Biological Phenotypes of Heart Failure With Preserved Ejection Fraction

Conceptualization of Heterogeneity of Chronic Diseases and Atherosclerosis as a Pathway to Precision Medicine: Endophenotype, Endotype, and Residual Cardiovascular Risk

The article discusses modern approaches to the conceptualization of pathogenetic heterogeneity in various branches of medical science. The concepts of endophenotype, endotype, and residual cardiovascular risk and the scope of their application in internal medicine and cardiology are considered. Based on the latest results of studies of the genetic architecture of atherosclerosis, five endotypes of atherosclerosis have been proposed. Each of the presented endotypes represents one or another pathophysiological mechanism of atherogenesis, having an established genetic substrate, a characteristic panel of biomarkers, and a number of clinical features. Clinical implications and perspectives for the study of endotypes of atherosclerosis are briefly reviewed.

Machine learning can predict survival of patients with heart failure from serum creatinine and ejection fraction alone

BACKGROUND

Cardiovascular diseases kill approximately 17 million people globally every year, and they mainly exhibit as myocardial infarctions and heart failures. Heart failure (HF) occurs when the heart cannot pump enough blood to meet the needs of the body.Available electronic medical records of patients quantify symptoms, body features, and clinical laboratory test values, which can be used to perform biostatistics analysis aimed at highlighting patterns and correlations otherwise undetectable by medical doctors. Machine learning, in particular, can predict patients' survival from their data and can individuate the most important features among those included in their medical records.

METHODS

In this paper, we analyze a dataset of 299 patients with heart failure collected in 2015. We apply several machine learning classifiers to both predict the patients survival, and rank the features corresponding to the most important risk factors. We also perform an alternative feature ranking analysis by employing traditional biostatistics tests, and compare these results with those provided by the machine learning algorithms. Since both feature ranking approaches clearly identify serum creatinine and ejection fraction as the two most relevant features, we then build the machine learning survival prediction models on these two factors alone.

RESULTS

Our results of these two-feature models show not only that serum creatinine and ejection fraction are sufficient to predict survival of heart failure patients from medical records, but also that using these two features alone can lead to more accurate predictions than using the original dataset features in its entirety. We also carry out an analysis including the follow-up month of each patient: even in this case, serum creatinine and ejection fraction are the most predictive clinical features of the dataset, and are sufficient to predict patients' survival.

CONCLUSIONS

This discovery has the potential to impact on clinical practice, becoming a new supporting tool for physicians when predicting if a heart failure patient will survive or not. Indeed, medical doctors aiming at understanding if a patient will survive after heart failure may focus mainly on serum creatinine and ejection fraction.

Diagnosis and treatment of heart failure with preserved left ventricular ejection fraction

Nearly six million people in United States have heart failure. Fifty percent of these people have normal left ventricular (LV) systolic heart function but abnormal diastolic function due to increased LV myocardial stiffness. Most commonly, these patients are elderly women with hypertension, ischemic heart disease, atrial fibrillation, obesity, diabetes mellitus, renal disease, or obstructive lung disease. The annual mortality rate of these patients is 8%-12% per year. The diagnosis is based on the history, physical examination, laboratory data, echocardiography, and, when necessary, by cardiac catheterization. Patients with obesity, hypertension, atrial fibrillation, and volume overload require weight reduction, an exercise program, aggressive control of blood pressure and heart rate, and diuretics. Miniature devices inserted into patients for pulmonary artery pressure monitoring provide early warning of increased pulmonary pressure and congestion. If significant coronary heart disease is present, coronary revascularization should be considered.

Implications of obesity across the heart failure continuum

The obesity paradox, which suggests a survival advantage for the obese in heart failure (HF) has sparked debate in the medical community. Studies demonstrate a survival advantage in obese patients with HF, including those with advanced HF requiring continuous inotropic support for palliation or disease modifying therapy with a left ventricular assist device (LVAD) or heart transplantation (HT). Importantly, the obesity paradox is affected by the level of cardiorespiratory fitness (CRF). It is now recommended that HF patients with body mass index ≥35 kg/m² achieve at least 5-10% weight loss, in order to improve symptoms and cardiac function, though more robust data are urgently needed. CRF may be the single best predictor of overall health and small improvements in fitness levels may lead to improved outcomes in HF. In addition to implications of obesity in chronic HF, we also discuss management of obese patients with advanced HF and their implications for therapies such as LVAD implantation and HT.

Heart failure with preserved ejection fraction: New approaches to diagnosis and management

The majority of older patients who develop heart failure (HF), particularly older women, have a preserved left ventricular ejection fraction (HFpEF). Patients with HFpEF have severe symptoms of exercise intolerance, poor quality-of-life, frequent hospitalizations, and increased mortality. The prevalence of HFpEF is increasing and its prognosis is worsening. However, despite its importance, our understanding of the pathophysiology of HFpEF is incomplete, and drug development has proved immensely challenging. Currently, there are no universally accepted therapies that alter the clinical course of HFpEF. Originally viewed as a disorder due solely to abnormalities in left ventricular (LV) diastolic function, our understanding has evolved such that HFpEF is now understood as a systemic syndrome, involving multiple organ systems, likely triggered by inflammation and with an important contribution of aging, lifestyle factors, genetic predisposition, and multiple-comorbidities, features that are typical of a geriatric syndrome. HFpEF is usually progressive due to complex mechanisms of systemic and cardiac adaptation that vary over time, particularly with aging. In this review, we examine evolving data regarding HFpEF that may help explain past challenges and provide future directions to care patients with this highly prevalent, heterogeneous clinical syndrome.

