We read with great interest the paper by Gatti et al. who compared the early and late outcomes of tricuspid valve annuloplasty with a flexible band (B-TVA) or a rigid ring (R-TVA). The authors found that the annuloplasty of tricuspid valve with rigid ring was associated with higher rates of low cardiac output and transient complete atrioventricular block. No significant difference was observed in hospital mortality between R-TVA and B-TVA. There were also no significant differences in freedom from all-cause death, cardiac, cerebrovascular deaths and grade of TR ≥2. The reverse remodelling of the right atrium and tricuspid valve, which was combined with reverse remodelling of the right ventricle occurred after R-TVA and not after B-TVA [1].
We would like to add some thoughts about tricuspid valve annuloplasty using a flexible band or a rigid ring. Phannmuller et al., in their retrospective analysis of 820 patients who underwent tricuspid valve repair with either a flexible band or a rigid ring, showed that patients who received a rigid ring had a 9-fold greater incidence of ring dehiscence than did patients who received a flexible band. These ring dehiscences were almost exclusively located at the septal leaflet portion of the annulus. The authors observed that the area where they found the ring dehiscences corresponded to the end of the annular section that was most prone to dilatation. Taking into account the systolic-diastolic dynamics of tricuspid annular motion and the rigidity of the annuloplasty device, they concluded that greater forces might exist on the sutures attached to a rigid ring than on those attached to a flexible band, which might follow the natural motion of the tricuspid annulus more easily [2]. Zhu et al. in their review, concluded that although there was less risk of ring dehiscence or ring facture in the flexible group, the rigid ring, particularly the new three-dimensional MC3 ring, was inclined to be better than the flexible band in terms of a sustained effect for maintaining stable postoperative grade of regurgitation according to the current available evidences [3].
Izutani et al., in their analysis of tricuspid ring annuloplasty using a flexible band or the MC3 rigid ring, showed that rigid ring annuloplasty might be more effective for decreasing functional TR in immediate and mid-term postoperative periods [4].
Both tricuspid valve annuloplasty methods are feasible and durable for correcting functional TR. The ring of choice though (rigid enough to reduce the size of the tricuspid annulus adequately and flexible enough to conserve the motion of the ring and the action of the sphincter) is yet to be found.
Prospective studies, with a large number of patients and new ring designs, are needed for confirming the best choice.
Conflict of interest: none declared.
References
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