Effective mitral regurgitant orifice area: clinical use and pitfalls of the proximal isovelocity surface area method

Echocardiography vs. CMR in the Quantification of Chronic Mitral Regurgitation: A Happy Marriage or Stormy Divorce?

Quantification of chronic mitral regurgitation (MR) is essential to guide patients’ clinical management and define the need and appropriate timing for mitral valve surgery. Echocardiography represents the first-line imaging modality to assess MR and requires an integrative approach based on qualitative, semiquantitative, and quantitative parameters. Of note, quantitative parameters, such as the echocardiographic effective regurgitant orifice area, regurgitant volume (RegV), and regurgitant fraction (RegF), are considered the most reliable indicators of MR severity. In contrast, cardiac magnetic resonance (CMR) has demonstrated high accuracy and good reproducibility in quantifying MR, especially in cases with secondary MR; nonholosystolic, eccentric, and multiple jets; or noncircular regurgitant orifices, where quantification with echocardiography is an issue. No gold standard for MR quantification by noninvasive cardiac imaging has been defined so far. Only a moderate agreement has been shown between echocardiography, either with transthoracic or transesophageal approaches, and CMR in MR quantification, as supported by numerous comparative studies. A higher agreement is evidenced when echocardiographic 3D techniques are used. CMR is superior to echocardiography in the calculation of the RegV, RegF, and ventricular volumes and can provide myocardial tissue characterization. However, echocardiography remains fundamental in the pre-operative anatomical evaluation of the mitral valve and of the subvalvular apparatus. The aim of this review is to explore the accuracy of MR quantification provided by echocardiography and CMR in a head-to-head comparison between the two techniques, with insight into the technical aspects of each imaging modality.

Impact of assuming a circular orifice on flow error through elliptical regurgitant orifices: computational fluid dynamics and in vitro analysis of proximal flow convergence

Grounded in hydrodynamic theory, proximal isovelocity surface area (PISA) is a simplistic and practical technique widely used to quantify valvular regurgitation flow. PISA provides a relatively reasonable, though slightly underestimated flow rate for circular orifices. However, for elliptical orifices frequently seen in functional mitral regurgitation, PISA underestimates the flow rate. Based on data obtained with computational fluid dynamics (CFD) and in vitro experiments using systematically varied orifice parameters, we hypothesized that flow rate underestimation for elliptical orifices by PISA is predictable and within a clinically acceptable range. We performed 45 CFD simulations with varying orifice areas 0.1, 0.3 and 0.5 cm², orifice aspect ratios 1:1, 2:1, 3:1, 5:1, and 10:1, and peak velocities (V_max) 400, 500 and 600 cm/s. The ratio of computed effective regurgitant orifice area to true effective area (EROA_C/EROA) against the ratio of aliasing velocity to peak velocity (V_A/V_max) was analyzed for orifice shape impact. Validation was conducted with in vitro imaging in round and 3:1 elliptical orifices. Plotting EROA_C/EROA against V_A/V_max revealed marginal flow underestimation with 2:1 and 3:1 elliptical axis ratios against a circular orifice (< 10% for 8% V_A/V_max), rising to ≤ 35% for 10:1 ratio. In vitro modeling confirmed CFD findings; there was a 8.3% elliptical EROA underestimation compared to the circular orifice estimate. PISA quantification for regurgitant flow through elliptical orifices produces predictable, but generally small, underestimation deemed clinically acceptable for most regurgitant orifices.

ECHOCARDIOGRAPHIC ASPECTS OF ASSESSMENT OF MITRAL INSUFFICIENCY IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION WITH REDUCED LEFT VENTRICULAR EJECTION FRACTION

OBJECTIVE

The aim is to analyze patients with acute myocardial infarction with reduced ejection fraction in order to determine risk factors for mitral insufficiency.

PATIENTS AND METHODS

Materials and methods: The study included 149 patients with acute myocardial infarction. Among the patients, there were 113 males (75.8%) and 36 females (24.2%). The age of the patients ranged from 43 to 86 years. Echocardiography was performed using a Phillips Epiq 7 machine. Patients were examined three times: upon admission to the hospital, after revascularization, and six months after discharge. Patients received transthoracic echocardiography, which was used to determine the presence and degree of mitral regurgitation.

RESULTS

Results: According to the results of the study, it was found that the presence of concomitant somatic pathology worsens the course of an acute myocardial infarction, in turn increasing the likelihood of valvular pathology. An increase in left ventricular volume indicators, such as end-diastolic volume, end-systolic volume, end-diastolic index, and the index of contractile function (ejection fraction) contributes to the development of mitral valve insufficiency.

CONCLUSION

Conclusions: The presence of mitral regurgitation in patients with acute myocardial infarction and reduced left ventricular ejection fraction worsens the course of the disease and negatively affects the prognosis.

