A novel method of proximal isovelocity surface area correction for quantitative assessment of tricuspid regurgitation severity

Aims The primary quantitative measure of tricuspid regurgitation (TR) severity uses the proximal isovelocity surface area (PISA) method to calculate effective regurgitant orifice area (EROA) and regurgitant volume (RegVol). However, EROAPISA has been demonstrated to underestimate TR severity due to reliance of several geometric assumptions. The aim of this study was to evaluate if correcting for these parameters would improve this underestimation. Methods and Results Patients with at least mild TR identified on transthoracic echocardiography were included in the study. EROAPISA and EROACORRECTED were compared with quantitative Doppler (EROADOPPLER) and 3-dimensional vena contracta area (3D-VCA). EROAPISA was corrected for flow, leaflet angle, and regurgitant orifice ellipticity (EROACORRECTED). Of 100 patients included in the study, EROAPISA (0.62 ± 0.47 cm2) was significantly lower than EROADOPPLER (1.40 ± 1.11 cm2) and 3D-VCA (1.66 ± 1.18 cm2). EROACORRECTED reduced the underestimation (1.31 ± 1.19 cm2, p = 0.73). Both EROAPISA and EROACORRECTED correlated well to EROADOPPLER (r = 0.81, r = 0.8, p < 0.001 for both) and 3D-VCA (r = 0.76, r = 0.70, p < 0.001 for both), although EROACORRECTED had higher agreement to both methods. EROACORRECTED ≥ 0.75 independently predicted morbidity and mortality on univariate (HR 1.84, CI 1.10-3.15, p = 0.02) and multivariate analysis (HR 2.00, CI 1.10-3.90, p = 0.04). EROADOPPLER and 3D-VCA ≥ 0.75 were also associated with worse outcomes on multivariate analysis. Conclusion Correcting PISA for flow, leaflet angle, and regurgitant orifice shape reduced its underestimation, and demonstrated high correlation and improved agreement with other quantitative methods.