Quantitation of mitral regurgitation

Clinical Outcomes of Mitral Valve Surgery in Atrial Functional Mitral Regurgitation in the REVEAL-AFMR Registry

Importance

The characteristics and treatment strategies of atrial functional mitral regurgitation (AFMR) are poorly understood.

Objective

To investigate the prevalence, clinical characteristics, and outcomes of mitral valve (MV) surgery in AFMR.

Design, Setting, and Participants

This retrospective cohort study, called the Real-World Observational Study for Investigating the Prevalence and Therapeutic Options for Atrial Functional Mitral Regurgitation (REVEAL-AFMR), was conducted across 26 Japanese centers (17 university hospitals, 1 national center, 3 public hospitals, and 5 private hospitals). All transthoracic echocardiography procedures performed from January 1 to December 31, 2019, were reviewed to enroll adult patients (aged ≥20 years) with moderate or severe AFMR, defined by preserved left ventricular function, a dilated left atrium, and an absence of degenerative valvular changes. Data were analyzed from May 8, 2023, to May 16, 2024.

Exposures

Mitral valve surgery, with or without tricuspid valve intervention.

Main Outcomes and Measures

The primary composite outcome included heart failure hospitalization and all-cause mortality.

Results

In 177 235 patients who underwent echocardiography, 8867 had moderate or severe MR. Within this group, 1007 (11.4%) were diagnosed with AFMR (mean [SD] age, 77.8 [9.5] years; 55.7% female), of whom 807 (80.1%) had atrial fibrillation. Of these patients, 113 underwent MV surgery, with 92 (81.4%) receiving concurrent tricuspid valve surgery. Patients who underwent surgery were younger but had more severe MR (57.5% [n = 65] vs 9.4% [n = 84]; P < .001), a larger mean (SD) left atrial volume index (152.5 [97.8] mL/m2 vs 87.7 [53.1] mL/m2; P < .001), and a higher prevalence of heart failure (according to the New York Heart Association class III [marked limitation of physical activity] or class IV [symptoms of heart failure at rest], 26.5% [n = 30] vs 9.3% [n = 83]; P < .001) than those who remained under medical therapy. During a median follow-up of 1050 days (IQR, 741-1188 days), 286 patients (28.4%) experienced the primary outcome. Despite a more severe disease status, only the surgical group showed a decrease in natriuretic peptide levels at follow-up and had a significantly lower rate of the primary outcome (3-year event rates were 18.3% vs 33.3%; log-rank, P = .03). Statistical adjustments did not alter these findings.

Conclusions and Relevance

The findings of this cohort study suggest that in patients with AFMR, who were typically older and predominantly had atrial fibrillation, MV surgery was associated with lower rates of adverse clinical outcomes. Future studies are warranted to investigate a possible causal relationship to better regulate cardiovascular medicine.

Ertugliflozin for Functional Mitral Regurgitation Associated With Heart Failure: EFFORT Trial

BACKGROUND

The morbidity and mortality rates of patients with heart failure (HF) and functional mitral regurgitation (MR) remain substantial despite guideline-directed medical therapy for HF. We evaluated the efficacy of ertugliflozin for reduction of functional MR associated with HF with mild to moderately reduced ejection fraction.

METHODS

The EFFORT trial (Ertugliflozin for Functional Mitral Regurgitation) was a multicenter, double-blind, randomized trial to examine the hypothesis that the sodium-glucose cotransporter 2 inhibitor ertugliflozin is effective for improving MR in patients with HF with New York Heart Association functional class II or III, 35%≤ejection fraction<50%, and effective regurgitant orifice area of chronic functional MR >0.1 cm2 on baseline echocardiography. We randomly assigned 128 patients to receive either ertugliflozin or placebo in addition to guideline-directed medical therapy for HF. The primary end point was change in effective regurgitant orifice area of functional MR from baseline to the 12-month follow-up. Secondary end points included changes in regurgitant volume, left ventricular (LV) volume indices, left atrial volume index, LV global longitudinal strain, and NT-proBNP (N-terminal pro-B-type natriuretic peptide).

RESULTS

The treatment groups were generally well-balanced with regard to baseline characteristics: mean age, 66±11 years; 61% men; 13% diabetes; 51% atrial fibrillation; 43% use of angiotensin receptor-neprilysin inhibitor; ejection fraction, 42±8%; and effective regurgitant orifice area, 0.20±0.12 cm2. The decrease in effective regurgitant orifice area was significantly greater in the ertugliflozin group than in the placebo group (-0.05±0.06 versus 0.03±0.12 cm2; P<0.001). Compared with placebo, ertugliflozin significantly reduced regurgitant volume by 11.2 mL (95% CI, -16.1 to -6.3; P=0.009), left atrial volume index by 6.0 mL/m2 (95% CI, -12.16 to 0.15; P=0.005), and LV global longitudinal strain by 1.44% (95% CI, -2.42% to -0.46%; P=0.004). There were no significant between-group differences regarding changes in LV volume indices, ejection fraction, or NT-proBNP levels. Serious adverse events occurred in one patient (1.6%) in the ertugliflozin group and 6 (9.2%) in the placebo group (P=0.12).

CONCLUSIONS

Among patients with functional MR associated with HF, ertugliflozin significantly improved LV global longitudinal strain and left atrial remodeling, and reduced functional MR. Sodium-glucose cotransporter 2 inhibitors may be considered for patients with functional MR.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04231331.

