Atrial Functional Tricuspid Regurgitation as a Distinct Pathophysiological and Clinical Entity: No Idiopathic Tricuspid Regurgitation Anymore

Functional tricuspid regurgitation (FTR) is a strong and independent predictor of patient morbidity and mortality if left untreated. The development of transcatheter procedures to either repair or replace the tricuspid valve (TV) has fueled the interest in the pathophysiology, severity assessment, and clinical consequences of FTR. FTR has been considered to be secondary to tricuspid annulus (TA) dilation and leaflet tethering, associated to right ventricular (RV) dilation and/or dysfunction (the “classical”, ventricular form of FTR, V-FTR) for a long time. Atrial FTR (A-FTR) has recently emerged as a distinct pathophysiological entity. A-FTR typically occurs in patients with persistent/permanent atrial fibrillation, in whom an imbalance between the TA and leaflet areas results in leaflets malcoaptation, associated with the dilation and loss of the sphincter-like function of the TA, due to right atrium enlargement and dysfunction. According to its distinct pathophysiology, A-FTR poses different needs of clinical management, and the various interventional treatment options will likely have different outcomes than in V-FTR patients. This review aims to provide an insight into the anatomy of the TV, and the distinct pathophysiology of A-FTR, which are key concepts to understanding the objectives of therapy, the choice of transcatheter TV interventions, and to properly use pre-, intra-, and post-procedural imaging.

319 Right heart chambers geometry and function in patients with the atrial and the ventricular phenotypes of functional tricuspid regurgitation

Aims Atrial functional tricuspid regurgitation (A-FTR) is a recently defined phenotype of FTR associated with persistent/permanent atrial fibrillation. Differently from the classical ventricular form of FTR (V-FTR), patients with A-FTR might present with severely dilated right atrium (RA) and tricuspid annulus (TA), and with preserved right ventricular (RV) size and systolic function. However, the geometry and function of the RV, RA, and TA in patients with A-FTR and V-FTR remain to be systematically evaluated. Accordingly, we sought to: (i) study the geometry and function of the RV, RA, and TA in A-FTR by two- and three-dimensional transthoracic echocardiography and (ii) compare them with those found in V-FTR. Methods and results We prospectively analysed 113 (44 men, age 68 ± 18 years) FTR patients (A-FTR = 55 and V-FTR = 58) that were compared to two groups of age- and sex-matched controls to develop the respective Z-scores. Severity of FTR was similar in A-FTR and V-FTR patients. Z-scores of RV size were significantly larger, and those of RV function were significantly lower in V-FTR than in A-FTR (P < 0.001 for all). The RA was significantly enlarged in both A-FTR and V-FTR compared to controls (P < 0.001, Z-scores > 2), with similar RA maximal volume (RAVmax) between A-FTR and V-FTR (P = 0.2). Whereas, the RA minimal volumes (RAVmin) were significantly larger in A-FTR than in V-FTR (P = 0.001). Conclusions Despite similar degrees of FTR, and RAVmax size, A-FTR patients show a larger RAVmin, and smaller TA areas than V-FTR patients. Conversely, V-FTR patients show dilated, more elliptic, and dysfunctional RV than A-FTR patients.

144 Atrial and ventricular phenotypes in a cohort of patients with functional tricuspid regurgitation: clinical, echocardiographic, and prognostic aspects

