HFpEF, a Disease of the Vasculature: A Closer Look at the Other Half

Targeted Quantitative Plasma Metabolomics Identifies Metabolite Signatures that Distinguish Heart Failure with Reduced and Preserved Ejection Fraction

Background

Two general phenotypes of heart failure (HF) are recognized: HF with reduced ejection fraction (HFrEF) and with preserved EF (HFpEF). To develop HF disease phenotype-specific approaches to define and guide treatment, distinguishing biomarkers are needed. The goal of this study was to utilize quantitative metabolomics on a large, diverse population to replicate and extend existing knowledge of the plasma metabolic signatures in human HF.

Methods

Quantitative, targeted LC/MS plasma metabolomics was conducted on 787 samples collected by the Penn Medicine BioBank from subjects with HFrEF (n=219), HFpEF (n=357), and matched non-failing Controls (n=211). A total of 90 metabolites were analyzed, comprising 28 amino acids, 8 organic acids, and 54 acylcarnitines. 733 of these samples were also processed via an OLINK protein panel for proteomic profiling.

Results

Consistent with previous studies, unsaturated forms of medium/long chain acylcarnitines were elevated in the HFrEF group to a greater extent than the HFpEF group compared to Controls. A number of amino acid derivatives, including 1- and 3-methylhistidine, homocitrulline, and symmetric (SDMA) and asymmetric (ADMA) dimethylarginine were elevated in HF, with ADMA elevated uniquely in HFpEF. Plasma branched-chain amino acids (BCAA) were not different across the groups; however, short-chain acylcarnitine species indicative of BCAA catabolism were significantly elevated in both HF groups. The ketone body 3-hydroxybutyrate (3-HBA) and its metabolite C4-OH carnitine were uniquely elevated in the HFrEF group. Linear regression models demonstrated a significant correlation between plasma 3-HBA and NT-proBNP in both forms of HF, stronger in HFrEF.

Conclusions

These results identify plasma signatures that are shared as well as potentially distinguish between HFrEF and HFpEF. Metabolite markers for ketogenic metabolic reprogramming in extra-cardiac tissues were identified as unique signatures in the HFrEF group, possibly related to the lipolytic action of increased levels of BNP. Future studies will be necessary to further validate these metabolites as HF biosignatures that may guide phenotype-specific therapeutics and provide insight into the systemic metabolic responses to HFpEF and HFrEF.

Association of COPD with adverse outcomes in heart failure patients with preserved ejection fraction

We performed a systematic review and meta-analysis to detect the impact of chronic obstructive pulmonary disease (COPD) on the prognosis of heart failure patients with preserved ejection fraction (HFpEF). We systematically screened eligible literature from three electronic databases, PubMed, EMBASE and Cochrane Library, up to April 2023. Two researchers participated in data collection independently. Risk ratios (RRs) from included studies with 95% confidence intervals (CIs) were pooled in the Review Manager version 5.40 software using a random-effects model for analysis. A total of 11 studies (3 post hoc analyses of RCTs and 8 observational studies) with 18 602 participants were included in this meta-analysis. After pooling all the data from eligible studies, our results indicated that COPD was associated with an increased risk of hospitalization (RR = 1.66, 95% CI, 1.47-1.87, P < 0.00001), mortality (RR = 1.62, 95% CI, 1.34-1.95, P < 0.00001), and the composition of hospitalization or mortality (RR = 1.84, 95% CI, 1.35-2.51, P < 0.001) in patients with HFpEF. In a subgroup analysis, the risks of cardiovascular-related mortality (RR = 1.59, 95% CI, 1.30-1.93, P < 0.00001) and post-discharge mortality risk (RR = 2.57, 1.34-4.93, P < 0.01) were increased in HFpEF patients comorbid with COPD, and these associations were also detected in HF-caused hospitalization (RR = 1.64, 95% CI, 1.44-1.87, P < 0.00001). Evidence from existing studies supported that COPD was an independent prognostic risk factor for patients with HFpEF. Developing rapid clinical diagnostic indicators and early use of novel drugs such as SGLT-2 and ARNI may improve the prognosis of this population, deserving further study.

