Comparison of accuracy of mitral valve regurgitation volume determined by three-dimensional transesophageal echocardiography versus cardiac magnetic resonance imaging

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

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.

Comparison of mitral regurgitation severity assessments based on magnetic resonance imaging and echocardiography in patients with hypertrophic cardiomyopathy

Mitral regurgitation (MR), which is one of the factors responsible for heart failure symptoms and the development of atrial fibrillation, is an important feature of hypertrophic cardiomyopathy (HCM), and its presence affects which treatment options are chosen. Although cardiac magnetic resonance imaging (MRI) is considered the reference standard for assessing the regurgitant volume (RV) and fraction (RF), echocardiography is the most common method for assessing MR severity. Accordingly, the aim of this study was to compare the results of echocardiography and cardiac MRI for assessing MR severity in a cohort of patients with HCM. MR severity was assessed in 53 patients using cardiac MRI by determining the mitral RV (MRV) and mitral RF (MRF). The results were graded according to thresholds recommended in current guidelines. MR severity assessed by echocardiography was graded by integrating indices of severity. Greater than mild MR, as assessed using echocardiography, was present in 22 patients (41.5%) with HCM and in none of the control patients (p = 0.001). In all, 31 patients (58.5%) had no more than mild MR. When MR severity was assessed using different methods, either moderate (kappa = 0.44, 95% confidence interval = 0.21–0.67), poor or no agreement was found between MRI-derived and echocardiography-derived grades. HCM patients with echocardiography-derived moderate and severe MR had similar median MRVs and MRFs (p = 0.59 and p = 0.11, respectively). In HCM patients, cardiac MRI and echocardiography were at most in modest agreement in assessing MR severity. Importantly, echocardiography-derived moderate and severe MR were not distinguishable by either MRV or MRF.

Quantification of tricuspid regurgitation area by 3-dimensional color Doppler echocardiography considering different clinical settings

PURPOSE

The precise assessment of tricuspid regurgitation (TR) using 2D imaging techniques may be associated with significant difficulties due to the nonround regurgitation area. Direct analysis of the regurgitation area by 3D color Doppler echocardiography at the vena contracta (3D VCA) has the potential to adequately quantify even complex TR. This study compared 3D VCA for quantification of the TR with the regurgitant area determined by proximal isovolumetric convergence method (PISA-EROA) considering different clinical settings.

METHODS

In 95 patients with TR of different severity, the regurgitant orifice area was determined by 3D color Doppler echocardiography and by PISA-EROA. Using 3D color Doppler echocardiography, the regurgitant orifice area was determined three times in each patient considering 3 datasets.

RESULTS

Mean 3D VCA was 0.27 ± 0.14, 0.27 ± 0.13, and 0.29 ± 0.14 cm² , respectively, as determined by three separate measurements in each of the 95 patients. There was a mean relative deviation between the three measurements in each patient of 12.4 ± 14.9%. The regurgitant orifice area using the PISA method was 0.28 ± 0.14 cm² . There was a mean difference of 0.07 cm² (95% CI -0.124 to 0.138 cm² ) between 3D VCA and PISA-EROA. The correlation between 3D VCA and PISA-EROA was r = .88 (P < .001). Considering a grading of TR severity in grade I (regurgitant area < 0.2 cm² ), grade II (area 0.2-0.4 cm² ), and grade III (area > 0.4 cm² ), there was a good agreement between severity grade determined by 3D VCA and severity grade determined by PISA-EROA (kappa 0.71).

CONCLUSION

The analysis of the VCA of a TR using 3D color Doppler echocardiography is an alternative method to determine the regurgitant severity with good agreement to the PISA method.

Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging

Mitral regurgitation (MR) is a common valvular heart disease and is the second most frequent indication for heart valve surgery in Western countries. Echocardiography is the recommended first-line test for the assessment of valvular heart disease, but cardiovascular magnetic resonance imaging (CMR) provides complementary information, especially for assessing MR severity and to plan the timing of intervention. As new CMR techniques for the assessment of MR have arisen, standardizing CMR protocols for research and clinical studies has become important in order to optimize diagnostic utility and support the wider use of CMR for the clinical assessment of MR. In this Consensus Statement, we provide a detailed description of the current evidence on the use of CMR for MR assessment, highlight its current clinical utility, and recommend a standardized CMR protocol and report for MR assessment.