Cardiac cachexia

Cachexia is a multifactorial disease characterized by a pathologic shift of metabolism towards a more catabolic state. It frequently occurs in patients with chronic diseases such as chronic heart failure and is especially common in the elderly. In patients at risk, cardiac cachexia is found in about 10% of heart failure patients. The negative impact of cardiac cachexia on mortality, morbidity, and quality of life demonstrates the urgent need to find new effective therapies against cardiac cachexia. Furthermore, exercise training and nutritional support can help patients with cardiac cachexia. Despite ongoing efforts to find new therapies for cachexia treatment, also new preventive strategies are needed.

Increased Myocardial Stiffness in Patients With High-Risk Left Ventricular Hypertrophy: The Hallmark of Stage-B Heart Failure With Preserved Ejection Fraction

BACKGROUND

Individuals with left ventricular hypertrophy (LVH) and elevated cardiac biomarkers in middle age are at high risk for the development of heart failure with preserved ejection fraction (HFpEF). However, it is unknown what the pathophysiological underpinnings of this high-risk state may be. We tested the hypothesis that patients with LVH and elevated cardiac biomarkers would demonstrate elevated left ventricular (LV) myocardial stiffness in comparison with healthy controls as a key marker for future HFpEF.

METHODS

Forty-six patients with LVH (LV septum >11 mm) and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide [>40 pg/mL] or troponin T [>0.6 pg/mL]) were recruited, along with 61 age- and sex-matched (by cohort) healthy controls. To define LV pressure-volume relationships, right heart catheterization and 3-dimensional echocardiography were performed while preload was manipulated using lower body negative pressure and rapid saline infusion.

RESULTS

There were significant differences in body size, blood pressure, and baseline pulmonary capillary wedge pressure between groups (eg, pulmonary capillary wedge pressure: LVH, 13.4±2.7 versus control, 11.7±1.7 mm Hg, P<0.0001). The LV was less distensible in LVH than in controls (smaller volume for the same filling pressure). When preload was expressed as transmural filling pressure (pulmonary capillary wedge pressure - right atrial pressure), LV myocardial stiffness was nearly 30% greater in LVH than in controls (LVH stiffness constant, 0.053±0.027 versus controls, 0.042±0.020, P=0.028).

CONCLUSIONS

LV myocardial stiffness in patients with LVH and elevated biomarkers (stage-B HFpEF) is greater than in age- and sex-matched controls and thus appears to represent a transitional state from a normal healthy heart to HFpEF. Although the LV myocardial stiffness of patients with LVH is greater than that of healthy controls at this early stage, further studies are required to clarify whether interventions such as exercise training to improve LV compliance may prevent the full manifestation of the HFpEF syndrome in these high-risk individuals.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT03476785 and NCT02039154.

Respiratory support in acute heart failure with preserved vs reduced ejection fraction

Background

There is little evidence addressing the use and differential impact of respiratory support in acute heart failure (AHF) patients with preserved (HFPEF) vs reduced (HFREF) ejection fraction. Therefore, our objective was to determine the usage and clinical outcomes of critical care respiratory support in AHF across the two populations.

Hypothesis

Respiratory support would be associated with adverse outcome in both HFPEF and HFREF.

Methods

We identified HFPEF, HFREF, invasive mechanical ventilation (IMV), and noninvasive ventilation (NIV) using International Classification of Disease‐Ninth Edition codes in the National Inpatient Sample between January 1, 2008 and December 31, 2014. We determined rates of IMV and NIV use. We identified predictors of need for IMV and NIV and the association between ventilation strategies and in‐hospital mortality in HFPEF vs HFREF.

Results

1.3 million AHF‐HFPEF and 1.7 million AHF‐HFREF hospitalizations were included; 5.98% of AHF HFPEF hospitalizations included NIV and 0.57% included IMV. Among HFREF hospitalizations, fewer (4.1%) included NIV and more (0.93%) included IMV. In HFPEF hospitalization, NIV use was associated with 2.24‐fold increased risk for death compared to no respiratory support in an adjusted model (HR 2.24 95% CI 2.05‐2.44) and IMV use was associated with 2.85‐fold increased risk for death (HR 2.85 95% CI 2.30‐3.53). This increased risk of in‐hospital mortality was similar among HFREF patients.

Conclusions

Use of respiratory support is increasing among patients with both HFPEF and HFREF and associated with substantially increased mortality in both heart failure subtypes.

Therapy for heart failure with preserved ejection fraction: current status, unique challenges, and future directions

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF. Among elderly women, HFpEF comprises more than 80% of incident HF cases. Adverse outcomes-exercise intolerance, poor quality of life, frequent hospitalizations, and reduced survival-approach those of classic HF with reduced EF (HFrEF). However, despite its importance, our understanding of the pathophysiology of HFpEF is incomplete, and despite intensive efforts, optimal therapy remains uncertain, as most trials to date have been negative. This is in stark contrast to management of HFrEF, where dozens of positive trials have established a broad array of effective, guidelines-based therapies that definitively improve a range of clinically meaningful outcomes. In addition to providing an overview of current management status, we examine evolving data that may help explain this paradox, overcome past challenges, provide a roadmap for future success, and that underpin a wave of new trials that will test novel approaches based on these insights.

Targeting coagulation in heart failure with preserved ejection fraction and cardiac fibrosis

Collapse

Risk factor-based subphenotyping of heart failure in the community

Background

Heart failure (HF) is a heterogeneous clinical syndrome with varying prognosis. Subphenotyping of HF is a research priority to advance our understanding of the syndrome. We formulated a subphenotyping schema and compared long-term mortality risk among the HF subphenotypes in the community-based Framingham Study.

