Prevalence and correlates of left ventricular diastolic dysfunction and heart failure with preserved ejection fraction in elderly community residents

FBXL4 protects against HFpEF through Drp1-Mediated regulation of mitochondrial dynamics and the downstream SERCA2a

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a devastating health issue although limited knowledge is available for its pathogenesis and therapeutics. Given the perceived involvement of mitochondrial dysfunction in HFpEF, this study was designed to examine the role of mitochondrial dynamics in the etiology of HFpEF.

METHOD AND RESULTS

Adult mice were placed on a high fat diet plus l-NAME in drinking water ('two-hit' challenge to mimic obesity and hypertension) for 15 consecutive weeks. Mass spectrometry revealed pronounced changes in mitochondrial fission protein Drp1 and E3 ligase FBXL4 in 'two-hit' mouse hearts. Transfection of FBXL4 rescued against HFpEF-compromised diastolic function, cardiac geometry, and mitochondrial integrity without affecting systolic performance, in conjunction with altered mitochondrial dynamics and integrity (hyperactivation of Drp1 and unchecked fission). Mass spectrometry and co-IP analyses unveiled an interaction between FBXL4 and Drp1 to foster ubiquitination and degradation of Drp1. Truncated mutants of FBXL4 (Delta-Fbox) disengaged interaction between FBXL4 and Drp1. Metabolomic and proteomics findings identified deranged fatty acid and glucose metabolism in HFpEF patients and mice. A cellular model was established with concurrent exposure of high glucose and palmitic acid as a 'double-damage' insult to mimic diastolic anomalies in HFpEF. Transfection of FBXL4 mitigated 'double-damage'-induced cardiomyocyte diastolic dysfunction and mitochondrial injury, the effects were abolished and mimicked by Drp1 knock-in and knock-out, respectively. HFpEF downregulated sarco(endo)plasmic reticulum (SR) Ca2+ uptake protein SERCA2a while upregulating phospholamban, RYR1, IP3R1, IP3R3 and Na+-Ca2+ exchanger with unaltered SR Ca2+ load. FBXL4 ablated 'two-hit' or 'double-damage'-induced changes in SERCA2a, phospholamban and mitochondrial injury.

CONCLUSION

FBXL4 rescued against HFpEF-induced cardiac remodeling, diastolic dysfunction, and mitochondrial injury through reverting hyperactivation of Drp1-mediated mitochondrial fission, underscoring the therapeutic promises of FBXL4 in HFpEF.

Considering impact of age and sex on cardiac cytoskeletal components

The cardiac cytoskeletal components are integral to cardiomyocyte function and are responsible for contraction, sustaining cell structure, and providing scaffolding to direct signaling. Cytoskeletal components have been implicated in cardiac pathology; however, less attention has been paid to age-related modifications of cardiac cytoskeletal components and how these contribute to dysfunction with increased age. Moreover, significant sex differences in cardiac aging have been identified, but we still lack a complete understanding to the mechanisms behind these differences. This review summarizes what is known about how key cardiomyocyte cytoskeletal components are modified because of age, as well as reported sex-specific differences. Thorough consideration of both age and sex as integral players in cytoskeletal function may reveal potential avenues for more personalized therapeutics.

Prevalence and prognosis of left ventricular diastolic dysfunction in community hypertension patients

Left ventricular diastolic dysfunction (LVDD) is common in hypertension and is a predictor of increased cardiovascular risk, however the effect of LVDD, detected by new guideline, on major adverse cardiac events (MACE) is unknown in hypertensive patients without known cardiovascular disease. The present study aims to evaluate LVDD in a community hypertension cohort study and assess the effect of LVDD on MACE. we studied 283 asymptomatic nonischemic patients with hypertension who had baseline echocardiogram between 2012 and 2014. Patients were followed for MACE (myocardial infarction, coronary revascularization procedures, heart failure, stroke, all-cause mortality) with mean follow-up of 5.4 years. A Cox proportional hazards model was used to assess the association of LVDD with MACE. At baseline, 35 of the 283 hypertensions were diagnosed with LVDD (12.3%) and 25 patients were women (15.5%). Women had higher frequency of LVDD than men (8%). During follow-up, there were 26.6% patients occurring MACE in the LVDD group at baseline, 9.9% patients occurring MACE in the group with normal diastolic function. In multivariable Cox regression analyses, LVDD was a stronger predictor of MACE (HR: 2.5; 95% CI: 1.20 to 5.25; c- statistics 0.805) than E/e' ratio (HR: 1.13; 95% CI: 1.04 to 1.22). LVDD was strongly associated with MACE in hypertension patients.

