Quantification Of Mitral Valve Regurgitation Research Articles

Quantification of Mitral Valve Regurgitation from 4D Flow MRI Using Semiautomated Flow Tracking.

To compare the accuracy of semiautomated flow tracking with that of semiautomated valve tracking in the quantification of mitral valve (MV) regurgitation from clinical four-dimensional (4D) flow MRI data obtained in patients with mild, moderate, or severe MV regurgitation. The 4D flow MRI data were retrospectively collected from 30 patients (21 men; mean age, 61 years ± 10 [standard deviation]) who underwent 4D flow MRI from 2006 to 2016. Ten patients had mild MV regurgitation, nine had moderate MV regurgitation, and 11 had severe MV regurgitation, as diagnosed by using semiquantitative echocardiography. The regurgitant volume (Rvol) across the MV was obtained using three methods: indirect quantification of Rvol (RvolINDIRECT), semiautomated quantification of Rvol using valve tracking (RvolVALVE), and semiautomated quantification of Rvol using flow tracking (RvolFLOW). A second observer repeated the measurements. Aortic valve flow was quantified as well to test for intervalve consistency. The Wilcoxon signed rank test, orthogonal regression, Bland-Altman analysis, and coefficients of variation were used to assess agreement among measurements and between observers. RvolFLOW was higher (median, 24.8 mL; interquartile range [IQR], 14.3-45.7 mL) than RvolVALVE (median, 9.9 mL; IQR, 6.0-16.9 mL; P < .001). Both RvolFLOW and RvolVALVE differed significantly from RvolINDIRECT (median, 19.1 mL; IQR, 4.1-47.5 mL; P = .03). RvolFLOW agreed more with RvolINDIRECT (ŷ = 0.78x + 12, r = 0.88) than with RvolVALVE (ŷ = 0.16x + 8.1, r = 0.53). Bland-Altman analysis revealed underestimation of RvolVALVE in severe MV regurgitation. Interobserver agreement was excellent for RvolFLOW (r = 0.95, coefficient of variation = 27%) and moderate for RvolVALVE (r = 0.72, coefficient of variation = 57%). Orthogonal regression demonstrated better intervalve consistency for flow tracking (ŷ = 1.2x - 13.4, r = 0.82) than for valve tracking (ŷ = 2.7x - 92.4, r = 0.67). Flow tracking enables more accurate 4D flow MRI-derived MV regurgitation quantification than valve tracking in terms of agreement with indirect quantification and intervalve consistency, particularly in severe MV regurgitation.Supplemental material is available for this article.© RSNA, 2020.

Validation of Semiautomated Quantification of Mitral Valve Regurgitation by Three-Dimensional Color Doppler Transesophageal Echocardiography

The aim of this study was to evaluate the accuracy of mitral regurgitation (MR) volume quantified on three-dimensional (3D) color Doppler transesophageal echocardiography (TEE) using new semiautomated software compared with conventional two-dimensional (2D) proximal isovelocity surface area (PISA) transthoracic echocardiography (TTE) and TEE and cardiac magnetic resonance imaging (CMR). Fifty-one patients (mean age, 63±16years; 35 men) prospectively underwent TTE, TEE, and CMR for MR evaluation. Regurgitant volume (RVol) by 3D MR flow quantification was compared with 2D TTE, TEE, and CMR, and the accuracy of evaluation of severe MR by 3D MR flow quantification was compared against guideline criteria by TEE. Twenty-nine patients had severe MR, 16 had moderate MR, and six had mild MR. Three-dimensional MR flow quantification was feasible in all patients, including prolapse (n=37), restriction (n=9), functional MR (n=5), and eccentric or multiple jects (n=41). RVol on 3D MR flow quantification correlated well with RVol on 2D PISA TTE (interclass correlation coefficient [ICC]=0.75, P<.001), quantitatively estimated RVol (ICC=0.74, P<.001), and 2D PISA TEE (ICC=0.79, P<.001). Three-dimensional MR flow quantification agreed better with CMR (ICC=0.86, P<.001) than did RVol on 2D PISA TTE (ICC=0.66, P<.001) and 2D PISA TEE (ICC=0.69, P<.001), with narrower limits of agreement on Bland-Altman analysis. Three-dimensional MR flow quantification had high accuracy for diagnosing severe MR using TEE (area under the curve=0.85, 95% CI 0.74-0.96, P<.001) or CMR (area under the curve=0.95; 95% CI, 0.89-1.00; P<.001) as the criterion. The new software enabled semiautomated 3D MR flow quantification in complex MR with multiple and eccentric jets and showed better agreement with CMR than 2D PISA TTE or TEE, suggesting that this method is more accurate than conventional 2D PISA TTE and TEE.

