Mechanism of dynamic regurgitant orifice area variation in functional mitral regurgitation: physiologic insights from the proximal flow convergence technique

Prognostic impact of vasopressor test in transcatheter edge-to-edge repair of secondary mitral regurgitation: The PETIT study

BACKGROUND

Vasopressor test (VPT) might be useful in patients with functional mitral regurgitation (MR) and left ventricular dysfunction (MITRA-FR-like patients) during transcatheter edge-to-edge repair (TEER).

AIMS

We aimed to evaluate the prognostic impact of VPT.

METHODS

MR treated with TEER were included in a multicenter prospective registry. VPT was used intraprocedurally in patients with left ventricular dysfunction and/or hypotension. The 1-year echocardiographic and clinical outcomes were compared according to the use of VPT. The primary endpoint was a combination of mortality + heart failure (HF) readmission at 1-year.

RESULTS

A total of 1115 patients were included, mean age was 72.8 ± 10.5 years and 30.4% were women. VPT was performed in 128 subjects (11.5%), more often in critically ill patients with biventricular dysfunction. Postprocedurally the VPT group had greater rate of MR ≥ 2+ (46.9% vs. 31.7%, p = 0.003) despite greater number of devices (≥2 clips, 52% vs. 40.6 p = 0.008) and device repositioning or new clip in 12.5%. At 1-year, the primary endpoint occurred more often in the VPT group (27.3% vs. 16.9%, p = 0.002) as well as all-cause mortality (21.9% vs. 8.1%, p ≤ 0.001) but no differences existed in HF readmission rate (14.8% vs. 13.2%, p = 0.610), cardiovascular mortality (4.4% vs. 3.9%, p = 0.713) or residual MR ≥ 2+ (51.1% vs 51.7%, p = 0.371).

CONCLUSIONS

Dynamic evaluation of MR during TEER procedure through VPT was performed in patients with worse baseline risk who also presented higher all-cause mortality at 1-year follow-up. However, 1-year residual MR, cardiovascular mortality and HF readmission rate remained comparable suggesting that VPT might help in the management of MITRA-FR-like patients.

The Pixel Variation Score: An Echocardiographic Index to Assess Temporal Variation of Mitral Regurgitant Flow

BACKGROUND

In mitral regurgitation (MR), temporal variation of MR flow has been considered an important reason for inaccurate MR grading. Current echocardiographic methods for assessing temporal MR flow variation are complex, and their clinical relevance has not been investigated. In this study, we investigated whether assessing MR flow variation using a dimensionless index with echocardiography is feasible, clinically meaningful, and related to patient outcomes.

METHODS

Consecutive patients with mitral valve prolapse (MVP, n = 244) and functional MR (FMR, n = 396) underwent comprehensive echocardiography. Mitral regurgitation severity was assessed using an integrated approach advocated by current guidelines. The MR continuous-wave Doppler envelope was divided into 3 segments of equal duration. Each segment's pixel intensity was assessed to calculate the pixel variation score (PVS).

RESULTS

The PVS was lower in FMR patients than in MVP patients. Lower PVS was associated with worse MR, larger left atrial and left ventricular dimensions, lower ejection fraction, and higher pulmonary artery pressures. In MVP, PVS was significantly associated with postoperative left ventricular reverse remodeling and was able to reclassify most patients in whom single-frame measures overestimated MR severity. Finally, PVS had incremental prognostic value on top of clinical and echocardiographic predictors of outcome.

CONCLUSIONS

Temporal variation in MR flow can reliably be assessed with echocardiography through analysis of the continuous-wave Doppler signal. A high PVS value may alert the echocardiographer to defer from single-frame MR grading and also suggests that the MR is probably not severe.

Arrythmia-Mediated Valvular Heart Disease

The aging population is rising at record pace worldwide. Along with it, a steep increase in the prevalence of atrial fibrillation and heart failure with preserved ejection fraction is to be expected. Similarly, both atrial functional mitral and tricuspid regurgitation (AFMR and AFTR) are increasingly observed in daily clinical practice. This article summarizes all current evidence regarding the epidemiology, prognosis, pathophysiology, and therapeutic options. Specific attention is addressed to discern AFMR and AFTR from their ventricular counterparts, given their different pathophysiology and therapeutic needs.

