Role of anatomical regurgitant orifice area and right ventricular contractile reserve in severe tricuspid regurgitation

AIMS: We sought to propose a novel risk stratification system for severe tricuspid regurgitation (TR) using 3D-anatomical regurgitant orifice area (3D-AROA) and the slope of tricuspid annular plane systolic excursion vs. systolic pulmonary artery pressure (TAPSE/SPAP) and to validate its prognostic significance. METHODS AND RESULTS: Sixty-four patients with severe functional TR (52% torrential) underwent 3D echocardiography and exercise-stress echocardiography. As an estimate of regurgitation severity, 3D-AROA was measured with the customized software package. As an index of right ventricular (RV) contractile reserve, the TAPSE/SPAP slope was calculated by plotting the relationship between TAPSE and SPAP during exercise test. Haemodynamic parameters were obtained by right heart catheterization (RHC). Based on receiver operating characteristics curves, optimal cut-off values of 3D-AROA and TAPSE/SPAP slope to identify all-cause mortality were 161 mm2 and 0.046 mm/mmHg, respectively. During a median follow-up of 559 days, 20 patients (31%) died. After correcting for potential confounders, 3DAROA≥ 161 mm2 (HR 4.37; 95% CI 1.34-14.07; P = 0.015) and TAPSE/SPAP slope≤0.046 mm/mmHg (HR 4.76; 95% CI 1.46-15.53; P = 0.009) were echocardiographic parameters independently associated with all-cause mortality. The cumulative survival rate was lower in patients with 3D-AROA≥161 mm2 and TAPSE/SPAP slope≤0.046 mm/mmHg compared with their counterparts (both P<0.05). RHC confirmed higher right atrial pressure (P<0.001) and lower cardiac index (P = 0.004) in patients with both 3D-AROA≥161 mm2 and TAPSE/SPAP slope ≤0.046 mm/mmHg. CONCLUSION: Large AROA and reduced RV contractile reserve during exercise are independently associated with poor prognosis. The new grading scheme of severe TR was validated by haemodynamics and may improve risk stratification.