Proteomics of the heart

Mass spectrometry-based proteomics is a sophisticated identification tool specializing in portraying protein dynamics at a molecular level. Proteomics provides biologists with a snapshot of context-dependent protein and proteoform expression, structural conformations, dynamic turnover, and protein-protein interactions. Cardiac proteomics can offer a broader and deeper understanding of the molecular mechanisms that underscore cardiovascular disease, and it is foundational to the development of future therapeutic interventions. This review encapsulates the evolution, current technologies, and future perspectives of proteomic-based mass spectrometry as it applies to the study of the heart. Key technological advancements have allowed researchers to study proteomes at a single-cell level and employ robot-assisted automation systems for enhanced sample preparation techniques, and the increase in fidelity of the mass spectrometers has allowed for the unambiguous identification of numerous dynamic posttranslational modifications. Animal models of cardiovascular disease, ranging from early animal experiments to current sophisticated models of heart failure with preserved ejection fraction, have provided the tools to study a challenging organ in the laboratory. Further technological development will pave the way for the implementation of proteomics even closer within the clinical setting, allowing not only scientists but also patients to benefit from an understanding of protein interplay as it relates to cardiac disease physiology.

The Stiffness of the Ascending Aorta Has a Direct Impact on Left Ventricular Function: An In Silico Model

During systole, longitudinal shortening of the left ventricle (LV) displaces the aortic root toward the apex of the heart and stretches the ascending aorta (AA). An in silico study (Living Left Heart Human Model, Dassault Systèmes Simulia Corporation) demonstrated that stiffening of the AA affects myocardial stress and LV strain patterns. With AA stiffening, myofiber stress increased overall in the LV, with particularly high-stress areas at the septum. The most pronounced reduction in strain was noted along the septal longitudinal region. The pressure-volume loops showed that AA stiffening caused a deterioration in LV function, with increased end-systolic volume, reduced systolic LV pressure, decreased stroke volume and effective stroke work, but elevated end-diastolic pressure. An increase in myofiber contractility indicated that stroke volume and effective stroke work could be recovered, with an increase in LV end-systolic pressure and a decrease in end-diastolic pressure. Longitudinal and radial strains remained reduced, but circumferential strains increased over baseline, compensating for lost longitudinal LV function. Myofiber stress increased overall, with the most dramatic increase in the septal region and the LV apex. We demonstrate a direct mechanical pathophysiologic link between stiff AA and reduced longitudinal left ventricular strain which are common in patients with HFpEF.

The effect of glucagon-like peptide-1 receptor agonists on cardiac function and structure in patients with or without type 2 diabetes mellitus: An updated systematic review and meta-analysis

AIMS

To conduct an updated systematic review and meta-analysis to evaluate the efficacy of glucagon-like peptide-1 receptor agonists (GLP-1RAs) with regard to cardiac function and structure in people with or without type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

We conducted a systematic search using the PubMed, Embase and ClinicalTrials.gov online databases. The primary outcome of interest was changes in mitral inflow E-velocity to tissue Doppler e' velocity (E/e') ratio. Secondary outcomes included other indicators of cardiac reverse remodelling and functional capacity comprising changes in left ventricular mass (LVM), left ventricular global longitudinal strain, left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF), early to atrial mitral inflow velocity ratio, left atrial volume (LAV), N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and 6-min walk test (6MWT) results.

RESULTS

A total of 15 trials involving 898 patients were included in this analysis. GLP-1RAs significantly improved E/e' ratio (mean difference [MD] = -0.73; 95% confidence interval [CI] -1.34, -0.13), LVM (MD = -3.86 g; 95% CI -7.60, -0.12), LAV (MD = -8.20 mL; 95% CI -12.37, -4.04), NT-proBNP level (standardized MD = -0.27; 95% CI -0.47, -0.06), and 6MWT result (MD = +22.31 m; 95% CI 1.64, 42.99). However, GLP-1RAs had no effect on LVEF (MD = +0.31%; 95% CI -1.02, 1.64).

CONCLUSIONS

In this systematic review and meta-analysis, GLP-1RAs were found to have a positive impact on left ventricle diastolic function, hypertrophy, and exercise capacity, but had no effect on systolic function.

Clinical characteristics and prognosis of patients with hypertrophic cardiomyopathy and heart failure with preserved ejection fraction

BACKGROUND

Whether heart failure with preserved ejection fraction (HFpEF) is associated with an increased risk of developing systolic dysfunction and a poor prognosis in hypertrophic cardiomyopathy (HCM) patients is unknown.