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.

An Integrative, Multiparametric Approach to Mitral Regurgitation Evaluation

Echocardiography is the first-line modality for assessing mitral regurgitation (MR). In addition to evaluation of the MR jet characteristics, echocardiography can provide quantitative parameters of MR severity. This case series illustrates the importance of integrating multiple parameters in the evaluation of MR and the role of multimodality imaging. (Level of Difficulty: Advanced.)

A Novel Approach for Semi Automated 3D Quantification of Mitral Regurgitant Volume Reflects a More Physiologic Approach to MR

BACKGROUND

Quantification of mitral regurgitation (MR) by echocardiography is an integral to assessing lesion severity, and entails integration of multiple Doppler-based parameters. These methods are primarily founded upon the principle of PISA (proximal isovelocity surface area), a 2D method known to employ several assumptions regarding MR jet characteristics. We analyzed the results of a semi-automated method of 3D-based RV estimation which accounts for jet behavior throughout the cardiac cycle, and compared it to conventional 2D PISA methods for MR.

METHODS

A total of 50 patients referred for transesophageal echocardiogram (TEE) for evaluation of primary (n= 25) and secondary MR (n=25) were included for analysis. 3D full volume color data sets were acquired, along with standard 2D methods for PISA calculation. 3D semi-automated MR flow quantification algorithm was applied offline to calculate 3D regurgitant volume (RVol), with simultaneous temporal curves generated from the 3D dataset. 3DRvol was compared to 2DRVol. 3D vena contracta area was also performed in all cases.

RESULTS

There was a modest correlation between 2DRVol and 3DRVol (r = 0.60). The semi-automated 3D approach resulted in significantly lower RV values compared to 2D PISA. Real-time and dynamic flow curve patterns were used for integral estimates of 3DRVol over the cardiac cycle, with a distinct bimodal pattern in functional MR, and brief and solitary peak in primary.

CONCLUSIONS

Using a semi-automated 3D software for quantification of mitral regurgitation allows for simultaneous calculation of 3D RVol with an automated generation of dynamic flow curves characteristic of the underlying MR mechanism. Our flow curve pattern results highlight well-known differences between MR flow dynamics in degenerative MR compared to functional MR.

Disproportionate Mitral Regurgitation Determines Survival in Acute Heart Failure

Objectives: To assess the prevalence and impact of mitral regurgitation (MR) on survival in patients presenting to hospital in acute heart failure (AHF) using traditional echocardiographic assessment alongside more novel indices of proportionality.

Background: It remains unclear if the severity of MR plays a significant role in determining outcomes in AHF. There is also uncertainty as to the clinical relevance of indexing MR to left ventricular volumes. This concept of disproportionality has not been assessed in AHF.

Methods: A total of 418 consecutive patients presenting in AHF over 12 months were recruited and followed up for 2 years. MR was quantitatively assessed within 24 h of recruitment. Standard proximal isovelocity surface area (PISA) and a novel proportionality index of effective regurgitant orifice/left ventricular end-diastolic volume (ERO/LVEDV) >0.14 mm²/ml were used to identify severe and disproportionate MR.

Results: Every patient had MR. About 331/418 (78.9%) patients were quantifiable by PISA. About 165/418 (39.5%) patients displayed significant MR. A larger cohort displayed disproportionate MR defined by either a proportionality index using ERO/LVEDV > 0.14 mm²/ml or regurgitant volumes/LVEDV > 0.2 [217/331 (65.6%) and 222/345 (64.3%), respectively]. The LVEDV was enlarged in significant MR−129.5 ± 58.95 vs. 100.0 ± 49.91 ml in mild, [p < 0.0001], but remained within the normal range. Significant MR was associated with a greater mortality at 2 years {44.2 vs. 34.8% in mild MR [hazard ratio (HR) 1.39; 95% CI: 1.01–1.92, p = 0.04]}, which persisted with adjustment for comorbid conditions (HR; 1.43; 95% CI: 1.04–1.97, p = 0.03). Disproportionate MR defined by ERO/LVEDV >0.14 mm²/ml was also associated with worse outcome [42.4 vs. 28.3% (HR 1.62; 95% CI 1.12–2.34, p = 0.01)].

