Practical guidance and clinical applications of transoesophageal echocardiography. A position paper of the working group of echocardiography of the Hellenic Society of Cardiology

Transoesophageal echocardiography (TOE) is a well-established imaging modality, providing more accurate and of higher quality information than transthoracic echocardiography (TTE) for a wide spectrum cardiac and extra-cardiac diseases. The present paper represents an effort by the Echocardiography Working Group (WG) of the Hellenic Cardiology Society to state the essential steps of the typical TOE exam performed in echo lab. This is an educational text, describing the minimal requirements and the preparation of a meticulous TOE examination. Most importantly, it gives practical instructions to obtain and optimize TOE views and analyses the implementation of a combined two-and multi-dimensional protocol for the imaging of the most common cardiac structures during a TOE. In the second part of the article a comprehensive review of the contemporary use of TOE in a wide spectrum of valvular and non-valvular cardiac diseases is provided, based on the current guidelines and the experience of the WG members.

Quantification of Mitral Regurgitation in Mitral Valve Prolapse by Three-Dimensional Vena Contracta Area: Derived Cutoff Values and Comparison With Two-Dimensional Multiparametric Approach

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Mitral Annular Calcification-Related Valvular Disease: A Challenging Entity

Mitral valve annular calcification-related valvular disease is increasingly common due to the rising prevalence of age-related mitral annular calcifications. Mitral annular calcification alters the structure and function of the mitral valve annulus, which in turn causes mitral valve regurgitation, stenosis, or both. As it frequently coexists with comorbid conditions and overlapping symptoms, mitral annular calcification-related valvular disease poses significant diagnostic and therapeutic challenges. For instance, left ventricular diastolic dysfunction hinders the assessment of mitral valvular disease. Detection of mitral annular calcifications and assessment of related mitral valve disease hinge on two-dimensional echocardiography. Comprehensive assessment of mitral annular calcifications and related mitral valve disease may require multidetector computed tomography and three-dimensional echocardiography. Invasive hemodynamic testing with exercise helps identify the cause of symptoms in patients with comorbid conditions, and transcatheter interventions have emerged as a viable therapeutic option for older patients. After an outline of the normal mitral annulus, we examine how mitral annular calcifications lead to mitral valve disease and how to accurately assess mitral regurgitation and stenosis. Lastly, we review surgical and transcatheter approaches to the management of mitral annular calcification-related mitral valve regurgitation, stenosis, or both.

Sex Differences in Epidemiology, Morphology, Mechanisms, and Treatment of Mitral Valve Regurgitation

Sex-related disparities have been recognized in incidence, pathological findings, pathophysiological mechanisms, and diagnostic pathways of non-rheumatic mitral regurgitation. Furthermore, access to treatments and outcomes for surgical and interventional therapies among women and men appears to be different. Despite this, current European and US guidelines have identified common diagnostic and therapeutic pathways that do not consider patient sex in decision-making. The aim of this review is to summarize the current evidence on sex-related differences in non-rheumatic mitral regurgitation, particularly regarding incidence, imaging modalities, surgical-derived evidence, and outcomes of transcatheter edge-to-edge repair, with the goal of informing clinicians about sex-specific challenges to consider when making treatment decisions for patients with mitral regurgitation.

Benefit of 3D Vena Contracta Area over 2D-Based Echocardiographic Methods in Quantification of Functional Mitral Valve Regurgitation

BACKGROUND

The two-dimensional proximal isovelocity surface area (2D PISA) method in the quantification of an effective regurgitation orifice area (EROA) has limitations in functional mitral valve regurgitation (FMR), particularly in non-circular coaptation defects.

OBJECTIVE

We aimed to validate a three-dimensional vena contracta area (3D VCA) against a conventional EROA using a 2D PISA method and anatomic regurgitation orifice area (AROA) in patients with FMR.