Imaging of the Mitral Valve

Echocardiographic imaging is the foundation for the evaluation of mitral valve dysfunction. Both transthoracic and transesophageal echocardiography provide insight into the anatomy, pathology, and classification mitral valve dysfunction. Echocardiography also provides a multi-parametric approach with semi-quantitative and quantitative parameters to assess the severity of mitral regurgitation and mitral stenosis. Transesophageal imaging is essential in the assessment of patients considered for surgical or transcatheter interventional strategies to treat mitral valve dysfunction. Cardiac computed tomography (CT) and cardiac MRI are useful adjunctive imaging techniques in mitral valve disease with CT providing detailed procedural specificity and MRI providing detailed ventricular and regurgitant flow analysis.

Correlation of n-terminal pro-brain-type natriuretic peptide levels with the severity of single mitral regurgitation or accompanied by mild aorta valve dysfunction in patients with rheumatic heart disease in Sanglah general hospital

BACKGROUND

The most frequent abnormality of the valves involved in rheumatic heart disease is mitral regurgitation. A promising supportive diagnostic tool for rheumatic heart disease is the N-terminal pro-brain natriuretic peptide, which can identify mitral valve damage.

OBJECTIVE

To prove a positive correlation between N-terminal pro-brain natriuretic peptide levels and the severity of mitral regurgitation or accompanied by mild aortic valve dysfunction in children with rheumatic heart disease.

MATERIAL AND METHOD

Children aged 1-18 years who had been identified as having rheumatic heart disease with a single mitral regurgitation or accompanied by mild aortic issues at Sanglah General Hospital, Denpasar, met the inclusion criteria for this cross-sectional study. Mitral regurgitation severity was determined using the parameters of vena contracta width, effective regurgitation orifice area, regurgitant jet area, and regurgitation volume. Bivariate analysis using the Spearman correlation test.

RESULTS

From 36 research subjects, the mean age was 11.32 years. In this study, there was a moderate positive correlation between the levels of N-terminal pro-brain natriuretic peptide and the regurgitation jet area. N-terminal pro-brain natriuretic peptide levels also had a moderately positive correlation with the vena contracta width and a weakly positive correlation with the regurgitation volume. Effective regurgitation orifice area and N-terminal pro-brain natriuretic peptide levels did not significantly correlate.

CONCLUSION

There was a moderately positive correlation between N-terminal pro-brain natriuretic peptide levels and the severity of mitral regurgitation on regurgitation jet area, a moderately positive correlation with the vena contracta width, and a weakly positive correlation with regurgitation volume in rheumatic heart disease patients.

Timing of Surgery for Asymptomatic Primary Mitral Regurgitation: Possible Value of Early, Serial Measurements of Left Ventricular Sphericity

Asymptomatic primary mitral regurgitation due to myxomatous degeneration of the mitral valve leaflets may remain so for long periods, even as left ventricular function progresses to a decompensated stage. During the early compensated stage, the ventricle's initial response to the volume overload is an asymmetric increase in the diastolic short axis dimension, accomplished by a diastolic shift of the interventricular septum into the right ventricular cavity, creating a more spherical left ventricular diastolic shape, increasing diastolic filling and stroke volume. Early valve repair is recommended to reduce postoperative left ventricular dysfunction. Early serial measurements of left ventricular sphericity index [LV-Si]. during the compensated stage of mitral regurgitation might identify subtle changes in left ventricular shape and assist in determining the optimal earliest timing for surgical intervention.

Impact of extra-mitral valve cardiac involvement in patients with primary mitral regurgitation undergoing transcatheter edge-to-edge repair

BACKGROUND

In the context of primary mitral regurgitation (PMR), the selection of patients for transcatheter edge-to-edge repair (TEER) does not include a systematic assessment of PMR-associated cardiac remodelling.

AIMS

We aimed to investigate the epidemiology and prognostic significance of different phenotypes of extra-mitral valve (MV) cardiac involvement in a large series of patients with PMR referred for TEER.

METHODS

The study included 654 patients from the multicentre Italian GIOTTO registry, stratified into groups according to extra-mitral valve (MV) cardiac involvement. The primary endpoint was all-cause death at 2-year follow-up.

RESULTS

Patients with no cardiac involvement (NI; n=58), left heart involvement (LHI; n=343) and right heart involvement (RHI; n=253) were analysed. Acute technical success was achieved in 98% of patients. Kaplan-Meier curve analysis revealed significantly worse survival in patients with LHI and RHI (p=0.041). On multivariate Cox regression analysis, extra-MV cardiac involvement, haemoglobin level and technical success were independent predictors of the primary endpoint occurrence.

CONCLUSIONS

Grading cardiac involvement may help refine risk stratification, since at least 1 group of extra-MV cardiac involvement represents in itself a negative predictor of midterm outcome.

Mitral Regurgitation: Advanced Imaging Parameters and Changing Treatment Landscape

Mitral regurgitation is a common valvular heart disease with increasing prevalence due to the aging population. In degenerative (primary) mitral regurgitation, medical therapies are limited and the mainstay of treatment is mitral valve surgery. Patients are referred for mitral valve surgery based on the American College of Cardiology/American Heart Association guidelines, which recommend surgery in patients with severe mitral regurgitation. Echocardiography uses multiple parameters that lack reproducibility and accuracy. Studies comparing cardiovascular magnetic resonance (CMR) and echocardiography have shown that CMR is a better predictor of clinical outcome and postsurgical left ventricular remodeling than echocardiography.