In this Consensus Statement, Garg and colleagues describe the current evidence on the use of cardiovascular magnetic resonance imaging for the assessment of mitral regurgitation, highlight its current clinical utility, and recommend a standardized imaging protocol and report.

Impact of a Geometric Correction for Proximal Flow Constraint on the Assessment of Mitral Regurgitation Severity Using the Proximal Flow Convergence Method

Background

Overestimation of the severity of mitral regurgitation (MR) by the proximal isovelocity surface area (PISA) method has been reported. We sought to test whether angle correction (AC) of the constrained flow field is helpful to eliminate overestimation in patients with eccentric MR.

Methods

In a total of 33 patients with MR due to prolapse or flail mitral valve, both echocardiography and cardiac magnetic resonance image (CMR) were performed to calculate regurgitant volume (RV). In addition to RV by conventional PISA (RV_PISA), convergence angle (α) was measured from 2-dimensional Doppler color flow maps and RV was corrected by multiplying by α/180 (RV_AC). RV measured by CMR (RV_CMR) was used as a gold standard, which was calculated by the difference between total stroke volume measured by planimetry of the short axis slices and aortic stroke volume by phase-contrast image.

Results

The correlation between RV_CMR and RV by echocardiography was modest [RV_CMR vs. RV_PISA (r = 0.712, p < 0.001) and RV_CMR vs. RV_AC (r = 0.766, p < 0.001)]. However, RV_PISA showed significant overestimation (RV_PISA - RV_CMR = 50.6 ± 40.6 mL vs. RV_AC - RV_CMR = 7.7 ± 23.4 mL, p < 0.001). The overall accuracy of RV_PISA for diagnosis of severe MR, defined as RV ≥ 60 mL, was 57.6% (19/33), whereas it increased to 84.8% (28/33) by using RV_AC (p = 0.028).

Conclusion

Conventional PISA method tends to provide falsely large RV in patients with eccentric MR and a simple geometric AC of the proximal constraint flow largely eliminates overestimation.

Echocardiographic 3D-guided 2D planimetry in quantifying left-sided valvular heart disease

Echocardiographic 3D-guided 2D planimetry can improve the accuracy of valvular disease assessment. Acquisition of 3D pyramidal dataset allows subsequent multiplanar reconstruction with accurate orthogonal plane alignment to obtain the correct borders of an anatomic orifice or flow area. Studies examining the 3D-guided 2D planimetry approach in left-sided valvular heart disease were identified and reviewed. The strongest evidence exists for estimating mitral valve area in patients with rheumatic mitral valve stenosis and vena contracta area in patients with mitral regurgitation (both primary and secondary). 3D-guided approach showed excellent feasibility and reproducibility in most studies, as well as time efficiency and good correlation with reference and comparator methods. Therefore, 3D-guided 2D planimetry can be used as an important clinical tool in quantifying left-sided valvular heart disease, especially mitral valve disorders.

Anatomic regurgitant orifice area obtained using 3D-echocardiography as an indicator of severity of mitral regurgitation in dogs with myxomatous mitral valve disease

OBJECTIVES

To determine feasibility and repeatability of measuring the anatomic regurgitant orifice area (AROA) using real-time three-dimensional transthoracic echocardiography (RT3DE) in dogs with myxomatous mitral valve disease (MMVD), and to investigate differences in the AROA of dogs with different disease severity and in different American College of Veterinary Internal Medicine (ACVIM) stages.

ANIMALS

Sixty privately-owned dogs diagnosed with MMVD.

METHODS

The echocardiographic database of our institution was retrospectively searched for dogs diagnosed with MMVD and RT3DE data set acquisition. Dogs were classified into mild, moderate, or severe MMVD according to a Mitral Regurgitation Severity Score (MRSS), and into stage B1, B2 or C according to ACVIM staging. The RT3DE data sets were imported into dedicated software and a short axis plane crossing the regurgitant orifice was used to measure the AROA. Feasibility, inter- and intra-observer variability of measuring the AROA was calculated. Differences in the AROA between dogs in different MRSS and ACVIM stages were investigated.