OBJECTIVE

We aimed to assess risk factors for the development of end-stage (ES) heart failure (HF) (ejection fraction < 50%) and compare the prognosis of different HF phenotypes.

METHODS

This retrospective study was conducted on patients with HCM in China between January 2009 and February 2023. Patients were stratified into three different groups: HCM-non-HF, HCM-HFpEF and HCM-heart failure with reduced ejection fraction (HCM-HFrEF). The primary outcome was a composite of major adverse cardiac events (MACEs), including all-cause deaths, HF hospitalization, sudden cardiac death and ventricular tachycardia.

RESULTS

Of 3,620 HCM patients enrolled, 1,553 (42.9%) had non-HF, 1,666 (46.0%) had HFpEF, and 579 patients (11.1%) had HFrEF at baseline. During the median follow-up period of 4.0 years (IQR 1.4-9.4 years), patients with HCM-HFpEF exhibited a higher incidence of ES-HF than those with HCM-non-HF (12.4% vs. 2.7%, P < 0.001). HFpEF was an independent risk factor for ES-HF development (HR 3.84, 2.54-5.80, P < 0.001). MACEs occurred in 26.9% with a higher incidence in HCM-HFpEF than HCM-non-HF (36.6% vs 12.2%, P < 0.001). HFpEF was an independent predictor of MACEs (HR 2.13, 1.75-2.59, P < 0.001).

CONCLUSIONS

HFpEF is common in HCM. Compared to non-HF, it increases the risk of LVEF decline and poor prognosis. It may aid in risk stratification and need close echocardiography follow-up.

Profiling the Biomechanical Responses to Workload on the Human Myocyte to Explore the Concept of Myocardial Fatigue and Reversibility: Rationale and Design of the POWER Heart Failure Study

It remains unclear why some patients develop heart failure without evidence of structural damage. One theory relates to impaired myocardial energetics and ventricular-arterial decoupling as the heart works against adverse mechanical load. In this original study, we propose the novel concept of myocardial fatigue to capture this phenomenon and aim to investigate this using human cardiomyocytes subjected to a modern work-loop contractility model that closely mimics in vivo cardiac cycles. This proof-of-concept study (NCT04899635) will use human myocardial tissue samples from patients undergoing cardiac surgery to develop a reproducible protocol to isolate robust calcium-tolerant cardiomyocytes. Thereafter, work-loop contractility experiments will be performed over a range of preload, afterload and cycle frequency as a function of time to elicit any reversible reduction in contractile performance (i.e. fatigue). This will provide novel insight into mechanisms behind heart failure and myocardial recovery and serve as a valuable research platform in translational cardiovascular research.

Thrombosis in the Coronary Microvasculature Impairs Cardiac Relaxation and Induces Diastolic Dysfunction

BACKGROUND

Heart failure with preserved ejection fraction is proposed to be caused by endothelial dysfunction in cardiac microvessels. Our goal was to identify molecular and cellular mechanisms underlying the development of cardiac microvessel disease and diastolic dysfunction in the setting of type 2 diabetes.

METHODS

We used Leprdb/db (leptin receptor-deficient) female mice as a model of type 2 diabetes and heart failure with preserved ejection fraction and identified Hhipl1 (hedgehog interacting protein-like 1), which encodes for a decoy receptor for HH (hedgehog) ligands as a gene upregulated in the cardiac vascular fraction of diseased mice.

RESULTS

We then used Dhh (desert HH)-deficient mice to investigate the functional consequences of impaired HH signaling in the adult heart. We found that Dhh-deficient mice displayed increased end-diastolic pressure while left ventricular ejection fraction was comparable to that of control mice. This phenotype was associated with a reduced exercise tolerance in the treadmill test, suggesting that Dhh-deficient mice do present heart failure. At molecular and cellular levels, impaired cardiac relaxation in DhhECKO mice was associated with a significantly decreased PLN (phospholamban) phosphorylation on Thr17 (threonine 17) and an alteration of sarcomeric shortening ex vivo. Besides, as expected, Dhh-deficient mice exhibited phenotypic changes in their cardiac microvessels including a prominent prothrombotic phenotype. Importantly, aspirin therapy prevented the occurrence of both diastolic dysfunction and exercise intolerance in these mice. To confirm the critical role of thrombosis in the pathophysiology of diastolic dysfunction, we verified Leprdb/db also displays increased cardiac microvessel thrombosis. Moreover, consistently, with Dhh-deficient mice, we found that aspirin treatment decreased end-diastolic pressure and improved exercise tolerance in Leprdb/db mice.