Prognostic Significance of Flail Mitral Leaflet in Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

Despite the growing experience with MitraClip in the broad spectrum of mitral regurgitation (MR), limited data are available regarding the independent prognostic role on survival of different mitral regurgitation etiology subtypes. We sought to evaluate the impact of flail leaflet etiology in a large series of patients with primary MR (PMR) who underwent MitraClip treatment. The study included 588 patients with significant PMR from the multicenter GIOTTO (Italian Society of Interventional Cardiology [GIse] registry Of Transcatheter treatment of mitral valve regurgitaTiOn), stratified into 2 groups according to MR etiology: flail+ (n = 300) and flail- (n = 288). The primary end point was a composite of cardiac death and first rehospitalization for heart failure (HF). To account for the baseline differences, patients were propensity score-matched 1:1. Flail leaflet etiology was present in about a half of the patients. Acute technical success was achieved in 98% of the overall cohort, with no significant differences between the study groups (p = 0.789). At the 2-year Kaplan-Meier analysis, the primary end point occurred in 13% of flail+ patients compared with 23% in flail- (p = 0.009). The flail+ group presented lower rates of both cardiac death and rehospitalization for HF, whereas a similar overall death rate was observed between the groups. A multivariate Cox regression analysis identified flail leaflet etiology as an independent predictor of favorable outcome in terms of the primary end point (hazard ratio 0.141, 95% confidence interval 0.049 to 0.401, p <0.001). After propensity score matching, flail+ patients had confirmed lower rates of cardiac mortality and rehospitalization for HF but similar rates of overall death. In conclusion, flail leaflet-related etiology was common in patients with PMR who underwent MitraClip treatment and was an independent predictor of midterm favorable clinical outcomes.

Impact of Percutaneous Mitral Valve Repair on Left Atrial Strain and Atrial Fibrillation Progression

Transcatheter edge-to-edge repair (TEER) currently represents a valuable therapeutic option for patients with severe mitral regurgitation (MR) considered at high surgical risk. Besides symptoms and left ventricular (LV) echocardiographic improvements upon TEER, it has been postulated that left atrial (LA) function plays a prognostic role. The aims of our study were to evaluate LA changes after TEER, measured by two-dimensional speckle-tracking echocardiography analysis (2D-STE), their association with atrial fibrillation (AF) occurrence, and relative arrhythmic burden. We considered in a single-center study 109 patients affected by symptomatic severe MR undergoing TEER from February 2015 to April 2022. By 2D-STE, LA reservoir (R_s), conduct (D_s), and contractile (C_s) strains were assessed along with four-chamber emptying fraction (LAEF-4CH) before, 1, 6, and 12 months following TEER. Statistical analysis for comparison among baseline, and follow-ups after TEER was carried out by ANOVA, MANOVA, and linear regression. Successful TEER significantly improved LV dimensions and LA performances, as indicated by all strain components, and LAEF-4CH after 1 year. Strikingly, a significant reduction in arrhythmic burden was observed, since only one case of subclinical AF detected by a previously implanted cardiac electronic device was found in the cohort of sinus rhythm patients (n = 48) undergone TEER; in addition, ventricular rate was reduced in the AF cohort (n = 61) compared to baseline, together with few episodes of nonsustained ventricular tachycardias (5/61, 8.2%) after MR improvement. Overall, TEER was associated with improved cardiac performance, LA function amelioration, and reduced arrhythmic burden.

Reclassification of Pre-Heart Failure Stages Using Cardiac Biomarkers: The ARIC Study

BACKGROUND

The recent heart failure (HF) guideline recommends the inclusion of cardiac biomarkers in defining Stage B HF.

OBJECTIVES

The authors evaluated the impact of incorporating cardiac biomarkers to reclassify HF in 5,324 participants (mean age: 75.8 years) without prevalent HF enrolled in the ARIC (Atherosclerosis Risk In Communities) study and assessed prognosis of Stage B using cardiac biomarkers.

METHODS

Using N-terminal pro-B-type natriuretic peptide (<125 pg/mL or ≥125 pg/mL), high-sensitivity troponin T (<14 ng/L or ≥14 ng/L), and abnormal cardiac structure/function by echocardiography, individuals were classified as Stage Anew and Stage Bnew HF, respectively. Stage Bnew was further evaluated as elevated biomarker only, abnormal echocardiogram only, and abnormalities in both (echo + biomarker). The authors assessed risk for incident HF and all-cause death using Cox regression.

RESULTS

Overall, 4,326 (81.3%) individuals were classified as Stage Bnew with 1,123 (21.1%) meeting criteria for elevated biomarkers only. Compared with Stage Anew, Stage Bnew was associated with increased risk for incident HF (HR: 3.70 [95% CI: 2.58-5.30]) and death (HR: 1.94 [95% CI: 1.53-2.46]). Stage Bbiomarkers only and Stage Becho only were associated with increased HF risk, whereas Stage Bbiomarkers only was also associated with increased death. Stage Becho+biomarker had the highest risk for HF (HR: 6.34 [95% CI: 4.37-9.19]) and death (HR: 2.53 [95% CI: 1.98-3.23]).

CONCLUSIONS

Incorporating biomarkers based on the new HF guideline reclassified approximately 1 in 5 older adults without prevalent HF to Stage B. The routine measurement of biomarkers can help to identify individuals at higher HF risk who may benefit most from HF prevention efforts.

Clinical Utility of Three-Dimensional Echocardiography in the Evaluation of Mitral Valve Disease: Tips and Tricks

Although real-time 3D echocardiography (RT3DE) has only been introduced in the last decades, its use still needs to be improved since it is a time-consuming and operator-dependent technique and acquiring a good quality data can be difficult. Moreover, the additive value of this important diagnostic tool still needs to be wholly appreciated in clinical practice. This review aims at explaining how, why, and when performing RT3DE is useful in clinical practice.

