Three-Dimensional Transthoracic Static and Dynamic Normative Values of the Mitral Valve Apparatus: Results from the Multicenter World Alliance Societies of Echocardiography Study

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography

BACKGROUND/AIM

Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE.

METHODS

We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group).

RESULTS

One hundred patients were included (mean age: 67 ± 10). Compared with SAM- patients (n = 60), SAM+ patients (n = 40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p < .01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126 ± 12° vs. 139 ± 11° in the SAM- group; p < .01) and a higher posterior mitral leaflet length (1.4 ± .27 cm vs. 1.25 ± .29, respectively; p < .01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p < .05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p < .01) was an independent predictor of SAM.

CONCLUSION

SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

Mitral valve repair with leaflet resection versus preservation for degenerative posterior leaflet prolapse

OBJECTIVES

The optimal technique for repairing posterior mitral valve leaflet prolapse remains undetermined. We aimed to compare leaflet resection and neochordae implantation in patients undergoing mitral valve repair for posterior leaflet prolapse, focusing on transmitral pressure gradient and recurrence of mitral regurgitation.

METHODS

We enrolled patients undergoing mitral valve repair using either leaflet resection or neochordae implantation for single-segment prolapse of posterior mitral valve leaflet between 2000 and 2021 at our institution. Longitudinal outcomes were evaluated after adjustments with inverse-probability-of-treatment weighting. Repeat echocardiographic measurements (n = 3473, 5.4/patient) of transmitral pressure gradient and significant (moderate or severe) mitral regurgitation recurrence were estimated using nonlinear mixed-effect models. Subgroup analyses were conducted based on the size and type of prosthesis.

RESULTS

Among 639 patients, leaflet resection was used in 479 (75.0%) and neochordae implantation was used in 160 (25.0%). In the inverse-probability-of-treatment weighting adjusted cohort, the risk of death (P = .623) and mitral valve reoperation (P = .340) did not significantly differ between the 2 groups during a median follow-up of 97.3 months. Echocardiographic data showed comparable mean (at 5 years, 3.8 vs 4.0 mm Hg; P = .442) and peak (9.6 vs 10.4 mm Hg; P = .131) pressure gradients between groups, which persisted in most subgroup analyses. However, neochordae implantation was associated with a higher probability of significant mitral regurgitation recurrence compared with leaflet resection (at 5 years, 16.1% vs 7.0%; P < .001).

CONCLUSIONS

Leaflet resection yielded similar clinical outcomes and transmitral pressure gradients compared with neochordae implantation after mitral valve repair, with a lower mitral regurgitation recurrence rate. These findings underscore the need to reassess the efficacy of neochordae implantation relative to leaflet resection.

Distinct leaflet-annular remodeling pattern in severe atrial functional mitral regurgitation: a three-dimensional echocardiography study

BACKGROUND

Atrial functional mitral regurgitation (AFMR) is best described with normal left ventricular size and function, structurally normal mitral leaflets and dilated left atrium. Unlike the ventricular functional phenotype, changes in the annular geometry more than the tethering forces are the main culprit for mitral regurgitation. The aim of this study is to illuminate the leaflet-annular remodeling in patients with mitral regurgitation and atrial fibrillation (AF) using three-dimensional transesophageal echocardiography (3D TOE).

