a 3D rigid ring [ 14 ]. This might be expected because the flexible band might have no effect on lowering the suture tie-down forces.…”

“…A previous study [ 14 ] used an experimental ovine model for TAP using a downsized 3D rigid ring; it showed that the average suture tie-down force was 4.34 (SD: 2.26) N, and CCFs at RVPs of 30, 50 and 70 mmHg were 0.19 (SD: 0.17) N, 0.25 (SD: 0.16) N and 0.26 (SD: 0.21) N, respectively. In addition, the previous study showed that suture tie-down forces [septal, posterior, anterior: 6.22 (SD: 1.93) N, 2.87 (SD: 2.07) N and 3.45 (SD: 1.25) N, respectively; P < 0.001] and CCFs [septal, posterior, anterior: 0.30 (SD: 0.08) N, 0.17 (SD: 0.09) N and 0.21 (SD: 0.17) N, respectively; P = 0.002] were higher in the septal area than in the other annular part.…”

Flexible Total Ring Annuloplasty With Continuous Wrapping Suture Considering the Anatomy and Histology of the Tricuspid Valve

“…9 Lim et al reported that the septal leaflet area had higher suture tie-down force loads when performing annuloplasty in an ovine model. 15 An annuloplasty technique considering the lack of fibrous structure and fragility is necessary for successful restrictive annuloplasty with a small size ring. We performed a continuous wrapping suture annuloplasty technique using a flexible total ring, which might be less affected by the number of leaflets and fragility of the annulus structure.…”

“…9 Lim et al reported that the septal leaflet area had higher suture tie-down force loads when performing annuloplasty in an ovine model. 15…”