CONCLUSIONS

Altogether, these results demonstrate that microvessel thrombosis may participate in the pathophysiology of heart failure with preserved ejection fraction.

HER2-Targeted Therapy-From Pathophysiology to Clinical Manifestation: A Narrative Review

Trastuzumab is the primary treatment for all stages of HER2-overexpressing breast cancer in patients. Though discovered over 20 years ago, trastuzumab-induced cardiotoxicity (TIC) remains a research topic in cardio-oncology. This review explores the pathophysiological basis of TIC and its clinical manifestations. Their understanding is paramount for early detection and cardioprotective treatment. Trastuzumab renders cardiomyocytes susceptible by inhibiting the cardioprotective NRG-1/HER2/HER4 signaling pathway. The drug acts on HER2-receptor-expressing cardiomyocytes, endothelium, and cardiac progenitor cells (see the Graphical Abstract). The activation of immune cells, fibroblasts, inflammation, and neurohormonal systems all contribute to the evolution of TIC. A substantial amount of research demonstrates that trastuzumab induces overt and subclinical left ventricular (LV) systolic failure. Data suggest the development of right ventricular damage, LV diastolic dysfunction, and heart failure with preserved ejection fraction. Further research is needed to define a chronological sequence of cardiac impairments to guide the proper timing of cardioprotection implementation.

Worsening Renal Function and Adverse Outcomes in Patients with HFpEF with or without Atrial Fibrillation

Since worsening renal function (WRF) and atrial fibrillation (AF) often coexist in preserved ejection fraction (HFpEF), we aimed to investigate the effect of WRF on the prognosis of HFpEF patients with and without AF. The study population of this study (n = 1763) was based on the subset of the Americas in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist Trial (TOPCAT). We found that the cumulative probabilities of the primary composite outcome and cardiovascular death were significantly higher in AF patients post-WRF when compared to non-AF patients. In the time-dependent Cox proportional hazard model, WRF was significantly associated with higher risks of adverse outcomes (primary composite outcome: HR = 1.58 (95% CI, 1.19-2.11); all-cause death: HR = 1.50 (95% CI, 1.10-2.06); cardiovascular death: HR, 2.00 (95% CI, 1.34-3.00)) after adjustments for confounding factors at baseline in HFpEF patients with AF, whereas in HFpEF patients without AF, WRF was not significantly associated with any adverse outcome. p for interactions for the primary composite outcome, cardiovascular death, and AF were significant. In conclusion, these findings highlight that WRF was associated with a greater risk of the primary composite outcome, all-cause death, and cardiovascular death in HFpEF patients with AF.

Artificial intelligence-assisted interpretation of systolic function by echocardiogram

OBJECTIVE

Precise and reliable echocardiographic assessment of left ventricular ejection fraction (LVEF) is needed for clinical decision-making. Recently, artificial intelligence (AI) models have been developed to estimate LVEF accurately. The aim of this study was to evaluate whether an AI model could estimate an expert read of LVEF and reduce the interinstitutional variability of level 1 readers with the AI-LVEF displayed on the echocardiographic screen.

METHODS

This prospective, multicentre echocardiographic study was conducted by five cardiologists of level 1 echocardiographic skill (minimum level of competency to interpret images) from different hospitals. Protocol 1: Visual LVEFs for the 48 cases were measured without input from the AI-LVEF. Protocol 2: the 48 cases were again shown to all readers with inclusion of AI-LVEF data. To assess the concordance and accuracy with or without AI-LVEF, each visual LVEF measurement was compared with an average of the estimates by five expert readers as a reference.

RESULTS

A good correlation was found between AI-LVEF and reference LVEF (r=0.90, p<0.001) from the expert readers. For the classification LVEF, the area under the curve was 0.95 on heart failure with preserved EF and 0.96 on heart failure reduced EF. For the precision, the SD was reduced from 6.1±2.3 to 2.5±0.9 (p<0.001) with AI-LVEF. For the accuracy, the root-mean squared error was improved from 7.5±3.1 to 5.6±3.2 (p=0.004) with AI-LVEF.

