Clinical Investigation
Mitral Regurgitation
Spatiotemporal Complexity of Vena Contracta and Mitral Regurgitation Grading Using Three-Dimensional Echocardiographic Analysis

https://doi.org/10.1016/j.echo.2022.09.021Get rights and content

Highlights

  • Echocardiography quantification of MR is usually based on single-frame, 2D methods.

  • Multiframe 3D VCA analysis challenges the circular and constant orifice assumption.

  • Peak measurements (VCAmax) may lead to a significant overestimation of MR severity.

  • VCAmid and VCAmean correlate better with PVF patterns and clinical status.

Background

Spatiotemporal complexity of the color Doppler vena contracta challenging the assumption of a circular and constant orifice may lead to mitral regurgitation (MR) grading inconsistencies. Using 3D transesophageal echocardiography, we characterized spatiotemporal vena contracta complexity and its impact on MR severity grading.

Methods

In 192 patients with suspected moderate or severe MR (100 primary MR [PMR]; 92 secondary MR [SMR]), we performed three-dimensional vena contracta area (VCA) quantification using single-frame (midsystolic or VCAmid, maximum or VCAmax) and multiframe (VCAmean) methods, as well as measures of orifice shape (shape index) and systolic variation of VCA. Vena contracta complexity and intermethod discrepancies were analyzed and correlated with functional class and pulmonary vein flow (PVF) patterns and with cardiac magnetic resonance (CMR) in a subset of cases (n = 20).

Results

The vena contracta was noncircular (shape index > 1.5) in 90% of patients. Severe noncircularity (shape index > 3) was more prevalent in SMR than in PMR (32.4% vs 14.6%). Variations of the VCA were more prominent in SMR than in PMR. VCAmid showed a low grading agreement with VCAmax (62%) and high grading agreement with VCAmean (83.3%). Pulmonary vein flow systolic reversal was associated with MR severity by VCA in SMR but not in PMR. VCAmid and VCAmean showed a stronger association with systolic flow reversal than VCAmax (area under the curve, 0.88, 0.86, and 0.79, respectively). In the subset of patients with CMR quantification, severe MR by VCAmax was graded as nonsevere by CMR more frequently compared with VCAmid and VCAmean.

Conclusions

Highly prevalent spatiotemporal vena contracta complexity features in MR challenge the assumption of a circular and constant orifice. VCAmid seems the best single-frame approximation to multiframe quantification, and VCAmax may lead to severity overestimation.

Section snippets

Study Design and Population

We conducted a single-center, cross-sectional, and retrospective study in patients undergoing a transesophageal echocardiography (TEE) study between 2017 and 2020. The study was approved by the Institutional Ethics Review Board of our institution. Out of 226 patients undergoing TEE with 3D color MR acquisitions, 34 (15%) were excluded (6 patients with trace MR and 28 patients with low-quality 3D color acquisitions and/or fewer than 3 systolic frames). A final sample of 192 patients was included

Patient Data

Data from excluded patients are provided in Supplemental Table 2. In the 192 patients included in the main analysis, 1,143 frames were analyzed in triplicate (3,357 frames were analyzed in total), with a median of 6 frames per patient.

Clinical and echocardiographic data are shown in Table 1 for the overall study sample (n = 192) and stratified by type of MR (PMR, n = 100; SMR, n = 92). In SMR patients, coronary artery disease and atrial fibrillation were more frequent. Moderate or severe aortic

Discussion

Color Doppler jet analysis is a fundamental tool for MR quantification.1 In this study, multiframe VCA was quantified using 3D echocardiography to characterize MR vena contracta complexity. In addition to a high prevalence of noncircular VCAs in both PMR and SMR, the timing of measurements was found to be key in 3D quantification according to our results: while single-frame midsystolic (VCAmid) is the closest approximation to multiframe quantifications (VCAmean), peak VCA (VCAmax) may lead to

Conclusions

Multiframe VCA analysis showed a high prevalence of spatiotemporal complexity features in MR color Doppler vena contracta, challenging the assumption of a circular and constant orifice, with important intermethod quantification discrepancies. VCAmid seems the best single-frame approximation to multiframe quantification, whereas peak VCA measurements may lead to potential overestimation of MR severity.

References (33)

Drs. Lozano-Edo and Jover-Pastor contributed equally to this work.

This work was supported by competitive grants from the Spanish Ministry of Economy and Competitiveness through the Carlos III Institute of Health-Fondo de Investigación Sanitaria (PI18/01626) and the VLC-BIOMED program (VLC-BIOMED PI2020-13) to J.A.

Conflicts of Interest: None.

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