Methods and results

In hierarchical order, we grouped participants with new-onset HF (stratified by HF with reduced [HFrEF] vs. preserved ejection fraction [HFpEF]) according to the presence of: (1) coronary heart disease (CHD), (2) metabolic syndrome (MetS), (3) hypertension, and (4) ‘other’ causes. Age at HF onset was lowest in people with the MetS (mean 76 vs. 77 years for HFrEF and HFpEF, respectively) and highest in those with hypertension only (mean 82 and 85 years for HFrEF and HFpEF, respectively). For HFrEF, 10-year cumulative mortality and hazards ratios [HR] were 87% for CHD (n = 219; referent group), 88% for MetS (n = 105; HR 0.95 [95% CI 0.73–1.23]), 82% for hypertension (n = 104; HR 0.71 [0.55–0.91]), and 78% for other (n = 37; HR 0.81 [0.55–1.19]). Corresponding 10-year cumulative mortality and HR data for HFpEF were: 85% for CHD (n = 84; referent), 83% for MetS (n = 118; HR 0.98 [0.72–1.33]), 81% for hypertension (n = 127; HR 0.71 [0.52–0.95]), and 76% for other (n = 43; HR 0.76 [0.50–1.14]). In a sample without overt heart failure (n = 5536), several echocardiographic and vascular indices showed graded worsening of age- and sex adjusted-values among those having CHD, MetS, hypertension, or obesity, compared with individuals not having these risk factors.

Conclusions

HF subphenotypes characterized by the presence of CHD or metabolic syndrome present at a younger age and are marked by greater mortality risk. The clinical utility of the proposed subphenotyping schema warrants further research.

Ventricular Arrhythmias Underlie Sudden Death in Rats With Heart Failure and Preserved Ejection Fraction

BACKGROUND

Heart failure (HF) with preserved ejection fraction (HFpEF) is increasingly common clinically, now rivaling or exceeding HF with reduced ejection fraction . Sudden death is the leading mode of exodus in patients with HFpEF, but the underlying causes are largely unknown. Using ambulatory recordings in a rat model, we test the hypothesis that ventricular arrhythmias (VA) underlie sudden death in HFpEF.

METHODS

Dahl salt-sensitive rats (7 weeks of age) were fed a high-salt diet to induce HFpEF (n=13) or a normal-salt diet (controls, n=9). Transthoracic echocardiography was performed to check systolic and diastolic function at 14 to 18 weeks of age. Telemetric electrocardiographic recordings were analyzed for QT interval duration, burden of premature ventricular contractions, spontaneous VA, and heart rate variability. Survival was monitored twice daily.

RESULTS

High-salt-fed rats with clear diastolic dysfunction, preserved ejection fraction, and HF signs were diagnosed with HFpEF at 14 to 15 weeks of age. QT and QTc intervals were prolonged in HFpEF rats compared with controls. Heart rate variability was reduced in HFpEF rats compared with controls. Spontaneous VA were more prevalent in HFpEF rats (6/13=46.1% versus 0/9=0% in controls; P<0.05), and sudden death was observed in 4 of 13 HFpEF rats. Three of the 4 sudden deaths were associated with VA as the terminal rhythm.

CONCLUSIONS

In this rat model with phenotypically verified HFpEF, sudden death was common and generally associated with VA. Further clinical studies are warranted to determine whether these insights translate to sudden death in HFpEF patients.

Usefulness of Right Ventricular to Pulmonary Circulation Coupling as an Indicator of Risk for Recurrent Admissions in Heart Failure With Preserved Ejection Fraction

In recent years, the study of right ventricular (RV) to pulmonary circulation (PC) coupling in heart failure with preserved ejection fraction (HFpEF) has been a matter of special interest. Tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) ratio has emerged as a reliable noninvasive index of RV to PC coupling. Thus, we hypothesized that TAPSE/PASP would be a predictor of readmission burden in HFpEF. One thousand one hundred and twenty seven consecutive HFpEF patients discharged for acute HF were included. In 367 patients (32.6%), PASP could not be accurately measured by echocardiography, leaving the final sample size to be 760 patients. Negative binomial regression method was used to evaluate the association between TAPSE/PASP ratio and recurrent admissions. Mean age of the cohort was 75.6 ± 9.7 years and 68.3% were women. At a median (interquartile range) follow-up of 2.0 (2.9) years, 352 (46.3%) patients died and 1,214 readmissions were registered in 482 patients (63.4%), being 506 of them HF-related. There was a stepwise increase in the rates of all-cause and HF readmissions by decreasing TAPSE/PASP ratio. After multivariable adjustment, TAPSE/PASP <0.36 was associated with a higher risk of HF-related recurrent admissions (incidence rate ratio [IRR] 1.51, 95% confidence interval [CI], 1.01 to 2.24; p = 0.040), whereas patients in the lowest quintile (TAPSE/PASP <0.28) exhibited the highest risk of both all-cause and HF-related recurrent admissions (IRR 1.40, 95% CI 1.04 to 1.87, p = 0.025; and IRR 1.85, 95% CI 1.22 to 2.80, p = 0.004, respectively). In conclusion, TAPSE/PASP ratio, as a noninvasive index of RV-PC coupling, emerges as a strong predictor of recurrent hospitalizations in HFpEF.