4D Flow cardiac magnetic resonance quantification of mitral regurgitation, comparison with transthoracic echocardiography

Mitral valve regurgitation (MR) is primarily assessed by a multiparametric approach with transthoracic echocardiography (TTE) that can be further completed by 2D Cardiac Magnetic Resonance (2D CMR) in case of doubt or poor acoustic window. TTE and 2D CMR have nevertheless imperfect agreement for MR quantification. Time-resolved phase-contrast CMR with flow-encoding in three spatial directions (4D Flow CMR) could help in MR quantification. Compare 4D Flow CMR quantification of MR with TTE using a multiparametric approach. We conducted a prospective study at the Institut Mutualiste Montsouris in Paris between November 2016 and 2017 including patients with chronic primitive MR. MR was evaluated with a multiparametric approach by two cardiologists with TTE and quantitatively by two radiologists with 4D Flow CMR. MR was classified as mild, moderate or severe and evaluated blindly with consensus in case of disagreement. 4D Flow CMR quantified MR regurgitant volume (RV) and MR regurgitant fraction (RF). 4D anterograde mitral flow was compared to left ventricular stroke volume using 2D-cine CMR. Thirty-three patients were included. Inter-observer agreement was good in TTE (kappa = 0.75 95%CI [0.57–0.92]) and excellent in 4D Flow CMR (ICC = 0.94 95%CI [0.79–0.95]). Agreement with TTE was excellent using optimized thresholds (Mild: RV ≤ 20 mL RF ≤ 20%, Moderate: RV = 21–39 mL RF = 21–36%, Severe: RV ≥ 40 mL RF ≥ 37%): kappa = 0.93 95%CI [0.8–1] for RV and kappa = 0.90 95%CI [0.7–0.9] for RF. A validation cohort confirmed that the 4D flow thresholds as determined were accurate for MR grading. Agreement between 4D anterograde mitral flow and 2D-cine CMR left ventricular stroke volume was also excellent (ICC = 0.92 95%CI [0.85–0.96]). 4D Flow CMR is a reliable tool for MR quantification. Providing direct quantitative evaluation of MR with low inter-observer variability, it may therefore be used as a gatekeeper before therapeutic decisions such as surgery.

Quantification of mitral valve regurgitation by 2D and 3D echocardiography compared with cardiac magnetic resonance a systematic review and meta-analysis

