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

Accurate quantification of mitral regurgitation (MR) is central to perioperative decision-making, yet the agreement and interchangeability of commonly used echocardiographic methods remain uncertain. This study evaluated quantitative MR parameters individually and within a multiparametric framework using three-dimensional (3D) vena contracta area (VCA) as an intraoperative reference. In this single-center retrospective analysis, intraoperative echocardiographic data from 85 patients undergoing mitral valve intervention between July 2024 and June 2025 were analyzed. Regurgitant volume (RVol) and regurgitant fraction (RF) were quantified using two-dimensional proximal isovelocity surface area (PISA), a 3D volumetric method, and a Doppler-based continuity equation. Agreement was assessed by Bland-Altman analysis, and categorical concordance was assessed by Cohen's kappa for individual and multiparametric grading strategies. Agreement between individual quantitative methods was limited, with substantial bias and wide limits of agreement for both RVol and RF, resulting in poor-to-fair concordance for MR severity classification. Incorporation of RVol and RF into multiparametric grading strategies improved concordance. Compared with 3D VCA, multiparametric integration incorporating PISA-derived measures showed the best overall performance, with high accuracy and sensitivity and moderate specificity. These findings indicate limited interchangeability of standalone quantitative echocardiographic methods and support reporting the applied technique and using a multiparametric approach anchored to 3D VCA when cardiac magnetic resonance imaging is unavailable.