1Universitäres Herz- und Gefäßzentrum Hamburg Allgemeine und Interventionelle Kardiologie Hamburg, Deutschland; 2Universitäres Herz- und Gefäßzentrum Hamburg Klinik und Poliklinik für Kardiologie Hamburg, Deutschland; 3Universitäres Herz- und Gefäßzentrum Hamburg Klinik für Kardiologie Hamburg, Deutschland; 4Universitäres Herz- und Gefäßzentrum Hamburg Klinik und Poliklinik für Herz- und Gefäßchirurgie Hamburg, Deutschland
BACKGROUND
Right ventricular (RV) dysfunction, assessed by the right ventricular to pulmonary artery (RV/PA) coupling, has been identified as a prognostic factor in patients with degenerative mitral regurgitation (DMR) undergoing transcatheter mitral edge-to-edge therapy (M-TEER). This parameter involves evaluation of tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary artery pressure (sPAP) ratio. Notably, sPAP can be determined non-invasively by echocardiography (TTE) or invasively by right heart catheterization (RHC). Since TTE estimates can be erroneous, additional RHC may offer more thorough RV functional assessment. Additionally, the pulmonary artery pulsatility index (PAPi) has been proposed to further distinguish RV dysfunction and is calculated as the difference between systolic and diastolic PAP divided by right atrial pressure.
AIM
Aim of this study was to compare clinical outcomes in patients with DMR treated with M-TEER, stratified by RV dysfunction as assessed by TTE vs. RHC.
METHODS
This retrospective single-center analysis included 293 patients with DMR treated by M-TEER. RV/PA coupling was determined using sPAP derived from either TTE (referred to as “Echo RV/PA”) or RHC (referred to as “Exp RV/PA”). Patients were categorized using established cutoffs for RV/PA coupling and PAPi (< vs. ≥0.307 and < vs. ≥3.65, respectively). An optimal cutoff value for Exp RV/PA was determined using Cox regression for outcome prediction. Clinical outcomes including all-cause mortality and a composite endpoint of mortality or cardiac rehospitalization using Kaplan-Meier (KM) method were analyzed.
RESULTS
Patients with DMR had a median age of 81.0 years (interquartile range [IQR]: 76.9-84.2) with 52.2% being male and median STS PROM score of 3.9% (IQR: 2.7-5.4). No significant differences in all-cause mortality or composite endpoints were observed when comparing patients with PAPi <3.65 to those with ≥3.65, according to KM analysis. Baseline characteristics between patients with Echo RV-PA <0.307 vs. ≥0.307 were similar, except NT-proBNP levels at baseline were higher (4032pg/mL [IQR: 2239-5271] vs. 2728pg/mL [IQR: 1335-4840]), though not reaching statistical significance. However, left atrial mean pressure was significantly greater in the Echo RV/PA <0.307 group (19 mmHg [IQR: 16-24] vs. 14 mmHg [IQR: 12-20], p=0.002). At 2-year follow-up, patients with Echo RV/PA coupling ratio <0.307 exhibited a significantly higher incidence of all-cause mortality (52.2% vs. 22.2%, p<0.001) and a higher rate of the composite endpoint (p=0.002), as demonstrated in KM analysis (see Fig. 1). The optimal cutoff for Exp RV/PA coupling was determined to be <0.315 from Cox regression analysis. Notably, patients with Exp RV/PA <0.315 experienced markedly higher rates of all-cause mortality (p=0.004) and the composite endpoint rates (p=0.002) than patients with Exp RV/PA ≥0.315.
CONCLUSION
In a direct comparison between PAPi and RV/PA Coupling in patients with DMR undergoing M-TEER, only RV/PA coupling emerged as a significant predictor of mortality. Furthermore, the invasive measurement of sPAP by means of RHC did not seem to provide additional predictive value compared to the non-invasive estimation via TTE. An "uncoupling" (low RV/PA) was associated with a significantly increased mortality and can be determined by means of simple TTE.
Figure 1