Pirfenidone in Heart Failure with Preserved Ejection Fraction-Rationale and Design of the PIROUETTE Trial

BACKGROUND

The PIROUETTE (PIRfenidOne in patients with heart failUre and preserved lEfT venTricular Ejection fraction) trial is designed to evaluate the efficacy and safety of the anti-fibrotic pirfenidone in patients with chronic heart failure and preserved ejection fraction (HFpEF) and myocardial fibrosis. HFpEF is a diverse syndrome associated with substantial morbidity and mortality. Myocardial fibrosis is a key pathophysiological mechanism of HFpEF and myocardial fibrotic burden is strongly and independently associated with adverse outcome. Pirfenidone is an oral anti-fibrotic agent, without haemodynamic effect, that leads to regression of myocardial fibrosis in preclinical models. It has proven clinical effectiveness in pulmonary fibrosis.

METHODS

The PIROUETTE trial is a randomised, double-blind, placebo-controlled phase II trial evaluating the efficacy and safety of 52 weeks of treatment with pirfenidone in patients with chronic HFpEF (symptoms and signs of heart failure, left ventricular ejection fraction ≥ 45%, elevated natriuretic peptides [BNP ≥ 100 pg/ml or NT-proBNP ≥ 300 pg/ml; or BNP ≥ 300 pg/ml or NT-proBNP ≥ 900 pg/ml if in atrial fibrillation]) and myocardial fibrosis (extracellular matrix (ECM) volume ≥ 27% measured using cardiovascular magnetic resonance). The primary outcome measure is change in myocardial ECM volume. A sub-study will investigate the relationship between myocardial fibrosis and myocardial energetics, and the impact of pirfenidone, using ³¹phosphorus magnetic resonance spectroscopy.

DISCUSSION

PIROUETTE will determine whether pirfenidone is superior to placebo in relation to regression of myocardial fibrosis and improvement in myocardial energetics in patients with HFpEF and myocardial fibrosis (NCT02932566).

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT02932566) https://clinicaltrials.gov/ct2/show/NCT02932566.

Depressed Myocardial Energetic Efficiency Increases Risk of Incident Heart Failure: The Strong Heart Study

An estimation of myocardial mechano-energetic efficiency (MEE) per unit of left ventricular (LV) mass (MEEi) can significantly predict composite cardiovascular (CV) events in treated hypertensive patients with normal ejection fraction (EF), after adjustment for LV hypertrophy (LVH). We have tested whether MEEi predicts incident heart failure (HF), after adjustment for LVH, in the population-based cohort of a “Strong Heart Study” (SHS) with normal EF. We included 1912 SHS participants (age 59 ± 8 years; 64% women) with preserved EF (≥50%) and without prevalent CV disease. MEE was estimated as the ratio of stroke work to the “double product” of heart rate times systolic blood pressure. MEEi was calculated as MEE/LV mass, and analyzed in quartiles. During a follow-up study of 9.2 ± 2.3 years, 126 participants developed HF (7%). HF was preceded by acute myocardial infarction (AMI) in 94 participants. A Kaplan-Meier plot, in quartiles of MEEi, demonstrated significant differences, substantially due to the deviation of the lowest quartile (p < 0.0001). Using AMI as a competing risk event, sequential models of Cox regression for incident HF (including significant confounders), demonstrated that low MEEi predicted incident HF not due to AMI (p = 0.026), after adjustment for significant effect of age, LVH, prolonged LV relaxation, diabetes, and smoking habits with negligible effects for sex, hypertension, antihypertensive therapy, obesity, and hyperlipemia. Low LV mechano-energetic efficiency per unit of LVM, is a predictor of incident, non-AMI related, HF in subjects with initially normal EF.

Younger- vs Older-Old Patients with Heart Failure with Preserved Ejection Fraction

OBJECTIVES

Heart failure with preserved ejection fraction (HFpEF) is now recognized as a geriatric syndrome with multifactorial pathophysiology and clinical heterogeneity rather than a solely left ventricular diastolic dysfunction. Because the pathophysiology of HFpEF is suggested to differ by age, this study compared the clinical characteristics and prognostic factors between HFpEF patients aged 65 to 84 years and those aged 85 years or older.

DESIGN

Retrospective cohort study.

SETTING

The Tokyo CCU Network including 73 hospitals in Tokyo, Japan.

PARTICIPANTS

Individuals aged 65 years or older with HFpEF (N = 4305).

MEASUREMENTS

Very old patients were defined as those aged 85 years or older. Potential risk factors for in-hospital mortality were selected by univariate analyses, and those with a P value <.10 were used in multivariate Cox regression analysis with forward selection (likelihood ratio) to identify significant factors.

RESULTS

Prevalence of hypertension was significantly higher in very old patients, whereas prevalence of coronary artery disease, diabetes mellitus, hyperlipidemia, and smoking was significantly higher in patients aged 65 to 84 years. In very old patients, low systolic blood pressure (hazard ratio [HR] = .988), high serum creatinine level (HR = 1.34), and coexisting chronic obstructive pulmonary disease (COPD; HR = 2.01) were identified as independent risk factors for in-hospital mortality. In contrast, low systolic blood pressure (HR = .987) and low body mass index (HR = .935) were identified as independent risk factors in patients aged 65 to 84 years.

CONCLUSION

Significant differences were observed in the clinical characteristics and prognostic factors for in-hospital mortality between HFpEF patients aged 65 to 84 and those 85 years and older. Of note, coexisting COPD was associated with significantly lower survival rate only in patients aged 85 years and older, suggesting the prognostic impact of concomitant pulmonary disease in HFpEF may increase with age. These results have implications for future research and management of older HFpEF patients. J Am Geriatr Soc 00:1-6, 2019. J Am Geriatr Soc 67:2123-2128, 2019.

