3D echocardiography volumetric assessment of the severity of tricuspid regurgitation

Abstract Background Quantifying tricuspid regurgitation (TR) severity by conventional Doppler echocardiography is challenging. Objectives We sought to: validate right ventricular (RV) stroke volumes (SV3DE) and tricuspid regurgitant volumes (RegVol3DE) measured by three-dimensional echocardiography (3DE). Then, we compared the quantitative metrics used to assess TR severity obtained by 3DE and both the conventional and the corrected PISA methods. Methods 3DE RV and left ventricular (LV) SV were collected simultaneously with direct Fick measurements at right heart catheterization (RVSVRHC) in 45 patients (66±14 years, 76% women) with no or trivial TR, and in 57 consecutive patients (73±13 years, 61% women) with mild to torrential (11% mild, 40% moderate, 26% severe, 16% massive, and 1% torrential) TR, and mild or no mitral or aortic regurgitation. In the latter group, RHC and 3DE were combined to derive TR regurgitant volume (RegVol3DE-RHC=RVSV3DE-RVSVRHC) and compared to the 3DE volumetric RegVol (RegVol3DE =RVSV3DE-LVSV3DE). Effective regurgitant orifice area (EROA) and regurgitant fraction (RegFr) were calculated from RegVol3DE, as well as through conventional and corrected PISA methods. Results The feasibility of RVSV3DE was 74%. Among patients with no or trivial TR, RVSV3DE and RVSVRHC showed a strong correlation (R2= 0.916, p0.0001), with a minimal bias (3.7 mL) and reasonable precision (limits of agreement, LOA: -10 mL;18 mL). In those with mild to torrential TR, RegVol3DE correlated with RegVol3DE-RHC (R2=0.918, p0.0001) and was accurate (bias= -1.3 mL, LOA:-17.9 mL;15.2 mL). EROA, RegVol and RegFr derived from conventional PISA (0.48±0.4 cm², 38±20 mL, and 36±18%, respectively) were significantly smaller (p0.05) than those obtained from corrected PISA (0.61±0.5 cm², 48±24 mL, and 46±24 %, respectively), and volumetric 3DE (0.62±0.5 cm², 46±25 mL, and 42±18%, respectively) (figure). Conclusions RVSV measured by 3DE is accurate (minimal bias, acceptable imprecision) when compared to direct Fick RVSVRHC.