The prognostic significance of right ventricular basal diameter in addition to tricuspid annulus diameter in patients underwent to tricuspid valve surgery

Abstract Funding Acknowledgements Type of funding sources: None. Background Functional tricuspid valve regurgitation occurs as a result of enlargement of the tricuspid annulus (TA) despite the normal valve structure (1). However, the tendency of the tricuspid annulus to enlarge in the posterior annular part suggests that the mediolateral diameter measurement measured by 2-dimensional (2-D) echocardiography does not provide an accurate anatomical evaluation (2). Inaccuracies in these measurements also affect the selection of the tricuspid ring in patients undergoing surgery and thus affect the short- and long-term outcomes (3). Therefore, new methods and reference points have developed in the measurement of the tricuspid annulus. Purpose In this study, we aimed to investigate the importance of apical 4-chamber tricuspid annulus diameter and right ventricular basal diameter measurements in choosing a surgical tricuspid ring size. Methods The records of 359 patients who underwent tricuspid ring annuloplasty for functional tricuspid valve regurgitation between 2018 and 2022 were retrospectively reviewed. Tricuspide anulus and right ventricular basal diameter measurements were re-evaluated echocardiographically, and surgical tricuspid ring sizes were recorded. Results There was no significant relationship between 2-D measurement of tricuspid annulus diameter and choosing surgical ring sizes (OR 0.74, 95% CI 0.51 – 1.09, p = 0.257), however, the increase in RV basal diameter size was associated with larger ring size selection (OR 2.63, 95%). CI 1.72 – 4.02, p<0.0001). Among the 5 models that predicted the surgical ring size according to the ordinal regression analysis, the models that most accurately predicted the surgical ring size were model-4, which included RV basal diameter, and model-5, which included RV basal diameter and TA diameter. (Table 1). Also, in model-5, RV basal diameter was superior to TA-diameter in showing variation in surgical ring size. Also, when the TA diameter is < 40 mm and the RV basal diameter is < 45 mm, the large ring selection rate (34 or 36) is 36.2%, but this rate is 70.9% when the TA diameter is < 40 mm and the RV basal diameter is ≥ 45. Conclusions In conclusion, when the measurements in the apical 4-chamber were compared, the effectiveness of the measurement of the tricuspid annulus in determining the surgical ring size was lower than the RV basal diameter. During pre-operative evaluation, RV basal measurement in addition to the tricuspid annulus may help in the selection of patients who require tricuspid valve annuloplasty and in determining the ring sizes.