METHODS

Both 2D and 3D full-volume color Doppler data were acquired during consecutive transoesophageal echocardiography (TEE) examinations. The EROA 2D PISA was calculated as recommended by current guidelines. Multiplanar reconstruction was used for offline analysis of the 3D VCA (with a color Doppler) and AROA (without a color Doppler). Receiver operating characteristic (ROC) analysis was used to calculate a cut-off value for the 3D VCA to discriminate between moderate and severe FMR as classified by the EROA 2D PISA.

RESULTS

From 2015 to 2018, 105 consecutive patients with complete and adequate imaging data were included. The 3D VCA correlated strongly with the 2D PISA EROA and AROA (r = 0.93 and 0.94). In the presence of eccentric or multiple regurgitant jets, there was no significant difference in correlations with the 3D VCA. We found a 3D VCA cut-off of 0.43 cm² to discriminate between moderate and severe FMR (area under curve = 0.98). The 3D VCA showed a higher interobserver agreement than the EROA 2D PISA (interclass correlation coefficient: 0.94 vs. 0.81).

CONCLUSIONS

The 3D VCA has excellent validity and lower variability than the conventional 2D PISA in FMR. Compared to the 2D PISA, the 3D VCA was not affected by the presence of eccentric or multiple regurgitation jets or non-circular regurgitation orifices. With a threshold of 0.43 cm² for the 3D VCA, we demonstrated reliable discrimination between moderate and severe FMR.

Intraprocedural Residual Mitral Regurgitation and Survival After Transcatheter Edge-to-Edge Repair: Prospective German Multicenter Registry (MITRA-PRO)

BACKGROUND

Residual mitral regurgitation (MR) is thought to be an important predictor of long-term survival following transcatheter edge-to-edge repair (TEER). Intraprocedural MR assessment using transesophageal echocardiography could be limited by image quality, hemodynamics, and patient sedation. The MitraScore is a validated multimodal approach for intraprocedural MR assessment during TEER.

OBJECTIVES

This study aimed to assess the impact of residual MR using the MitraScore on 1-year mortality.

METHODS

Patients undergoing mitral TEER were eligible for inclusion in the prospective, multicenter MITRA-PRO registry (A Prospective Registry Study on 1-Year Mortality and the Prognostic Significance of MitraScore After MitraClip Implantation in Patients With Mitral Regurgitation). Patients with a MitraScore ≤3 were defined as patients with mild residual MR after mitral TEER, whereas a MitraScore ≥4 was considered as relevant residual MR. Mortality, rehospitalization, and major adverse events were assessed 1 year after TEER.

RESULTS

A MitraScore ≤3 was found in 1,059 patients (71.0%), whereas 432 patients revealed a MitraScore ≥4 (29.0%). One-year mortality was significantly lower in patients with nonrelevant residual MR (MitraScore ≤3 14.6% vs MitraScore≥4 22.1%). An almost linear relationship between intraprocedural MitraScore after TEER and mortality was observed. The combined clinical endpoint of mortality and rehospitalization within the 1-year follow-up was also significantly lower in the MitraScore ≤3 group (31.5%) than in the MitraScore ≥4 group (40.8%). A subgroup analysis confirmed the predictive value of the MitraScore in patients with primary, secondary, or mixed MR etiologies.

CONCLUSIONS

Residual MR assessed by intraprocedural MitraScore after TEER predicts 1-year mortality and rehospitalization. Therefore, the multimodal MitraScore improves MR assessment during mitral TEER and might improve patient survival.(A Prospective Registry Study on 1-Year Mortality and the Prognostic Significance of MitraScore After MitraClip Implantation in Patients With Mitral Regurgitation [MITRA-PRO]; DRKS00012288).

