A Revised Grading Scheme for Secondary Tricuspid Valve Regurgitation

The conventional 3-grade scheme recommended by American Society of Echocardiography (ASE) for secondary tricuspid regurgitation (STR) is 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 4-grade scheme has better inherent agreement compared to the ASE scheme and further improved it as a revised 4-grade scheme using the corrected proximal isovelocity surface area (PISA) method to calculate effective regurgitant orifice area (EROA) and regurgitant volume (RegVol), along with the integration of other quantitative parameters.

A total of 178 patients with STR were included. The moderate grade according to the 3-grade ASE-recommended scheme was split into mild-moderate and moderate-severe grades following recent expert 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 receiver operating characteristic curve analyses to develop the revised 4-grade scheme with involvement of corrected PISA method.

The expert-recommended 4-grade scheme demonstrated better multiparametric and single-parameter agreement of RegVol (к = 0.901) in TR grading compared to the ASE-recommended 3-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 < .05). The new cutoff values of EROA (0.34 cm²; area under the curve = 0.945) and RegVol (35 mL; area under the curve = 0.958), obtained using the corrected PISA method, demonstrated excellent accuracy in distinguishing mild-moderate from moderate-severe STR.

The revised 4-grade scheme for STR severity exhibited better inherent agreement than the ASE-recommended scheme as well as matching with the right heart functional variations.