Intraoperative Quantification of Severe Mitral Regurgitation: A Comparative Assessment of Two-Dimensional Flow Convergence, Three-Dimensional Volumetric, and Doppler-Based Methods

Figures

• 

  Figure 1. (a) PISA method combining hemispheric flow convergence radius with CW Doppler interrogation of the MR jet. (b) Forward SV measurement at the LVOT using PW Doppler-derived VTI and 3D LVOT cross-sectional area obtained by MPR. (c) 3D LV total SV calculated as the difference between EDV and ESV obtained by MPR. (d) Continuity equation method combining PW Doppler assessment of mitral inflow with 3D mitral annular area obtained by MPR. Abbreviations: PISA = proximal isovelocity surface area; CW = continuous-wave; MR = mitral regurgitation; VTI = velocity time integral; SV = stroke volume; LVOT = left ventricular outflow tract; PW = pulsed-wave; 3D = three-dimensional; MPR = multiplanar reconstruction; LV = left ventricular; MV = mitral valve; EDV = end-diastolic volume; ESV = end-systolic volume.

• 

  Figure 2. 3D VCA measurement derived from MPR of a 3D zoom dataset with color Doppler of the MV. Orthogonal multiplanar reconstruction planes were interactively aligned to the regurgitant jet to ensure true cross-sectional analysis. (a) Commissural plane. (b) Long-axis plane (c) Short-axis plane positioned perpendicular to the jet at the narrowest flow convergence (vena contracta) level, allowing direct planimetric measurement of the VCA. (d) En face MV view, Abbreviations: 3D = three-dimensional; VCA = vena contracta area; MPR = multiplanar reconstruction; MV = mitral valve.

• 

  Figure 3. Bland–Altman plots for pairwise comparisons of regurgitant volume (RVol) and regurgitant fraction (RF) measurements. Top row: Bland–Altman plots comparing RV measurements (A) PISA vs. Volumetric method (B) PISA vs. Continuity methods (C) Volumetric vs. continuity method; bottom row: Bland–Altman plots comparing RF measurements (D) PISA vs. Volumetric method (E) PISA vs. Continuity methods (F) Volumetric vs. continuity method. Each plot illustrates the mean difference (bias) and limits of agreement (±1.96 SD) between paired methods. Abbreviations: RVol = regurgitant volume; RF = regurgitant fraction; n = number; LOA (limits of agreement); CI = (confidence interval); PISA = proximal isovelocity surface area.

• 

  Figure 4. ROC curves comparing the performance of MR severity grading by PISA, volumetric, and the continuity equation methods against the reference standard of 3D VCA. The area under the curve values indicate the diagnostic accuracy of each method for classifying MR severity. Abbreviations: ROC = receiver operating characteristic; MR = mitral regurgitation; PISA = proximal isovelocity surface area; 3D VCA = three-dimensional vena contracta area; RVol = regurgitant volume; RF = regurgitant fraction; n = number; LOA = limits of agreement; CI = confidence interval; PISA = proximal isovelocity surface area.