Macrophage hypoxia signaling regulates cardiac fibrosis via Oncostatin M

The fibrogenic response in tissue-resident fibroblasts is determined by the balance between activation and repression signals from the tissue microenvironment. While the molecular pathways by which transforming growth factor-1 (TGF-β1) activates pro-fibrogenic mechanisms have been extensively studied and are recognized critical during fibrosis development, the factors regulating TGF-β1 signaling are poorly understood. Here we show that macrophage hypoxia signaling suppresses excessive fibrosis in a heart via oncostatin-m (OSM) secretion. During cardiac remodeling, Ly6C^hi monocytes/macrophages accumulate in hypoxic areas through a hypoxia-inducible factor (HIF)-1α dependent manner and suppresses cardiac fibroblast activation. As an underlying molecular mechanism, we identify OSM, part of the interleukin 6 cytokine family, as a HIF-1α target gene, which directly inhibits the TGF-β1 mediated activation of cardiac fibroblasts through extracellular signal-regulated kinase 1/2-dependent phosphorylation of the SMAD linker region. These results demonstrate that macrophage hypoxia signaling regulates fibroblast activation through OSM secretion in vivo.

Fibrosis is a hallmark of several cardiac pathologies and its underlying mechanisms are still poorly defined. Here the authors show that macrophage hypoxia signaling following transverse aortic constriction in mice suppresses the activation of cardiac fibroblasts by secreting oncostatin M.

Western Diet-Fed, Aortic-Banded Ossabaw Swine: A Preclinical Model of Cardio-Metabolic Heart Failure

The development of new treatments for heart failure lack animal models that encompass the increasingly heterogeneous disease profile of this patient population. This report provides evidence supporting the hypothesis that Western Diet-fed, aortic-banded Ossabaw swine display an integrated physiological, morphological, and genetic phenotype evocative of cardio-metabolic heart failure. This new preclinical animal model displays a distinctive constellation of findings that are conceivably useful to extending the understanding of how pre-existing cardio-metabolic syndrome can contribute to developing HF.

Hypoxia-inducible factor 1-alpha (HIF-1α) as a factor mediating the relationship between obesity and heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF), a common condition with an increased mortality, is strongly associated with obesity and the metabolic syndrome. The latter two conditions are associated with increased epicardial fat that can extend into the heart. This review advances the proposition that hypoxia-inhibitory factor-1α (HIF-1α) maybe a key factor producing HFpEF. HIF-1α, a highly conserved transcription factor that plays a key role in tissue response to hypoxia, is increased in adipose tissue in obesity. Increased HIF-1α expression leads to expression of a potent profibrotic transcriptional programme involving collagen I, III, IV, TIMP, and lysyl oxidase. The net effect is the formation of collagen fibres leading to fibrosis. HIF-1α is also responsible for recruiting M1 macrophages that mediate obesity-associated inflammation, releasing IL-6, MCP-1, TNF-α, and IL-1β with increased expression of thrombospondin, pro α2 (I) collagen, transforming growth factor β, NADPH oxidase, and connective tissue growth factor. These factors can accelerate cardiac fibrosis and impair cardiac diastolic function. Inhibition of HIF-1α expression in adipose tissue of mice fed a high-fat diet suppressed fibrosis and reduces inflammation in adipose tissue. Delineation of the role played by HIF-1α in obesity-associated HFpEF may lead to new potential therapies.

Dysregulation of IL-33/ST2 signaling and myocardial periarteriolar fibrosis

Microvascular dysfunction in the heart and its association with periarteriolar fibrosis may contribute to the diastolic dysfunction seen in heart failure with preserved ejection fraction. Interleukin-33 (IL-33) prevents global myocardial fibrosis in a pressure overloaded left ventricle by acting via its receptor, ST2 (encoded by the gene, Il1rl1); however, whether this cytokine can also modulate periarteriolar fibrosis remains unclear. We utilized two approaches to explore the role of IL-33/ST2 in periarteriolar fibrosis. First, we studied young and old wild type mice to test the hypothesis that IL-33 and ST2 expression change with age. Second, we produced pressure overload in mice deficient in IL-33 or ST2 by transverse aortic constriction (TAC). With age, IL-33 expression increased and ST2 expression decreased. These alterations accompanied increased periarteriolar fibrosis in aged mice. Mice deficient in ST2 but not IL-33 had a significant increase in periarteriolar fibrosis following TAC compared to wild type mice. Thus, loss of ST2 signaling rather than changes in IL-33 expression may contribute to periarteriolar fibrosis during aging or pressure overload, but manipulating this pathway alone may not prevent or reverse fibrosis.

Vagus nerve stimulation for the treatment of heart failure

Heart failure (HF) is one of the most prevalent cardiovascular diseases and is associated with high morbidity and mortality. Mechanistically, HF is characterized by an overactive sympathetic nervous system and parasympathetic withdrawal, and this autonomic imbalance contributes to the progression of the disease. As such, modulation of autonomic nervous system by device-based therapy is an attractive treatment target. In this review, we discuss the role of autonomic nervous system dysfunction in the pathogenesis of HF and present the available evidence regarding vagus nerve stimulation for HF, with special emphasis on optimization of stimulation parameters. Finally, we discuss future avenues of research for neuromodulation in patients with HF.