Conclusions: MR was a universal feature in AHF and determines outcome in significant cases. Furthermore, disproportionate MR, defined either by effective regurgitant orifice (ERO) or volumetrically, is associated with a worse prognosis despite the absence of adverse left ventricular (LV) remodeling. These findings outline the importance of adjusting acute volume overload to LV volumes and call for a review of the current standards of MR assessment.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02728739, identifier NCT02728739.

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.

Optimal Quantification of Functional Mitral Regurgitation: Comparison of Volumetric and Proximal Isovelocity Surface Area Methods to Predict Outcome

Background

Effective orifice area (EOA) ≥0.2 cm² or regurgitant volume (Rvol) ≥30 mL predicts prognostic significance in functional mitral regurgitation (FMR). Both volumetric and proximal isovelocity surface area (PISA) methods enable calculation of these metrics. To determine their clinical value, we compared EOA and Rvol derived by volumetric and PISA quantitation upon outcome of patients with FMR.

Methods and Results

We examined the outcome of patients with left ventricular ejection fraction <35% and moderate to severe FMR. All had a complete echocardiogram including EOA and Rvol by both standard PISA and volumetric quantitation using total stroke volume calculated by left ventricular end‐diastolic volume×left ventricular ejection fraction and forward flow by Doppler method: EOA=Rvol/mitral regurgitation velocity time integral. Primary outcome was all‐cause mortality or heart transplantation. We examined 177 patients: mean left ventricular ejection fraction 25.2% and 34.5% with ischemic cardiomyopathy. Echo measurements were greater by PISA than volumetric quantitation: EOA (0.18 versus 0.11 cm²), Rvol (24.7 versus 16.9 mL), and regurgitant fraction (61 versus 37 %) respectively (all P value <0.001). During 3.6±2.3 years’ follow‐up, patients with EOA ≥0.2 cm² or Rvol ≥30 mL had a worse outcome than those with EOA <0.2 cm² or Rvol <30 mL only by volumetric (log rank P=0.003 and 0.004) but not PISA quantitation (log rank P=0.984 and 0.544), respectively.

Conclusions

Volumetric and PISA methods yield different measurements of EOA and Rvol in FMR; volumetric values exhibit greater prognostic significance. The echo method of quantifying FMR may affect the management of this disorder.

Secondary valve regurgitation in patients with heart failure with preserved ejection fraction, heart failure with mid-range ejection fraction, and heart failure with reduced ejection fraction

Secondary mitral regurgitation and secondary tricuspid regurgitation due to heart failure (HF) remain challenging in almost every aspect: increasing prevalence, poor prognosis, notoriously elusive in diagnosis, and complexity of therapeutic management. Recently, defined HF subgroups according to three ejection fraction (EF) ranges (reduced, mid-range, and preserved) have stimulated a structured understanding of the HF syndrome but the role of secondary valve regurgitation (SVR) across the spectrum of EF remains undefined. This review expands this structured understanding by consolidating the underlying phenotype of myocardial impairment with each type of SVR. Specifically, the current understanding, epidemiological considerations, impact, public health burden, mechanisms, and treatment options of SVR are discussed separately for each lesion across the HF spectrum. Furthermore, this review identifies important gaps in knowledge, future directions for research, and provides potential solutions for diagnosis and treatment. Mastering the challenge of SVR requires a multidisciplinary collaborative effort, both, in clinical practice and scientific approach to optimize patient outcomes.