Quantification of primary mitral regurgitation by echocardiography: A practical appraisal

The accurate quantification of primary mitral regurgitation (MR) and its consequences on cardiac remodeling is of paramount importance to determine the best timing for surgery in these patients. The recommended echocardiographic grading of primary MR severity relies on an integrated multiparametric approach. It is expected that the large number of echocardiographic parameters collected would offer the possibility to check the measured values regarding their congruence in order to conclude reliably on MR severity. However, the use of multiple parameters to grade MR can result in potential discrepancies between one or more of them. Importantly, many factors beyond MR severity impact the values obtained for these parameters including technical settings, anatomic and hemodynamic considerations, patient's characteristics and echocardiographer' skills. Hence, clinicians involved in valvular diseases should be well aware of the respective strengths and pitfalls of each of MR grading methods by echocardiography. Recent literature highlighted the need for a reappraisal of the severity of primary MR from a hemodynamic perspective. The estimation of MR regurgitation fraction by indirect quantitative methods, whenever possible, should be central when grading the severity of these patients. The assessment of the MR effective regurgitant orifice area by the proximal flow convergence method should be used in a semi-quantitative manner. Furthermore, it is crucial to acknowledge specific clinical situations in MR at risk of misevaluation when grading severity such as late-systolic MR, bi-leaflet prolapse with multiple jets or extensive leak, wall-constrained eccentric jet or in older patients with complex MR mechanism. Finally, it is debatable whether the 4-grades classification of MR severity would be still relevant nowadays, since the indication for mitral valve (MV) surgery is discussed in clinical practice for patients with 3+ and 4+ primary MR based on symptoms, specific markers of adverse outcome and MV repair probability. Primary MR grading should be seen as a continuum integrating both quantification of MR and its consequences, even for patients with presumed "moderate" MR.

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.

Role of Multimodality Imaging in Transcatheter Structural Interventions

Cardiac imaging is the backbone for safe and optimal transcatheter structural interventions. Transthoracic echocardiogram is the initial modality to assess valvular disorders, while transesophageal echocardiogram is best to delineate the mechanism of valvular regurgitation, preprocedural assessment for transcatheter edge-to-edge repair, and for intraprocedural guidance. Cardiac computed tomography is the modality of choice for assessing calcifications, maneuvering multiplaner reconstruction of different cardiac structures, preprocedural planning for various transcatheter valve replacement, and assessing for hypoattenuated leaflet thickening and reduced leaflet motion. Cardiac magnetic resonance imaging is best known for most accurate volumetric assessment of valvular regurgitation and chamber size quantification. Cardiac positron emission tomography is the only modality that could assess active infection through using fluorine 18 fluorodeoxyglucose radiotracer.

Quantifying Valve Regurgitation Using 3-D Doppler Ultrasound Images and Deep Learning

Accurate quantification of cardiac valve regurgitation jets is fundamental for guiding treatment. Cardiac ultrasound is the preferred diagnostic tool, but current methods for measuring the regurgitant volume (RVol) are limited by low accuracy and high interobserver variability. Following recent research, quantitative estimators of orifice size and RVol based on high frame rate 3-D ultrasound have been proposed, but measurement accuracy is limited by the wide point spread function (PSF) relative to the orifice size. The aim of this article was to investigate the use of deep learning to estimate both the orifice size and the RVol. A simulation model was developed to simulate the power-Doppler images of blood flow through orifices with different geometries. A convolutional neural network (CNN) was trained on 30 000 image pairs. The network was used to reconstruct orifices from power-Doppler data, which facilitated estimators for regurgitant orifice areas and flow volumes. We demonstrate that the network improves orifice shape reconstruction, as well as the accuracy of orifice area and flow volume estimation, compared with a previous approach based on thresholding of the power-Doppler signal (THD), and compared with spatially invariant deconvolution (DC). Our approach reduces the area estimation error on simulations: (THD: 13.2 ± 9.9 mm2, DC: 12.8 ± 15.8 mm2, and ours: 3.5 ± 3.2 mm2). In a phantom experiment, our approach reduces both area estimation error (THD: 10.4 ± 8.4 mm2, DC: 10.98 ± 8.17, and ours: 9.9 ± 6.0 mm2) and flow rate estimation error (THD: 20.3 ± 9.9 ml/s, DC: 18.14 ± 13.01 ml/s, and ours: 7.1 ± 10.6 ml/s). We also demonstrate in vivo feasibility for six patients with aortic insufficiency, compared with standard echocardiography and magnetic resonance references.

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.