RESULTS

The AROA was measurable in 60 data sets of 81 selected to be included in the study (74%). The inter- and intra-observer coefficients of variation were 26% and 21%, respectively. The AROA was significantly greater in dogs with a severe MRSS compared with dogs with mild MRSS (p=0.045). There was no difference between the AROA of dogs in different ACVIM clinical stages.

CONCLUSIONS

Obtaining the AROA using RT3DE is feasible and might provide additional information to stratify mitral regurgitation severity in dogs with MMVD. Diagnostic and prognostic utility of the AROA deserves further investigation.

Multi-parametric quantification of tricuspid regurgitation using cardiovascular magnetic resonance: A comparison to echocardiography

BACKGROUND

Velocity-encoding is used to quantify tricuspid regurgitation (TR) by cardiovascular magnetic resonance (CMR), but requires additional dedicated imaging. We hypothesized that size and signal intensity (SI) of the cross-sectional TR jet area in the right atrium in short-axis steady-state free-precession images could be used to assess TR severity.

METHODS

We studied 61 patients with TR, who underwent CMR and echocardiography within 24h. TR severity was determined by vena contracta: severe (N=20), moderate or mild (N=41). CMR TR jet area and normalized SI were measured in the plane and frame that depicted maximum area. ROC analysis was performed in 21/61 patients to determine diagnostic accuracy of differentiating degrees of TR. Optimal cutoffs were independently tested in the remaining 40 patients.

RESULTS

Measurable regions of signal loss depicting TR jets were noted in 51/61 patients, while 9/10 remaining patients had mild TR by echocardiography. With increasing TR severity, jet area significantly increased (15±14 to 38±20mm2), while normalized SI decreased (57±27 to 23±11). ROC analysis showed high AUC values in the derivation group and good accuracy in the test group.

CONCLUSION

TR can be quantified from short-axis CMR images in agreement with echocardiography, while circumventing additional image acquisition.

Controversies in quantification of mitral valve regurgitation: role of cardiac magnetic resonance imaging

PURPOSE OF REVIEW

Mitral regurgitation remains a common problem, and when severe, is associated with significant morbidity and mortality. At present, echocardiography remains the primary modality for assessing both mechanism and severity of mitral regurgitation. However, recent studies demonstrate that the echocardiographic assessment of mitral regurgitation severity may be subject to variability as a result of semiquantitative parameters, dependence upon loading conditions and significant interobserver variability.

RECENT FINDINGS

Cardiac magnetic resonance (CMR) imaging is the gold standard in the assessment of cardiac function and structure, and offers an alternative method to estimate mitral regurgitation severity. Herein, we discuss the pitfalls of echocardiography in the assessment of mitral regurgitation and describe recent data demonstrating improved accuracy of CMR in the assessment of mitral regurgitation severity. Further, CMR derived regurgitant volume of ≤55 ml is associated with freedom from surgical intervention, in contrast to traditional volumetric measures, which fail to predict the need for surgical intervention.

SUMMARY

The CMR assessment of mitral regurgitation severity is easily performed and appears to be more accurate and predictive of the need for surgery than traditional echocardiography. These promising findings require further confirmation in larger outcome trials.

Quantitation of mitral regurgitation with cardiac magnetic resonance imaging: a systematic review

In this review discuss the application of cardiac magnetic resonance (CMR) to the evaluation and quantification of mitral regurgitation and provide a systematic literature review for comparisons with echocardiography. Using the 2015 Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology, we searched Medline and PubMed for original research articles published since 2000 that provided data on the quantification of mitral regurgitation by CMR. We identified 220 articles of which 33 were included. Four main techniques of mitral regurgitation quantification were identified. Reproducibility varied substantially between papers but was high overall for all techniques. However, quantification differed between the techniques studied. When compared with two-dimensional echocardiography, mitral regurgitation fraction and regurgitant volume measured by CMR were comparable but typically lower. CMR has high reproducibility for the quantification of mitral regurgitation in experienced centres, but further technological refinement is needed. An integrated and standardised approach that combines multiple techniques is recommended for optimal reproducibility and precise mitral regurgitation quantification. Definitive outcome studies using CMR as a basis for treatment are lacking but needed.

