Left heart longitudinal deformation analysis in mitral regurgitation

Mitral Regurgitation Evaluation in Modern Echocardiography: Bridging Standard Techniques and Advanced Tools for Enhanced Assessment

Mitral regurgitation (MR) is one of the most common valvular heart diseases worldwide. Echocardiography remains the first line and most effective imaging modality for the diagnosis of mitral valve (MV) pathology and quantitative assessment of MR. The advent of three-dimensional echocardiography has significantly enhanced the evaluation of MV anatomy and function. Furthermore, recent advancements in cardiovascular imaging software have emerged as step-forward tools, providing a powerful support for acquisition, analysis, and interpretation of cardiac ultrasound images in the context of MR. This review aims to provide an overview of the contemporary workflow for echocardiographic assessment of MR, encompassing standard echocardiographic techniques and the integration of semiautomated and automated ultrasound solutions. These novel approaches include advancements in segmentation, phenotyping, morphological quantification, functional grading, and chamber quantification.

Myocardial work and left heart deformation parameters across primary mitral regurgitation severity

AIMS

Myocardial work (MW) estimation by pressure-strain loops using speckle tracking echocardiography (STE) has shown to evaluate left ventricular (LV) contraction overcoming the load-dependency limit of LV global longitudinal strain (GLS). This has proved useful in hemodynamic variation settings e.g. heart failure and valvular heart disease. However, the variation of MW and strain parameters across different stages of primary mitral regurgitation (MR) and its impact on symptoms, which was the aim of our study, has never been investigated.

METHODS AND RESULTS

Consecutive patients with mild, moderate and severe MR were prospectively enrolled. Exclusion criteria were: chronic atrial fibrillation, valvular heart prosthesis, previous cardiac surgery. Clinical evaluation, blood sample tests, ECG and echocardiography with STE and MW measurement were performed. Patients were then divided into groups according to MR severity. Differences among the groups and predictors of symptoms (as NYHA class≥2) were explored as study endpoints. Overall, 180 patients were enrolled (60 mild,60 moderate,60 severe MR). LV GLS and global peak atrial longitudinal strain (PALS) reduced according to MR severity. Global constructive work (GCW) and global wasted work (GWW) significantly improved, while global work efficiency (GWE) reduced, in patients with moderate and severe MR. Among echocardiographic parameters, global PALS emerged as the best predictor of NYHA class (p < 0.001;area under curve,AUC = 0.7).

CONCLUSIONS

MW parameters accurately describe the pathophysiology of MR, with initial attempt of LV increased contractility to compensate volume overload parallel to the disease progress, although with low efficacy, while global PALS is the most associated with the burden of MR symptoms.

Left atrial strain analysis in the realm of pediatric cardiology: Advantages and implications

BACKGROUND

Left atrial (LA) strain analysis has emerged as a noninvasive technique for assessing LA function and early detection of myocardial deformation. Recently, its application has also shown promise in the pediatric population, spanning diverse cardiac conditions that demand accurate and sensitive diagnostic measures.

OBJECTIVE

This research article endeavors to explore the role of LA strain parameters and contribute to the growing body of knowledge in pediatric cardiology, paving the way for more effective and tailored approaches to patient care.

METHODS

A comprehensive literature review was conducted to gather evidence from studies using echocardiographic strain imaging techniques across pediatric populations.

RESULTS

LA strain parameters exhibited greater sensitivity than conventional atrial function indicators, with early detection of diastolic dysfunction and LA remodeling in pediatric cardiomyopathy, children with multisystem inflammatory syndrome, rheumatic heart disease, as well as childhood renal insufficiency and obesity offering prognostic relevance as potential markers in these pediatric subpopulations. However, there remains a paucity of evidence concerning pediatric mitral valve pathology, justifying further exploration.

CONCLUSION

LA strain analysis carries crucial clinical and prognostic implications in pediatric cardiac conditions, with reliable accuracy and sensitivity to early functional changes.

Speckle tracking echocardiography in primary mitral regurgitation: should we reconsider the time for intervention?

