Impact of regurgitant orifice ellipticity on quantitation of tricuspid regurgitation using the proximal isovelocity surface area method

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background The proximal isovelocity surface area (PISA) method to quantify tricuspid regurgitation (TR) severity relies on the geometric assumption of a circular, planar regurgitant orifice. However, the TR orifice is often non-circular resulting in underestimation of TR severity when calculating the effective regurgitant orifice area (EROA) and regurgitant volume (RegVol). Purpose To evaluate the effect of ellipticity of the tricuspid annulus on EROA-PISA correlation with quantitative Doppler (EROA-Dopp), and three-dimensional vena contracta area (VCA-3D). Methods Patients undergoing both transthoracic (TTE) and transesophageal (TEE) echo evaluation of TR severity were included in this study. Regurgitant orifice ellipticity was calculated as the ratio of the vena contracta maximum and minimum widths (VC-Ratio). Quantification of EROA and RegVol were performed on TTE for EROA-PISA and EROA-Dopp. Vena contract area was measured on TEE (VCA-3D). Results Of 44 total pts, the median age was 80 ± 9, 61% were female, 89% had atrial fibrillation, (86%) had functional TR, 32% were graded as severe, and 71% had a EROA-PISA ≥ 0.4 cm2. Median VC-Ratio was 1.3 (IQR 1.1-1.8) and was used to differentiate more circular orifices (VC-Ratio <1.3) from more elliptical orifices (VC-Ratio ≥1.3) (Table). EROA-PISA was significantly smaller compared to EROA-Dopp and VCA-3D in the whole group as well as elliptical subgroups (p < 0.0001 for all). There was no significant difference between EROA-Dopp and 3D-VCA for the whole group, or in circular or elliptical orifice subgroups (p > 0.5 for all). EROA-PISA correlated better with both EROA-Dopp and VCA-3D in circular compared to elliptical orifices (Table). EROA-Dopp and VCA-3D demonstrated high correlation for both circular and elliptical orifices (r = 0.76, p < 0.0001 and r = 0.77, p < 0.0001 respectively). Conclusion Our study demonstrated that there is a significant difference in quantitative measurements of tricuspid regurgitant orifice area, with EROA-PISA significantly underestimating both EROA-Dopp and VCA-3D. In more circular orifices, the EROA-PISA correlation was higher, however EROA-Dopp and VCA-3D were still significantly larger. Whether EROA-Dopp and VCA-3D are more predictive of outcomes requires further study. Abstract Table 1 Abstract Figure 1