Comparison of two- and three-dimensional transthoracic echocardiography to cardiac magnetic resonance imaging for assessment of paravalvular regurgitation after transcatheter aortic valve implantation

This study evaluated 2-dimensional (2D) transthoracic echocardiography (TTE) using Valve Academic Research Consortium-2 (VARC-2) criteria and 3-dimensional (3D) TTE for assessment of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) in comparison with cardiac magnetic resonance (CMR) imaging. In 71 patients, 2D TTE, 3D TTE, and CMR imaging were performed to assess AR severity after TAVI. Using 2D TTE, AR severity was graded according to VARC-2 criteria and regurgitant volume (RVol) was determined. Three-dimensional color Doppler TTE allowed direct planimetry of the vena contracta area of the paravalvular regurgitation jet and calculation of the RVol as product with the velocity-time integral. RVol by CMR imaging was measured by phase-contrast velocity mapping in the ascending aorta. After TAVI, mean RVol determined by CMR imaging was 9.2 ± 9.6 ml/beat and mean regurgitant fraction was 13.3 ± 10.3%. AR was assessed as none or mild in 58 patients (82%) by CMR imaging. Correlation of 3D TTE and CMR imaging on RVol was better than correlation of 2D TTE and CMR imaging (r = 0.895 vs 0.558, p <0.001). There was good agreement between RVol by CMR imaging and by 3D TTE (mean bias = 2.4 ml/beat). Kappa on grading of AR severity was 0.357 between VARC-2 and CMR imaging versus 0.446 between 3D TTE and CMR imaging. Intraobserver variability for analysis of RVol of AR after TAVI was 73.5 ± 52.2% by 2D TTE, 16.7 ± 21.9% by 3D TTE, and 2.2 ± 2.0% by CMR imaging. In conclusion, 2D TTE considering VARC-2 criteria has limitations in the grading of AR severity after TAVI when CMR imaging is used for comparison. Three-dimensional TTE allows quantification of AR with greater accuracy than 2D TTE. Observer variability on RVol after TAVI is considerable using 2D TTE, significantly less using 3D TTE, and very low using CMR imaging.

Assessment of left ventricular volumes and primary mitral regurgitation severity by 2D echocardiography and cardiovascular magnetic resonance

Background

Two-dimensional transthoracic echocardiography (2DTTE) remains the first-line diagnostic imaging tool to assess primary mitral regurgitation although cardiovascular magnetic resonance (CMR) has proven to establish left ventricular function more accurately and might evaluate mitral regurgitation severity more reliably. We sought to compare routine evaluation of left ventricular function and mitral regurgitation severity by 2DTTE with assessment by CMR in moderate to severe primary mitral regurgitation without overt left ventricular dysfunction.

Methods

We prospectively included 38 patients (79% of male, age 57 ± 14 years) with at least moderate primary mitral regurgitation, a left ventricular ejection fraction ≥60% and a left ventricular end-systolic diameter ≤45 mm. Patients with evidence of coronary artery disease, arrhythmias or significant concomitant valvular disease were excluded. All patients were scheduled for 2DTTE and CMR.

Results

Left ventricular end-diastolic and end-systolic volumes were significantly underestimated by 2DTTE in comparison with CMR, although there was a strong correlation (Pearson r = 0.81, p < 0.00001 and r = 0.7, p < 0.00001, respectively). Measurement of the regurgitant orifice was similar between 2DTTE PISA method and planimetry by CMR (47 ± 24 vs. 42 ± 16 mm², p = 0.12) with a strong correlation between both imaging techniques (Pearson r = 0.76, p < 0.0001). By contrast, assessment of the regurgitant volume by 2DTTE and by phase contrast velocity mapping by CMR showed poor agreement.

Conclusions

In moderate to severe primary mitral regurgitation without overt left ventricular dysfunction, 2DTTE significantly underestimates left ventricular remodelling in comparison to CMR. Measurement of the regurgitant orifice with planimetry by CMR shows good agreement with the PISA method by 2DTTE and thus may be a valuable alternative to assess mitral regurgitation severity.

A bioenergetic assessment of mitral regurgitation: a new tool to assess severity?