Echocardiographic assessment of mitral regurgitation: discussion of practical and methodologic aspects of severity quantification to improve diagnostic conclusiveness

The echocardiographic assessment of mitral valve regurgitation (MR) by characterizing specific morphological features and grading its severity is still challenging. Analysis of MR etiology is necessary to clarify the underlying pathological mechanism of the valvular defect. Severity of mitral regurgitation is often quantified based on semi-quantitative parameters. However, incongruent findings and/or interpretations of regurgitation severity are frequently observed. This proposal seeks to offer practical support to overcome these obstacles by offering a standardized workflow, an easy means to identify non-severe mitral regurgitation, and by focusing on the quantitative approach with calculation of the individual regurgitant fraction. This work also indicates main methodological problems of semi-quantitative parameters when evaluating MR severity and offers appropriateness criteria for their use. It addresses the diagnostic importance of left-ventricular wall thickness, left-ventricular and left atrial volumes in relation to disease progression, and disease-related complaints to improve interpretation of echocardiographic findings. Finally, it highlights the conditions influencing the MR dynamics during echocardiographic examination. These considerations allow a reproducible, verifiable, and transparent in-depth echocardiographic evaluation of MR patients ensuring consistent haemodynamic plausibility of echocardiographic results.

Impact of effective regurgitant orifice area on outcome of secondary mitral regurgitation transcatheter repair

OBJECTIVES

To assess the value of effective regurgitant orifice (ERO) in predicting outcome after edge-to-edge transcatheter mitral valve repair (TMVR) for secondary mitral regurgitation (SMR) and identify the optimal cut-off for patients' selection.

METHODS

Using the EuroSMR (European Registry of Transcatheter Repair for Secondary Mitral Regurgitation) registry, that included patients undergoing edge-to-edge TMVR for SMR between November 2008 and January 2019 in 8 experienced European centres, we assessed the optimal ERO threshold associated with mortality in SMR patients undergoing TMVR, and compared characteristics and outcomes of patients according to baseline ERO.

RESULTS

Among 1062 patients with severe SMR and ERO quantification by proximal isovelocity surface area method in the registry, ERO was < 0.3 cm² in 575 patients (54.1%), who were more symptomatic at baseline (NYHA class ≥ III: 91.4% vs. 86.9%, for ERO < vs. ≥ 0.3 cm²; P = 0.004). There was no difference in all-cause mortality at 2-year follow-up according to baseline ERO (28.3% vs. 30.0% for ERO < vs. ≥ 0.3 cm², P = 0.585). Both patient groups demonstrated significant improvement of at least one NYHA class (61.7% and 73.8%, P = 0.002), resulting in a prevalence of NYHA class ≤ II at 1-year follow-up of 60.0% and 67.4% for ERO < vs. ≥ 0.3 cm², respectively (P = 0.05).

CONCLUSION

All-cause mortality at 2 years after TMVR does not differ if baseline ERO is < or ≥ 0.3 cm², and both groups exhibit relevant clinical improvements. Accordingly, TMVR should not be withheld from patients with ERO < 0.3 cm² who remain symptomatic despite optimal medical treatment, if TMVR appropriateness was determined by experienced teams in dedicated valve centres.

Disproportionate secondary mitral regurgitation: myths, misconceptions and clinical implications

Secondary (functional) mitral regurgitation (SMR) most commonly arises secondary to left ventricular (LV) dilation/dysfunction. The concept of disproportionately severe SMR was proposed to help explain the different results of two randomised trials of transcatheter edge-to-edge mitral valve repair (TEER) versus medical therapy. This concept is based on the fact that effective regurgitant orifice area (EROA) depends on LV end-diastolic volume (LVEDV), ejection fraction, regurgitant fraction and the velocity-time integral of SMR. This review focuses on the haemodynamic framework underlying the concept and the myths and misconceptions arising from it. Each component of EROA/LVEDV is prone to measurement error which can result in misclassification of individual patients. Moreover, EROA is typically measured at peak systole rather than its mean value over the duration of MR. This can result in physiologically impossible values of EROA or regurgitant volume. Although the EROA/LVEDV ratio (1) emphasises that grading MR severity needs to consider LV size and function and (2) helps explain the different outcomes between COAPT and MITRAFR, there are important factors that are not included. Among these are left atrial compliance, LV pressure and ejection fraction, pulmonary hypertension, right ventricular function and tricuspid regurgitation. Because medical therapy can reduce LV volumes and improve both LV function and SMR severity, the key to patient selection is forced titration of neurohormonal antagonists to the target doses that have been proven in clinical trials (along with cardiac resynchronisation when appropriate). Patients who continue to have symptomatic severe SMR after doing so should be considered for TEER.