CONCLUSIONS

AI can assist with the interpretation of systolic function on an echocardiogram for level 1 readers from different institutions.

The Role of the Vasculature in Heart Failure

The contribution of the vasculature in the development and progression of heart failure (HF) syndromes is poorly understood and often neglected. Incorporating both arterial and venous systems, the vasculature plays a significant role in the regulation of blood flow throughout the body in meeting its metabolic requirements. A deterioration or imbalance between the cardiac and vascular interaction can precipitate acute decompensated HF in both preserved and reduced ejection fraction phenotypes. This is characterised by the increasingly recognised concept of ventricular-arterial coupling: a well-balanced relationship between ventricular and vascular stiffness, which has major implications in HF. Often, the cause of decompensation is unknown, with international guidelines mainly centred on arrhythmia, infection, acute coronary syndrome and its mechanical complications as common causes of decompensation; the vascular component is often underrecognised. A better understanding of the vascular contribution in cardiovascular failure can improve risk stratification, earlier diagnosis and facilitate earlier optimal treatment. This review focuses on the role of the vasculature by integrating the concepts of ventricular-arterial coupling, arterial stiffness and venous return in a failing heart.

Study on the Efficacy of Sacubitril/Valsartan in Patients with Heart Failure with Preserved Ejection Fraction Undergoing Peritoneal Dialysis

INTRODUCTION

Cardiovascular disease is the most common cause of death and morbidity in patients with end-stage renal disease. Sacubitril/valsartan (SAC/VAL) can reduce the risk of cardiovascular mortality among patients with heart failure (HF). The present study set out to evaluate the efficacy of SAC/VAL in the treatment of patients with HF with preserved ejection fraction (HFpEF) undergoing peritoneal dialysis (PD) (HFpEF&PD).

METHODS

A total of 160 patients with HFpEF&PD were enrolled and randomly divided into the control group (N = 80) and SAC/VAL group (N = 80). The cardiac function efficacy, HF scoring efficacy, echocardiographic parameters, serological indicators, and 6-minute walking test were compared before and after treatment.

RESULTS

After 6 months of treatment, the total number of patients who responded to treatment in the SAC/VAL group was higher than that of the control group in terms of cardiac function and HF scoring efficacy. After treatment, levels of early diastolic/late diastolic filling velocity and left ventricular ejection fraction were increased in both groups, while the levels of left atrial diameter, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, inter-ventricular septal diameter, and left ventricular posterior wall diameter were decreased; the NT-proBNP levels were diminished in both groups, while hemoglobin levels and the 6-minute walk distance were increased; the systolic blood pressure, diastolic blood pressure, and 24-h ultrafiltration volume were lowered in all patients. The changes in these indexes in the SAC/VAL group were more obvious than those in the controls.

CONCLUSION

SAC/VAL can significantly improve cardiac function in patients with HFpEF&PD.

Potential traditional Chinese medicines with anti-inflammation in the prevention of heart failure following myocardial infarction

Inflammation plays an important role in the development of heart failure (HF) after myocardial infarction (MI). Suppression of post-infarction inflammatory cascade has become a new strategy to delay or block the progression of HF. At present, there are no approved anti-inflammatory drugs used to prevent HF following MI. Traditional Chinese medicine (TCM) has been used clinically for cardiovascular disease for a long time. Here, we summarized the recent progress about some TCM which could both improve cardiac function and inhibit inflammation in patients or experimental models with MI or HF, in order to provide evidence for their potential application in reducing the onset of HF following MI. Among them, single Chinese medicinal herbs (eg. Astragalus and Salvia miltiorrhiza) and Chinese herbal formulas (eg. Gualou Xiebai Decoction and Sini Tang) are discussed separately. The main targets for their anti-inflammation effect are mainly involved the TLR4/NF-κB signaling, as well as pro-inflammatory cytokines IL-1β, IL-6 or TNF-α. It is worthy of further evaluating their potential, experimentally or clinically, in the prevention or delay of HF following MI.

SIRT6 Mitigates Heart Failure With Preserved Ejection Fraction in Diabetes

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a growing health problem without effective therapies. Epidemiological studies indicate that diabetes is a strong risk factor for HFpEF, and about 45% of patients with HFpEF are suffering from diabetes, yet the underlying mechanisms remain elusive.