Substitute parameters of exercise-induced pulmonary hypertension and usefulness of low workload exercise stress echocardiography in mitral regurgitation

In asymptomatic patients with mitral regurgitation (MR), data of exercise-induced pulmonary hypertension (EIPH) are limited, and feasibility of evaluating EIPH is not high. We aimed to investigate prognostic impact of EIPH and its substitute parameters. Exercise stress echocardiography (ESE) were performed in 123 consecutive patients with moderate to severe degenerative MR. The endpoint was a composite of death, hospitalization for heart failure, and worsening of symptoms. EIPH [tricuspid regurgitation peak gradient (TRPG) at peak workload ≥ 50 mmHg] was shown in 57 patients (46%). TRPG at low workload was independently associated with TRPG at peak workload (β = 0.67, p < 0.001). Early surgical intervention (within 6 months after ESE) was performed in 65 patients. Of the remaining 58 patients with the watchful waiting strategy, the event free survival was lower in patients with EIPH than in patients without EIPH (48.1 vs. 97.0% at 1-year, p < 0.001). TRPG at low workload ≥ 35.0 mmHg as well as EIPH were associated with poor prognosis in patients with the watchful waiting strategy. In conclusion, the importance of ESE and evaluating EIPH in patients with MR was re-acknowledged. TRPG at peak workload can be predicted by TRPG at low workload, and TRPG at low workload may be useful in real-world clinical settings.

Multi-modality imaging assessment of native valvular regurgitation: an EACVI and ESC council of valvular heart disease position paper

Valvular regurgitation represents an important cause of cardiovascular morbidity and mortality. Imaging is pivotal in the evaluation of native valve regurgitation and echocardiography is the primary imaging modality for this purpose. The imaging assessment of valvular regurgitation should integrate quantification of the regurgitation, assessment of the valve anatomy and function, and the consequences of valvular disease on cardiac chambers. In clinical practice, the management of patients with valvular regurgitation largely relies on the results of imaging. It is crucial to provide standards that aim at establishing a baseline list of measurements to be performed when assessing native valve regurgitation. The present document aims to present clinical guidance for the multi-modality imaging assessment of native valvular regurgitation.

Concomitant Mitral Regurgitation in Patients Undergoing Surgical Aortic Valve Replacement for Aortic Stenosis: A Systematic Review

Background: Concomitant mitral regurgitation (MR) is frequently seen in patients undergoing surgical aortic valve replacement (AVR) for severe aortic stenosis (AS). When the severity of MR is moderate or less, the decision to undertake simultaneous mitral valve intervention can be challenging.

Methods: A systematic search of Medline, PubMed (NCBI), Embase and Cochrane Library was conducted to qualitatively assess the current evidence for concomitant mitral valve intervention for MR in patients with AS undergoing AVR. The primary outcome for this systematic review was the postoperative change in the severity of MR and other outcomes of interest included factors that predict improvement or persistence of MR and long-term impacts of residual MR.

Results: A total of 17 studies were included. The percentage of patients demonstrating improvement in MR severity following AVR ranged from 17.2% to 72%; the studies that exclusively included patients with moderate functional MR and reported longer term echocardiographic follow-up of greater than 12 months demonstrated an improvement in MR severity of 45% to 72%.

Conclusion: This systematic review demonstrates that a proportion of patients can exhibit an improvement in MR following isolated surgical AVR, but whether this confers any long-term morbidity and mortality benefit remains unclear.

Computational Analysis of Virtual Echocardiographic Assessment of Functional Mitral Regurgitation for Validation of Proximal Isovelocity Surface Area Methods

BACKGROUND

Mitral regurgitation (MR) quantification by the proximal isovelocity surface area (PISA) method remains challenging. Using computer models, the authors evaluated the accuracy of different PISA methods and quantified their errors.

METHODS

Five functional MR computer models of different geometric and tethering abnormalities were created, validated, and treated as phantom models, from which the reference values were directly obtained. Virtual two-dimensional (2D) PISA and three-dimensional (3D) PISA (both peak and integrated values) were performed on these phantom models. By comparing virtual PISA results with reference values, the accuracy of different PISA methods was evaluated, and their sources of errors were quantified.

RESULTS

Compared with reference values of regurgitant flow rate, excellent correlations were found for true PISA (r = 0.99, bias = 32.3 ± 35.3 mL/sec), 3D PISA (r = 0.97, bias = -24.4 ± 55.5 mL/sec), followed by multiplane 2D hemicylindrical PISA (r = 0.88, bias = -24.1 ± 85.4 mL/sec) and hemiellipsoidal PISA (r = 0.91, bias = -55.7 ± 96.6 mL/sec). Weaker correlations were found for single-plane 2D hemispherical PISA (parasternal long-axis: r = 0.71, bias = -77.6 ± 124.5 mL/sec; apical two-chamber: r = 0.69, bias = -52.0 ± 122.0 mL/sec; apical four-chamber: r = 0.82, bias = -65.5 ± 107.3 mL/sec). For regurgitant volume quantification, integrated PISA was more accurate than peak PISA. The bias of 3D PISA improved from -12.7 ± 7.8 mL (peak PISA) to -2.1 ± 5.3 mL (integrated PISA).

CONCLUSIONS

For functional MR quantification, 2D hemispherical PISA had significant underestimation, multiplane 2D hemiellipsoidal and hemicylindrical PISA showed improved accuracy, and 3D PISA was the most accurate. The PISA method is subject to both systematic underestimation due to the Doppler angle effect and systematic overestimation when regurgitant flow is not perpendicular to PISA contour. Integrated PISA is able to capture dynamic MR and is therefore more accurate than peak PISA. The sum of regurgitant flow rates is the most feasible way to perform integrated PISA.