Outcome of degenerative nonprolapse mitral regurgitation using the average pixel intensity method

BACKGROUND

Primary mitral valve regurgitation (MR) is a comprehensive term that mostly comprises mitral valve prolapse (MVP), while other causes of degenerative MR are often not considered. We describe the echocardiographic characteristics of degenerative nonprolapse mitral regurgitation (DMR) and assess the outcome at medium-term follow-up using the novel average pixel intensity (API) method.

METHODS

Of 126 patients with any nonprolapse DMR were consecutively included. MR was graded according to all guideline-recommended parameters and with the API method. MR flow dynamics in DMR were compared to MVP-MR and functional MR (FMR).

RESULTS

DMR is associated with moderate-to-severe calcifications of the mitral valve apparatus, and a low event rate was observed at a mean follow-up of 27 months. The API grading method had a higher feasibility (94%) compared to proximal isovelocity surface area (PISA) (60%) method and vena contracta width (VCW) (71%) for assessing MR. The API method was predictive for events. The API method also provides insights into DMR flow dynamics: A triphasic pattern was observed with a midsystolic nadir for both API and PISA-EROA, which is similar to the dynamic flow pattern described in FMR, but distinct from holosystolic MVP-MR. Compared to FMR and MVP-MR patients, DMR is less severe and patients with DMR are generally older than MVP-MR patients.

CONCLUSIONS

DMR is a distinct MR pathology and conveys a relatively low event rate. MR grading was feasible with the API method, and flow dynamics demonstrated a similar triphasic pattern compared to FMR but distinct from holosystolic MVP-MR.

Comparative quantification of primary mitral regurgitation by computer modeling and simulated echocardiography

Clinical investigations have demonstrated that mitral regurgitation (MR) quantification using echocardiography (echo) may significantly underestimate or overestimate the regurgitant volume, especially for two-dimensional (2D) echo. Computer modeling and simulated echo were conducted to evaluate the fundamental assumptions in the echo quantification of primary MR that is due to posterior mitral leaflet prolapse. The theoretical flaw of the proximal isovelocity surface area (PISA) method originates from the assumption that the MR flow rate is the product of the isovelocity surface area and aliasing velocity, which is only valid when the velocity vectors are perpendicular to the isovelocity surface. Other factors such as the Doppler angle effect, the view planes of 2D echo, and the single time instant of PISA were also analyzed. We find that the hemielliptic PISA method gives the smallest error for moderate and severe MR cases compared with other PISA methods. Compared with the PISA method, the volumetric technique (VT) is theoretically more robust. By considering correction factors that are caused by nonflat velocity profiles and the closing volume of the aortic valve, the accuracy of the VT method can be significantly improved. The corrected volumetric technique provides more accurate results compared with the PISA methods, especially for mild MR.NEW & NOTEWORTHY We evaluate the accuracy of common echocardiography techniques for the quantification of primary mitral regurgitations using computer modeling. The hemielliptic proximal isovelocity surface area (PISA) method gives the smallest error (within 15%) for moderate and severe mitral regurgitation cases compared with other PISA methods. The volumetric method is theoretically more robust than the PISA method. The accuracy of the volumetric method can be improved by a correction factor around 0.7 because of the nonflat velocity profiles and the closing volume of the aortic valve.

3-Dimensional Echocardiography: Latest Developments and Future Directions

The ongoing refinements in 3-dimensional (3D) echocardiography technology continue to expand the scope of this imaging modality in clinical cardiology by offering new features that stem from the ability to image the heart in its complete dimensionality. Over the years, countless publications have described these benefits and tested new frontiers where 3D echocardiographic imaging seemed to offer promising ways to improve patients' care. These include improved techniques for chamber quantification and novel ways to visualize cardiac valves, including 3D printing, virtual reality, and holography. The aims of this review article are to focus on the most important developments in the field in the recent years, discuss the current utility of 3D echocardiography, and highlight several interesting future directions.