RESULTS

Consecutive fifty patients with AFMR underwent transthoracic echocardiography and 3D TOE: 25 patients with AF and non-mild MR and 25 patients with AF and mild MR were studied. A special mitral valve analysis software was used to accurately assess the three unique pillars for MR: annular size, leaflets' geometry and tenting parameters. Compared to the mild MR group, non-mild MR group had long-standing AF of more than 1 year and larger left atrial volumes (51.83 ± 12.07 ml/m2 vs 33.68 ± 10.97 ml/m2, p < 0.001). No significant differences were noted in respect of tenting height, area and volume (13.06 ± 2.57 mm vs 11.43 ± 2.89 mm, p = 0.064, 3.58 ± 1.26 cm2 vs 2.80 ± 0.95 cm2, 0.081 and 6.70 ± 2.96 cm3 vs 5.04 ± 2.32 cm3, p = 0.081). Conversely, the non-mild MR group had larger annular area and perimeter (16.20 ± 3.90 cm2 vs 13.51 ± 3.85 cm2, p = 0.023 and 14.73 ± 1.72 cm vs 13.46 ± 1.79 cm, p = 0.033). Similarly, the non-mild MR group had larger anterior and posterior leaflets' areas (10.18 ± 4.02 cm2 vs 8.71 ± 3.08 cm2, p = 0.04 and 8.96 ± 2.60 cm2 vs 7.30 ± 2.17 cm2, p = 0.029). Correspondingly, more disproportionate leaflet-annular remodeling, as assessed by the ratio of total leaflets' area to the annular area, was noted in the non-mild MR as opposed to the mild MR group (1.22 ± 0.04 vs 1.26 ± 0.04, p = 0.008).

CONCLUSIONS

Recently, AFMR has been recognized as a remarkable entity of secondary MR with unique mechanisms. Annular dilatation with disproportionate leaflet remodeling can validate the central regurgitation. However, the call for more parameters is being emphasized to characterize the suitable candidates for percutaneous interventions.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy: do mitral valve leaflet length, septal thickness, or sex affect the outcome?

This retrospective cohort study aimed to assess whether basal septal wall thickness (BSWT), anterior (AML) and posterior (PML) mitral leaflet length, or sex were associated with remaining left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA). One hundred fifty-four patients who underwent ASA at the Karolinska University Hospital in Stockholm, Sweden, between 2009 and 2021, were included retrospectively. Anatomical and hemodynamic parameters were collected from invasive catheterization before and during ASA, and from echocardiography (ECHO) examinations before, during, and at 1-year follow-up after ASA. Linear and logistic regression models were used to assess the association between sex, BSWT, AML, PML, and outcome, which was defined as the remaining LVOTO (≥ 30 mmHg) after ASA. The median follow-up was 364 days (interquartile range 334-385 days). BSWT ≥ 23 mm (n = 13, 12%) was associated with remaining LVOTO at follow-up (p = 0.004). Elongated mitral valve leaflet length (either AML or PML) was present in 125 (90%) patients. Elongated AML (> 24 mm) was present in 67 (44%) patients, although AML length was not associated with remaining LVOTO at follow-up. Elongated PML (> 14 mm) was present in 114 (74%) patients and was not associated with remaining LVOTO at follow-up. No significant sex differences were observed regarding the remaining LVOTO. ECHO measurement of BSWT can be effectively used to select patients for successful ASA and identify those patients with a risk of incomplete resolution of LVOTO after ASA.

Anatomic, stage-based repair of secondary mitral valve disease

OBJECTIVE

Intervention for repair of secondary mitral valve disease is frequently associated with recurrent regurgitation. We sought to determine if there was sufficient evidence to support inclusion of anatomic indices of leaflet dysfunction in the management of secondary mitral valve disease.

METHODS

We performed a systematic review and meta-analysis of published reports comparing anatomic indices of leaflet dysfunction with the complexity of valve repair and the outcome from intervention. Patients were stratified by the severity of leaflet dysfunction. A secondary analysis was performed comparing outcomes when procedural complexity was optimally matched to severity of leaflet dysfunction and when intervention was not matched to dysfunction.

RESULTS

We identified 6864 publications, of which 65 met inclusion criteria. An association between the severity of leaflet dysfunction and the procedural complexity was highly predictive of satisfactory freedom from recurrent regurgitation. Patients were categorized into 4 groups based on stratification of leaflet dysfunction. Satisfactory results were achieved in 93.7% of patients in whom repair complexity was appropriately matched to severity of leaflet dysfunction and in 68.8% in whom repair was not matched to dysfunction (odds ratio, 0.148; 95% confidence interval, 0.119-0.184; P < .0001).