Mitral prolapsing volume is associated with increased cardiac dimensions in patients with mitral annular disjunction

Introduction

In patients with mitral annular disjunction (MAD), it can be difficult to assess the severity of mitral regurgitation (MR), as they present with a prolapsing volume (i.e. volume resulting from mitral valve prolapse, blood volume shift) rather than a regurgitant jet. The influence of the mitral prolapsing volume (MPV) on cardiac dimensions is unknown. We hypothesised that the severity of MR is underestimated in these patients. Our aim was to measure MPV and to investigate its influence on cardiac dimensions in patients with MAD.

Methods

We retrospectively included 131 consecutive patients with MAD from our institution’s echocardiographic database. Transthoracic echocardiography was used to assess MPV. Additionally, we established a control group of 617 consecutive patients with degenerative mitral valve disease and performed propensity score matching.

Results

Median MPV in the MAD group was 12 ml. MPV was an independent predictor for left ventricular end-diastolic (LVEDD) and end-systolic diameter (LVESD) and left atrial volume (all p < 0.001). In patients with large prolapsing volumes (> 15 ml), LVEDD (56 ± 6 mm vs 51 ± 6 mm, p < 0.001), LVESD [38 mm (34–41) vs 34 mm (31–39), p < 0.01] and left atrial volume [105 ml (86–159) vs 101 ml (66–123), p = 0.04] were significantly increased compared to matched patients with degenerative mitral valve disease and similarly assessed severity of MR.

Conclusion

Due to a volume shift based on the MPV rather than an actual regurgitant jet, MR severity cannot be assessed adequately in MAD patients. Increased MPV induces ventricular and atrial enlargement. These findings warrant future studies to focus on MPV as an additional parameter for assessment of the severity of MR in MAD patients.

Supplementary Information

The online version of this article (10.1007/s12471-021-01575-6) contains supplementary material, which is available to authorized users.

Concordance and Discordance of Echocardiographic Parameters Recommended for Assessing the Severity of Mitral Regurgitation

BACKGROUND

The American College of Cardiology/American Heart Association and American Society of Echocardiography guidelines recommend assessing several echocardiographic parameters when evaluating mitral regurgitation (MR) severity. These parameters can be discordant, making the assessment of MR challenging. The degree to which echocardiographic parameters of MR severity are concordant is not well studied.

METHODS

We enrolled 159 patients in a prospective multicenter study. Eight parameters were included in this analysis: proximal isovelocity surface area (PISA)-derived regurgitant volume, PISA-derived effective regurgitant orifice area, vena contracta, color Doppler jet/left atrial area, left atrial volume index, left ventricular end-diastolic volume index, peak E wave, and the presence of pulmonary vein systolic reversal. Each echocardiographic parameter was determined to represent severe or nonsevere MR according to the American Society of Echocardiography guidelines. A concordance score was calculated as [Formula: see text] so that a higher score reflects greater concordance. There was no discordance when all the echocardiographic parameters agreed and high discordance when 3 or 4 parameters were discordant.

RESULTS

The mean concordance score was 75±14% for the entire cohort. There were 9 (6%) patients with complete agreement of all parameters and 61 (38%) with high discordance. There was greater discordance in patients with severe MR but no difference between primary versus secondary or central versus eccentric jets. There was an improvement in concordance when only considering PISA-based regurgitant volume, PISA-based effective regurgitant orifice area, and vena contracta with agreement in 68% of patients.

CONCLUSIONS

There was limited concordance between the echocardiographic parameters of MR severity, and the discordance was worse with more severe MR. Concordance improved when considering only 3 quantitative measures of vena contracta and PISA-based effective regurgitant orifice area and regurgitant volume. These findings highlight the challenges facing echocardiographers when assessing the severity of MR and emphasize the difficulty of using an integrated approach that incorporates multiple components. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04038879.

Clinical Significance and Prognostic Value of Novel Echocardiographic Index for the Severity of Mitral Regurgitation

Background: Recently, the left ventricular early inflow-outflow index (LVEIO), calculated by dividing mitral E-wave velocity by the left ventricular outflow velocity time integral, has been proposed as a simple method for evaluating mitral regurgitation (MR). This study determined the optimal LVEIO threshold to assess severe MR with different etiologies and assessed its prognostic value.

Methods and Results: The records of 18,692 consecutive patients who underwent echocardiography were reviewed. MR was classified into 4 groups: Grade 0/1, no, trivial, or mild MR; Grade 2, moderate MR; Grade 3, moderate to severe MR; and Grade 4, severe MR. The mean (±SD) LVEIO of Grades 0/1, 2, 3, and 4 was 3.6±1.4, 6.0±2.5, 7.4±3.1, and 9.5±2.8, respectively. An optimal LVEIO threshold of 5.4 was determined to distinguish moderate to severe or severe MR from non-severe MR (sensitivity 84%, specificity 91%). Kaplan-Meier survival analysis revealed high mortality in the group with LVEIO ≥5.4 (P=0.009, hazard ratio 1.833). This was found only in primary MR when separate analyses were performed according to etiology. Multivariate analysis revealed that LVEIO was an independent predictor for all-cause death only in primary MR.

Conclusions: Using appropriate thresholds, LVEIO is a simple and useful method to diagnose severe MR regardless of etiology. LVEIO can also be useful for predicting prognosis in primary MR.