Anatomical and Technical Predictors of Three-Dimensional Mitral Valve Area Reduction After Transcatheter Edge-To-Edge Repair

BACKGROUND

Among current transcatheter therapies for the treatment of mitral regurgitation, the MitraClip (MC; Abbott Vascular, Abbott Park, IL) system is the most commonly used. MitraClip implantation is usually contraindicated in patients with a mitral valve area (MVA) < 4.0 cm². However, little is known about the real impact of MC implantation on MVA. Our goal was to investigate the factors influencing MVA reduction and derive the minimal MVA required to prevent the development of a clinically significant mitral stenosis (MVA < 1.5 cm²) in different clinical scenarios.

METHODS

Using three-dimensional data sets, the annulus and leaflet anatomy and MVA before clip implantation (MVA_BC) were assessed. After each MC implant (NTR or XTR), the relative MVA reduction and the absolute residual MVA were measured and their predictors evaluated.

RESULTS

The present analysis included 116 patients. An MC XTR was the first device implanted in 50% of the subjects, and 53% were treated with a single implant. The MVA reduction following one XTR was 57% ± 7% versus 52% ± 8% after one NTR (P = .001). A lower MVA reduction was observed when the MC was placed commissural/central versus paracentral (50% ± 8% vs 57% ± 7%, P < .0001). After a second device, the additional MVA reduction was higher when creating a triple-compared with a double-orifice morphology (34% ± 11% vs 25% ± 9%, P = .001). The MVA after one MC correlated with MVA_BC as well as with the clip type and position (r = 0.91, P < .0001). The MVA_BC, orifice morphology, and first device position predicted MVA after two implants (r = 0.82, P < .0001). Based on the mathematical relationship between these parameters, the minimal MVA_BC needed in eight different clinical scenarios was summarized in a decision algorithm: the values ranged from 3.5 to 4.7 cm² for one and 4.5 to 6.3 cm² for two MC strategies.

CONCLUSIONS

The minimal native MVA preventing clinically relevant MS after transcatheter edge-to-edge repair is predicted by the number and location of clip(s), orifice morphology, and device type. Based on these parameters, an algorithm has been derived to optimize patient selection and preprocedural planning.

State-of-the-art intra-procedural imaging for the mitral and tricuspid PASCAL Repair System

Advanced intra-procedural imaging techniques have been integral to technical and procedural success transcatheter devices. A novel leaflet approximation therapy, the PASCAL Transcatheter Valve Repair System (Edwards Lifesciences, Irvine, CA, USA) has demonstrated high procedural success, acceptable safety, and significant clinical improvement in patients with severe mitral and tricuspid regurgitation and has CE mark approval in Europe with pivotal trials underway in the USA. This review outlines the pre-procedural imaging views and advanced transoesophageal imaging protocols both mitral and tricuspid valve device implantation.

Multimodality Cardiac Imaging for Procedural Planning and Guidance of Transcatheter Mitral Valve Replacement and Mitral Paravalvular Leak Closure

Transcatheter mitral valve interventions are an evolving and growing field in which multimodality cardiac imaging is essential for diagnosis, procedural planning, and intraprocedural guidance. Currently, transcatheter mitral valve-in-valve with a balloon-expandable valve is the only form of transcatheter mitral valve replacement (TMVR) approved by the FDA, but valve-in-ring and valve-in-mitral annular calcification interventions are increasingly being performed. Additionally, there are several devices under investigation for implantation in a native annulus. Paravalvular leak (PVL) is a known complication of surgical or transcatheter valve implantation, where regurgitant flow occurs between the prosthetic sewing ring and the native mitral annulus. We sought to describe the role and applications of multimodality cardiac imaging for TMVR, and PVL closure, including the use of Cardiovascular Computed Tomography Angiography and 3-Dimensional Transesophageal Echocardiography for diagnosis, prosthetic valve evaluation, pre-procedural planning, and intraprocedural guidance, as well as evolving technologies such as fusion imaging and 3D printing.

