Tricuspid annuloplasty is recommended during left-heart valve surgery when tricuspid annulus (TA) is dilated, independently of the degree of tricuspid regurgitation, but the methodology to measure TA and thresholds are not clearly defined. We aimed to compare TA diameter (TAD) measurements performed using bi-dimensional transthoracic echocardiography (2D-TTE) in the 4 different views to three-dimensional measurements performed during transesophageal echocardiography (3D-TEE) and to define thresholds of TA enlargement for routine practice.

2D-TTE measurement of the TAD was performed in parasternal long-axis view of the right ventricle inflow, parasternal short-axis, apical 4-chamber (A4C) and sub-costal views in 195 prospectively enrolled patients and 66 healthy volunteers. 3D dynamic volumetric datas of the TA were also acquired by TEE using a matrix array transducer (X7-2t, Philips) in the 195 patients. Multiplanar reconstructions were performed offline using dedicated software (QLab7, Philips) to measure the long-axis (LA) of the TA.

In the 195 patients, TAD measurements were not different between the 4 TTE views (P=0.13), but A4C was the most feasible and the most reproducible method (Table). TAD measurement in A4C view by TTE (3.90±0.62cm) was well correlated (r=0.84, p<0.0001) to LA by 3D-TEE (4.33±0.63cm), but with a systematic 4mm underestimation. In the healthy volunteers, mean value of TAD in A4C was 3.2±0.4cm or 1.8±0.23cm/m² and the upper limit of 95% confidence interval was 4.2cm or 2.3cm/m².

TAD measurement in A4C view by 2D-TTE was highly feasible, reproducible and accurately reflected TA size, even if it was systematically underestimating its maximal diameter. Based on measurements in healthy volunteers, we suggest to consider tricuspid annuloplasty during left-heart valve surgery when TA is more than 2.3cm/m² or 4.2cm in A4C.