A Revised Grading Scheme for Secondary Tricuspid Valve Regurgitation.

Background: The conventional three-grade scheme recommended by American Society of Echocardiography (ASE) for secondary tricuspid regurgitation (STR) are limited by the frequent disagreement between multiparametric and single-parameter classifications, and heterogeneous prognosis within the moderate group. We tested the hypothesis that the expert-recommended four-grade scheme has better inherent agreement compared to ASE scheme, and further improved it as a revised four-grade scheme using the corrected proximal isovelocity surface area (PISA) method to calculate effective orifice area (EROA) and regurgitant volume (RegVol), along with the integration of other quantitative parameters.

Methods: A total of 178 patients with STR were included. The moderate grade according to the three-grade ASE-recommended scheme was split into mild-moderate and moderate-severe grades following the recent experts' suggestions. The agreement between the multiparametric and single-parameter grading in TR severity was analyzed using the weighted Kappa test. The structure and function of tricuspid valve and right heart, including the conventional parameters, strains, and the right ventricular‒pulmonary artery (RV-PA) coupling, were compared across grade severities. The partition values of quantitative regurgitation parameters were further determined by ROC curve analyses to develop the revised four-grade scheme with involvement of corrected proximal isovelocity surface area (PISA) method.

Results: The expert-recommended four-grade scheme demonstrated better multiparametric and single-parameter agreement of RegVol (к=0.901) in TR grading compared to the ASE-recommended three grade scheme (к=0.506). Both RV strain and RV-PA coupling were significantly lower in patients with moderate-severe STR compared to those with mild-moderate STR (P < 0.05). The new cut-off values of EROA (0.34 cm²; AUC = 0.945) and RegVol (35 mL; AUC = 0.958), obtained using the corrected PISA method, demonstrated excellent accuracy in distinguishing mild-moderate from moderate-severe STR.

Conclusions: The revised four-grade scheme for STR severity exhibited better inherent agreement than the ASE recommended scheme, and matching with the right heart functional variations.