Relation of Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease to Left Ventricular Diastolic Function and Exercise Tolerance

The purpose of this study was to determine the relation between liver histology, exercise tolerance, and diastolic function in patients with nonalcoholic fatty liver disease (NAFLD). Myocardial remodeling and diastolic dysfunction have been associated with NAFLD. However, its physiological impact and relationship to the histological severity of NAFLD is not known. Cardiopulmonary exercise testing and stress echocardiography was performed in subjects with biopsy-confirmed NAFLD. Maximal aerobic exercise capacity (peak oxygen consumption [VO2]) was related to diastolic function (mitral annulus Doppler velocity e' and ratio of early diastolic filling pressure [E] to e' [E/e']) at rest and peak exercise. Autonomic dysfunction was determined from heart rate recovery after exercise. Independent predictors of cardiac function and exercise capacity were identified by multivariable regression. Thirty-six subjects (nonalcoholic fatty liver [NAFL  =  15], nonalcoholic steatohepatitis [NASH  =  21]) were enrolled. NASH was associated with impaired exercise capacity compared with NAFL (median peak VO2 17.0 [15.4, 18.9] vs 19.9 [17.4, 26.0], p  =  001); pVO2 declined with increasing fibrosis (F0  =  22.5, F1  =  19.9, F2  =  19.0, F3  =  16.6 ml·kg-1·min-1; p  =  0.01). Similarly, E/e' during exercise increased progressively with increasing fibrosis (F0  =  5.6, F1  =  6.5, F2  =  8.7, F3  =  9.8; P  =  0.02). Finally, heart rate recovery, a marker of autonomic function, was blunted in those with higher fibrosis stages (F0  =  25 [20, 30], F1  =  23 [17.5, 27.0], F2  =  17 [11.8, 21.5], F3  =  11 [8.5, 18.0] beats per minute; p <0.01). Fibrosis was an independent predictor of these functional outcomes. In conclusion, NASH is associated with impaired exercise capacity and diastolic dysfunction compared with NAFL. The severity of impairment is directly related to the severity of fibrosis stage in precirrhotic stages of NAFLD.

Right Ventricular Dysfunction and Its Contribution to Morbidity and Mortality in Left Ventricular Heart Failure

PURPOSE

In patients with left-sided HF, there has been less emphasis on the pathophysiology of the RV in terms of diagnostic evaluation and treatment, versus focus on structural abnormalities of the LV. This review seeks to delineate the importance of RV dysfunction in terms of its contribution to symptomatic limitations and cardiovascular outcomes in patients with left-sided HF.

RECENT FINDINGS

Recent studies have demonstrated that RV dysfunction is common in both HFpEF and HFrEF, but more pronounced in HFrEF. LV dysfunction and atrial fibrillation are most commonly associated with RV dysfunction in left-sided HF. RV dysfunction may develop due to afterload-dependent and afterload-independent pathways. Regardless, RV dysfunction is strongly associated with functional limitations and worsened survival in patients with left-sided HF. In patients with HFpEF, a recent study showed that RV failure was the most common cause of overall mortality. Among LVAD patients and patients post-cardiac transplantation, RV dysfunction is also strongly associated with survival. Despite a number of previous and ongoing clinical trials that target the RV directly or decrease RV afterload in left-sided HF, there are no definitive therapies specifically targeting RV dysfunction in left-sided HF patients CONCLUSIONS: RV dysfunction is an important determinant of symptomatic limitations and cardiovascular outcomes in patients with left-sided HF. Further research is needed to developed pharmacotherapy that may target the RV specifically in left-sided HF patients.

Effect of the peptides Relaxin, Neuregulin, Ghrelin and Glucagon-like peptide-1, on cardiomyocyte factors involved in the molecular mechanisms leading to diastolic dysfunction and/or heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) represents an important cardiac condition because of its increasing prevalence, resistance to treatment and high associated morbidity and mortality. Two of the major mechanisms responsible for HFpEF are impaired cardiomyocyte sarcoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA2a), which is responsible for calcium reuptake into the SR, and cardiac fibroblasts/myofibroblasts that produce collagen or myocardial fibrosis. Phospholamban (PLB), in the SR and endoplasmic reticulum, is the primary regulator of SERCA2a in the heart and acts as a reversible inhibitor of SERCA2a. Glucagon-like peptide-1, a 30 amino acid peptide, improves diastolic function through increasing SERCA2a expression and activity as well as by decreasing phosphorylation of Ryanodine receptors. It also enhances collagen production through enhanced procollagen IalphaI/IIIalphaI, connective tissue growth factor, fibronectin, TGF-β3 as well as Interleukin -10, -1beta, and -6 gene expression. Relaxin-2, a two chain, 53 amino acid peptide, increases Ser16- and Thr17-phosphorylation levels of PLB, thereby relieving SERCA2a of its inhibition. H3 Relaxin inhibits TGF-β1-stimulated collagen deposition through H3 relaxin-induced increases in pSmad2. Neuregulin-1, an epidermal growth factor, induces nitric oxide and PI-3 kinase activation that enhance SERCA2 activity. Neuregulin-1 was associated with less myocardial macrophage infiltration and cytokine expression reducing collagen deposition. Ghrelin, a 28 amino acid peptide, improves SERCA2a function by inducing PLB phosphorylation. Ghrelin also reduces cardiac fibrosis. In summary, Glucagon-like peptide-1, Relaxin-2, Neuregulin-1, and Ghrelin each modify calcium dynamics, collagen expression, and myocardial fibrosis through attenuation of deleterious signaling cascades, and induction of adaptive pathways, representing potential therapeutic targets for HFpEF.