Selection of the Optimal Candidate to MitraClip for Secondary Mitral Regurgitation: Beyond Mitral Valve Morphology

Secondary mitral regurgitation (MR) occurs despite structurally normal valve apparatus due to an underlying disease of the myocardium leading to disruption of the balance between tethering and closing forces with ensuing failure of leaflet coaptation. In patients with heart failure (HF) and left ventricular dysfunction, secondary MR is independently associated with poor outcome, yet prognostic benefits related to the correction of MR have remained elusive. Surgery is not recommended for the correction of secondary MR outside coronary artery bypass grafting. Percutaneous mitral valve repair (PMVR) with MitraClip implantation has recently evolved as a new transcatheter treatment option of inoperable or high-risk patients with severe MR, with promising results supporting the extension of guideline recommendations. MitraClip is highly effective in reducing secondary MR in HF patients. However, the derived clinical benefit is still controversial as two randomized trials directly comparing PMVR vs. optimal medical therapy in severe secondary MR yielded virtually opposite conclusions. We reviewed current evidence to identify predictors of PMVR-related outcomes in secondary MR useful to improve the timing and the selection of patients who would derive maximal benefit from MitraClip intervention. Beyond mitral valve anatomy, optimal candidate selection should rely on a comprehensive diagnostic workup and a fine-tuned risk stratification process aimed at (i) recognizing the substantial heterogeneity of secondary MR and its complex interaction with the myocardium, (ii) foreseeing hemodynamic consequences of PMVR, (iii) anticipating futility and (iv) improving symptoms, quality of life and overall survival.

Multimodality Imaging in Secondary Mitral Regurgitation

Secondary mitral regurgitation (sMR) is characterized by left ventricular (LV) dilatation or dysfunction, resulting in failure of mitral leaflet coaptation. sMR complicates up to 35% of ischaemic cardiomyopathies (1) and 57% of dilated cardiomyopathies (2). Due to the prevalence of coronary artery disease worldwide, ischaemic cardiomyopathy is the most frequently encountered cause of sMR in clinical practice. Although mortality from cardiovascular disease has gradually fallen in Western countries, severe sMR remains an independent predictor of mortality (3) and hospitalization for heart failure (4). The presence of even mild sMR following acute MI reduces long-term survival free of major adverse events (1). Such adverse outcomes worsen as the severity of sMR increases, due to a cycle in which LV remodeling begets sMR and vice versa. Current guidelines do not recommend invasive treatment of the sMR alone as a first-line approach, due to the paucity of evidence supporting improvement in clinical outcomes. Furthermore, a lack of international consensus on the thresholds that define severe sMR has resulted in confusion amongst clinicians determining whether intervention is warranted (5, 6). The recent Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial (7) assessing the effectiveness of transcatheter mitral valve repair is the first study to demonstrate mortality benefit from correction of sMR and has reignited interest in identifying patients who would benefit from mitral valve intervention. Multimodality imaging, including echocardiography and cardiovascular magnetic resonance (CMR), plays a key role in helping to diagnose, quantify, monitor, and risk stratify patients for surgical and transcatheter mitral valve interventions.

Sources of Variability in Vena Contracta Area Measurement for Tricuspid Regurgitation Severity Grading: Comparison of Technical Settings and Vendors

BACKGROUND

Previous studies found different cutoffs of vena contracta area (VCA) to define severe tricuspid regurgitation (TR). The aim of this study was to investigate the factors associated with such variability by comparing technical variables and vendors.

METHODS

Sixty-nine patients with scheduled tricuspid surgery were included in this prospective study. For each patient, TR data sets were obtained on three-dimensional color Doppler transthoracic echocardiography on at least two of three systems: GE Vivid E95 (n = 39), Siemens SC2000 Prime (n = 64), and Philips EPIQ 7C (n = 60). VCA was measured using default settings or with color baseline shifted on all three platforms and with minimal color gain (10%-20%) on the GE platform.

RESULTS

Color gain reduction and baseline shift caused significant change sin VCA measurement (-46% and 10%, respectively). Intervendor comparison exhibited wide limits of agreement (narrowest range, -74% to 167%), with either default or optimized settings. Different technical settings, platforms, and reference methods all produced different VCA cutoffs for severe TR.