CONCLUSIONS

For patients with secondary mitral valve disease, satisfactory outcome from valve repair improves when procedural complexity is matched to anatomic indices of leaflet dysfunction. Anatomic indices of leaflet dysfunction should be considered when planning interventions for secondary mitral regurgitation. Routine inclusion of anatomic indices in trial design and reporting should facilitate comparison of results and strengthen guidelines. There are sufficient data to support anatomic staging of secondary mitral valve disease.

Implications of the Mitral Leaflet Coaptation Pattern on Clinical Outcomes in Patients With Functional Mitral Regurgitation

The classification of secondary mitral regurgitation (MR) is based on atrial functional MR (AFMR) or ventricular functional MR (VFMR) and volume changes, but the mitral leaflet coaptation angle also contributes to the MR mechanism. The clinical implications of the coaptation angle on cardiovascular (CV) outcomes have not been well evaluated. A total of 469 consecutive patients (265 AFMR vs 204 VFMR) with more than moderate MR were evaluated for the occurrence of heart failure, mitral valve operations, and CV death. The coaptation angle was assessed by measuring the internal angle between both leaflets at mid-systole using the apical 3-chamber view. A coaptation angle ≥130° was classified as leaflet flattening, and an angle <130° was classified as leaflet tethering. AFMR and VFMR were associated with higher frequencies of leaflet flattening and tethering, respectively. AFMR was more likely to be associated with older age, atrial fibrillation, and preserved ejection fraction, all of which were related to leaflet flattening. During a follow-up of 2.3 years, 83 patients had heart failure (17.7%), 21 patients underwent mitral valve operations (4.5%), and 34 patients died (7%). Compared with leaflet tethering, leaflet flattening was more significantly related to CV events, whereas CV event rates were less markedly different in A/VFMR. Irrespective of A/VFMR, leaflet flattening and atrial fibrillation were associated with a higher frequency of CV events. Adjusted analysis showed that leaflet flattening remained an independent predictor of CV events (hazard ratio 3.5, 95% confidence interval 1.11 to 4.88, p = 0.003), whereas A/VFMR did not. In conclusion, the leaflet coaptation angle in patients with functional MR could provide risk stratification superior to that of A/VFMR. Leaflet flattening appears to be associated with unfavorable clinical outcomes.

Mitral Regurgitation in Female Patients: Sex Differences and Disparities

Mitral regurgitation is the most common valvular disease, particularly in older adults. Recent literature has consistently supported that there are significant differences in mitral regurgitation outcomes between male and female patients and that this is likely multifactorial. Numerous sex differences in anatomy and pathophysiology may play a role in delayed diagnoses, referrals, and treatments for female patients. Despite the recognition of these discrepancies in the literature, many guidelines that steer clinical care do not incorporate these factors into society recommendations. Identifying and validating sex-specific diagnostic parameters and increasing the representation of female patients in trials of new mitral regurgitation treatment modalities are key factors in improving outcomes for female patients.

Normative values of the aortic valve area and Doppler measurements using two-dimensional transthoracic echocardiography: results from the Multicentre World Alliance of Societies of Echocardiography Study

AIMS

Aortic valve area (AVA) used for echocardiographic assessment of aortic stenosis (AS) has been traditionally interpreted independently of sex, age and race. As differences in normal values might impact clinical decision-making, we aimed to establish sex-, age- and race-specific normative values for AVA and Doppler parameters using data from the World Alliance Societies of Echocardiography (WASE) Study.

METHODS AND RESULTS

Two-dimensional transthoracic echocardiographic studies were obtained from 1903 healthy adult subjects (48% women). Measurements of the left ventricular outflow tract (LVOT) diameter and Doppler parameters, including AV and LVOT velocity time integrals (VTIs), AV mean pressure gradient, peak velocity, were obtained according to ASE/EACVI guidelines. AVA was calculated using the continuity equation. Compared with men, women had smaller LVOT diameters and AVA values, and higher AV peak velocities and mean gradients (all P < 0.05). LVOT and AV VTI were significantly higher in women (P < 0.05), and both parameters increased with age in both sexes. AVA differences persisted after indexing to body surface area. According to the current diagnostic criteria, 13.5% of women would have been considered to have mild AS and 1.4% moderate AS. LVOT diameter and AVA were lower in older subjects, both men and women, and were lower in Asians, compared with whites and blacks.