METHODS

Using a combination of echocardiography, hemodynamics, RNA-sequencing, molecular biology, in vitro and in vivo approaches, we investigated the roles of SIRT6 (sirtuin 6) in regulation of endothelial fatty acid (FA) transport and HFpEF in diabetes.

RESULTS

We first observed that endothelial SIRT6 expression was markedly diminished in cardiac tissues from heart failure patients with diabetes. We then established an experimental mouse model of HFpEF in diabetes induced by a combination of the long-term high-fat diet feeding and a low-dose streptozocin challenge. We also generated a unique humanized SIRT6 transgenic mouse model, in which a single copy of human SIRT6 transgene was engineered at mouse Rosa26 locus and conditionally induced with the Cre-loxP technology. We found that genetically restoring endothelial SIRT6 expression in the diabetic mice ameliorated diastolic dysfunction concurrently with decreased cardiac lipid accumulation. SIRT6 gain- or loss-of-function studies showed that SIRT6 downregulated endothelial FA uptake. Mechanistically, SIRT6 suppressed endothelial expression of PPARγ through SIRT6-dependent deacetylation of histone H3 lysine 9 around PPARγ promoter region; and PPARγ reduction mediated SIRT6-dependent inhibition of endothelial FA uptake. Importantly, oral administration of small molecule SIRT6 activator MDL-800 to diabetic mice mitigated cardiac lipid accumulation and diastolic dysfunction.

CONCLUSIONS

The impairment of endothelial SIRT6 expression links diabetes to HFpEF through the alteration of FA transport across the endothelial barrier. Genetic and pharmacological strategies that restored endothelial SIRT6 function in mice with diabetes alleviated experimental HFpEF by limiting FA uptake and improving cardiac metabolism, thus warranting further clinical evaluation.

Aging and Heart Failure with Preserved Ejection Fraction

Heart failure is a clinical syndrome characterized by the inability of the cardiovascular system to provide adequate cardiac output at normal filling pressures. This results in a clinical syndrome characterized by dyspnea, edema, and decreased exertional tolerance. Heart failure with preserved ejection fraction (HFpEF) is an increasingly common disease, and the incidence of HFpEF increases with age. There are a variety of factors which contribute to the development of HFpEF, including the presence of hypertension, diabetes, obesity, and other pro-inflammatory states. These comorbid conditions result in changes at the biochemical and cell signaling level which ultimately lead to a disease with a great deal of phenotypic heterogeneity. In general, the physiologic dysfunction of HFpEF is characterized by vascular stiffness, increased cardiac filling pressures, pulmonary hypertension, and impaired volume management. The normal and abnormal processes associated with aging serve as an accelerant in this process, resulting in the hypothesis that HFpEF represents a form of presbycardia. In this article, we aim to review the processes importance of aging in the development of HFpEF by examining the disease and its causes from the biochemical to physiologic level. © 2022 American Physiological Society. Compr Physiol 12: 1-10, 2022.

Endothelial Dysfunction in Heart Failure With Preserved Ejection Fraction: What are the Experimental Proofs?

Heart failure with preserved ejection fraction (HFpEF) has been recognized as the greatest single unmet need in cardiovascular medicine. Indeed, the morbi-mortality of HFpEF is high and as the population ages and the comorbidities increase, so considerably does the prevalence of HFpEF. However, HFpEF pathophysiology is still poorly understood and therapeutic targets are missing. An unifying, but untested, theory of the pathophysiology of HFpEF, proposed in 2013, suggests that cardiovascular risk factors lead to a systemic inflammation, which triggers endothelial cells (EC) and coronary microvascular dysfunction. This cardiac small vessel disease is proposed to be responsible for cardiac wall stiffening and diastolic dysfunction. This paradigm is based on the fact that microvascular dysfunction is highly prevalent in HFpEF patients. More specifically, HFpEF patients have been shown to have decreased cardiac microvascular density, systemic endothelial dysfunction and a lower mean coronary flow reserve. Importantly, impaired coronary microvascular function has been associated with the severity of HF. This review discusses evidence supporting the causal role of endothelial dysfunction in the pathophysiology of HFpEF in human and experimental models.