Mitral regurgitation is frequently classified as mild, moderate or severe based on echocardiography. Patients with mild mitral regurgitation are usually managed medically. We hypothesise that mild mitral regurgitation as assessed volumetrically can in fact be severe when analysed from a bioenergetics point of view. The conservation of energy predicts that any regurgitant volume will require the heart to provide more work energy to support the circulation. Mitral regurgitation involves the left ventricle imparting potential energy, via blood pressure, and kinetic energy, via regurgitant velocity, to the regurgitant blood volume. This implies that regurgitant volume, regurgitant velocity, systolic blood pressure, heart rate, regurgitant orifice area and cardiac output are all important factors. We present limited data to demonstrate our hypothesis. A bioenergetic analysis of mitral regurgitation, may identify patients whose mitral regurgitation, assessed via echocardiography as mild, is actually clinically significant. In addition we identify the importance of blood pressure and heart rate control in patients with mitral regurgitation. The concept that a bit of mitral regurgitation in patients with poor left ventricles is a good thing, as it helps offload the left ventricle is from an engineering point fundamentally flawed.

Criteria for mitral regurgitation classification were inadequate for dilated cardiomyopathy

Background

Mitral regurgitation (MR) is common in patients with dilated cardiomyopathy (DCM). It is unknown whether the criteria for MR classification are inadequate for patients with DCM.

Objective

We aimed to evaluate the agreement among the four most common echocardiographic methods for MR classification.

Methods

Ninety patients with DCM were included. Functional MR was classified using four echocardiographic methods: color flow jet area (JA), vena contracta (VC), effective regurgitant orifice area (ERO) and regurgitant volume (RV). MR was classified as mild, moderate or important according to the American Society of Echocardiography criteria and by dividing the values into terciles. The Kappa test was used to evaluate whether the methods agreed, and the Pearson correlation coefficient was used to evaluate the correlation between the absolute values of each method.

Results

MR classification according to each method was as follows: JA: 26 mild, 44 moderate, 20 important; VC: 12 mild, 72 moderate, 6 important; ERO: 70 mild, 15 moderate, 5 important; RV: 70 mild, 16 moderate, 4 important. The agreement was poor among methods (kappa = 0.11; p < 0.001). It was observed a strong correlation between the absolute values of each method, ranging from 0.70 to 0.95 (p < 0.01) and the agreement was higher when values were divided into terciles (kappa = 0.44; p < 0.01)

Conclusion

The use of conventional echocardiographic criteria for MR classification seems inadequate in patients with DCM. It is necessary to establish new cutoff values for MR classification in these patients.

Analysis of procedural effects of percutaneous edge-to-edge mitral valve repair by 2D and 3D echocardiography

BACKGROUND

Analysis of procedural effects in patients undergoing percutaneous mitral valve repair (PMVR) using the edge-to-edge technique is complex, and common methods to define mitral regurgitation severity based on 2-dimensional (2D) echocardiography are not validated for postprocedural double-orifice mitral valve. This study used 3D transesophageal echocardiography (TEE) to determine the functional and morphological effects of PMVR.

METHODS AND RESULTS

In 39 high-risk surgical patients with moderate to severe functional mitral valve regurgitation, 3D TEE with and without color Doppler as well as 2D transthoracic and TEE was performed before and after PMVR (MitraClip device). Mitral valve regurgitant volume by color Doppler 3D TEE was determined as the product of vena contracta areas defined by direct planimetry and velocity time integral using continuous-wave Doppler. Regurgitant volume was reduced from 84.1±38.3 mL preintervention to 35.6±25.6 mL postintervention. Patients in whom vena contracta area could be reduced >50% had a smaller preprocedural mitral annulus area compared with patients with ≤50% reduction (11.9±3.9 versus 16.1±8.5 cm(2), respectively; P=0.036) and tended to have a smaller mitral annulus circumference (13.0±2.0 versus 14.8±4.1 cm, respectively; P=0.112). At 6 months follow-up, left atrial and left ventricular end-diastolic volumes were significantly more reduced in patients in whom regurgitant vena contracta area was reduced by >50% compared with those with less reduction (-11.4±5.2 versus -4.8±7.7%; P=0.005, and -11.0±7.2 versus -4.5±9.3%; P=0.028). The maximum diastolic mitral valve area decreased from 6.0±2.0 to 2.9±0.9 cm(2) (P<0.0001).

CONCLUSIONS

Three dimensional TEE demonstrates significant reduction of regurgitant volume after PMVR. The unique visualization of the mitral valve by 3D TEE allows improved understanding of the morphological and functional changes induced by PMVR.