CONCLUSIONS

VCA measurement in TR is sensitive to technical factors and demonstrates intervendor variability. Technical variables in VCA measurement should be reported in detail to allow comparison among research studies. The same vendor and settings should be used for longitudinal analysis of TR VCA in the same patient in multivendor echocardiography laboratories.

Degenerative mitral regurgitation

PURPOSE OF REVIEW

Degenerative mitral regurgitation (DMR) continues to be an important cause of morbidity and mortality with surgical mitral valve repair remaining the gold standard for the treatment of severe disease. The purpose of this review is to summarize recent advances in the understanding of DMR as well as the progress made in its assessment with a focus on imaging techniques.

RECENT FINDINGS

Recent insights into the anatomy and physiology of DMR challenge the assumption that fibroelastic deficiency and Barlow disease are part of a single DMR spectrum. Advances in echocardiography and cardiovascular MRI have the potential to improve quantification of mitral regurgitation, provide unique information on prognosis and impact of DMR, further the association between DMR and arrhythmic risk and aide in decision-making for DMR treatment.

SUMMARY

With growing interest in the use of noninvasive transcatheter therapies in the mitral valve space, comprehensive assessment of the mitral valve is critical to instruct decision-making and guide therapeutic strategy.

Understanding Non-P2 Mitral Regurgitation Using Real-Time Three-Dimensional Transesophageal Echocardiography: Characterization and Factors Leading to Underestimation

BACKGROUND

P2 prolapse is a common cause of degenerative mitral regurgitation (MR); echocardiographic characteristics of non-P2 prolapse are less known. Because of the eccentric nature of degenerative MR jets, the evaluation of MR severity is challenging. The aim of this study was to test the hypotheses that (1) the percentage of severe MR determined by transthoracic echocardiography (TTE) would be lower compared with that determined by transesophageal echocardiography (TEE) in patients with non-P2 prolapse and also in a subgroup with "horizontal MR" (a horizontal jet seen on TTE that hugs the leaflets without reaching the atrial wall, particularly found in non-P2 prolapse) and (2) the directions of MR jets between TTE and real-time (RT) three-dimensional (3D) TEE would be discordant.

METHODS

One hundred eighteen patients with moderate to severe and severe degenerative MR defined by TEE were studied. The percentage of severe MR between TTE and TEE was compared in P2 and non-P2 prolapse groups and in horizontal and nonhorizontal MR groups. Additionally, differences in the directions of the MR jets between TTE and RT 3D TEE were assessed.

RESULTS

Eighty-six percent of patients had severe MR according to TEE. TTE underestimated severe MR in the non-P2 group (severe MR on TTE, 57%; severe MR on TEE, 85%; P < .001) but not in the P2 group (severe MR on TTE, 79%; severe MR on TEE, 91%; P = .157). Most "horizontal" MR jets were found in the non-P2 group (85%), and this subgroup showed even more underestimation of severe MR on TTE (TTE, 22%; TEE, 89%; P < .001). There was discordance in MR jet direction between two-dimensional TTE and RT 3D TEE in 41% of patients.

CONCLUSIONS

Non-P2 and "horizontal" MR are significantly underestimated on TTE compared with TEE. There is substantial discordance in the direction of the MR jet between RT 3D TEE and TTE. Therefore, TEE should be considered when these subgroups of MR are observed on TTE.

[Evaluation of mitral regurgitation : How much quantification do we need?]