Blood pressure changes during routine transthoracic echocardiography

Background

Increased afterload affects many of the flow dependent metrics assessed during transthoracic echocardiography (TTE) especially in the evaluation valvular disease. A single timepoint blood pressure (BP) may not accurately reflect the afterload present at the time of flow-dependent imaging and quantification. We assessed the magnitude of change in BP at discrete timepoints during routine TTE.

Method

We conducted a prospective study where participants underwent automated BP measurement while undergoing a clinically indicated TTE. The first reading was obtained right after the patient lay supine and subsequent readings were taken at 10-min intervals during image acquisition.

Result

We included 50 participants (66% were male, with a mean age of 64 years). After 10 min, 40 (80%) participants had a drop in systolic BP of >10 mmHg. Compared to the baseline, there was a significant drop in systolic BP (mean decrease 20.0 ± 12.8 mmHg; P < 0.05), and diastolic BP (mean decrease 15.7 ± 13.2 mmHg; P < 0.05) at 10 min. The systolic BP remained different from the baseline value throughout the duration of the study (average decrease from baseline to study end was 12.4 ± 16.0 mmHg, p < 0.05).

Conclusion

BP recorded just prior to TTE does not accurately reflect the afterload present during most of the study. This finding has important implications for valvular heart disease imaging protocols that incorporate flow dependent metrics, where the presence or absence of hypertension may lead to under- or over-estimation of disease severity.

Comparative modeling of the mitral valve in normal and prolapse conditions

Introduction

Computational modeling is one of the best non-invasive approaches to predicting the functional behavior of the mitral valve (MV) in health and disease. Mitral valve prolapse (MVP) due to partial or complete chordae tendineae rapture is the most common valvular disease and results in mitral regurgitation (MR).

Methods

In this study, Image-based fluid-structure interaction (FSI) models of the human MV are developed in the normal physiological and posterior leaflet prolapse conditions. Detailed geometry of the healthy human MV is derived from Computed Tomography imaging data. To provide prolapse condition, some chords attached to the posterior leaflet are removed from the healthy valve. Both normal and prolapsed valves are embedded separately in a straight tubular blood volume and simulated under physiological systolic pressure loads. The Arbitrary Lagrangian-Eulerian finite element method is used to accommodate the deforming intersection boundaries of the blood and MV.

Results

The stress values in the mitral components, and also flow patterns including the regurgitant flow rates are obtained and compared in both conditions through the simulation. These simulations have the potential to improve the treatment of patients with MVP, and also help surgeons to have more realistic insight into the dynamics of the MV in health and prolapse.

Conclusion

In the prolapse model, computational results show incomplete leaflet coaptation, higher MR severity, and also a significant increment of posterior leaflet stress compared to the normal valve. Moreover, it is found more deviation of the regurgitant jet towards the left atrium wall due to the posterior leaflet prolapse.

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

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

The Common Combination of Aortic Stenosis with Mitral Regurgitation: Diagnostic Insight and Therapeutic Implications in the Modern Era of Advanced Echocardiography and Percutaneous Intervention

The combination of aortic stenosis (AS) and mitral regurgitation (MR) is common in patients with degenerative valvular disease. It is characterized by having complex pathophysiology, leading to potential diagnostic pitfalls. Evidence is scarce in the literature to direct the diagnostic framework and treatment of patients with this particular combination of multiple valvular diseases. In this complex scenario, the appropriate use of advanced echocardiography and multimodality imaging methods plays a central role. Transcatheter mitral valve replacement or repair and transcatheter aortic valve replacement widen the surgical options for valve diseases. Therefore, there is an increasing need to reconsider the function, timing, and mode intervention for patients with a combination of AS with MR towards more personalized treatment.

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.

Guide to functional mitral regurgitation: a contemporary review

Functional mitral regurgitation (FMR) occurs in the absence of organic mitral valve (MV) disease and is a result of LV dysfunction due to ischemic vs. non ischemic etiologies. The prevalence of FMR is increasing, as 2.0-2.5 million people in the USA were diagnosed with FMR in 2000-and this number is expected to double to 4 million by 2030. FMR tends to develop in a significant number of patients after myocardial infarction (MI) and many develop heart failure (HF) subsequently with mortality rates ranging from 15-40% at 1 year. Therefore, there has been much interest and effort to develop optimized methods for quantifying and classifying the severity of FMR, as well as developing effective therapeutic interventions to improve outcomes in patients with significant FMR. Echocardiogram is typically the primary diagnostic method of assessment, however, there have been various technological advances including cardiac CT and cardiac MRI that can better guide quantification and management of this disease. Management of this disease is mostly aimed at optimizing left ventricular (LV) remodeling with surgical and transcatheter management gaining more popularity with recent times. The purpose of this paper is to provide a comprehensive review of the current evaluation methods and interventional strategies for FMR.

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.

Transcatheter mitral valve interventions: pre-procedural planning and intra-procedural guidance

Mitral regurgitation is the most prevalent valve disease worldwide. Percutaneous mitral valve interventions are emerging as alternative options for high-risk patients with severe mitral regurgitation not eligible for conventional surgery. Accurate patient selection is based on a detailed pre-procedural multimodality imaging evaluation. Morphology and functional anatomy of the mitral valve should be evaluated to determine the feasibility of treatments and to identify the best therapeutic approach. The procedures are guided by fluoroscopy, transoesophageal echocardiography and fusion imaging, ensuring a continuous communication between the interventionalist and the imaging specialist. The present review will cover the pre-procedural planning and the intra-procedural guidance of the most used transcatheter approaches in the setting of native mitral valve regurgitation: edge to edge repair, percutaneous direct and indirect annuloplasty, transapical beating-heart chordal implantation and transcatheter mitral valve replacement.