Reactive Oxygen Species Induced Pathways in Heart Failure Pathogenesis and Potential Therapeutic Strategies

With respect to structural and functional cardiac disorders, heart failure (HF) is divided into HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Oxidative stress contributes to the development of both HFrEF and HFpEF. Identification of a broad spectrum of reactive oxygen species (ROS)-induced pathways in preclinical models has provided new insights about the importance of ROS in HFrEF and HFpEF development. While current treatment strategies mostly concern neuroendocrine inhibition, recent data on ROS-induced metabolic pathways in cardiomyocytes may offer additional treatment strategies and targets for both of the HF forms. The purpose of this article is to summarize the results achieved in the fields of: (1) ROS importance in HFrEF and HFpEF pathophysiology, and (2) treatments for inhibiting ROS-induced pathways in HFrEF and HFpEF patients. ROS-producing pathways in cardiomyocytes, ROS-activated pathways in different HF forms, and treatment options to inhibit their action are also discussed.

Catheter Ablation for Atrial Fibrillation in Patients with Heart Failure with Preserved Ejection Fraction: A Systematic Review and Meta-Analysis

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) has been proposed as a means of improving outcomes among patients with heart failure and reduced ejection fraction (HFrEF) who are otherwise receiving appropriate treatment. Unlike HFrEF, treatment options are more limited in patients with preserved ejection fraction (HFpEF) and the data pertaining to the management of AF in these patients are controversial. The aim of this systematic review and meta-analysis was to investigate the effects of CA on outcomes of patients with AF and HFpEF, such as functional status, post-procedural complications, hospitalization, morbidity and mortality, based on data from observational studies.

METHODS

We systematically searched the electronic databases MEDLINE, PUBMED, EMBASE and the Cochrane Library for Central Register of Clinical Trials until May 2020.

RESULTS

Overall, the pooling of our data showed that sinus rhythm was achieved long-term in 58.0% (95% CI 0.44-0.71). Long-term AF recurrence was noticed in 22.3% of patients. Admission for HF occurred in 6.2% (95% CI 0.04-0.09) whilst all-cause mortality was identified in 6.3% (95% CI 0.02-0.13).

CONCLUSION

This meta-analysis is the first to focus on determining the benefits of a rhythm control strategy for patients with AF and HFpEF using CA, suggesting it may be worthwhile to investigate the effects of a CA rhythm control strategy as the default treatment of AF in HFpEF patients in randomized trials.

Sex and age interaction in fundamental circulatory volumetric variables at peak working capacity

Background

Whether the fundamental hematological and cardiac variables determining cardiorespiratory fitness and their intrinsic relationships are modulated by major constitutional factors, such as sex and age remains unresolved.

Methods

Transthoracic echocardiography, central hemodynamics and pulmonary oxygen (O₂) uptake were assessed in controlled conditions during submaximal and peak exercise (cycle ergometry) in 85 healthy young (20–44 year) and older (50–77) women and men matched by age-status and moderate-to-vigorous physical activity (MVPA) levels. Main outcomes such as peak left ventricular end-diastolic volume (LVEDV_peak), stroke volume (SV_peak), cardiac output (Q_peak) and O₂ uptake (VO_2peak), as well as blood volume (BV), BV–LVEDV_peak and LVEDV_peak–SV_peak relationships were determined with established methods.

Results

All individuals were non-smokers and non-obese, and MVPA levels were similar between sex and age groups (P ≥ 0.140). BV per kg of body weight did not differ between sexes (P ≥ 0.118), but was reduced with older age in men (P = 0.018). Key cardiac parameters normalized by body size (LVEDV_peak, SV_peak, Q_peak) were decreased in women compared with men irrespective of age (P ≤ 0.046). Older age per se curtailed Q_peak (P ≤ 0.022) due to lower heart rate (P < 0.001). In parallel, VO_2peak was reduced with older age in both sexes (P < 0.001). The analysis of fundamental circulatory relationships revealed that older women require a higher BV for a given LVEDV_peak than older men (P = 0.024).

Conclusions

Sex and age interact on the crucial circulatory relationship between total circulating BV and peak cardiac filling, with older women necessitating more BV to fill the exercising heart than age- and physical activity-matched men.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00409-9.

EAT Thickness as a Predominant Feature for Evaluating Arterial Stiffness in Patients with Heart Failure with Preserved Ejection Fraction

OBJECTIVE

Heart failure with preserved ejection fraction (HFpEF) is an intricacy heterogeneous syndrome. However, the association between EAT and arterial stiffness in HFpEF patients remains unknown.

