Computed tomographic analysis of the morphometrics and dynamics of the tricuspid annulus in secondary functional tricuspid regurgitation.

Objectives: Secondary functional tricuspid regurgitation (FTR) management remains controversial mainly due to the lack of knowledge in its pathogenesis and the difficulties to measure the actual dimensions of tricuspid annulus (TA) with current imaging methods. Using a novel method based on multiphase cardiac computed tomography (CT) scan acquisition to accurately analyze the right atrioventricular junction size, we sought to explore modifications of TA morphometry and dynamics in secondary FTR.

Methods: Echocardiographic and cardiac CT studies were obtained from 21 patients with severe mitral regurgitation (MR group) and 21 patients with dilated cardiomyopathy (DCMP group). Using an in-house software, a 3-dimensiontal (3D) semiautomated delineation of the TA perimeter was assessed. Modifications of diameters, 2-dimensional/3D areas and perimeters were analyzed through time. These 2 groups of patients were compared with 30 healthy subjects, considering the presence of a significant (≥2+) versus nonsignificant (<2+) FTR in each group.

Results: Maximum TA 3D areas were 7.0 ± 1.2 cm/m in healthy subjects at mid-to-late diastole and were smaller than in the MR group (9.8 ± 2.1 cm/m,  < .001) and the DCMP group (9.2 ± 3.0 cm/m,  < .001). In the MR group, patients with FTR <2+ had also larger TA areas and diameters than healthy patients ( < .01 for all 3D/2-dimensional parameters). TA shape was more circular only in the DCMP group with FTR ≥2+ compared with other patients ( < .05 for eccentricity). In multivariate analysis, both RA area ( < .001) and RV volume ( = .002) were independently related to TA dilatation.

Conclusions: Based on multiphase CT image analyses, TA dilatation was directly related to RV and RA enlargement. Patients with severe mitral myxomatous disease and nondysfunctional tricuspid valve had yet dilated TA, which questioned the current cut-off recommendation for concomitant tricuspid annuloplasty in this specific population.