Aims Atrial functional tricuspid regurgitation (A-FTR) has emerged as a newly recognized phenotype of functional tricuspid regurgitation (FTR), occurring in patients with atrial fibrillation and right atrial (RA) dilation but normal right ventricular (RV) size and function. Its prevalence, echocardiographic features, and prognosis have not yet clarified since most evidence to date has included indiscriminately FTR patients with A-FTR and ventricular form (V-FTR). Aim of this study was to investigate the differences between these two phenotypes of FTR in terms of clinical correlates, echocardiographic aspects, and prognosis. Methods and results A total of 180 consecutive patients with moderate to severe FTR referred for echocardiography in two Italian centres were retrospectively enrolled. A-FTR was defined as: (1) longstanding atrial fibrillation; (2) PASP <50 mmHg; (3) left ventricular ejection fraction > 60% (complete according to the ACC guidelines); and (4) no significant left side valve disease. 3D TTE was used for the quantitative assessment of TR and chamber sizing and function. The composite endpoint of death for any cause and heart failure (HF) hospitalization was used as primary outcome of this analysis; secondary endpoint was HF-hospitalization. Patients with A-FTR were 30% of the population; they were older than those one with V-FTR; with higher systolic blood pressure and less advanced symptoms. Chronic obstructive pulmonary disease was more prevalent in V-FTR. Patients with V-FTR had larger 3D-derived right ventricle (RV) volumes, both diastolic and systolic, while right ventricle ejection fraction (RVEF) was similar. RV functional parameters as TAPSE, RVFWLS, and RVGLS were significantly lower in the V-FTR patients as well as all the parameters of RV-pulmonary arterial (PA) coupling. After a median follow-up of 24 months (IQR: 2–48), 72 patients (40%) reached the primary endpoint and 64 (36%) hospitalized for HF. The rate of composite endpoint tended to be lower in A-FTR than in V-FTR (29% vs. 44%, P-value: 0.1); the rate of hospitalization for HF was higher in V-FTR patients (22% vs. 41%, P-value: 0.04). Correlates of combined endpoint in both groups were: functional class of dyspnoea (NYHA class III–IV vs. I–II), severe TR grade (HR in V-FTR: 2.88 [1.63–5.06], P < 0.01; HR in A-FTR: 8[3–17], P < 0.01); RV volumes, RA volumes. Estimated SPAP as well as all the parameters of RV function and of RV-PA coupling were correlates of prognosis only in V-FTR; conversely, parameters of TA dimensions were related to combined Endpoint in A-FTR phenotype, while RV function and RV-PA coupling indexes did not. Conclusions Patients having A-FTR have an incidence of combined endpoint slightly different, without reaching a statistically significant difference, thus remarking the fact that A-FTR could not be considered ‘more benign’ and should therefore be targeted. Prognostic predictors are different between A-.FTR and V-FTR patients.

145 Prognostic value of three-dimensional echocardiographic assessment of tricuspid valve geometry in atrial and ventricular functional tricuspid regurgitation

