Right Ventricular–Pulmonary Artery Uncoupling in Secondary Tricuspid Regurgitation: Invasive Validation of Echocardiographic Surrogates

BACKGROUND: Assessment of right ventricular (RV) function can be challenging in patients with RV volume overload associated with secondary tricuspid regurgitation and heart failure with preserved ejection fraction. We sought to validate echocardiographic metrics that might serve as non-invasive RV-pulmonary artery (PA) coupling surrogates. METHODS: Invasive RV pressure-volume loops were obtained in 16 patients with heart failure, preserved ejection fraction and at least moderate secondary tricuspid regurgitation. RV end-systolic elastance (Ees), arterial elastance (Ea), tricuspid regurgitation-adjusted Ea (Epa), as well as related RV-PA coupling indices (Ees/Ea, Ees/Epa) were derived. We explored correlations between RV-PA coupling, hemodynamics, conventional and three-dimensional echocardiographic metrics, including forward stroke volume/RV end-systolic volume ratio, effective RV ejection fraction, tricuspid regurgitant volume, and regurgitant fraction. RESULTS: r=-0.02, p=0.93). CONCLUSIONS: In our small cohort of patients with tricuspid regurgitation secondary to heart failure with preserved ejection fraction, RV-PA uncoupling was frequent, underestimated by tricuspid regurgitation-unadjusted metrics, and associated with more impaired hemodynamics. Three-dimensional echocardiography-derived forward stroke volume/RV end-systolic volume, effective RV ejection fraction, tricuspid regurgitant volume and regurgitant fraction were associated with Ees/Epa, while tricuspid annular plane systolic excursion/PA systolic pressure was not.