The assessment of mitral valve disease: a guideline from the British Society of Echocardiography

Mitral valve disease is common. Mitral regurgitation is the second most frequent indication for valve surgery in Europe and despite the decline of rheumatic fever in Western societies, mitral stenosis of any aetiology is a regular finding in all echo departments. Mitral valve disease is, therefore, one of the most common pathologies encountered by echocardiographers, as both a primary indication for echocardiography and a secondary finding when investigating other cardiovascular disease processes. Transthoracic, transoesophageal and exercise stress echocardiography play a crucial role in the assessment of mitral valve disease and are essential to identifying the aetiology, mechanism and severity of disease, and for helping to determine the appropriate timing and method of intervention. This guideline from the British Society of Echocardiography (BSE) describes the assessment of mitral regurgitation and mitral stenosis, and replaces previous BSE guidelines that describe the echocardiographic assessment of mitral anatomy prior to mitral valve repair surgery and percutaneous mitral valvuloplasty. It provides a comprehensive description of the imaging techniques (and their limitations) employed in the assessment of mitral valve disease. It describes a step-wise approach to identifying: aetiology and mechanism, disease severity, reparability and secondary effects on chamber geometry, function and pressures. Advanced echocardiographic techniques are described for both transthoracic and transoesophageal modalities, including TOE and exercise testing.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

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.

Quantitating Mitral Regurgitation in Clinical Trials: The Need for a Uniform Approach

BACKGROUND

There is an established relationship between the degree of mitral regurgitation (MR) and prognosis. Quantitation of MR severity guides therapeutic approaches. Inconsistent definitions and categorization of MR severity in clinical studies limit meaningful comparisons between trials and compromise development of an effective evidence base. The purpose of this study was to quantify heterogeneity in grading systems for MR severity in the contemporary literature.

METHODS

We performed a systematic review of randomized (RCT) and propensity score (PS) adjusted clinical studies of MV interventions (surgical or percutaneous). A total of 35 articles from 2015-2020 were included (15 RCT, 20 PS).

RESULTS

There were 22 studies that reported MR severity in numerical categories, either values from the historical "plus" system or numerical MR grades, while 9 studies reported MR severity using text-only descriptive categories. Among the studies that used numerical categories, 2+ MR was defined as moderate in 64% of studies, mild in 27%, and mild-moderate in 9% and 3+ MR was defined as moderate in 14%, moderate-severe in 52%, and severe in 14%.

CONCLUSIONS

There was substantial variability in MR severity definition and reporting in contemporary clinical studies of MV interventions. We recommend the historical "plus" numerical grading system be abandoned and that inclusion and outcome criteria in MR clinical trials be based on American and European guideline-recommended categories as none/trace, mild, moderate, and severe. Adoption of these simple recommendations will improve the consistency and quality of MR clinical trial design and reporting.

Association of Effective Regurgitation Orifice Area to Left Ventricular End-Diastolic Volume Ratio With Transcatheter Mitral Valve Repair Outcomes: A Secondary Analysis of the COAPT Trial

Importance

Transcatheter mitral valve repair (TMVr) plus maximally tolerated guideline-directed medical therapy (GDMT) reduced heart failure (HF) hospitalizations (HFHs) and all-cause mortality (ACM) in symptomatic patients with HF and secondary mitral regurgitation (SMR) compared with GDMT alone in the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation (COAPT) trial but not in a similar trial, Multicenter Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation (MITRA-FR), possibly because the degree of SMR relative to the left ventricular end-diastolic volume index (LVEDVi) was substantially lower.

Objective

To explore contributions of the degree of SMR using the effective regurgitation orifice area (EROA), regurgitant volume (RV), and LVEDVi to the benefit of TMVr in the COAPT trial.

Design, Setting, and Participants

This post hoc secondary analysis of the COAPT randomized clinical trial performed December 27, 2012, to June 23, 2017, evaluated a subgroup of COAPT patients (group 1) with characteristics consistent with patients enrolled in MITRA-FR (n = 56) (HF with grade 3+ to 4+ SMR, left ventricular ejection fraction of 20%-50%, and New York Heart Association function class II-IV) compared with remaining (group 2) COAPT patients (n = 492) using the end point of ACM or HFH at 24 months, components of the primary end point, and quality of life (QOL) (per the Kansas City Cardiomyopathy Questionnaire overall summary score) and 6-minute walk distance (6MWD). The same end points were evaluated in 6 subgroups of COAPT by combinations of EROA and LVEDVi and of RV relative to LVEDVi.

Interventions

Interventions were TMVr plus GDMT vs GDMT alone.

Results

A total of 548 participants (mean [SD] age, 71.9 [11.2] years; 351 [64%] male) were included. In group 1, no significant difference was found in the composite rate of ACM or HFH between TMVr plus GDMT vs GDMT alone at 24 months (27.8% vs 33.1%, P = .83) compared with a significant difference at 24 months (31.5% vs 50.2%, P < .001) in group 2. However, patients randomized to receive TMVr vs those treated with GDMT alone had significantly greater improvement in QOL at 12 months (mean [SD] Kansas City Cardiomyopathy Questionnaire summary scores: group 1: 18.36 [5.38] vs 0.43 [4.00] points; P = .01; group 2: 16.54 [1.57] vs 5.78 [1.82] points; P < .001). Group 1 TMVr-randomized patients vs those treated with GDMT alone also had significantly greater improvement in 6MWD at 12 months (mean [SD] paired improvement: 39.0 [28.6] vs -48.0 [18.6] m; P = .02). Group 2 TMVr-randomized patients vs those treated with GDMT alone tended to have greater improvement in 6MWD at 12 months, but the difference did not reach statistical significance (mean [SD] paired improvement: 35.0 [7.7] vs 16.0 [9.1] m; P = .11).

