Effects of early, late, and long-term nonselective β-blockade on left ventricular remodeling, function, and survival in chronic organic mitral regurgitation

Predictive Factors of Cardiac Mortality Following TEER in Patients with Secondary Mitral Regurgitation

Background: Transcatheter edge-to-edge mitral valve repair (TEER) has emerged as a viable approach to addressing substantial secondary mitral regurgitation. In the contemporary landscape where ultimate heart failure-specific therapies, such as cardiac replacement modalities, are available, prognosticating a high-risk cohort susceptible to early cardiac mortality post-TEER is pivotal for formulating an effective therapeutic regimen. Methods: Our study encompassed individuals with secondary mitral regurgitation and chronic heart failure enlisted in the multi-center (Optimized CathEter vAlvular iNtervention (OCEAN)-Mitral registry. We conducted an assessment of baseline variables associated with cardiac death within one year following TEER. Results: Amongst the 1517 patients (median age: 78 years, 899 males), 101 experienced cardiac mortality during the 1-year observation period after undergoing TEER. Notably, a history of heart failure-related admissions within the preceding year, utilization of intravenous inotropes, and elevated plasma B-type natriuretic peptide levels emerged as independent prognosticators for the primary outcome (p < 0.05 for all). Subsequently, we devised a novel risk-scoring system encompassing these variables, which significantly stratified the cumulative incidence of the 1-year primary outcome (16%, 8%, and 4%, p < 0.001). Conclusions: Our study culminated in the development of a new risk-scoring system aimed at predicting 1-year cardiac mortality post-TEER.

The association of left ventricular fraction shortening with cardiovascular events in peritoneal dialysis patients

BACKGROUND

Peritoneal dialysis (PD) patients have a high incidence of cardiovascular events (CVEs). Left ventricular fraction shortening (LVFS), one of the echocardiographic parameters, is an independent risk factor for mortality in previous studies. The aim of this study was to evaluate associations between LVFS and CVEs in PD patients.

METHODS

This was a single-center observational cohort study. Seven hundred and eighty-four PD patients were enrolled from 1 January 2012 to 1 June 2021 and followed until 1 June 2022. The primary outcome was the incidence of CVEs. PD patients were categorized into three groups according to the tertiles of LVFS levels (tertile 1-tertile 3). Kaplan-Meier method, Cox proportional hazard models and competing risk regression models were used for survival analysis. The areas under the curve (AUC) of receiver-operating characteristic analysis was used to determine the predictive values of LVFS for CVEs. A preplanned subgroup analysis was assessed according to age, gender, and the presence of hypertension and dyslipidemia, etc.

RESULTS

During a median follow-up period of 42.3 months (interquartile range 24.0-79.0 months), 259 CVEs occurred. Compared to the other two groups respectively, patients in tertile 3 group had the lowest incidence of CVEs (24.5% vs 31.6% vs 43.0%, respectively, p < 0.05). After multiple adjustments, the tertile 3 group was associated with the 45.1% decrease in the CVEs hazard compared to that of the tertile1 group (SHR = 0.549, 95%CI: 0.395-0.762, p < 0.001). Subgroup analysis demonstrated that tertile 1 group as the reference, the association between LVFS and CVEs in tertile 3 group was robust among female patients (HR = 0.506, 95%CI: 0.309-0.829, p = 0.007), aged < 45 years (HR = 0.496, 95%CI: 0.331-0.744, p = 0.001), history of hypertension (HR = 0.586, 95%CI: 0.349-0.872, p = 0.008) and combined with dyslipidemia (HR = 0.464, 95%CI: 0.269-0.799, p = 0.006).

CONCLUSIONS

This study suggests that LVFS is independently associated with the increased risk of CVEs in PD patients, especially those with aged < 45 years, female, with hypertension and dyslipidemia.

Dynamic Changes in the Molecular Signature of Adverse Left Ventricular Remodeling in Patients With Compensated and Decompensated Chronic Primary Mitral Regurgitation

BACKGROUND

There is no proven medical therapy that attenuates adverse left ventricular remodeling in patients with chronic primary mitral regurgitation (CPMR). Identification of molecular pathways important in the progression of left ventricular remodeling in patients with CPMR may lead to development of new therapeutic strategies.