Role of spironolactone in the treatment of heart failure with preserved ejection fraction

Heart failure (HF) is the leading cause of morbidity and mortality globally. Heart failure with preserved ejection fraction (HFpEF) is currently responsible for about half of the patients affected with HF and is associated with impaired functional capacity, as well as significant morbidity due to frequent hospitalizations. Unfortunately, despite its poor prognosis, the management of HFpEF is very controversial and no therapy has been so far shown to reduce mortality in HFpEF. Spironolactone antagonizes the effect of aldosterone and can lead to a reduction in fibrosis and an improvement in left ventricular (LV) function. Furthermore, spironolactone decreases extracellular matrix turnover and myocardial collagen content and improves endothelial vasomotor dysfunction, mechanisms known to influence the progression of HF. Thus, given the aforementioned beneficial actions of spironolactone, extensive research has been conducted to explore the effects of spironolactone on HFpEF. Our review aims to present and discuss the clinical and scientific data pertaining to the role of spironolactone in the treatment of patients with HFpEF.

Limited Impact of β-Adrenergic Receptor Activation on Left Ventricular Diastolic Function in Rat Models of Hypertensive Heart Disease

BACKGROUND

Hypertension is a major cause of left ventricular (LV) diastolic dysfunction. Although β-adrenergic receptor (β-AR) blockers are often used to manage hypertension, the impact of β-AR activation on LV lusitropic effects and hence filling pressures in the hypertensive heart with LV diastolic dysfunction is uncertain.

METHODS

Using tissue Doppler imaging and Speckle tracking software, we assessed LV function in isoflurane anesthetised spontaneously hypertensive (SHR) and Dahl salt-sensitive (DSS) rats before and after β-AR activation [isoproterenol (ISO) administration].

RESULTS

As compared to normotensive Wistar Kyoto control rats, or DSS rats not receiving NaCl in the drinking water, SHR and DSS rats receiving NaCl in the drinking water had a reduced myocardial relaxation as indexed by lateral wall e' (early diastolic tissue velocity at the level of the mitral annulus) and an increased LV filling pressure as indexed by E/e'. However, LV ejection fraction and deformation and motion were preserved in both SHR and DSS rats. The administration of ISO resulted in a marked increase in ejection fraction and decrease in LV filling volumes in all groups, and an increase in e' in SHR, but not DSS rats. However, after ISO administration, although E/e' decreased in DSS rats in association with a reduced filling volume, E/e' in SHR remained unchanged and SHR retained greater values than Wistar Kyoto control.

CONCLUSIONS

The hypertensive heart is characterized by reductions in myocardial relaxation and increases in filling pressures, but β-AR activation may fail to improve myocardial relaxation and when this occurs, it does not reduce LV filling pressures.

Characterization of a mouse model of obesity-related fibrotic cardiomyopathy that recapitulates features of human heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is caused, or exacerbated by, a wide range of extracardiac conditions. Diabetes, obesity, and metabolic dysfunction are associated with a unique HFpEF phenotype, characterized by inflammation, cardiac fibrosis, and microvascular dysfunction. Development of new therapies for HFpEF is hampered by the absence of reliable animal models. The leptin-resistant db/ db mouse has been extensively studied as a model of diabetes-associated cardiomyopathy; however, data on the functional and morphological alterations in db/ db hearts are conflicting. In the present study, we report a systematic characterization of the cardiac phenotype in db/ db mice, focusing on the time course of functional and histopathological alterations and on the identification of sex-specific cellular events. Although both male and female db/ db mice developed severe obesity, increased adiposity, and hyperglycemia, female mice had more impressive weight gain and exhibited a modest but significant increase in blood pressure. db/ db mice had hypertrophic ventricular remodeling and diastolic dysfunction with preserved ejection fraction; the increase in left ventricular mass was accentuated in female mice. Histological analysis showed that both male and female db/ db mice had cardiomyocyte hypertrophy and interstitial fibrosis, associated with marked thickening of the perimysial collagen, and expansion of the periarteriolar collagen network, in the absence of replacement fibrosis. In vivo and in vitro experiments showed that fibrotic changes in db/ db hearts were associated with increased collagen synthesis by cardiac fibroblasts, in the absence of periostin, α-smooth muscle actin, or fibroblast activation protein overexpression. Male db/ db mice exhibited microvascular rarefaction. In conclusion, the db/ db mouse model recapitulates functional and histological features of human HFpEF associated with metabolic dysfunction. Development of fibrosis in db/ db hearts, in the absence of myofibroblast conversion, suggests that metabolic dysfunction may activate an alternative profibrotic pathway associated with accentuated extracellular matrix protein synthesis. NEW & NOTEWORTHY We provide a systematic analysis of the sex-specific functional and structural myocardial alterations in db/ db mice. Obese diabetic C57BL6J db/ db mice exhibit diastolic dysfunction with preserved ejection fraction, associated with cardiomyocyte hypertrophy, interstitial/perivascular fibrosis, and microvascular rarefaction, thus recapitulating aspects of human obesity-related heart failure with preserved ejection fraction. Myocardial fibrosis in db/ db mice is associated with a matrix-producing fibroblast phenotype, in the absence of myofibroblast conversion, suggesting an alternative mechanism of activation.

Targeted HFpEF therapy based on matchmaking of human and animal models

The diversity in clinical phenotypes and poor understanding of the underlying pathophysiology of heart failure with preserved ejection fraction (HFpEF) is the main reason why no effective treatments have been found yet. Targeted, instead of one size fits all, treatment seems the only promising approach for treating HFpEF. To be able to design a targeted, phenotype-specific HFpEF treatment, the matrix relating clinical phenotypes and underlying pathophysiological mechanisms has to be clarified. This review discusses the opportunities for additional evaluation of the underlying pathophysiological processes, e.g., to evaluate biological phenotypes on top of clinical routine, to guide us toward a phenotype-specific HFpEF treatment. Moreover, a translational approach with matchmaking of animal models to biological HFpEF phenotypes will be a valuable step to test the effectiveness of novel, targeted interventions in HFpEF. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/personalized-medicine-in-hfpef/ .

