Identification of Subclinical Myocardial Dysfunction and Association with Survival after Transcatheter Mitral Valve Repair

Prognostic value of left ventricular global longitudinal strain in mitral regurgitation: a systematic review

Conventional echocardiographic assessment may overestimate the left ventricular (LV) function in mitral regurgitation (MR). LV global longitudinal strain (GLS) is more sensitive marker to detect subclinical LV dysfunction. Multiple studies have investigated the prognostic value of LV-GLS in MR to examine its potential to determine the timing and indication of intervention. This systematic review aimed to assess the prognostic value of LV-GLS in patients with mitral regurgitation (MR) to define its clinical applicability. PUBMED and EMBASE were queried through July 2021 to identify studies investigating the prognostic value of LV-GLS in MR. A total of 24 observational studies with 5267 patients were identified. Sixteen studies investigated for primary MR, 7 studies for secondary MR, and 1 study for both. Most studies included patients who underwent intervention. There was significant heterogeneity in patient population, intervention status, follow-up period, LV-GLS cutoff value, outcomes, and statistical methods among the studies. Meta-analysis was not performed considering the significant variability. With exception to 1 study, all studies demonstrated significant association between impaired LV-GLS and worse clinical and echocardiographic outcomes in primary MR. Prognostic value of LV-GLS in secondary MR was less certain due to inconsistent findings and limited reporting. LV-GLS is a promising parameter of prognostication in primary MR and can be considered as alternative to determine the timing of intervention. However, the optimal cutoff value remains unclear. The prognostic value of LV-GLS in secondary MR is less clear. Further large-scale prospective study is warranted before its routine clinical application.

Left Ventricular Global Longitudinal Strain as a Predictor of Outcomes in Patients with Heart Failure with Secondary Mitral Regurgitation: The COAPT Trial

BACKGROUND

Left ventricular (LV) global longitudinal strain (GLS) is a sensitive marker of LV function and may help identify patients with heart failure (HF) and secondary mitral regurgitation who would have a better prognosis and are more likely to benefit from edge-to-edge transcatheter mitral valve repair with the MitraClip. The aim of this study was to assess the prognostic utility of baseline LV GLS during 2-year follow-up of patients with HF with secondary mitral regurgitation enrolled in the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation trial.

METHODS

Patients with symptomatic HF with moderate to severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated guideline-directed medical therapy (GDMT) were randomized to transcatheter mitral valve repair plus GDMT or GDMT alone. Speckle-tracking-derived LV GLS from baseline echocardiograms was obtained in 565 patients and categorized in tertiles. Death and HF hospitalization at 2-year follow-up were the principal outcomes of interest.

RESULTS

Patients with better baseline LV GLS had higher blood pressure, greater LV ejection fraction and stroke volume, lower levels of B-type natriuretic peptide, and smaller LV size. No significant difference in outcomes at 2-year follow-up were noted according to LV GLS. However, the rate of death or HF hospitalization between 10 and 24 months was lower in patients with better LV GLS (P = .03), with no differences before 10 months. There was no interaction between GLS tertile and treatment group with respect to 2-year clinical outcomes.

CONCLUSIONS

Baseline LV GLS did not predict death or HF hospitalization throughout 2-year follow-up, but it did predict outcomes after 10 months. The benefit of transcatheter mitral valve repair over GDMT alone was consistent in all subgroups irrespective of baseline LV GLS.

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.