Echocardiographic grading of mitral regurgitation (MR) in mitral valve prolapse (MVP) is challenging. Three-dimensional (3D) vena contracta area (VCA) has been proposed as a valuable method. However, data defining the cutoff values of severity and validation in the subset of patients with MVP are scarce. The aim of this study was to validate the 3D VCA by 3D color-Doppler transesophageal echocardiography (TEE) in patients with MVP and to define the cutoff values of severity grading. The secondary aim was to compare 3D VCA to the effective regurgitant orifice area estimation by proximal isovelocity surface area (EROA-PISA) method.

A total of 1,138 patients with at least moderate MR who underwent TEE were included. Three-dimensional VCA was measured, and the cutoff value and area under the curve (AUC) for the prediction of severe MR were estimated by receiver operating characteristic curve using a guideline-suggested multiparametric approach as the reference standard. In a subgroup of patients, 3D regurgitant volume (RV) and 3D fraction were calculated from mitral and left ventricular outflow tract stroke volumes to further validate 3D VCA against a 3D volumetric reference standard.

The optimal 3D VCA cutoff value for predicting severe MR was 0.45 cm² (specificity, 0.87; sensitivity, 0.90) with an AUC of 0.95 using a multiparametric approach as reference. Three-dimensional VCA had a good linear correlation with EROA-PISA (r = 0.62, P < .05) with larger values compared to EROA-PISA (0.63 cm² vs 0.44 cm², P < .05). A cutoff of 0.50 cm² (AUC of 0.84; sensitivity, 0.78; specificity, 0.78) predicts an EROA-PISA of 0.40 cm². Three-dimensional VCA had a good linear correlation with 3D RV (r = 0.56, P < .01), with an AUC of 0.86 to predict a 3D fraction >50%.

The present study suggests 0.45 cm² as the best cutoff value of 3D VCA to define severe MR in patients with MVP, showing an optimal agreement with the reference standard multiparametric approach and 3D RV.

From the cohort of included patients with MVP, a multiparametric approach suggested by current guidelines was adopted to grade MR and stratify patients into the moderate or severe group. Subsequently, 3D VCA was blindly reconstructed using 3D TEE color Doppler datasets. Agreement with the multiparametric approach was then assessed using ROC curves, and the optimal cutoff was established. Additionally, a comparison between 3D VCA and EROA-PISA was conducted. Three-dimensional VCA demonstrated optimal agreement with the multiparametric approach (AUC = 0.95), with the best cutoff value for severe MR set at >0.45 cm². This cutoff value was also tested against the 3D RF > 50% calculated from 3D Doppler stroke volumes.