Current Prevalence, Incidence, and Outcomes of Heart Failure with Preserved Ejection Fraction

The current trends of prevalence, incidence, and mortality in heart failure with preserved ejection fraction are summarized. We describe the differences in the definitions of heart failure with preserved ejection fraction used in community-based studies, heart failure registries, and clinical trials. The worldwide prevalence of heart failure with preserved ejection fraction is approximately 2%; it is becoming the dominant form of heart failure owing to the aging population. The longitudinal trend of mortality in this disease is decreasing, and the risk of mortality is similar between heart failure with preserved ejection fraction and heart failure with reduced ejection fraction.

Prevalence and determinants of systolic and diastolic cardiac dysfunction and heart failure in acute ischemic stroke patients: The SICFAIL study

AIMS

Ischaemic stroke (IS) might induce alterations of cardiac function. Prospective data on frequency of cardiac dysfunction and heart failure (HF) after IS are lacking. We assessed prevalence and determinants of diastolic dysfunction (DD), systolic dysfunction (SD), and HF in patients with acute IS.

METHODS AND RESULTS

The Stroke-Induced Cardiac FAILure in mice and men (SICFAIL) study is a prospective, hospital-based cohort study. Patients with IS underwent a comprehensive assessment of cardiac function in the acute phase (median 4 days after IS) including clinical examination, standardized transthoracic echocardiography by expert sonographers, and determination of blood-based biomarkers. Information on demographics, lifestyle, risk factors, symptoms suggestive of HF, and medical history was collected by a standardized personal interview. Applying current guidelines, cardiac dysfunction was classified based on echocardiographic criteria into SD (left ventricular ejection fraction < 52% in men or <54% in women) and DD (≥3 signs of DD in patients without SD). Clinically overt HF was classified into HF with reduced, mid-range, or preserved ejection fraction. Between January 2014 and February 2017, 696 IS patients were enrolled. Of them, patients with sufficient echocardiographic data on SD were included in the analyses {n = 644 patients [median age 71 years (interquartile range 60-78), 61.5% male]}. In these patients, full assessment of DD was feasible in 549 patients without SD (94%). Prevalence of cardiac dysfunction and HF was as follows: SD 9.6% [95% confidence interval (CI) 7.6-12.2%]; DD in patients without SD 23.3% (95% CI 20.0-27.0%); and clinically overt HF 5.4% (95% CI 3.9-7.5%) with subcategories of HF with preserved ejection fraction 4.35%, HF with mid-range ejection fraction 0.31%, and HF with reduced ejection fraction 0.78%. In multivariable analysis, SD and fulfilment of HF criteria were associated with history of coronary heart disease [SD: odds ratio (OR) 3.87, 95% CI 1.93-7.75, P = 0.0001; HF: OR 2.29, 95% CI 1.04-5.05, P = 0.0406] and high-sensitive troponin T at baseline (SD: OR 1.78, 95% CI 1.31-2.42, P = 0.0003; HF: OR 1.66, 95% CI 1.17-2.33, P = 0.004); DD was associated with older age (OR 1.08, 95% CI 1.05-1.11, P < 0.0001) and treated hypertension vs. no hypertension (OR 2.84, 95% CI 1.23-6.54, P = 0.0405).

CONCLUSIONS

A substantial proportion of the study population exhibited subclinical and clinical cardiac dysfunction. SICFAIL provides reliable data on prevalence and determinants of SD, DD, and clinically overt HF in patients with acute IS according to current guidelines, enabling further clarification of its aetiological and prognostic role.

Opportunistic screening models for high-risk men and women to detect diastolic dysfunction and heart failure with preserved ejection fraction in the community

Background

The prevalence of undetected left ventricular diastolic dysfunction is high, especially in the elderly with comorbidities. Left ventricular diastolic dysfunction is a prognostic indicator of heart failure, in particularly of heart failure with preserved ejection fraction and of future cardiovascular and all-cause mortality. Therefore we aimed to develop sex-specific diagnostic models to enable the early identification of men and women at high-risk of left ventricular diastolic dysfunction with or without symptoms of heart failure who require more aggressive preventative strategies.

Design

Individual patient data from four primary care heart failure-screening studies were analysed (1371 participants, excluding patients classified as heart failure and left ventricular ejection fraction <50%).

Methods

Eleven candidate predictors were entered into logistic regression models to be associated with the presence of left ventricular diastolic dysfunction/heart failure with preserved ejection fraction in men and women separately. Internal-external cross-validation was performed to develop and validate the models.

Results

Increased age and β-blocker therapy remained as predictors in both the models for men and women. The model for men additionally consisted of increased body mass index, moderate to severe shortness of breath, increased pulse pressure and history of ischaemic heart disease. The models performed moderately and similarly well in men (c-statistics range 0.60–0.75) and women (c-statistics range 0.51–0.76) and the performance improved significantly following the addition of N-terminal pro b-type natriuretic peptide (c-statistics range 0.61–0.80 in women and 0.68–0.80 in men).

Conclusions

We provide an easy-to-use screening tool for use in the community, which can improve the early detection of left ventricular diastolic dysfunction/heart failure with preserved ejection fraction in high-risk men and women and optimise tailoring of preventive interventions.