By means of systematic literature review and meta-analysis, we compared results of studies examining different echocardiographic methods assessing severity of mitral valve regurgitation volume (MVR) with cardiac magnetic resonance imaging (CMR) as standard reference. A systematic search of electronic databases revealed twenty studies eligible for meta-analysis. Results of 2D- and 3D-trans-thoracic (TTE) and trans-esophageal echocardiographic (TEE) proximal isovelocity surface area (PISA) and volumetric methods were compared with CMR. Mean differences (ml) with 95% limits of agreement (LoA) derived from Bland-Altman tests and correlations coefficients [(R) 95% confidence interval (CI)] were pooled together. Overall 1187 patients [mean age = 59 ± 13years and 678(57%) males] with primary or secondary mild to severe MVR were included. Comparing all echocardiographic methods with CMR showed an overestimation and moderate agreement with difference and 95% LoA of 8.05(- 3.40, 19.49) ml, R = 0.73(95% CI 0.71-0.76) p < 0.001. 3D-PISA followed by 3D-volumetric methods showed the better agreement with an underestimation of - 3.20(- 12.33, 5.92) ml, R = 0.84(95% CI 0.78-0.89) p < 0.001 and overestimation of 3.73(- 9.17, 16.61) ml, R = 0.90(95% CI 0.87, 0.94) p < 0.001, respectively. 2D-volumetric method showed the poorest agreement with difference and 95% LoA of 23.56(- 4.19, 51.31) ml, R = 0.64(95% CI 0.54-0.73) p < 0.001. In patients (n = 280) with severe MVR, 2D technique incorrectly estimated regurgitation volume severity in 106 (38%) compared to 4(14%) patients using 3D technique. Among echocardiographic methods 3D-PISA agreed best with CMR as reference, making 3D-PISA the most reliable method to quantify MVR. CMR can be considered in severe MVR where uncertainties arise and a decision-making prior valve surgery is required. Further powerful studies are needed to assess the accuracy of different echocardiographic methods.

Abstract 17072: A Novel Algorithm for Quantification of Mitral Valve Regurgitation Based on Pixel Density Analysis of Continuous Wave Doppler Imaging

Introduction: Echocardiography is important for the assessment of mitral valve regurgitation (MR) and to guide clinical decision making. Echocardiographic methods are being used to quantify MR severity but their applicability, accuracy, and reproducibility have been debated. Hypothesis: To test the feasibility and in vitro validation of a novel custom-made transthoracic echocardiographic method for the assessment of MR severity based on pixel density analysis (PDA) of the continuous wave (CW) envelope in digital images. Methods: MR was prospectively assessed in 290 patients on a VIVID E9 echo machine (GE) with fixed settings. MR severity was evaluated according to international guidelines using color doppler, vena contracta (VC) width, proximal iso-velocity surface area (PISA) method, and PDA. The applicability, inter-observer, and intra-observer variability of all methods were compared. For validation of the PDA algorithm, a pulsatile in vitro cardiac phantom was used with prosthetic mitral valves with different regurgitant orifices (13.2, 27.2, 54.7, and 86.5 mm2). Regurgitant volume (RV) was calculated by multiplying the regurgitant orifice with the time velocity integral. Results: The PDA method showed a linear correlation with color doppler (r=0.82), VC width (r=0.67), PISA-effective regurgitant orifice area (EROA, r=0.72), and PISA-RV (r=0.67); p&lt;0.001 for all. The PDA was significantly more applicable than VC width (n= 275/290, 95% vs. 218/290, 75% p&lt;0.001) and PISA-based methods (n=191/290, 65% p&lt;0.001). Additionally, PDA showed a stronger intra- and inter-observer agreement compared to the VC, PISA-EROA, and PISA-RV (intra-observer ICC = 0.96 vs. 0.79, 0.87, and 0.82 respectively; inter-observer ICC = 0.96 vs. 0.46, 0.89, and 0.85 respectively). In the in vitro validation, PDA showed a strong linear correlation with regurgitant volumes (r=0.92, p&lt;0.001). Conclusions: We showed the clinical feasibility and in vitro validation of a novel digital quantitative echocardiographic method to assess MR severity. This method is more applicable and has less inter- and intra-observer variability compared to current quantitative methods. Patient follow-up is ongoing to validate the novel methods against clinical endpoints in MR.

Quantification of Mitral Valve Regurgitation: New Solutions Provided by 3D Echocardiography

The accurate quantification of mitral regurgitation (MR) using 2D imaging tools is difficult due to its structural complexity; however, it is crucially important in clinical medicine as MR severity has prognostic consequences. Novel 3-dimensional (3D) echocardiography and 3-dimensional (3D) color Doppler methods can provide quantitative and qualitative classification of MR including measurement of the vena contracta area, regurgitant volume, regurgitant fraction, and effective regurgitant orifice area (EROA). Nevertheless, with so many conventional and developing techniques it can be difficult to decide which technique to use for selected patients. We suggest using an approach that is focused not only on the techniques and measurements but also combines imaging portability, availability, clinical efficiency, and accurate and reproducible assessments. In this review we discuss the established and emerging applications of 3D color Doppler for the quantification of MR severity.