Thanks to the improvement in mitral regurgitation (MR) diagnostic and therapeutic management, with the introduction of minimally invasive techniques which have considerably reduced the individual surgical risk, the optimization of the timing for MR “open” or percutaneous surgical treatment has become a main concern which has highly raised scientific interest. In fact, the current indications for intervention in MR, especially in asymptomatic patients, rely on echocardiographic criteria with high severity cut-offs that are fulfilled only when not only mitral valve apparatus but also the cardiac chambers’ structure and function are severely impaired, which results in poor benefits for post-operative clinical outcome. This led to the need of new indices to redefine the optimal surgical timing in these patients. Speckle tracking echocardiography provides early markers of cardiac dysfunction due to subtle myocardial impairment; therefore, it could offer pivotal information in this setting. In fact, left ventricular and left atrial strains have already shown evidence about their usefulness in recognizing MR impact not only on symptoms and quality of life but also on cardiovascular events and new-onset atrial fibrillation in these patients. Moreover, right ventricular strain could be used to identify those patients with advanced cardiac damage and different grades of right ventricular dysfunction, which entails higher risks for cardiac surgery that could overweigh surgical benefits. This review aims to describe the importance of reconsidering the timing of intervention in MR and to analyze the potential additive value of speckle tracking echocardiography in this clinical setting.

Determining the thresholds for abnormal left ventricular strains in healthy subjects by echocardiography: a meta-analysis

Background

Left ventricular global longitudinal strain (LVGLS), circumferential strain (LVGCS) and radial strain (LVGRS) are echocardiographic parameters with wide clinical applicability. However, the thresholds for abnormal left ventricular (LV) strains, particularly the lower limits of normal (LLN), are not well established. This meta-analysis determined the mean and LLN of two- (2D) and three-dimensional (3D) LV strain in healthy subjects and factors that influence strain measurements.

Methods

We searched PubMed, Embase and Cochrane databases until 31 December 2019 for studies reporting left ventricular (LV) global strain in at least 50 healthy subjects. We pooled means and LLNs of 2D and 3D LV strain using random-effects models, and performed subgroup and meta-regression analysis for LVGLS.

Results

Forty-four studies were eligible totaling 8,910 subjects. The pooled means and LLNs (95% confidence intervals) were -20.1% (-20.7%, -19.6%) and -15.4% (-16.0%, -14.7%) respectively for 2D-LVGLS; -21.9% (-23.4%, -20.3%) and -15.3% (-16.9%, -13.8%) respectively for 2D-LVGCS; and 48.4% (43.8%, 53.0%) and 25.5% (17.8%, 33.1%) respectively for 2D-LVGRS. All pooled analyses demonstrated significant heterogeneity, and means and LLNs of and 3D-LV strains differed marginally from 2D. Only vendor software was associated with differences in pooled means and LLN of 2D-LVGLS.

Conclusions

In conclusion, pooled means and LLNs of 2D- and 3D-LV global strain parameters in healthy subjects were reported. Based on the pooled LLNs, thresholds for abnormal, borderline and normal strains can be defined, such as less negative than -14.7%, between -14.7% and -16.0% and more negative than -16.0% respectively for 2D-LVGLS, and 2D-LVGLS values are only affected by vendor software.

Left atrial strain as a pre-operative prognostic marker for patients with severe mitral regurgitation

BACKGROUND

In patients with severe mitral regurgitation (MR), additional echocardiographic indices could be helpful to optimize surgical timing before irreversible left heart myocardial dysfunction has occurred. We investigated the correlation of left atrial (LA) strain by speckle tracking echocardiography with prognosis after mitral surgery for severe MR, and its association with LA fibrosis.

METHOD

71 patients with primary severe MR undergoing pre-operative echocardiographic assessment were initially enrolled. Exclusion criteria were: other valvular disease>moderate, history of coronary artery disease, heart failure (HF), hypertrophic cardiomyopathy, left bundle branch block, previous pacemaker implantation, heart transplantation, poor acoustic window. The primary endpoint was the occurrence of composite events (HF and mortality); the secondary endpoint was post-operative functional capacity (NYHA and Borg CR10 class). LA fibrosis was assessed by atrial biopsy specimens in a subset of patients.

