Comparison between Three-Dimensional Echocardiography and Computed Tomography for Comprehensive Tricuspid Annulus and Valve Assessment in Severe Tricuspid Regurgitation: Implications for Tricuspid Regurgitation Grading and Transcatheter Therapies.

BACKGROUND: Tricuspid valve imaging is frequently challenging and requires the use of multiple modalities. Knowledge of limitations and methodologic discrepancies among different imaging techniques is crucial for planning transcatheter valve interventions.

METHODS: Thirty-eight patients with severe symptomatic tricuspid regurgitation were included in this retrospective analysis. Tricuspid annulus (TA) measurements were made during mid-diastole using three-dimensional (3D) transthoracic echocardiographic direct planimetry (TTE_direct) and transesophageal echocardiographic direct planimetry (TEE_direct). Moreover, a semiautomated software was used to generate two-dimensional (2D) and 3D perimeter and area on transesophageal echocardiography (TEE) images. Both methods were compared with direct computed tomographic planimetry (CT_direct) and cubic spline interpolation (CT_indirect). The different TA values were used to calculate the effective regurgitant orifice area and compared with 3D Doppler vena contracta area. For tricuspid valve area TEE_direct and CT_direct as well as CT_indirect were measured.

RESULTS: Agreement between TEE and computed tomography (CT) for TA sizing was obtained using semiautomated methods (3D TEE_indirect and CT_indirect). TTE_direct was overall less reliable compared with CT. TA area quantified by TEE_direct was 25% (difference 305 ± 238 mm2 , P < .001, R = 0.9) and 19% (166 ± 247 mm2 , P < .001, R = 0.89) smaller compared with CT_direct and CT_indirect, respectively. TA perimeter measurements by TEE_direct differed by 11% compared with CT_direct (12 ± 11 mm, P < .001, R = 0.87) and 3D CT_indirect (12 ± 11 mm, P < .001, R = 0.88), and 9% compared with 2D CT_indirect (7 ± 11 mm, P = .002, R = 0.87). TEE_direct of the TA allows the most accurate calculation of effective regurgitant orifice area compared with 3D vena contracta area (-8 ± 62 mm2 , P = .50, R = 0.85). Tricuspid valve area by CT_indirect best correlated with conventional TEE_direct (80 ± 250 mm2 , P = .11, R = 0.80).

CONCLUSIONS: In patients with severe tricuspid regurgitation, semiautomated indirect planimetry results in high agreement between TEE and CT for TA sizing and measurement of the tricuspid valve area. TEE_direct of the TA allows the most accurate measurement of diastolic stroke volume for the calculation of regurgitation severity compared with 3D vena contracta area.