Total Intravenous Anesthesia Maintained the Degree of Pre-Existing Mitral Regurgitation Better than Isoflurane Anesthesia in Cardiac Surgery: A Randomized Controlled Trial

Accurate assessment of mitral regurgitation (MR) is critical during mitral valve repair surgery. However, anesthesia may influence the degree of mitral regurgitation by changing pre- and after-load or cardiac contractility. Therefore, we compared changes in mitral regurgitation by total intravenous anesthesia (TIVA) and inhalation anesthesia in patients with pre-existing mitral regurgitation. This was a double-blind randomized controlled study conducted at a tertiary care center in 2018. Fifty-four mitral regurgitation patents undergoing elective cardiac surgery were randomly assigned to receive TIVA or isoflurane. Primary endpoint was change of regurgitation volume by anesthesia. The reduction of regurgitation volume by anesthesia was greater in the isoflurane group than in the TIVA group (mean (95% confidence interval CI): -0.20 (-6.15, 5.75) vs. -9.66 (-15.77, -3.56), mL·beat^-1, p = 0.0266) and this phenomenon was more prominent with severe mitral regurgitation (grade 3 or 4) (mean (95% CI): -0.33 (-9.10, 8.44) vs. -16.20 (-24.22, -8.18), mL·beat^-1, p = 0.0079). Among patients with MR grade 3 or 4, 94% remained the same with TIVA during anesthesia compared to 56% with isoflurane. In conclusion, TIVA maintained the pre-anesthetic state of mitral regurgitation relatively well, while the severity of mitral regurgitation tended to decrease with isoflurane anesthesia.

4D flow MRI quantification of mitral and tricuspid regurgitation: Reproducibility and consistency relative to conventional MRI

BACKGROUND

In patients with mitral or tricuspid valve regurgitation, evaluation of regurgitant severity is essential for determining the need for surgery. While transthoracic echocardiography is widely accessible, it has limited reproducibility for grading inlet valve regurgitation. Multiplanar cardiac MRI is the quantitative standard but requires specialized local expertise, and is thus not widely available. Volumetric 4D flow MRI has potential for quantitatively grading the severity of inlet valve regurgitation in adult patients.

PURPOSE

To evaluate the accuracy and reproducibility of volumetric 4D flow MRI for quantification of inlet valvular regurgitation compared to conventional multiplanar MRI, which may simplify and improve accessibility of cardiac MRI.

STUDY TYPE

This retrospective, HIPAA-compliant imaging-based comparison study was conducted at a single institution.

SUBJECTS

Twenty-one patients who underwent concurrent multiplanar and 4D flow cardiac MRI between April 2015 and January 2017.

FIELD STRENGTH/SEQUENCES

3T; steady-state free-precession (SSFP), 2D phase contrast (2D-PC), and postcontrast 4D flow.

ASSESSMENT

We evaluated the intertechnique (4D flow vs. 2D-PC), intermethod (direct vs. indirect measurement), interobserver and intraobserver reproducibility of measurements of regurgitant flow volume (RFV), fraction (RF), and volume (RVol).

STATISTICAL TESTS

Statistical analysis included Pearson correlation, Bland-Altman statistics, and intraclass correlation coefficients.

RESULTS

There was high concordance between 4D flow and multiplanar MRI, whether using direct or indirect methods of quantifying regurgitation (r = 0.813-0.985). Direct interrogation of the regurgitant jet with 4D flow showed high intraobserver consistency (r = 0.976-0.999) and interobserver consistency (r = 0.861-0.992), and correlated well with traditional indirect measurements obtained as the difference between stroke volume and forward outlet valve flow.

DATA CONCLUSION

4D flow MRI provides highly reproducible measurements of mitral and tricuspid regurgitant volume, and may be used in place of conventional multiplanar MRI.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1147-1158.

A Comparative Assessment of Echocardiographic Parameters for Determining Primary Mitral Regurgitation Severity Using Magnetic Resonance Imaging as a Reference Standard

BACKGROUND

The American Society of Echocardiography (ASE) guidelines suggest the use of several echocardiographic methods to assess mitral regurgitation severity using an integrated approach, without guidance as to the weighting of each parameter. The purpose of this multicenter prospective study was to evaluate the recommended echocardiographic parameters against a reference modality and develop and validate a weighting for each echocardiographic measure of mitral regurgitation severity.

METHODS

This study included 112 patients who underwent evaluation with echocardiography and magnetic resonance imaging (MRI). Echocardiographic parameters recommended by the ASE were included and compared with MRI-derived regurgitant volume (MRI-RV).

RESULTS

Echocardiographic parameters that correlated best with MRI-RV were proximal isovelocity surface area (PISA) radius (r = 0.65, P < .0001), PISA-derived effective regurgitant orifice area (r = 0.65, P < .0001), left ventricular end-diastolic volume (r = 0.56, P < .0001), and PISA-derived regurgitant volume (r = 0.52, P < .0001). In the linear regression models PISA-derived effective regurgitant orifice area, PISA-derived regurgitant volume, left ventricular end-diastolic volume, and the presence of a flail leaflet independently predicted MRI-RV.

CONCLUSION

Echocardiographic parameters of mitral regurgitation as recommended by the ASE had moderate correlations with MRI-RV. The best predictors of MRI-RV were PISA-derived effective regurgitant orifice area, PISA-derived regurgitant volume, left ventricular end-diastolic volume, and the presence of a flail leaflet, suggesting that these parameters should be weighted more heavily than other echocardiographic parameters in the application of the ASE-recommended integrated approach.