Severe mitral regurgitation (MR) is associated with increased morbidity and mortality. Thus, the correct evaluation of the underlying etiology, pathomechanism and severity is crucial for optimal treatment. Echocardiography is the predominant diagnostic modality in the clinical routine as it enables grading of mitral regurgitation, which can frequently be achieved by readily available qualitative parameters. Additionally, echocardiography provides several methods to quantify the hemodynamic significance of MR. The effective regurgitation orifice area (EROA) is the quantitative parameter best correlated with clinical events. American and European imaging guidelines both recommend the use of quantitative parameters even though they disagree on the cut-off values for secondary MR. The evaluation of MR should always include an assessment of the adjacent heart chambers in order to be able to assess the impact of volume overload on size and function of the left ventricle and left atrium. The final interpretation of the quantitative parameters requires knowledge of left ventricular volume and ejection fraction. Newer 3D-echocardiographic approaches to quantify MR are less dependent on mathematical assumptions and have shown convincing results in several studies but still lack sufficient clinical validation. As an alternative to echocardiography, for specific indications cardiac magnetic resonance imaging (MRI) has proven to be a systematic and observer-independent method for quantification of MR.

Treatment of Functional Mitral Regurgitation in Heart Failure

PURPOSE OF REVIEW

To analyze the current state of the art of functional mitral regurgitation (FMR) treatment.

RECENT FINDINGS

The first-line treatment of severe FMR consists of guideline medical therapy (GMT) and resynchronization therapy when indicated; the impact of new medical therapies like sacubitril/valsartan needs further assessment. Valvular intervention may be considered in FMR symptomatic patients despite GMT, and can be performed surgically or percutaneously. MitraClip is a safe percutaneous procedure associated with symptoms improvement. Recently, the COAPT trial showed superior outcomes for MitraClip versus GMT contrasting the MITRA-FR trial which showed no benefit of MitraClip compared with GMT. These results should be interpreted as complementary rather than opposite. The COAPT trial provided a "proof of concept" that percutaneous treatment of severe FMR in patients without too advanced left ventricular disease translates into a prognostic benefit. Careful patient selection will play a critical role in defining the clinical niche for successful interventions.

Echocardiographic assessment of mitral regurgitation

Mitral regurgitation (MR) is one of the most frequent indications for valve surgery in developed countries, and echocardiographic assessment is an essential tool to evaluate its etiologies, severity, and therapeutic indications. The mitral valve apparatus is a complex structure composed of several parts: apart from the mitral valve leaflets and annulus, it also includes the chordae tendineae, papillary muscles, and left ventricular (LV) wall. MR can be caused not only by organic changes of the mitral valve leaflets or chordae (primary MR) but also by extreme mitral annular enlargement or mitral leaflet tethering due to displacement and malfunction of papillary muscles and LV wall (secondary MR). In secondary MR with LV dysfunction, a milder degree of MR can be associated with adverse outcomes compared with primary MR. Grading the severity is the first step in evaluation of indication for surgical/transcatheter interventions. As such, there are several techniques to assess the severity of MR using echocardiography. However, none of the techniques is reliable enough by itself, and it is always recommended to integrate multiple methods. In cases where echocardiographic assessment of MR severity is inconclusive, magnetic resonance may be helpful. In addition to the severity, anatomical information, such as localization in primary MR due to mitral valve prolapse and LV size in secondary MR due to LV dilatation/dysfunction, is an important concern in presurgical echocardiography. Transesophageal echocardiography and three-dimensional echocardiography are key techniques for anatomical evaluation including mitral valve and LV volumes. In transcatheter intervention for MR, echocardiography plays a pivotal role as a guide for procedures and endpoints. In this review article, the authors provide a comprehensive summary of current standards of echocardiographic assessment of MR.

Multimodality imaging assessment of mitral valve anatomy in planning for mitral valve repair in secondary mitral regurgitation

Secondary mitral regurgitation (MR) is frequent valvular heart disease and conveys worse prognostic. Therapeutic surgical or percutaneous options are available in the context of severe symptomatic secondary MR, but the best approach to treat these patients remains unclear, given the lack of clear clinical evidence of benefit. A comprehensive evaluation of the mitral valve apparatus and the left ventricle (LV) has the ability to clearly define and characterize the disease, and thus determine the best option for the patient to improve its clinical outcomes, as well as quality of life and symptoms. The current report reviews the mitral valve (MV) anatomy, the underlying mechanisms associated with secondary MR, the related therapeutic options available, and finally the usefulness of a multimodality imaging approach for the planning of surgical or percutaneous mitral valve intervention.