Conclusions and Relevance

A small subgroup of COAPT-resembling patients enrolled in MITRA-FR did not achieve improvement in ACM or HFH at 24 months but had a significant benefit on patient-centered outcomes (eg, QOL and 6MWD). Further subgroup analyses with 24-month follow-up suggest that the benefit of TMVr is not fully supported by the proportionate-disproportionate hypothesis.

Trial Registration

ClinicalTrials.gov Identifier: NCT01626079.

Dynamic Systolic Changes in Tricuspid Regurgitation Vena Contracta Size and Proximal Isovelocity Surface Area in Hypoplastic Left Heart Syndrome: A Three-Dimensional Color Doppler Echocardiographic Study

BACKGROUND

The aims of this study were to investigate the dynamic changes in the vena contracta (VC) and proximal isovelocity surface area (PISA) through systole in patients with hypoplastic left heart syndrome and tricuspid regurgitation and to identify the stage of systole (early, mid, or late) in which VC and PISA radius are optimal.

METHODS

Twenty-eight patients with hypoplastic left heart syndrome were prospectively studied using continuous two-dimensional (2D) and three-dimensional (3D) echocardiography. Two-dimensional VC width, 3D VC area, and PISA radii (2D and 3D) were measured frame by frame throughout systole. The maximal 2D VC width, 3D VC area, and PISA radii in the first, middle, and last thirds of systole were compared, and correlations were explored with 3D tricuspid annular areas, right atrial volumes, and right ventricular volumes.

RESULTS

In all, 35 data sets that met inclusion criteria were analyzed. On frame-by-frame analysis, maximal 2D VC width and 3D VC area were found in the first third of systole in 17% and 20% of studies, in the second third in 34% and 31%, and in the final third in 49% and 49%. Similarly, the maximal 2D and 3D PISA radii were found in the first third of systole in 26% and 17% of studies, in the second third in 28% and 34%, and in the final third in 46% and 49%.

CONCLUSIONS

In hypoplastic left heart syndrome, detailed temporal analysis of tricuspid regurgitation-associated VC and PISA by 2D and 3D echocardiography reveals no reliable pattern predicting when in systole these parameters peak. Frame-by-frame measurement is necessary for identification of maximal VC and PISA radius on 2D and 3D color Doppler echocardiography because the severity of tricuspid regurgitation could be underestimated because of temporal variability in VC and PISA.

Diagnostic and Prognostic Value of Several Color Doppler Jet Grading Methods in Patients With Mitral Regurgitation

Color Doppler is a widely used ultrasound imaging method for assessing mitral regurgitation (MR) in clinical practice. Nevertheless, color Doppler-based grading of the MR jet has been rarely considered in clinical studies. We investigated the diagnostic and prognostic value of several color Doppler MR jet grading methods and compared them with quantitative grading of MR. The MR color Doppler jet was assessed in 476 MR patients using an 'integrated' eyeballing approach by quantifying the color Doppler jet area, jet area/left atrium area and jet length and using quantitative methods. Clinical endpoints were scored as major adverse clinical events, including cardiovascular death, heart failure hospitalization and mitral valve intervention. When assessed by three echocardiographers, there was a moderate inter-observer agreement for eyeballing color Doppler grade of MR (intraclass correlation coefficient 0.69, p < 0.001). The intra-observer agreement was good for all color Doppler approaches. In primary MR, eyeballing color Doppler correlated well with (in)direct measures of MR severity, with a negative predictive value of 91% when using a grade 2 color Doppler as cut-off. In secondary MR, eyeballing color Doppler grade and jet length were predictors of clinical outcome in Cox proportional hazards analysis (p = 0.003), independent of pulmonary pressures, atrial and ventricular volumes. Overall, the integrated eyeballing approach performed better than color Doppler quantification of the MR jet area and length. In conclusion, this study shows that color Doppler grading of the distal MR jet performs well in predicting events in primary and secondary MR, compared to quantitative grading methods.

4D flow MRI left atrial kinetic energy in hypertrophic cardiomyopathy is associated with mitral regurgitation and left ventricular outflow tract obstruction

To noninvasively assess left atrial (LA) kinetic energy (KE) in hypertrophic cardiomyopathy (HCM) patients using 4D flow MRI and evaluate coupling associations with mitral regurgitation (MR) and left ventricular outflow tract (LVOT) obstruction. Twenty-nine retrospectively identified patients with HCM underwent 4D flow MRI. MRI-estimated peak LVOT pressure gradient (∆P_MRI) was used to classify patients into non-obstructive and obstructive HCM. Time-resolved volumetric LA kinetic energy (KE_LA) was computed throughout systole. Average systolic (KE_LA-avg) and peak systolic (KE_LA-peak) KE_LA were compared between non-obstructive and obstructive HCM groups, and associations to MR severity and LVOT ∆P_MRI were tested.The study included 15 patients with non-obstructive HCM (58.6 [45.9, 65.2] years, 7 females) and 14 patients with obstructive HCM (51.9 [47.6, 62.6] years, 6 females). Obstructive HCM patients demonstrated significantly elevated instantaneous KE_LA over all systolic time-points compared to non-obstructive HCM (P < 0.05). Obstructive HCM patients also demonstrated higher KE_LA-avg (14.8 [10.6, 20.4] J/m³ vs. 33.4 [23.9, 61.3] J/m³, P < 0.001) and KE_LA-peak (22.1 [15.9, 28.7] J/m³ vs. 57.2 [44.5, 121.4] J/m³, P < 0.001) than non-obstructive HCM. MR severity was significantly correlated with KE_LA-avg (rho = 0.81, P < 0.001) and KE_LA-peak (rho = 0.79, P < 0.001). LVOT ∆P_MRI was strongly correlated with KE_LA metrics in obstructive HCM (KE_LA-avg: rho = 0.86, P < 0.001; KE_LA-peak: rho = 0.85, P < 0.001).In HCM patients, left atrial kinetic energy, by 4D flow MRI, is associated with MR severity and the degree of LVOT obstruction.