Mitral Valve and Subvalvular Repair for Secondary Mitral Regurgitation: Rationale and Clinical Outcomes of the Papillary Muscle Sling

Secondary mitral regurgitation (MR) is a common finding in patients with dilated cardiomyopathy, and it is associated with poor outcomes. It is the result of incomplete systolic closure of the mitral valve (MV) as a consequence of left ventricular dilatation, papillary muscle displacement with impaired systolic shortening, and mitral leaflet tethering. MV surgery may be performed in cases of significant secondary MR despite guideline-directed medical therapy. However, MV repair, which is most commonly performed with an undersized ring annuloplasty, is associated with a 30-60% recurrence of moderate or greater MR at mid-term follow-up. To improve MV repair durability, several adjunctive subvalvular procedures have been proposed, one of which is the addition of papillary muscle approximation utilizing a papillary muscle sling. Recent studies comparing the outcomes of a conventional undersized ring annuloplasty with a MV repair utilizing a papillary muscle sling have reported a significant reduction in recurrent moderate or severe MR, greater left ventricular reverse remodeling, and improved MV apparatus geometry with the addition of the papillary muscle sling. We present a comprehensive review of the pathophysiology of secondary MR, and the rationale and clinical outcomes of MV repair with papillary muscle sling placement for the treatment of secondary MR.

Identification and Quantification of Degenerative and Functional Mitral Regurgitation for Patient Selection for Transcatheter Mitral Valve Repair

Chronic mitral regurgitation (MR), whether due to valve degeneration or secondary to myocardial disease, affects an increasing proportion of the aging population. Percutaneous mitral valve interventions, including edge-to-edge repair, are emerging as feasible and effective therapy for patients with severe MR at high or prohibitive surgical risk. Imaging with echocardiography is crucial for patient selection by evaluating mitral anatomy, the mechanism of dysfunction, and MR severity. In this article, the authors review the imaging characteristics for identifying and quantifying degenerative and functional MR for transcatheter mitral valve repair.

Evolution of secondary mitral regurgitation

Aims

Secondary mitral regurgitation (MR) drives adverse remodelling towards late heart failure stages. Little is known about the evolution of MR under guideline-directed therapy (GDT) and its relation to cardiac remodelling and outcome. We therefore aimed to assess incidence, impact, and predictors of progressive secondary MR in patients under GDT.

Methods and results

We prospectively enrolled 249 patients with chronic heart failure and reduced ejection fraction receiving GDT in this long-term observational study. Of patients with non-severe MR at baseline 81% remained stable whereas 19% had progressive MR. Those patients were more symptomatic (P < 0.001), had higher neurohumoral activation (encompassing various neurohumoral pathways in heart failure, all P < 0.05), larger left atrial size (P = 0.004) and more tricuspid regurgitation (TR, P = 0.02). During a median follow-up of 61 months (IQR 50-72), 61 patients died. Progression of MR conveyed an increased risk of mortality-univariately (HR 2.33; 95% CI 1.34-4.08; P = 0.003), that persisted after multivariate adjustment using a bootstrap-selected confounder model (adjusted HR 2.48; 95% CI 1.40-4.39; P = 0.002). In contrast, regression of MR was not associated with a beneficiary effect on outcome (crude HR 0.84; 95% CI 0.30-2.30; P = 0.73).

Conclusions

Every fifth patient with chronic heart failure suffers from MR progression. This entity is associated with a more than two-fold increased risk of death even after careful multivariable adjustment. Symptomatic status, left atrial size, TR, and neurohumoral pathways help to identify patients at risk for progressive secondary MR in an early disease process and open the possibility for closer follow-up and timely intervention.

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.

Imaging of Valvular Heart Disease in Heart Failure

Valvular heart disease (VHD) and heart failure (HF) are major health issues that are steadily increasing in prevalence in Western populations. VHD and HF frequently co-exist, which can complicate the accurate diagnosis of the severity of valve stenosis or regurgitation and affect decisions about therapeutic options. Transthoracic echocardiography is the first-line imaging modality to determine left ventricular (LV) systolic function, to grade valvular stenosis or regurgitation and to characterise the mechanism underlying valvular dysfunction. 3D transoesophageal echocardiography, cardiovascular magnetic resonance and cardiac CT are alternative imaging modalities that help in the diagnosis of patients with HF and VHD. The integration of multimodality cardiovascular imaging is important when deciding whether the patient should receive transcatheter aortic valve repair and replacement therapies. In this article, the use of multimodality imaging to diagnose and treat patients with VHD and HF is reviewed.

