Significant functional mitral regurgitation affects left atrial function in heart failure patients: haemodynamic correlations and prognostic implications

An Overview of Sport Participation and Exercise Prescription in Mitral Valve Disease

The incidence of heart valve disease (HVD) has been rising over the last few decades, mainly due to the increasing average age of the general population, and mitral valve (MV) disease is the second most prevalent HVD after calcific aortic stenosis, but MV disease is a heterogeneous group of different pathophysiological diseases. It is widely proven that regular physical activity reduces all-cause mortality rates, and exercise prescription is part of the medical recommendations for patients affected by cardiovascular diseases. However, changes in hemodynamic balance during physical exercise (including the increase in heart rate, preload, or afterload) could favor the progression of the MV disease and potentially trigger major cardiac events. In young patients with HVD, it is therefore important to define criteria for allowing competitive sport or exercise prescription, balancing the positive effects as well as the potential risks. This review focuses on mitral valve disease pathophysiology, diagnosis, risk stratification, exercise prescription, and competitive sport participation selection, and offers an overview of the principal mitral valve diseases with the aim of encouraging physicians to embody exercise in their daily practice when appropriate.

Impact of gliflozins on cardiac remodeling in patients with type 2 diabetes mellitus & reduced ejection fraction heart failure: a pilot prospective study. GLISCAR Study

AIMS

Type 2 diabetes mellitus (T2DM) and heart failure are closely related entities and together determine an increased risk of mortality compared to patients suffering from only one of these diseases. Sodium-glucose co-transporter type 2 inhibitors (SGLT-2i) have shown favorable effects on cardiovascular system, particularly on heart failure. Aim of this study is to verify whether in individuals with T2DM and heart failure with reduced ejection fraction (HFrEF) treated with SGLT-2i, echocardiographic signs of favorable reverse remodeling follow longitudinal observation.

METHODS

31 subjects with T2DM and HFrEF were finally included. All individuals performed clinical visit, medical history, blood sampling and echocardiography at time 0' and at the end of 6 months of follow-up on SGLT-2i treatment.

RESULTS

After 6 months follow-up, left ventricular ejection fraction (LVEF), global work index (GWI), global work efficiency (GWE), global longitudinal strain (GLS), left atrial expansion index (LAEI) and total left atrial emptying fraction (TLAEF), tricuspid annular plane systolic excursion (TAPSE), septal thickness (St), pulmonary artery systolic pressures (PASP) and TAPSE/PASP ratio significantly improved.

CONCLUSIONS

Despite the lack of a favorable effect on cardiac remodeling, SGLT-2i treatment significantly improved LV systolic and diastolic function, left atrial (LA) reservoir and total emptying function, RV systolic function and pulmonary artery pressure.

Quantified mitral regurgitation and left atrial function in heart failure with reduced ejection fraction: interplay and outcome implications

AIMS

The clinical and prognostic importance of functional mitral regurgitation (FMR) in heart failure patients with reduced ejection fraction (HFrEF) has been highly debated. This study aims to define FMR linkage to cardiovascular (CV) outcomes and the interplay with left atrial (LA) function in a prospective cohort of consecutive HFrEF outpatients.

METHODS AND RESULTS

Overall, 286 consecutive outpatients with chronic HFrEF were prospectively enrolled. FMR was quantified by effective regurgitant orifice area (EROA). Global peak atrial longitudinal strain (PALS) was measured by speckle tracking echocardiography. The primary endpoint was a composite of congestive heart failure hospitalization or CV death. During a mean follow-up of 4.1 ± 1.5 years, the primary endpoint occurred in 99 patients (35%). The spline modelling of the risk by FMR severity showed an excess event risk starting at about the EROA value of 0.1 cm2 . There was a remarkable graded association between the EROA strata, even if tested per 0.1 cm2 increase, and the risk of CV events (hazard ratio [HR] EROA per 0.10 cm2 increase: 1.42, 95% confidence interval [CI] 1.19-1.68; p < 0.0001). EROA ≥0.30 cm2 was associated with CV events regardless of LA function (HR 2.34, 95% CI 1.29-4.19; p = 0.005). Less severe FMR (EROA ≥0.10 cm2 ) was associated with a dismal outcome only in patients with reduced LA function (PALS <14%) (5-year CV event rate 51 ± 4%); conversely, the risk of events was relative reduced when preserved global PALS and FMR coexisted (5-year CV event rate 38 ± 6%).

CONCLUSIONS

Our results refine the independent association between FMR and CV outcome among HFrEF outpatients. Within a moderate EROA range, LA function mitigates the clinical consequences of mitral regurgitation, providing measurable proof of the interplay between regurgitation and LA compliance.

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber.

Extramitral Valvular Cardiac Involvement in Patients With Significant Secondary Mitral Regurgitation

Patients with secondary mitral regurgitation (SMR) often have extramitral valve cardiac involvement, which can influence the prognosis. SMR can be defined according to groups of extramitral valve cardiac involvement. The prognostic implications of such groups in patients with moderate and severe SMR (significant SMR) are unknown. A total of 325 patients with significant SMR were classified according to the extent of cardiac involvement on echocardiography: left ventricular involvement (group 1), left atrial involvement (group 2), tricuspid valve and pulmonary artery vasculature involvement (group 3), or right ventricular involvement (group 4). The primary end point was all-cause mortality. The prevalence of each cardiac involvement group was 17% in group 1, 12% in group 2, 23% in group 3%, and 48% in group 4. Group 3 and group 4 were independently associated with all-cause mortality (hazard ratio 1.794, 95% confidence interval 1.067 to 3.015, p = 0.027 and hazard ratio 1.857, 95% confidence interval 1.145 to 3.012, p = 0.012, respectively). In conclusion, progressive extramitral valve cardiac involvement (group 3 and group 4) was independently associated with all-cause mortality in patients with significant SMR.