Ischemic functional mitral regurgitation: from pathophysiological concepts to current treatment options. A systemic review for optimal strategy

OBJECTIVE

The current treatment of ischemic functional mitral regurgitation (FMR) remains debated due to differences in inclusion criteria of randomized studies and baseline characteristics. Also, the role of left ventricular pathophysiology and the role of subvalvular apparatus have not been thoroughly investigated in recent literature.

METHODS

A literature search was performed from PubMed inception to June 2020.

RESULTS

Novel concepts of pathophysiology, such as the proportionate/disproportionate conceptual framework, the role of papillary muscles and left ventricular dysfunction, the impact of myocardial ischemia and revascularization, left ventricular remodeling, and the effect of restrictive annuloplasty or subvalvular procedures have been reviewed.

CONCLUSIONS

The clinical benefits associated with the use of MitraClip is more evident in patients with disproportionate FMR with greater and sustained left ventricular reverse remodeling. Importantly, in the absence of myocardial revascularization, expansion of myocardial scar tissue and non-perfused areas of ischemic myocardium occur with time, and this impact on outcomes with a longer follow-up period cannot be quantified. In advanced phases of FMR, neither mitral ring annuloplasty nor percutaneous therapies could significantly modify the established pathoanatomic alterations.

Percutaneous Edge-to-Edge Mitral Valve Repair

Percutaneous edge-to-edge mitral valve repair, using the MitraClip device for severe mitral regurgitation (MR) was first introduced in 2003. Since then, more than 100,000 cases have been performed worldwide and it remains the most established percutaneous therapy available for the treatment of severe MR. Currently, it is indicated for severe, symptomatic functional MR in patients who continue to have significant symptoms despite optimal guideline directed medical therapy, as well as in symptomatic patients with severe degenerative MR who are deemed too high risk for conventional surgical therapy in the opinion of the heart team. In this paper, we discuss the evolution of the MitraClip device, the clinical studies supporting its use as well as the important concept of proportionate and disproportionate MR.

Role of the Imager in Transcatheter Mitral Valve Repair

PURPOSE OF REVIEW

To describe the key role of the structural imager/interventional echocardiographer in transcatheter mitral valve therapies, particularly edge-to-edge repair. In addition, we review important recent advances in structural imaging and briefly describe several novel devices for transcatheter mitral valve repair.

RECENT FINDINGS

Structural imagers represent a new subspecialty in cardiology and anesthesiology with specific skillset and training requirements. Their role is particularly important in imaging-based transcatheter interventions such as edge-to-edge mitral valve repair. This therapy has increasingly been used to treat primary (degenerative) mitral regurgitation when surgical risk is prohibitive and has recently been extended to patients with secondary (functional) mitral regurgitation. As novel transcatheter therapies continue to emerge, so do new multimodality imaging technologies. Structural imagers have become an integral part of the heart team. Their role is particularly visible in transcatheter mitral procedures. Rapidly developing transcatheter therapies have helped shape this new subspecialty and spark innovation in imaging technologies.

Does the Presence of Significant Mitral Regurgitation prior to Transcatheter Aortic Valve Implantation for Aortic Stenosis Impact Mortality? – Meta-Analysis and Systematic Review

Background: Mitral regurgitation (MR) is commonly encountered in patients with severe aortic stenosis (AS). However, its independent impact on mortality in patients undergoing transcatheter aortic valve implantation (TAVI) has not been established. Methods: We performed a systematic search for studies reporting characteristics and outcome of patients with and without significant MR and/or adjusted mortality associated with MR post-TAVI. We conducted a meta-analysis of quantitative data. Results: Seventeen studies with 20,717 patients compared outcomes and group characteristics. Twenty-one studies with 32,257 patients reported adjusted odds of mortality associated with MR. Patients with MR were older, had a higher Society of Thoracic Surgeons score, lower left ventricular ejection fraction, a higher incidence of prior myocardial infarction, atrial fibrillation, and a trend towards higher NYHA class III/IV, but had similar mean gradient, gender, and chronic kidney disease. The MR patients had a higher unadjusted short-term (RR = 1.46, 95% CI 1.30–1.65) and long-term mortality (RR = 1.40, 95% CI 1.18–1.65). However, 16 of 21 studies with 27,777 patients found no association between MR and mortality after adjusting for baseline variables. In greater than half of the patients (0.56, 95% CI 0.45–0.66) MR improved by at least one grade following TAVI. Conclusion: The patients with MR undergoing TAVI have a higher burden of risk factors which can independently impact mortality. There is a lack of robust evidence supporting an increased mortality in MR patients, after adjusting for other compounding variables. MR tends to improve in the majority of patients post-TAVI.