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.

2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways

Mitral regurgitation (MR) is a complex valve lesion that can pose significant management challenges for the cardiovascular clinician. This Expert Consensus Document emphasizes that recognition of MR should prompt an assessment of its etiology, mechanism, and severity, as well as indications for treatment. A structured approach to evaluation based on clinical findings, precise echocardiographic imaging, and when necessary, adjunctive testing, can help clarify decision making. Treatment goals include timely intervention by an experienced heart team to prevent left ventricular dysfunction, heart failure, reduced quality of life, and premature death.

Exercise Dynamics in Secondary Mitral Regurgitation: Pathophysiology and Therapeutic Implications

Secondary mitral valve regurgitation (MR) remains a challenging problem in the diagnostic workup and treatment of patients with heart failure. Although secondary MR is characteristically dynamic in nature and sensitive to changes in ventricular geometry and loading, current therapy is mainly focused on resting conditions. An exercise-induced increase in secondary MR, however, is associated with impaired exercise capacity and increased mortality. In an era where a multitude of percutaneous solutions are emerging for the treatment of patients with heart failure, it becomes important to address the dynamic component of secondary MR during exercise as well. A critical reappraisal of the underlying disease mechanisms, in particular the dynamic component during exercise, is of timely importance. This review summarizes the pathophysiological mechanisms involved in the dynamic deterioration of secondary MR during exercise, its functional and prognostic impact, and the way current treatment options affect the dynamic lesion and exercise hemodynamics in general.

Echocardiographic Assessment of Ischaemic Mitral Regurgitation, Mechanism, Severity, Impact on Treatment Strategy and Long Term Outcome

Introduction:

The commonest mitral regurgitation etiologies are degenerative (60%), rheumatic post-inflammatory, 12%) and functional (25%). Due to the large number of patients with acute MI, the incidence of ischaemic MR is also high. Ischaemic mitral regurgitation is a complex multifactorial disease that involves left ventricular geometry, the mitral annulus, and the valvular/subvalvular apparatus. Ischaemic mitral regurgitation is an important consequence of LV remodeling after myocardial infarction.

Research Objectives:

The objective of this study is to determine the role of echocardiography in detecting and assessment of mitral regurgitation mechanism, severity, impact on treatment strategy and long term outcome in patients with myocardial infarction during the follow up period of 5 years. Also one of objectives to determine if the absence or presence of ischaemic MR is associated with increased morbidity and mortality in patients with myocardial infarction.

Patients and methods:

The study covered 138 adult patients. All patients were subjected to echocardiography evaluation after acute myocardial infarction during the period of follow up for 5 years. The patients were examined on an ultrasound machine Philips iE 33 xMatrix, Philips HD 11 XE, and GE Vivid 7 equipped with all cardiologic probes for adults and multi-plan TEE probes. We evaluated mechanisms and severity of mitral regurgitation which includes the regurgitant volume (RV), effective regurgitant orifice area (EROA), the regurgitant fraction (RF), Jet/LA area, also we measured the of vena contracta width (VC width cm) for assessment of IMR severity, papillary muscles anatomy and displacement, LV systolic function ± dilation, LV regional wall motion abnormality WMA, LV WMI, Left ventricle LV remodeling, impact on treatment strategy and long term mortality.