Multimodality imaging for the quantitative assessment of mitral regurgitation

The natural history of mitral regurgitation (MR) results in significant morbidity and mortality. Innovations in non-invasive imaging have provided new insights into the pathophysiology and quantification of MR, in addition to early detection of left ventricular (LV) dysfunction and prognostic assessment in asymptomatic patients. Transthoracic (TTE) and transesophageal (TOE) echocardiography are the mainstay for diagnosis, assessment and serial surveillance. However, the advance from 2D to 3D imaging leads to improved assessment and characterization of mitral valve (MV) disease. Cardiovascular magnetic resonance (CMR) is increasingly used for MR quantitation and can provide an alternative imaging method if echocardiography is suboptimal or inconclusive. Other techniques such as exercise echocardiography, tissue Doppler imaging and speckle-tracking echocardiography can further offer complementary information on prognosis. This review summarises the current evidence for state-of-the-art cardiovascular imaging for the investigation of MR. Whilst advanced echocardiographic techniques are superior in the evaluation of complex MV anatomy, CMR appears the most accurate technique for the quantification of MR severity. Integration of multimodality imaging for the assessment of MR utilises the advantages of each imaging technique and offers the most comprehensive assessment of MR.

Quantification of Multiple Mitral Regurgitant Jets: An In Vitro Validation Study Comparing Two- and Three-Dimensional Proximal Isovelocity Surface Area Methods

BACKGROUND

The accuracy of the proximal isovelocity surface area (PISA) method for the quantification of mitral regurgitation (MR), in the case of multiple jets, is unknown. The aim of this study was to evaluate different two-dimensional (2D) and three-dimensional (3D) PISA methods using 3D color Doppler data sets.

METHODS

Several regurgitant volumes (Rvols) were simulated using a pulsatile pump connected to a phantom equipped with single and double regurgitant orifices of different sizes and interspaces. A flowmeter served as the reference method. Transthoracic (TTE) and transoesophageal echocardiography (TEE) were used to acquire the 3D data sets. Offline, Rvols were calculated by 2D PISA methods based on hemispheric and hemicylindric assumptions and by 3D integrated PISA.

RESULTS

A fusion of the PISA was observed in the setting of narrow-spaced regurgitant orifices; compared with flowmeter, Rvol was underestimated using the single hemispheric PISA model (TTE: Bland-Altman bias ± limit of agreement, -17.5 ± 8.9 mL; TEE: -15.9 ± 7.3 mL) and overestimated using the double hemispheric PISA model (TTE: +7.1 ± 14.6 mL; TEE: +10.4 ± 11.9 mL). The combined approach (hemisphere for single orifice, hemicylinder with two bases for nonfused PISAs, and hemicylinder with one base for fused PISAs) was more precise (TTE: -3.4 ± 6.3 mL; TEE: -1.9 ± 5.6 mL). Three-dimensional integrated PISA was the most accurate method to quantify Rvol (TTE: -2.1 ± 6.5 mL; TEE -3.2 ± 4.8 mL).

CONCLUSIONS

In the setting of double MR orifices, the 2D combined approach and integrated 3D PISA appear to be superior as compared with the conventional hemispheric method, thus providing tools for the challenging quantification of MR with multiple jets.

Effect of cardiac resynchronization therapy on mitral valve geometry: a novel aspect as "reversed mitral remodeling"

Amelioration of the valvular geometry is a possible mechanism for mitral regurgitation (MR) improvement in patients receiving cardiac resynchronization therapy (CRT). We aimed to establish the precise definition, incidence, and predictors of reversed mitral remodeling (RMR), as well as the association with MR improvement and short-term CRT outcome. Ninety-five CRT recipients were retrospectively evaluated for the end-point of "MR response" defined as the absolute reduction in regurgitant volume (RegV) at 6 months. To identify RMR, changes in mitral deformation indices were tested for correlation with MR response and further analyzed for functional and echocardiographic CRT outcomes. Overall, MR response was observed in 50 patients (53%). Among the echocardiographic indices, the change in tenting area (TA) had the highest correlation with the change in RegV (r = 0.653, p < 0.001). The mean TA significantly decreased in MR responders (4.15 ± 1.05 to 3.67 ± 1.01 cm² at 6 months, p < 0.001) and increased in non-responders (3.68 ± 1.04 to 3.98 ± 0.97 cm², p = 0.014). The absolute TA reduction was used to identify patients with RMR (47%) which was found to be associated with higher rates of functional improvement (p = 0.03) and volumetric CRT response (p = 0.036) compared to those without RMR. Non-ischemic etiology and the presence of LBBB independently predicted RMR at multivariate analysis. In conclusion, reduction in TA is a reliable index of RMR, which relates to MR response, and functional and echocardiographic improvement with CRT. LBBB and non-ischemic etiology are independent predictors of RMR.

Assessment of the severity of native mitral valve regurgitation

Mitral regurgitation (MR) is a major cause of cardiovascular morbidity and mortality. MR is classified as primary (organic) if it is due to an intrinsic valve abnormality, or secondary (functional) if the etiology is because of remodeling of left ventricular geometry and/or valve annulus. Transthoracic echocardiography (TTE) is the initial modality for MR evaluation. Parameters used for the assessment of MR include valve structure, cardiac remodeling, and color and spectral Doppler. Quantitative measurements include effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. Knowledge of advantages and limitations of echo-Doppler parameters is essential for accurate results. An integrative approach is recommended in overall grading of MR as mild, moderate, or severe since singular parameters may be affected by several factors. When the mechanism and/or grade of MR is unclear from the TTE or is discrepant with the clinical scenario, further evaluation with transesophageal echocardiography or cardiac magnetic resonance imaging is recommended, the latter emerging as a powerful MR quantitation tool.