Mitral Valve Leakage Quantification by Means of Experimental and Numerical Flow Modeling

Accurate quantification of mitral valve regurgitation (MR) is a challenging task in clinical cardiology. In order to develop and refine new algorithms for estimating the severity of MR using real-time 3D Doppler echocardiography (RT3DE), an experimental and numerical flow model have been designed and constructed. Using CAD, Rapid Prototyping Manufacturing (RPM) and five-axis milling technology, a hydraulic in vitro flow model, compatible for flow investigation with 2D normal speed Particle Image Velocimetry (PIV) and 2D Doppler Echocardiography. The same CAD model was used to conduct the Computational Fluid Dynamics (CFD) analysis. PIV, 2D Doppler Echocardiography and CFD results compare successfully in the upstream converging region and in the downstream turbulent regurgitated jet zone. These results are expected to improve the clinical assessment of mitral valve regurgitation severity by means of Doppler echocardiography.

Evaluation of effective regurgitant orifice area of mitral valvular regurgitation by multislice cardiac computed tomography

The purpose of our study was to assess the diagnostic accuracy of multislice computed tomography (MSCT) for the identification and quantification of mitral valve regurgitation in comparison with transthoracic echocardiography (TTE). Twenty-six patients (15 females, 11 males with a mean age of 44.6±14.1 years) who were in follow-up with the diagnosis of mitral regurgitation and those who were referred for MSCT were enrolled. MSCT results were compared with TTE measurements. The mean effective mitral regurgitant orifice area at MSCT was 23.1±13.0 mm² and at echocardiography was 24.4±16.0 mm². Bland-Altman analysis showed good agreement between the two imaging methods. MSCT provides reliable and good results for the evaluation of mitral regurgitation.

Quantification of mitral-valve regurgitation in a paediatric population by real-time three-dimensional echocardiography

Evaluation of mitral-regurgitation (MR) severity in infants is challenging. Real-time three-dimensional echocardiography (RT3DE) allows accurate left-ventricular volumetric measurements in adults. To validate RT3DE by measuring stroke volume in a normal paediatric population, then to use this new method to calculate regurgitant volume in paediatric patients with MR. Fifty-four patients, aged one week to 19 years, (29 without and 25 with MR) had two-dimensional echocardiography coupled with RT3DE left-ventricular volumetric acquisition. Stroke volume was calculated by the Doppler method at the aortic annulus (SV(D)). End-systolic and end-diastolic left-ventricular volumes were measured using the QLab semi-automated method; three-dimensional stroke volume (SV(3D)) was calculated as their difference. In the MR group, regurgitant volume was calculated by the PISA method (RV(PISA)) and as the difference between SV(3D) and SV(D) (RV(3D)). Regurgitant fraction was also evaluated by these methods (RF(PISA) and RF(3D)). Measurement feasibility was 88%. In the normal group, SV(3D) (27.9+/-18.1 ml) was highly correlated with SV(D) (30.7+/-19.6 ml; r=0.98; p<0.000). In the MR group, RV(PISA) (15.7+/-14.4 ml) and RV(3D) (11.0+/-10.2 ml) were well correlated (r=0.83; p<0.001). Regurgitant fractions were also well correlated (RF(PISA)=30.4+/-17.0%; RF(3D)=24.3+/-15.9%; r=0.79, p=0.006). RT3DE is a simple, rapid and reliable method for evaluating stroke volume in children and may, therefore, be useful for evaluating regurgitant volume and fraction in paediatric patients with MR.