Aims Atrial and ventricular functional tricuspid regurgitation (A-FTR and V-FTR) have recently emerged as different phenotypes of FTR. Given the difference in mechanisms that are postulated to be underlying these two entities, a different remodelling of tricuspid valve (TV) apparatus can occur and therefore also a specific quantitative approach could be deemed. Moreover, considered the known limitation of the two-dimensional flow convergence method (2D-PISA) for quantifying FTR in advanced valve apparatus remodelling with irregular effective valve orifice (ERO) morphology, it would be expected that also the parameters of severity of FTR can be different in these two types of FTR. The aim of this study was to investigate the TV apparatus remodelling in the two different phenotypes of FTR: ventricular (V-FTR) and atrial (A-FTR) and the role of echocardiographic parameters of TV remodelling and TR severity to predict clinical outcomes. Methods and results The present retrospective study included consecutive patients with moderate to severe functional tricuspid regurgitation (FTR) referred for echocardiography in two Italian centres. The composite endpoint of death for any cause and heart failure (HF) hospitalization was used as primary outcome of this analysis. According to more recent guidelines, patients were considered having A-FTR if having history of long-standing atrial fibrillation, without history of pulmonary hypertension and left side heart disease. A total of 180 patients were included. Despite the right atrial volume (RAV) was not different in the two groups, in A-FTR tethering height was significantly lower (11.7 ± 4.8 mm vs. 15.0 ± 5.5 in V-FTR. P < 0.01) and the 3D-derived tricuspid annulus (TA) diameters were larger both in end-diastolic and mid-systolic phase (3D-TA-End diastolic-major axis: 45.2 ± 6.2 mm in A-FTR vs. 42.8 ± 5.4 in V-FTR. P = 0.04; 3D-TA mid systolic major axis: 41.7 ± 6.4 mm in A-FTR vs. 37.9 ± 5.1 in V-FTR, P < 0.01). 3D-TA-End diastolic-minor axis: 39.7 ± 6.8 vs. 37.1 ± 5.2. P = 0.03. Regarding the parameters of severity of FTR, patients with V-FTR had larger vena contracta (VC), either when 2D estimated or 3D (2D-VC-average: 5.3 ± 2.8 mm in A-FTR vs. 6.6 ± 3.7 in V-FTR. P = 0.02; 3D-VCA: 0.9 ± 0.4 cm2 vs. 1.3 ± 1.1 cm2, P = 0.02); conversely the value of 2D-ERO and regurgitant volume estimated with 2D-PISA method did not show significant difference between the two groups. After a median follow-up of 24 months (IQR: 2–48) 72 patients (40%) reached the primary endpoint and 64 (36%) hospitalized for HF. Different predictors of combined endpoint were found in the two groups: tenting height. 2D-VC. 3D-VCA and regurgitant fraction were prognostic correlates in V-FTR; TA dimensions as well as all the parameters of severe TR, including EROA with PISA method were related to the prognosis in A-FTR. Conclusions Different TV remodelling occurs in patients with A- and V-FTR, having the second more pronounce tethering of TV leaflets; the prognostic role of quantitative parameters of FTR in these two groups is different, thus reaffirming: (1) the limitation of PISA method without correction in case of more pronounced tenting of leaflets; (2) the difference in underlying pathogenic mechanisms; and (3) the needing for a more specific diagnostic approach and prognostic stratification in these two FTR phenotypes.

732 TEE role in patients selection for transcatheter edge to edge tricuspid repair

Aims The natural history of tricuspid valve (TV) regurgitation is characterized by dismal prognosis and high in-hospital mortality when treated with isolated TV surgery. Although the anatomy and the imaging of the TV are very challenging, the edge-to-edge repair with the TriClip (Abbott Vascular, Santa Clara, CA) showed promising results. We report preliminary results of our experience with the TriClip System in a cohort of ‘real life’ patients with functional tricuspid regurgitation (TR). Methods and results From January to September 2021, 30 consecutive patients with severe TR has been screened, 8 underwent transcatheter TriClip repair. The anatomical feasibility was established according to a complete transesophageal echocardiogram (TEE) and a dedicated CT scan for the right cardiac chambers. All the echocardiographic projections focused on right ventricle were used during the procedure, with the aim of optimizing the visualization of the catheters and device with respect to the anatomical structures of the tricuspid valve complex. The procedure was conducted under general anesthesia, guided by TEE and fluoroscopy. In-hospital and 30-day clinical and echocardiographic outcomes were recorded. The annulus septo-lateral diameter was enlarged in all cases, and functional TR was present in all patients. In two patients, the pacemaker lead interfered with leaflets coaptation. TR jet was predominantly central. The implant and procedural success were achieved in all cases, implanting one device in five patients and two in three patients. The final TR grade was 2+ in four patients and and 1+ in the others. All patients were extubated in the catheterization laboratory. There were no procedural or in-hospital adverse events. At 30-day follow-up, we observed significant improvement in clinical and echocardiographic outcomes. Conclusions In our experience, 26% of screened patients were selected for the procedure. Favourable anatomical findings for the TV edge-to-edge repair were the following: moderate leaflet tethering (coaptation depth <10 mm); large annulus but with small coaptation gap (<7 mm); antero-septal or postero-septal jet location; commissural jet; small right ventricular dimensions; pacemaker lead with no leaflet tethering. The best transcatheter approach consists of obliterating the antero-septal coaptation rim for a more favourable angle between the inferior vena cava and valvular plane. High-quality TEE imaging during the procedure is required for obtaining procedural success. Patient selection and tricuspid valve anatomy characterization with TEE and cardiac CT scan is critical for procedural success and clinical improvements.