Echocardiography in Advanced Heart Failure for Diagnosis, Management, and Prognosis

Advanced heart failure, an end-stage disease characterized by high mortality and morbidity despite standard medical therapy, requires various therapeutic strategies like heart transplant and long-term mechanical circulatory support. Echocardiography is the main imaging technique to identify transitions to advanced stages of disease and guide risk stratification and therapeutic decision-making processes. Progressive development of advanced echocardiographic techniques allows more comprehensive assessment of the hemodynamic and structural profiles of patients with advanced heart failure, and its use in clinical practice continues to expand. This article provides an overview of basic and emerging echocardiographic tools to assess patients with advanced heart failure.

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.

Left Atrial Volumetric/Mechanical Coupling Index: A Novel Predictor of Outcome in Heart Failure With Reduced Ejection Fraction

BACKGROUND

Left atrial assessment is complex, particularly in heart failure with reduced ejection fraction due to interactions with functional mitral regurgitation (FMR). Pilot data suggest that left atrial volumetric/mechanical coupling index (LACI) may be useful, but large outcome data are lacking.

METHODS

We enrolled a comprehensively characterized cohort of patients in sinus rhythm with heart failure with reduced ejection fraction diagnosis at Mayo Clinic from 2007 to 2011. Routinely measured left atrial volume index and tissue-doppler-imaging a' allowed LACI calculation as (left atrial volume index)/(tissue-doppler-imaging a'). Survival was the outcome measured.

RESULTS

The cohort's 4196 patients (69 [58-77] years, ejection fraction 40 [31-45]%) had mild FMR in 1505 and moderate-severe FMR in 1068. LACI was overall 5.06 (3.50-8.10) and increased with each FMR grade (3.86 [2.94-5.29] without FMR, 5.38 [3.80-8.02] with mild, 5.45 [1.49-8.07] with moderate/severe FMR; P<0.0001). At diagnosis, higher LACI was independently determined by more severe FMR and by higher left ventricular mass index, lower ejection fraction, higher E/e', and lower glomerular filtration rate (all P<0.0001). During follow-up 1588 (38%) patients died. In spline modeling, excess mortality appeared around LACI=6 and steeply increased thereafter (5-year survival 72±1% with LACI<6 and 49±2% with LACI ≥6, P<0.0001). Multivariable comprehensive adjustment showed LACI strong association with excess mortality (adjusted hazard ratio, 1.41 [1.23-1.61], P<0.0001 for LACI ≥6). Independent link to mortality persistent across FMR grades (adjusted hazard ratio, 1.45 [1.13-1.86], P=0.004 without FMR, 1.42 [1.16-1.77], P=0.0008 with mild FMR, and 1.38 [1.01-1.66], P=0.04 with moderate/severe FMR) without interaction (P=0.3). LACI independent impact on outcome was incremental to that of left atrial volume index, tissue-doppler-imaging a', or any other characteristic including the Meta-Analysis Global Group in Chronic-score (least significant P=0.02).

CONCLUSIONS

In this large cohort, left atrial volumetric/mechanical coupling measured by LACI in routine practice integrates the influence of several morphological/hemodynamic determinants but displays progressive deterioration with increasing FMR severity in heart failure with reduced ejection fraction. About outcome, higher LACI is strongly, independently, and incrementally associated with excess mortality, irrespective of FMR grade and in all subsets. Hence, LACI is a novel and critical measure in heart failure with reduced ejection fraction, quantifiable in routine practice, which should be integrated in prognostication and decision-making.

MiR-375-3p regulates rat pulmonary microvascular endothelial cell activity by targeting Notch1 during hypoxia

Objective

Pulmonary microvascular endothelial cells (PMECs) exhibit specific responses in adaptation to hypoxia. However, the mechanisms regulating PMEC activities during hypoxia remain unclear. This study investigated the potential involvement of a microRNA, miR-375-3p, in the regulation of PMEC activities.

Methods

Primary PMECs were isolated from rats. The expression levels of miR-375-3p and Notch1 in the PMECs were detected by quantitative PCR and western blotting. Luciferase reporter assays were performed to explore the transcriptional regulation of Notch1 by miR-375-3p. The proliferation and chemotaxis of the PMECs were measured with the Cell Counting Kit-8 and Transwell invasion assays, respectively. Additionally, the capacity of hypoxia-treated PMECs for angiogenesis and inflammatory response was determined with tube formation assays and ELISA, respectively.

Results

The expression of miR-375-3p and Notch1 in the PMECs was significantly down-regulated and up-regulated during hypoxia, respectively. The results demonstrated that miR-375-3p directly targets Notch1 in PMECs, thereby suppressing the transcriptional expression of Notch1. It was further revealed that miR-375-3p regulates the proliferation, chemotaxis, angiogenesis, and inflammatory response of PMECs.

Conclusions

Our findings revealed the important role of miR-375-3p in the regulation of PMEC function and suggest the potential involvement of miR-375-3p in the development of lung diseases.