Effects of Endurance Training on Detrimental Structural, Cellular, and Functional Alterations in Skeletal Muscles of Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is underpinned by detrimental skeletal muscle alterations that contribute to disease severity, yet underlying mechanisms and therapeutic treatments remain poorly established. This study used a nonhuman animal model of HFpEF to better understand whether skeletal muscle abnormalities were (1) fiber-type specific and (2) reversible by various exercise training regimes.

METHODS AND RESULTS

Lean control rats were compared with obese ZSF1 rats at 20 weeks and then 8 weeks after sedentary, high-intensity interval training, or moderate continuous treadmill exercise. Oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles were assessed for fiber size, capillarity, glycolytic metabolism, autophagy, and contractile function. HFpEF reduced fiber size and capillarity by 20%-50% (P < .05) in both soleus and EDL, but these effects were not reversed by endurance training. In contrast, both endurance training regimes in HFpEF attenuated the elevated lactate dehydrogenase activity observed in the soleus. Autophagy was down-regulated in EDL and up-regulated in soleus (P < .05), with no influence of endurance training. HFpEF impaired contractile forces of both muscles by ∼20% (P < .05), and these were not reversed by training.

CONCLUSIONS

Obesity-related HFpEF was associated with detrimental structural, cellular, and functional alterations to both slow-oxidative and fast-glycolytic skeletal muscles that could not be reversed by endurance training.

Aldosterone Receptor Blockade in Heart Failure with Preserved Ejection Fraction

More than 50% of patients with clinical heart failure have a preserved ejection fraction. Despite mortality that is similar to or slightly lower than heart failure with reduced ejection fraction, trials to date have not shown a therapy that imparts a mortality benefit in heart failure with preserved ejection fraction (HFpEF). HFpEF represents a heterogeneous disorder with a complex pathophysiologic basis, and this may contribute to the negative results in clinical trials. Geographic variations in both patient selection and adherence to study medications confound the interpretation of the trial results. Mineralocorticoid receptor antagonists may be useful in selected patients.

Heart Failure With Preserved Ejection Fraction Expert Panel Report: Current Controversies and Implications for Clinical Trials

The number of persons with heart failure has continued to rise over the last several years. Approximately one-half of those living with heart failure have heart failure with preserved ejection fraction, but critical unsolved questions remain across the spectrum of basic, translational, clinical, and population research in heart failure with preserved ejection fraction. In this study, the authors summarize existing knowledge, persistent controversies, and gaps in evidence with regard to the understanding of heart failure with preserved ejection fraction. Our analysis is based on an expert panel discussion "Think Tank" meeting that included representatives from academia, the National Institutes of Health, the U.S. Food and Drug Administration, the Centers for Medicare & Medicaid Services, and industry.

Biomarkers, myocardial fibrosis and co-morbidities in heart failure with preserved ejection fraction: an overview

The prevalence of heart failure with preserved ejection fraction (HFpEF) is steadily increasing. Its diagnosis remains difficult and controversial and relies mostly on non-invasive echocardiographic detection of left ventricular diastolic dysfunction and elevated filling pressures. The large phenotypic heterogeneity of HFpEF from pathophysiologic al underpinnings to clinical manifestations presents a major obstacle to the development of new therapies targeted towards specific HF phenotypes. Recent studies suggest that natriuretic peptides have the potential to improve the diagnosis of early HFpEF, but they still have significant limitations, and the cut-off points for diagnosis and prognosis in HFpEF remain open to debate. The purpose of this review is to present potential targets of intervention in patients with HFpEF, starting with myocardial fibrosis and methods of its detection. In addition, co-morbidities are discussed as a means to treat HFpEF according to cut-points of biomarkers that are different from usual. Biomarkers and approaches to co-morbidities may be able to tailor therapies according to patients' pathophysiological needs. Recently, soluble source of tumorigenicity 2 (sST2), growth differentiation factor 15 (GDF-15), galectin-3, and other cardiac markers have emerged, but evidence from large cohorts is still lacking. Furthermore, the field of miRNA is a very promising area of research, and further exploration of miRNA may offer diagnostic and prognostic applications and insight into the pathology, pointing to new phenotype-specific therapeutic targets.

Cardiotoxicity of Anticancer Therapeutics

As cancer therapeutics continues to improve and progress, the adverse side effects associated with anticancer treatments have also attracted more attention and have become extensively explored. Consequently, the importance of posttreatment follow-ups is becoming increasingly relevant to the discussion. Contemporary treatment methods, such as tyrosine kinase inhibitors, anthracycline chemotherapy, and immunotherapy regimens are effective in treating different modalities of cancers; however, these reagents act through interference with DNA replication or prevent DNA repair, causing endothelial dysfunction, generating reactive oxygen species, or eliciting non-specific immune responses. Therefore, cardiotoxic effects, such as hypertension, heart failure, and left ventricular dysfunction, arise posttreatment. Rising awareness of cardiovascular complications has led to meticulous attention for the evolution of treatment strategies and carefully monitoring between enhanced treatment effectiveness and minimization of adverse toxicity to the cardiovasculature, in which psychological assessments, early detection methods such as biomarkers, magnetic resonance imaging, and various drugs to reverse the damage from cardiotoxic events are more prevalent and their emphasis has increased tremendously. Fully understanding the mechanisms by which the risk factors action for various patients undergoing cancer treatment is also becoming more prevalent in preventing cardiotoxicity down the line.