Cardiac Magnetic Resonance Imaging Features in Hypertrophic Cardiomyopathy Diagnosed at <21 Years of Age

Hypertrophic cardiomyopathy (HC) is the most common inherited cardiomyopathy, with varied timing of phenotypic and clinical presentation. Literature describing cardiac magnetic resonance (CMR) imaging and late gadolinium enhancement (LGE) in young patients with HC is limited. This study included patients diagnosed with HC at young age (<21 years) between January 1990 and January 2015 who underwent transthoracic echocardiography and CMR with assessment of LGE at a single tertiary referral center. LGE was quantified via a method of 6 standard deviations and patients were grouped based upon presence or absence of LGE (≤1% and >1% LGE, respectively). Sudden cardiac death (SCD) risk was assessed in patients >16 years of age using the European SCD risk score. A composite outcome of New York Heart Association class III-IV symptoms, aborted SCD, heart transplantation, and all-cause mortality was assessed via Kaplan-Meier curves with log-rank analysis. Overall, 126 patients were included (78 male; 62%). Median age of diagnosis was 15 (12 to 18) years. LGE was present in 81 (64%) patients, although only 4 (3%) patients had LGE >15%. Median age at CMR imaging was 19 (15 to 23) years. Patients with LGE had greater wall thickness (25 ± 8 mm vs 22 ± 7 mm, p = 0.01). Median European SCD risk score was 4.7 (2.9 to 6.5). Median follow-up was 6.5 (2.5 to 13) years with 26 patients (21%) meeting the composite outcome. There were no significant differences in composite outcome since age of diagnosis when stratified by presence/absence of LGE (p = 1.0). The presence of LGE in young HC patients was not an independent risk factor for cardiovascular morbidity and mortality. Wall thickness was greater in patients with LGE. There remains a need for further evaluation of this unique HC cohort.

The Impact of Self-Expandable Transcatheter Aortic Valve Replacement on Concomitant Functional Mitral Regurgitation: A Comprehensive Engineering Analysis

Background

Mitral regurgitation (MR) is present in a large proportion of patients who undergo transcatheter aortic valve replacement (TAVR). However, existing clinical data on the impact of TAVR on early post-procedural MR severity are contradictory. Using a comprehensive computational engineering methodology, this study aimed to evaluate quantitatively the structural and hemodynamic impact of TAVR on aortic-mitral continuity and MR severity in a rigorously developed and validated patient-specific left heart (LH) computer model with aortic stenosis and concomitant functional MR.

Methods

TAVR procedure was virtually simulated using a self-expandable valve (SEV) at three implantation heights. Pre- and post-TAVR LH dynamics as well as intra-operative biomechanics were analyzed.

Results

No significant differences in early MR improvement (<10%) were noted at the three implantation depths when compared to the pre-TAVR state. The high deployment model resulted in the highest stress in the native aortic leaflets, lowest stent-tissue contact force, highest aortic-mitral angle, and highest MR reduction for this patient case. When comparing SEV vs. balloon-expandable valve (BEV) performance at an optimal implantation height, the SEV gave a higher regurgitant volume ⋅ than the pre-TAVR model (40.49 vs 37.59 ml), while the BEV model gave the lowest regurgitant volume (33.84 vs 37.59 ml).

Conclusions

Contact force, aortic-mitral angle, and valve annuli compression were identified as possible mechanistic parameters that may suggest avenues for acute MR improvement. Albeit a single patient parametric study, it is our hope that such detailed engineering analysis could shed some light into the underlying biomechanical mechanisms of TAVR impact on MR.

Average pixel intensity method for prediction of outcome in secondary mitral regurgitation

Background

Echocardiographic grading of secondary mitral regurgitation (SMR) severity is challenging and involves multiple guideline-recommended parameters. We previously introduced the average pixel intensity (API) method for grading SMR. In this study, the clinical outcome in SMR based on the API method for grading MR was compared with conventional grading methods.

Methods

231 patients with systolic heart failure and reduced ejection fraction (ischaemic/non-ischaemic) and SMR were prospectively enrolled. MR was graded using all guideline-recommended parameters and the API method, which is based on the pixel intensity of the continuous wave Doppler signal. The primary outcome was MACE (major adverse cardiac event).

Results

The API method was applicable in 98% of patients with SMR (n=227). During a median follow-up of 24 months, 98 patients (43%) had a MACE (cardiovascular mortality (n=50, 22%), heart failure hospitalisation (n=44, 19%), mitral valve surgery (n=11, 5%), percutaneous mitral intervention (n=12, 5%), heart transplantation (n=5, 2%)). On log-rank test, the API method was highly significant in predicting clinical outcome. On multivariable Cox proportional hazard analysis, SMR grading with the API method was an independent predictor of clinical outcome (along with NYHA class and right ventricular systolic pressure; p<0.001), increasing the event risk by 9% per 10 au API rise (p=0.001). In the same multivariable analysis, proximal isovelocity surface area (PISA)-effective regurgitant orifice area or PISA-regurgitant volume were not independent predictors of events (p=0.18 and 0.26, respectively).

Conclusion

SMR grading with the API method is an independent predictor of clinical outcome and provides prognostic information in addition to clinical and other echocardiographic variables.

Advanced Imaging Techniques for Mitral Regurgitation

Mitral regurgitation (MR) is one of the most commonly encountered valvular lesions in clinical practice. MR can be either primary (degenerative) or secondary (functional) depending on the etiology of MR and the pathology of the mitral valve (MV). Echocardiography is the primary diagnostic tool for MR and is key in determining this etiology as well as MR severity. While clinicians usually turn to 2 Dimensional echocardiography as first-line imaging, 3 Dimensional echocardiography (3DE) has continually shown to be superior in terms of describing MV anatomy and pathology. This review article elaborates on 3DE techniques, modalities, and advances in software. Furthermore, the article demonstrates how 3DE has reformed MR evaluation and has played a vital role in determining patient management.