Mitral Valve Prolapse: Multimodality Imaging and Genetic Insights

Mitral valve prolapse (MVP) is a common heritable valvulopathy affecting approximately 2.4% of the population. It is the most important cause of primary mitral regurgitation (MR) requiring surgery. MVP is characterized by fibromyxomatous changes and displacement of one or both mitral leaflets into the left atrium. Echocardiography represents the primary diagnostic modality for assessment of MVP. Accurate quantitation of ventricular volumes and function for surgical planning in asymptomatic severe MR can be provided with both echocardiography and cardiac magnetic resonance. In addition, assessment of myocardial fibrosis using late gadolinium enhancement and T1 mapping allows better understanding of the impact of MVP on the myocardium. Imaging in MVP is important not only for diagnostic and prognostic purposes, but is also essential for detailed phenotyping in genetic studies. Genotype-phenotype studies in MVP pedigrees have allowed the identification of milder, non-diagnostic MVP morphologies by echocardiography. Such morphologies represent early expression of MVP in gene carriers. This review focuses on multimodality imaging and the phenotypic spectrum of MVP. Moreover, the review details the recent genetic discoveries that have increased our understanding of the pathophysiology of MVP, with clues to mechanisms and therapy.

Modern Imaging Techniques in Cardiomyopathies

Modern advanced imaging techniques have allowed increasingly more rigorous assessment of the cardiac structure and function of several types of cardiomyopathies. In contemporary cardiology practice, echocardiography and cardiac magnetic resonance imaging are widely used to provide a basic framework in the evaluation and management of cardiomyopathies. Echocardiography is the quintessential imaging technique owing to its unique ability to provide real-time images of the beating heart with good temporal resolution, combined with its noninvasive nature, cost-effectiveness, availability, and portability. Cardiac magnetic resonance imaging provides data that are both complementary and uniquely distinct, thus allowing for insights into the disease process that until recently were not possible. The new catchphrase in the evaluation of cardiomyopathies is multimodality imaging, which is purported to be the efficient integration of various methods of cardiovascular imaging to improve the ability to diagnose, guide therapy, or predict outcomes. It usually involves an integrated approach to the use of echocardiography and cardiac magnetic resonance imaging for the assessment of cardiomyopathies, and, on occasion, single-photon emission computed tomography and such specialized techniques as pyrophosphate scanning.

An easy-to-use scoring index to determine severity of mitral regurgitation by 2D echocardiography in clinical practice

PURPOSE

Mitral regurgitation (MR) grading by two-dimensional transthoracic echocardiography is challenging, but important to determine the best treatment strategy in patients with MR. Current guidelines advocate an integrative approach, although no recommendation is provided on how to do so. An easy-to-use index will be helpful for standardized and reproducible MR grading.

METHODS

Eleven echocardiographic parameters were retrospectively evaluated in 145 patients with moderate or severe MR. Parameters were scored positive or negative for severe MR, where expert panel consensus reading was considered as the reference standard. Logistic regression was performed, and adjusted coefficients were used to create a risk score for severe MR per patient (ROSE-index). The best cutoff with corresponding predictive values was determined.

RESULTS

Eighty-two percent of all parameters could be determined. Multivariable analysis revealed five parameters that remained significant predictors for severe MR: morphology, jet characteristics, vena contracta, systolic reversal, and left ventricular dimensions. With different weighing, a total score of 8 could be obtained. Median total ROSE-index score for moderate (2.0) and severe MR (5.0) did significantly differ. The cutoff score (≥4) revealed sensitivity 0.84 and specificity 0.83 to diagnose severe MR. Negative predictive value was 100% for score 0 and 1; score 6-8 showed a 100% positive predictive value. Inter- and intra-observer agreements were excellent (K-values >0.80).

CONCLUSION

Here, we propose an easy-to-use tool for integrated analysis of guideline parameters to assess MR severity. Using this so-called ROSE-index revealed reliable and reproducible assessment of severe MR (cutoff≥4) that may be helpful for clinical decision making.

Primary mitral valve regurgitation: Update and review

Mitral regurgitation is the second most common valvular disorder requiring surgical intervention worldwide. This review summarizes the current understanding of primary, degenerative mitral regurgitation with respect to etiology, comprehensive assessment, natural history and management. The new concept of staging of the valvular disorders, newer predictors of adverse and controversy of “watchful waiting” versus “early surgical intervention” for severe, asymptomatic, primary mitral regurgitation are addressed.

Vena contracta analysis by color Doppler three-dimensional transesophageal echocardiography shows geometrical differences between prolapse and pseudoprolapse in eccentric mitral regurgitation

AIMS

Evaluation of eccentric mitral regurgitation (MR) remains extremely difficult and the role played by its etiology, functional or degenerative, is not well understood. This study aimed to demonstrate the value of three-dimensional transesophageal echocardiography (3DTEE) in the evaluation of eccentric MR identifying geometric differences in the vena contracta area between functional and degenerative etiologies.