CONCLUSION

WASE data provide clinically relevant information about significant differences in normal AVA and Doppler parameters according to sex, age, and race. The implementation of this information into clinical practice should involve development of specific normative values for each ethnic group using standardized methodology.

Dynamic assessment of the tricuspid annulus in a healthy Asian population: A four-dimensional echocardiography study

BACKGROUND

Tricuspid annulus (TA) geometry and function reference values are limited, especially for Asian populations. We aimed to explore TA using four-dimensional echocardiography (4DE) in a healthy Asian population.

METHODS

A total of 355 healthy Asian volunteers (median age 34 years; 52% males) were prospectively enrolled. TA geometry and function were analyzed using 4DE throughout the cardiac cycle.

RESULTS

The TA area, perimeter, and dimensions were smallest at end systole (ES) and largest at late diastole (LD). Normal TA parameters at end diastole (ED) in different sex and age groups were obtained. TA areas, perimeters, and dimensions in males were significantly larger than those in females at ED; BSA-indexed perimeters and BSA-indexed dimensions in males were significantly smaller than those in females at ED. TA parameters correlated well with tricuspid valve (TV) tenting, right ventricle (RV), and right atrium (RA) parameters.

CONCLUSIONS

Reference values of TA parameters were obtained by 4DE in an Asian population. Quantitative data on TA geometry and function are essential for TA pathology and therapeutics.

A case report of transcatheter repair of severe functional mitral regurgitation in cardiac amyloidosis

Background

Transcatheter therapy has become an alternative for functional mitral regurgitation (FMR) in patients at high surgical risk. However, the intervention of FMR in cardiac amyloidosis (CA) with transcatheter edge-to-edge repair (TEER) is controversial due to the potential risk of left atrial pressure (LAP) elevation.

Case summary

An 83-year-old woman with repeated heart failure (HF) and severe mitral regurgitation (MR) was referred to our centre for TEER. Pre-procedural transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) confirmed the degree of MR and a functional aetiology. A peculiar LAP increase in this patient occurred immediately after successful TEER clip implantation and her n-terminal prohormone of brain natriuretic peptide significantly increased post-operatively. The diagnosis of CA was suspected and was subsequently established through endomyocardial biopsy. Aggressive anti-HF therapy was initiated and the patient was discharged after her HF symptoms were relieved. At 6-month follow-up, the patient was still alive and no episode of acute HF was experienced.

Discussion

Severe functional MR in CA treated with TEER has the potential risk of increasing LAP. During the short-term follow-up, TEER appears beneficial for left heart function (reduction of MR) but harmful for right heart function (increase of LAP). CA patients with severe FMR should be carefully evaluated about the benefits and potential harm of TEER intervention.

Atrial Functional Mitral Regurgitation: A JACC: Cardiovascular Imaging Expert Panel Viewpoint

Functional or secondary mitral regurgitation (MR) is associated with increased cardiovascular morbidity and mortality. Mechanistically, secondary MR is attributable to an imbalance between mitral leaflet tethering and closure forces, leading to poor coaptation. The pathophysiology of functional MR is most often the result of abnormalities in left ventricular function and remodeling, seen in ischemic or nonischemic conditions. Less commonly and more recently recognized is the scenario in which left ventricular geometry and function are preserved, the culprit being mitral annular enlargement associated with left atrial dilatation, termed atrial functional mitral regurgitation (AFMR). This most commonly occurs in the setting of chronic atrial fibrillation or heart failure with preserved ejection fraction. There is variability in the published reports and in current investigations as to the definition of AFMR. This paper reviews the pathophysiology of AFMR and focus on the need for a collective definition of AFMR to facilitate consistency in reported data and enhance much-needed research into outcomes and treatment strategies in AFMR.