RESULTS

Of 65 eligible patients, the primary endpoint occurred in 30 patients (medium follow-up: 3.7 ± 1 years for event-group, 6.8 ± 1 years for non-event group). After Kaplan-Meier analysis, peak atrial longitudinal strain (PALS) provided good risk stratification (5-year event-free survival:90 ± 5% for PALS≥21% vs 30 ± 9% for PALS<21%, p < 0.0001); it was an independent and incremental predictor of outcome in four multivariate Cox adjusted models. There was also an association between PALS and the secondary endpoint (NYHA: r² = 0.11, p = 0.04; Borg CR10: r² = 0.10, p = 0.02) and an inverse correlation between PALS<21% and LA fibrosis (r² 0.80, fibrosis: 76.6 ± 20.7% vs 31.9 ± 20.8%;p < 0.0001).

CONCLUSIONS

Global PALS emerged as a reliable predictor of outcome and functional capacity for severe primary MR, and as a marker of LA fibrosis.

MitraClip and left ventricular reverse remodelling: a strain imaging study

AIMS

The purpose of this study is to identify echocardiography predictors of clinical response and reverse left ventricular (LV) remodelling in patients with functional mitral regurgitation (FMR) treated with MitraClip.

METHOD AND RESULTS

We retrospectively analysed 86 high surgical risk patients with severe FMR; of those, 58 were implanted a MitraClip, and 28 received medical treatment and served as controls. At baseline and at 1-year follow-up, we performed clinical and echocardiography evaluation to assess global longitudinal strain (GLS) and myocardial work [global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE)]. Mitral regurgitation was significantly reduced after MitraClip implantation (3.7 ± 0.4 vs. 1.7 ± 0.8, P < 0.001), and the procedure was associated with improvement in brain natriuretic peptide levels (980 ± 1027 vs. 420 ± 338 pg/mL, P < 0.001), New York Heart Association class status (3.2 ± 0.55 vs. 2.0 ± 0.6, P < 0.001), 6-min walking test (233 ± 154 vs. 286 ± 114 m, P = 0.01) at follow-up and reduction of left ventricle end-systolic (LVESV) and left ventricle end-diastolic volumes (LVEDV) (152 ± 68 vs. 136 ± 43 mL, P = 0.004 & 219 ± 74 vs. 193 ± 66 mL, P = 0.001, respectively). MitraClip procedure was associated with improvement of LV performance and significant increase of GWI (607 ± 282 vs. 650 ± 260 mmHg%, P = 0.045) and GCW (854 ± 288 vs. 949 ± 325 mmHg%, P < 0.001). Baseline ejection fraction (EF), GLS, GWI, GCW, and effective regurgitant orifice area were the variables that were associated with reduction of LVEDV 1 year after intervention (P < 0.05 for all) and baseline GCW of the LV was the only variable associated with reduction of LVESV (P = 0.002). Receiver operating characteristic curve analysis identified that a GLS cut-off value of -8.65% (AUC 0.815, P = 0.007) was associated with a 20% reduction of the LVEDV with a sensitivity and specificity of 72% and 70%, respectively, and that a GCW cut-off value of 846 mmHg% (AUC 0.759, P = 0.007) was associated with a 10% reduction of LVESV with sensitivity and specificity 79% and 74%, respectively.

CONCLUSIONS

Mitral valve repair with MitraClip has positive clinical and echocardiographic impact in patients with FMR 1 year after implantation. Preserved GLS and GCW values appear to be associated with LV reverse remodelling post intervention.

Impact of Mitral Surgery for Mitral Regurgitation on Coexisting Aortic Regurgitation

Background: There is no clear finding on the course of coexisting aortic regurgitation (AR) after treatment of mitral regurgitation (MR). We investigated the effect of mitral surgery for MR on coexisting AR.

Methods: Between January 2008 and December 2016, 75 patients underwent mitral surgery for MR coexisting mild AR. Of these, 65 patients who were available to follow-up postoperative echocardiographic tests 1 year after surgery were included in the present study. Patients were divided into two groups according to the degree of postoperative AR. We investigated the predictive factors for continued AR and perioperative cardiac function.

Results: In all, 22 patients’ AR improved and became less than mild and 43 patients’ persisted at mild or increased. The predictive factor for continued AR was left atrial diameter >50 mm (P = 0.021, odds ratio = 4.739, 95% confidence interval: 1.259–17.846) in multivariate logistic regression analysis. No patients underwent reoperation for continued AR in both groups. However, one patient was rehospitalized for heart failure in the continued AR group.

Conclusion: Left atrial diameter may be an important prognostic factor for continued AR after mitral surgery for MR. MR with mild AR should be treated as soon as before the left atrium expands.