METHODS AND RESULTS

We studied 61 patients with eccentric MR (30 functional and 31 degenerative). Regurgitant orifice area was determined by the two-dimensional proximal isovelocity surface area (2DPISA) and the 3DTEE methods. The ratio between maximum and minimum lengths of the vena contracta was calculated in each patient. Effective regurgitant orifice area by the 2DPISA method was smaller than that estimated by 3DTEE (0.56±0.21 vs 0.72±0.25 cm² ). A better correlation between both methods was seen in degenerative mitral regurgitation (DMR; r=.83), with a mean underestimation of 8.2% by the 2DPISA method. A much worse correlation was found in functional mitral regurgitation (FMR; r=.39), where a mean underestimation by the 2DPISA method of 29.1% was observed. There was a more elongated and curved vena contracta in FMR compared to that in DMR (length ratio: 3.4±1.0 vs 2.2±0.7, P<.0001).

CONCLUSION

Three-dimensional transesophageal echocardiography identifies a more elongated regurgitant orifice in eccentric FMR compared to that in eccentric DMR. This difference may explain the greater underestimation of effective regurgitant orifice area by the 2DPISA method in FMR. High-quality 3DTEE analysis of vena contracta area would be a highly recommended alternative.

Predictors of Exercise-Induced Pulmonary Hypertension in Patients with Asymptomatic Degenerative Mitral Regurgitation: Mechanistic Insights from 2D Speckle-Tracking Echocardiography

Presence of exercise-induced pulmonary hypertension (EIPH) in asymptomatic degenerative mitral regurgitation (DMR) determines prognosis. This study aimed to elucidate the mechanism and predictors of EIPH in asymptomatic DMR. Ninety-one consecutive asymptomatic patients with DMR who underwent exercise stress echocardiography were prospectively included. We obtained various conventional echocardiographic parameters at rest and during peak exercise, as well as left atrial (LA) function at rest using 2-dimensional speckle-tracking analysis. The 25 patients (33.3%) with EIPH were significantly older and had a greater ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity during peak exercise than those without EIPH. LA strain (LAS)-s and LAS-e, indices of LA reservoir and conduit function, respectively, were significantly lower in those with EIPH than in those without EIPH. Multivariate analysis indicated that LAS-s was the only resting echocardiographic parameter that independently predicted EIPH, with a cut-off value of 26.9%. Furthermore, Kaplan-Meier curve analysis showed that symptom-free survival was markedly lower among those with reduced LAS-s. In conclusion, decreased LA reservoir function contributes to EIPH, and LAS-s at rest is a useful indicator for predicting EIPH in asymptomatic patients with DMR.

Mitral Valve Prolapse, Psychoemotional Status, and Quality of Life: Prospective Investigation in the Current Era

OBJECTIVE

The purpose of this study is to investigate whether mitral valve prolapse is associated with the patient's psychoemotional status and health-related quality of life.

METHODS

Mitral valve prolapse and mitral regurgitation were prospectively and comprehensively assessed in 281 patients (age 61 ± 13 years; 63% men); 216 patients with mitral valve prolapse were compared with 65 without mitral valve prolapse (of similar age and sex). Simultaneously, we assessed the patient's psychoemotional status (anxiety, depression, posttraumatic stress symptoms), health-related quality of life, and perceived severity of illness using validated questionnaires.

RESULTS

Twenty-nine percent of the patients had either no or mild mitral regurgitation (area of effective regurgitant orifice ≤0.2), and 71% had clinically significant mitral regurgitation (moderate/severe). Stratifying patients into no/mild vs moderate/severe mitral regurgitation revealed no differences in psychoemotional status or mental health-related quality of life between patients with mitral valve prolapse vs those without mitral valve prolapse within each subgroup; no/mild mitral regurgitation and moderate/severe mitral regurgitation (all P ≥ .5). In multivariate analysis, mitral valve prolapse was not independently associated with psychoemotional status or health-related quality of life (all P ≥ .4). In addition, while objective severity of the illness was not related to psychoemotional status or health-related quality of life (all P ≥ .2), the patient's perceived severity of illness predicted in and of itself all psychoemotional (all P < .03) and quality-of-life outcomes (all P < .003).

CONCLUSION

Mitral valve prolapse is not a determinant of the patient's psychoemotional status or quality of life. Psychoemotional status and health-related quality of life are determined by the patient's perception of the severity of the mitral valve disease, rather than by the presence of mitral valve prolapse.

Prognostic Importance of Exercise Brain Natriuretic Peptide in Asymptomatic Chronic Organic Severe Mitral Regurgitation: An Observational Study

BACKGROUND

The optimal timing of surgery in patients with chronic organic severe mitral regurgitation (MR) continues to be debated, especially for those who are asymptomatic. The aim of the study was to determine independent and additive prognostic value of exercise brain natriuretic peptide (eBNP) in patients with severe asymptomatic MR and normal left ventricular ejection fraction (LVEF).

METHODS

Two hundred twenty-three consecutive patients with severe MR defined by effective regurgitant orifice (ERO) area ≥ 40 mm² and/or residual volume ≥ 60 mL, LVEF > 60%, and normal LV end-systolic diameter < 40 mm underwent symptom limited exercise treadmill test (TMT). Echocardiography was done immediately after exercise. Data were obtained within 3 minutes of peak exercise. BNP levels were assessed before echo (after 30 minutes of supine rest) and at exercise (i.e., within the 3 minutes of the end of effort). Patients were followed up every 3 months up to 15 months for major adverse cardiac events (MACEs) (cardiovascular death, need for mitral valve surgery and hospitalization for acute pulmonary edema or heart failure).

