1LMU Klinikum der Universität München Medizinische Klinik und Poliklinik I München, Deutschland
Background:
Patients with severe tricuspid regurgitation (TR) are known to be heterogenous and complex in terms of etiology, comorbidities and state of disease. Right ventricular (RV) function has shown to play a key prognostic role in the context of transcatheter tricuspid valve repair (T-TEER). Nevertheless, the assessment of RV function using 2-dimensional transthoracic echocardiography is challenging and most parameters used in daily clinical practice are subject to a variety of limitations. In this context, 3-dimensional (3D) echocardiography including strain imaging addresses some of these limitations. Recently, the concept of RV to pulmonary coupling (RVPAc) has emerged as a more precise parameter to describe RV function while respecting the mutual interdependence of the RV and the pulmonary circulation. However, despite the advantages of RVPAc as a 2D echocardiographic RV function parameter, it fails to respect the degree of volume overload/dilation of the RV, which is a key clinical tracer for right ventricular dysfunction (RVD).
Objectives:
Therefore, we aimed to analyze the complex interplay of RV dilation and RV function and its impact on outcome after T-TEER.
Methods and results:
A total of 262 patients who underwent T-TEER between April 2016 until February 2022 and had complete 3D echocardiography datasets were included in this analysis. TR patients (median age 83 [78-87) years, 46.6% female) were severely symptomatic (NYHA≥III 95.5%) with TR ≥4+ in 45.8%. RV function and dimensions were analyzed using 3D echocardiography and RV dimensions were indexed to body surface area (BSA). Predictors for 1-year mortality were evaluated using multivariate regression models. RV dilation according to 3D RV end-diastolic volume was defined as (3D-RVEDV) ≥117ml/m2 and patients were dichotomized accordingly. RV dilation was associated with increased 1-year mortality after T-TEER (HR 1.85; 1.10, 3.12; p=0.020) and increased 3D-RVEDV showed to be an independent predictor for 1-year mortality in multivariate regression analysis (HR 1.01, 1.00, 1.01, p=0.006). RV function (across all measured parameters) did not differ between groups. However, impaired RV free wall longitudinal strain (RVFWLS) was associated with increased 1-year mortality (HR 1.73, 1.02, 2.92, p=0.042). Respecting the predictive value of RV dilation, we integrated 3D-RVEDV into the concept of RVPAc. A modified RVPAc-parameter [RVFWLS/(3D-RVEDV*sPAPinvasive)] was established. 1-year survival rate of TR patients with impaired modified RVPAc was 66.1% (HR 2.87, 1.5-5.7, p=0.003). NYHA IV and a lower ratio of [3D-RVFWLS/(3D-RVEDV*sPAPinvasive)] were independent predictors for 1-year mortality after T-TEER (NYHA IV: HR 2.66, 95%CI: 1.4-5.0, p=0.003; Modified RVPAc: HR 0.10, 95%CI: 0.02-0.44, p=0.002). Additionally, the multivariate model was numerically superior to RV to pulmonary uncoupling (c-index 0.668 vs. 0.648, p=0.59).
Conclusion:
3-dimensional echocardiography is a key diagnostic tool for the assessment of the RV. The interplay of RV dimension, function and afterload seems to play an important role in the prediction of RV dysfunction and survival after T-TEER. These results further highlight the importance of adequate timing of intervention in the context of severe TR and RV dysfunction.