Quantification of mitral valve regurgitation in dogs with degenerative mitral valve disease by use of the proximal isovelocity surface area method

To determine the within-day and between-day variability of regurgitant fraction (RF) assessed by use of the proximal isovelocity surface area (PISA) method in awake dogs with degenerative mitral valve disease (MVD), measure RF in dogs with MVD, and assess the correlation between RF and several clinical and Doppler echocardiographic variables. Prospective study. 6 MVD-affected dogs with no clinical signs and 67 dogs with MVD of differing severity (International Small Animal Cardiac Health Council [ISACHC] classification). The 6 dogs were used to determine the repeatability and reproducibility of the PISA method, and RF was then assessed in 67 dogs of various ISACHC classes. Mitral valve regurgitation was also assessed from the maximum area of regurgitant jet signal-to-left atrium area (ARJ/LAA) ratio determined via color Doppler echocardiographic mapping. Within- and between-day coefficients of variation of RF were 8% and 11%, respectively. Regurgitation fraction was significantly correlated with ISACHC classification and heart murmur grade and was higher in ISACHC class III dogs (mean +/- SD, 72.8 +/- 9.5%) than class II (57.9 +/- 20.1%) or I (40.7 +/- 19.2%) dogs. Regurgitation fraction and left atriumto-aorta ratio, fractional shortening, systolic pulmonary arterial pressure, and ARJ/LAA ratio were significantly correlated. Results suggested that RF is a repeatable and reproducible variable for noninvasive quantitative evaluation of mitral valve regurgitation in awake dogs. Regurgitation fraction also correlated well with disease severity. It appears that this Doppler echocardiographic index may be useful in longitudinal studies of MVD in dogs.

Quantification of Functional Mitral Valve Regurgitation in Patients With Congestive Heart Failure

We sought to determine the agreement between electron-beam computed tomography (CT) and cardiac catheterization for the quantification of mitral regurgitation and to evaluate their association with echocardiographic assessment. Fifty patients with congestive heart failure were examined both by electron-beam CT and catheterization to calculate mitral regurgitation volume and fraction based on the difference between the left ventricular stroke and aortic flow volume. The severity of regurgitation was also compared with visual assessment by echocardiography (grade, 0-4+). The mean values for the mitral regurgitation volume and fraction did not differ significantly between electron-beam CT and catheterization (mean differences: 0.2 mL/m2 and -0.9%, P > 0.05 each, limits of agreement: -14.0 to 14.4 mL/m2 and -26.3 to 24.5%, respectively) and showed a good correlation (r = 0.79 and r = 0.76, respectively; P < 0.05 each). Good levels of correlation were observed between echocardiographic severity grading and quantitative measurements of regurgitation volume and fraction, which were somewhat better between echocardiography and electron-beam CT (rS = 0.78 and rS = 0.84, respectively; P < 0.05 each) than between echocardiography and catheterization (rS = 0.72 and rS = 0.81, respectively; P < 0.05 each). Our results suggest that electron-beam CT allows for quantification of mitral valve regurgitation with similar accuracy as cardiac catheterization. Measurements with both modalities correlated well with the results of echocardiographic assessment.

Some theoretical aspects of quantification of mitral valve regurgitation by the indicator-dilution method; sufficient and insufficient experiments.

A theoretical analysis of indicator-dilution curves produced by a pulsatile, two-chamber mathematical model simulating a normal in vivo heart and one with atrioventricular valve regurgitation is presented. A set of difference equations is developed expressing the concentrations within the chambers at the end of each cycle in terms of the number of cycles or beats. It is shown theoretically that the downstroke slope of the dilution curve is insensitive to the extent of regurgitation. Solution of the difference equations for the parameters of the heart governing the curve (chamber volumes, forward output, and regurgitant flow), when the dilution curve is sampled from the chamber in which the injection is made, is achieved through a system of four equations in four unknowns. Sampling of the concentration curve from the chamber which does not receive the injection produces a theoretical curve giving three equations in four unknowns and results in an indeterminate solution. As a consequence, quantification of atrioventricular valve regurgitation through analysis of a single distal indicator-dilution curve following proximal injection cannot be accomplished.