METHODS AND RESULTS

We performed baseline echocardiographic, cardiac catheterization, and serum NT-pro-BNP analysis in patients with severe CPMR awaiting mitral valve surgery and stratified the study population into compensated or decompensated CPMR. We obtained left ventricular endomyocardial biopsies (n=12) for mRNA expression analysis, and compared baseline transcript levels of 109 genes important in volume-overload left ventricular remodeling with levels in normal hearts (n=5) and between patients with compensated (n=6) versus decompensated (n=6) CPMR. Patients were then randomized to treatment with and without carvedilol and followed until the time of surgery (mean follow-up 8.3 months) when repeat endomyocardial biopsies were obtained to correlate transcriptional dynamics with indices of adverse remodeling. CPMR was associated with increased NPPA expression levels (21.6-fold, P=0.004), decreased transcripts of genes important in cell survival, and enrichment of extracellular matrix genes. Decompensated CPMR was associated with downregulation of SERCA2 (0.77-fold, P=0.009) and mitochondrial gene expression levels and upregulation of genes related to inflammation, the extracellular matrix, and apoptosis, which were refractory to carvedilol therapy.

CONCLUSIONS

Transition to decompensated CPMR is associated with calcium dysregulation, increased expression of inflammatory, extracellular matrix and apoptotic genes, and downregulation of genes important in bioenergetics. These changes are not attenuated by carvedilol therapy and highlight the need for development of specific combinatorial therapies, targeting myocardial inflammation and apoptosis, together with urgent surgical or percutaneous valve interventions.

Left ventricular remodelling in chronic primary mitral regurgitation: implications for medical therapy

Surgical repair or replacement of the mitral valve is currently the only recommended therapy for severe primary mitral regurgitation. The chronic elevation of wall stress caused by the resulting volume overload leads to structural remodelling of the muscular, vascular and extracellular matrix components of the myocardium. These changes are initially compensatory but in the long term have detrimental effects, which ultimately result in heart failure. Understanding the changes that occur in the myocardium due to volume overload at the molecular and cellular level may lead to medical interventions, which potentially could delay or prevent the adverse left ventricular remodelling associated with primary mitral regurgitation. The pathophysiological changes involved in left ventricular remodelling in response to chronic primary mitral regurgitation and the evidence for potential medical therapy, in particular beta-adrenergic blockers, are the focus of this review.

Impact of Beta-Blockade on Cardiac Events in Patients with Chronic Severe Nonischemic Mitral Regurgitation

OBJECTIVES

The aim of this study was to examine the impact of beta-blockade on cardiac events among patients with initially asymptomatic chronic severe nonischemic mitral valve regurgitation (MR).

METHODS

Data from 52 consecutive patients in our prospective natural history study of isolated chronic severe nonischemic MR were assessed post hoc over 19 years to examine the relation of chronic beta-blockade use to subsequent cardiac events (death or indications for mitral valve surgery, MVS). At entry, all patients were free of surgical indications; 9 received beta-blockers. Cardiac event rate differences were analyzed by Kaplan-Meier log rank comparison.

RESULTS

During follow-up, cardiac events included sudden death (1), heart failure (8), atrial fibrillation (6), left ventricular dimensions at systole ≥4.5 cm (11), left ventricular ejection fraction <60% (6), right ventricular ejection fraction <35% (2), and a combination of cardiac events (7). The cardiac event risk was 4-fold higher among patients receiving beta-blockers (average annual risk = 60.6%) versus those not receiving beta-blockers (average annual risk = 15.2%; p = 0.001). These effects remained statistically significant (p = 0.005) when analysis was adjusted for other baseline covariates.

CONCLUSIONS

Beta-blockade appears to confer an increased risk of sudden cardiac death or indications for MVS among patients with chronic severe nonischemic MR. Randomized trials are needed to confirm these findings.

Mitral valve disease--morphology and mechanisms

Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but--even in adult life--remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular-ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease.

Drug Therapy for Heart Valve Diseases

Valvular heart diseases (VHDs) are progressive. When not caused by acute comorbidities they are generally characterized by long asymptomatic phases during which hemodynamic severity may progress leading to morbidity and mortality. Treatment depends on VHD type and severity but when severe and symptomatic, usually involves mechanical intervention. Asymptomatic patients, and those who lack objective descriptors associated with high risk, are closely observed clinically with optimization of associated cardiovascular risk factors until surgical indications develop. Though often prescribed based on theory, no rigorous evidence supports pharmacological therapy in most chronic situations though drugs may be appropriate in acute valvular diseases, or as a bridge to surgery in severely decompensated patients. Herein, we examine evidence supporting drug use for chronic VHDs.

Myofilament dysfunction as an emerging mechanism of volume overload heart failure

Two main hemodynamic overload mechanisms [i.e., volume and pressure overload (VO and PO, respectively] result in heart failure (HF), and these two mechanisms have divergent pathologic alterations and different pathophysiological mechanisms. Extensive evidence from animal models and human studies of PO demonstrate a clear association with alterations in Ca(2+) homeostasis. By contrast, emerging evidence from animal models and patients with regurgitant valve disease and dilated cardiomyopathy point toward a more prominent role of myofilament dysfunction. With respect to VO HF, key features of excitation-contraction coupling defects, myofilament dysfunction, and extracellular matrix composition will be discussed.