RESULTS

Mean age was 31.2 ± 9 years (range: 18 - 40) with majority being male (n = 153; 68%). Etiologies were rheumatic (n = 201; 90%), mitral valve prolapse (n = 17; 7.6%) and hypertrophic cardiomyopathy (n = 5; 2.4%). BNP level significantly increased from rest (65.24 ± 43.92 pg/mL; median: 43.5 pg/mL) to exercise (100.24 ± 98.24 pg/mL; median: 66.5 pg/mL; P < 0.001). Patients were divided into three tertiles according to eBNP levels (T₁ = 15 - 44; T₂ = 45 - 104; T₃ = 105 - 400). There was trend for significantly lower exercise time in T₃. During TMT, 66 (29.5%) stopped exercise due to dyspnea. They had similar resting BNP level compared with others but had significantly higher eBNP level (136 ± 109.7 pg/mL vs. 84.88 ± 90.2 pg/mL; P < 0.001). During follow-up (15 months), MACE occurred in 83 patients (37.2%): mitral valve replacement (MVR) in 59 patients (symptomatic: 43; LV dilatation or dysfunction: 9; both symptoms and dilatation/dysfunction: 7), 17 hospitalizations for congestive heart failure, five patients developing acute pulmonary edema and atrial fibrillation in remaining two patients. This was 7.6%, 35% and 69% in T₁, T₂ and T₃, respectively and had significantly higher eBNP level than without any event (165 ± 119 pg/mL vs. 57 ± 48 pg/mL; P < 0.001). Using receiver operating characteristic curve analysis, the best cut-off value of eBNP level to predict cardiac events was 90 pg/mL (sensitivity: 75%; specificity: 88.6%; positive predictive value: 79%; negative predictive value: 83.9%).

CONCLUSION

In asymptomatic patients, eBNP level provides incremental prognostic value beyond echocardiographic data and those with elevated eBNP should be considered at high risk for reduced event-free survival and might be considered for early MVR.

Plasma brain natriuretic peptide concentrations in patients with valvular heart disease

Objective

Plasma brain natriuretic peptide (BNP) concentrations predict prognosis in patients with valvular heart disease (VHD), but it is unclear whether this directly relates to disease severity. We assessed the relationship between BNP and echocardiographic measures of disease severity in patients with VHD.

Methods

Plasma BNP concentrations were measured in patients with normal left ventricular (LV) systolic function and isolated VHD (mitral regurgitation (MR), n=33; aortic regurgitation (AR), n=39; aortic stenosis (AS), n=34; mitral stenosis (MS), n=30), and age-matched and sex-matched controls (n=39) immediately prior to exercise stress echocardiography.

Results

Compared with controls, patients with VHD had elevated plasma BNP concentrations (MR median 35 (IQR 23–52), AR 34 (22–45), AS 31 (22–60), MS 58 (34–90); controls 24 (16–33) pg/mL; p<0.01 for all). LV end diastolic volume index varied by valve lesion; (MR (mean 77±14), AR (91±28), AS (50±17), MS (43±11), controls (52±13) mL/m²; p<0.0001). There were no associations between LV volume and BNP. Left atrial (LA) area index varied (MR (18±4 cm²/m²), AR (12±2), AS (11±3), MS (19±6), controls (11±2); p<0.0001), but correlated with plasma BNP concentrations: MR (r=0.42, p=0.02), MS (r=0.86, p<0.0001), AR (r=0.53, p=0.001), AS (r=0.52, p=0.002). Higher plasma BNP concentrations were associated with increased pulmonary artery pressure and reduced exercise capacity. Despite adverse cardiac remodelling, 81 (60%) patients had a BNP concentration within the normal range.

Conclusions

Despite LV remodelling, plasma BNP concentrations are often normal in patients with VHD. Conversely, mild elevations of BNP occur with LA dilatation in the presence of normal LV. Plasma BNP concentrations should be interpreted with caution when assessing patients with VHD.

Effect of QRS Narrowing After Cardiac Resynchronization Therapy on Functional Mitral Regurgitation in Patients With Systolic Heart Failure

The determinants of improvement in functional mitral regurgitation (FMR) after cardiac resynchronization therapy (CRT) remain unclear. We evaluated the predictors of FMR improvement and hypothesized that CRT-induced change in QRS duration (ΔQRS) might have an impact on FMR response after CRT. One hundred ten CRT recipients were enrolled. CRT response (≥ 15 reduction in left ventricular end-systolic volume) and FMR response (absolute reduction in FMR volume) were assessed with echocardiography before and 6 months after CRT. The study end points included all-cause death or hospitalization assessed in 12 ± 3 months (range 1 to 18). A total of 71 patients (65%) responded to CRT at 6 months. FMR response was observed in 49 (69%) of the CRT responders and 8 (20%) of the CRT nonresponders (p <0.001). Although the baseline QRS durations were similar, the paced QRS durations were shorter (p = 0.012) and the ΔQRS values were greater (p = 0.003) in FMR responders compared with FMR nonresponders. There was a linear correlation between ΔQRS and change in regurgitant volume (r = 0.49, p <0.001). At multivariate analysis, baseline tenting area (p = 0.012) and ΔQRS (p = 0.028) independently predicted FMR response. A ΔQRS ≥ 20 ms was related to CRT response, FMR improvement, and lower rates of death or hospitalization during follow-up (p values <0.05). In conclusion, QRS narrowing after CRT independently predicts FMR response. A ΔQRS ≥ 20 ms after CRT is associated with a favorable outcome in all clinical end points.