Results:

We analyzed and follow up 138 patients with previous (>16 days) Q-wave myocardial infarction by ECG who underwent TTE and TEE echocardiography for detection and assessment of ischaemic mitral regurgitation (IMR) with baseline age (62 ± 9), ejection fraction (EF 41±12%), the regurgitant volume (RV) were 42±21 mL/beat, and effective regurgitant orifice area (EROA) 20±16 mm², the regurgitant fraction (RF) were 48±10%, Jet/LA area 47±12%. Also we measured the of vena contracta width (VC width cm) 0,4±0,6 for assessment of IMR severity. During 5 years follow up, total mortality for patients with moderate/severe IMR–grade II-IV (54.2±1.8%) were higher than for those with mild IMR–grade I (30.4±2.9%) (P<0.05), the total mortality for patients with EROA ≥20 mm²(54±1.9%) were higher than for those with EROA <20 mm²(27.2±2.7%) (P<0.05), and the total mortality for patients with RVol ≥30 mL (56.8±1.7%) were higher than for those with RVol<30ml (29.4±2.9%) (P<0.05). After assessment of IMR and during follow up period 64 patients (46%) underwent CABG alone or combined CABG with mitral valve repair or replacement. In this study, the procedure of concomitant down-sized ring annuloplasty at the time if CABG surgery has a failure rate around 24% in terms of high late recurrence rate of IMR during the follow period especially after 18–42 months.

Conclusion:

The presence of ischaemic MR is associated with increased morbidity and mortality. Chronic IMR, an independent predictor of mortality with a reported survival of 40–60% at 5 years. Ischaemic mitral regurgitation has important prognosis implications in patients with coronary heart disease. Recognizing the mechanism of valve incompetence is an essential point for the surgical planning and for a good result of the mitral repair. It is important that echocardiographers understand the complex nature of the condition. Despite remarkable progress in reparative surgery, further investigation is still necessary to find the best approach to treat ischaemic mitral regurgitation.

Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation

Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.

Comparison of Transesophageal and Transthoracic Echocardiographic Measurements of Mechanism and Severity of Mitral Regurgitation in Ischemic Cardiomyopathy (from the Surgical Treatment of Ischemic Heart Failure Trial)

Mitral regurgitation (MR) is common in ischemic heart disease and contributes to symptoms and mortality. This report compares the results of baseline transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) imaging of the mechanism and severity of functional MR in patients with ischemic cardiomyopathy in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Independent core laboratories measured both TTE and TEE images on 196 STICH participants. Common measurements to both models included MR grade, mitral valve tenting height and tenting area, and mitral annular diameter. For each parameter, correlations were assessed using Spearman rank correlation coefficients. A modest correlation was present between TEE and TTE for overall MR grade (n = 176, r = 0.52). For mechanism of MR, modest correlations were present for long-axis tenting height (n = 152, r = 0.35), tenting area (n = 128, r = 0.27), and long-axis mitral annulus diameter (n = 123, r = 0.41). For each measurement, there was significant scatter. Potential explanations for the scatter include different orientation of the imaging planes between TEE and TTE, a mean temporal delay of 6 days between TEE and TTE, and statistically significant differences in heart rate and blood pressure and weight between studies. In conclusion, TEE and TTE measurements of MR mechanism and severity correlate only modestly with enough scatter in the data that they are not interchangeable.

Effects of the Mueller maneuver on functional mitral regurgitation and implications for obstructive sleep apnea

Obstructive sleep apnea is prevalent and adversely affects cardiovascular health. However, little is known of the acute effects of an obstructive apnea on cardiovascular physiology. We hypothesized that pre-existing functional mitral regurgitation (MR) would worsen during performance of a Mueller maneuver (MM) used to simulate an obstructive apnea; 15 subjects with an ejection fraction ≤35% and pre-existing functional MR were studied with Doppler echocardiography. The radius of the proximal flow convergence was used as a measure of mitral regurgitant flow. Measurements were made at baseline, during the MM, and post-MM. Areas of all 4 chambers were also measured at these time points, both in systole and diastole. Mean flow convergence radius for the group decreased significantly during the transition from the late-MM to post-MM (0.65 → 0.57 mm, p = 0.001), implying increased MR during the MM. In addition, in 3 subjects, duration of MR increased during the MM. Right atrial (RA) areas, both systolic and diastolic, increased during the maneuver, whereas RA fractional area change decreased, indicating reduced RA emptying. Left ventricular emptying decreased early in the maneuver, probably because of the increased afterload burden, and then recovered. In conclusion, high negative intrathoracic pressure produces changes that, repeated hundreds of times per night in patients with obstructive sleep apnea, have the potential to worsen heart failure and predispose affected subjects to atrial fibrillation.