Functional Tricuspid Regurgitation

Functional tricuspid regurgitation (FTR) is an important prognosticator in many cardiac diseases. Although surgical intervention has been being frequently applied, the success of current repair techniques is often uncertain and observation of residual or progressive FTR after tricuspid valve annuloplasty is not uncommon. Standard views obtained with two-dimensional transthoracic echocardiography, due to its inherent limitations, failed to evaluate geometric changes associated with FTR accurately. Transthoracic three-dimensional echocardiography (3DE) has revolutionized our approach for better understanding the 3D geometry of the tricuspid annulus both in normal subjects and in patients with FTR. The tricuspid annulus was found to be a non-planar structure with a distinct bimodal or saddle-shaped pattern like the mitral annulus, whereas, in patients with FTR, the annular area was larger and the annulus was flatter with markedly decreased annular height, which diminished the saddle shape. Potential contribution of right ventricular or right atrial geometric changes to the tricuspid annulus remodeling in FTR can also be evaluated using transthoracic 3DE data sets. 3DE, performed before and after the tricuspid annuloplasty, can provide an excellent opportunity to evaluate geometric changes associated with persistent or progressive FTR after the tricuspid annuloplasty. The current surgical approach can achieve tricuspid annulus size reduction at the expense of aggravation of leaflet tenting, which can explain suboptimal surgical results. 3DE color Doppler images can be adequately used for cross-sectional images of the vena contracta using multiplanar reconstruction images, which is useful to assess the severity of FTR. Thus, comprehensive and accurate evaluation of FTR is possible using 3DE and its impact to improve clinical outcome should be further tested.