METHODS

A total of 102 patients were enrolled into the study, and brachial-ankle pulse-wave velocity (baPWV), epicardial adipose tissue (EAT) and body composition were assessed. Linear regression analysis was carried out to model the relationship between variables (especially EAT thickness) and baPWV.

RESULTS

The results showed that patients with the thicker EAT fat pad (≥3.55 mm) tended to have comorbidities of hypertension, coronary artery disease (CAD), diabetes and hyperlipidemia, also with a higher level of obesity, fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), total cholesterol (TC) and triglyceride (TG). The level of baPWV was higher in EAT ≥3.55 mm group than the other group. BaPWV was positively associated with EAT, age, heart rate, waist circumference, visceral fat area, systolic and diastolic blood pressure, CRP and FBG. After adjusting for EAT, age and visceral fat area, EAT thickness (β = 0.256, P = 0.009) and visceral fat area (β = 0.229, P = 0.036) significantly associated with baPWV.

CONCLUSION

The study assessed for the first time that the increased EAT thickness was closely related with baPWV in HFpEF patients, suggesting patients with the thicker EAT may be independently associated with arterial stiffness under the context of HFpEF.

A potential role of autophagy-mediated vascular senescence in the pathophysiology of HFpEF

Heart failure with preserved ejection fraction (HFpEF) is one of the most complex and most prevalent cardiometabolic diseases in aging population. Age, obesity, diabetes, and hypertension are the main comorbidities of HFpEF. Microvascular dysfunction and vascular remodeling play a major role in its development. Among the many mechanisms involved in this process, vascular stiffening has been described as one the most prevalent during HFpEF, leading to ventricular-vascular uncoupling and mismatches in aged HFpEF patients. Aged blood vessels display an increased number of senescent endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). This is consistent with the fact that EC and cardiomyocyte cell senescence has been reported during HFpEF. Autophagy plays a major role in VSMCs physiology, regulating phenotypic switch between contractile and synthetic phenotypes. It has also been described that autophagy can regulate arterial stiffening and EC and VSMC senescence. Many studies now support the notion that targeting autophagy would help with the treatment of many cardiovascular and metabolic diseases. In this review, we discuss the mechanisms involved in autophagy-mediated vascular senescence and whether this could be a driver in the development and progression of HFpEF.

The Global Ambulatory Blood Pressure Monitoring (ABPM) in Heart Failure with Preserved Ejection Fraction (HFpEF) Registry. Rationale, design and objectives

Hypertension is a major risk factor for the development of heart failure with preserved ejection fraction (HFPEF) and blood pressure (BP) in itself is an important marker of prognosis. The association of BP levels, and hemodynamic parameters, measured by ambulatory blood pressure monitoring (ABPM), with outcomes, in patients with HFPEF is largely unknown. Patients with HFPEF have a substantial burden of co-morbidities and frailty. In addition there are marked geographic differences in HFPEF around the world. How these difference influence the association between BP and outcomes in HFPEF are unknown. The Global Ambulatory Blood Pressure Monitoring (ABPM) in Heart Failure with Preserved Ejection Fraction (HFpEF) Registry aims to assess the relevance of BP parameters, measured by ABPM, on the outcome of HFPEF patients worldwide. Additionally, the influence of other relevant factors such as frailty and co-morbidities will be assessed. Stable HFPEF patients with a previous hospitalization, will be included. Patients should be clinically and hemodynamically stable for at least 4 weeks before study inclusion. Specific data related to HF, biochemical markers, ECG and echocardiography will be collected. An ABPM and geriatric and frailty evaluation will be performed and the association with morbidity and mortality assessed. Follow up will be at least one year.

Soluble vascular endothelial growth factor receptor 2 and prognosis in patients with chronic heart failure

Aims

Endothelial cell vascular endothelial growth factor receptor 2 (VEGFR‐2) plays a pivotal role in angiogenesis, which induces physiological cardiomyocyte hypertrophy via paracrine signalling between endothelial cells and cardiomyocytes. We investigated whether a decrease in circulating soluble VEGFR‐2 (sVEGFR‐2) levels is associated with poor prognosis in patients with chronic heart failure (HF).

Methods and results

We performed a multicentre prospective cohort study of 1024 consecutive patients with HF, who were admitted to hospitals due to acute decompensated HF and were stabilized after initial management. Serum levels of sVEGFR‐2 were measured at discharge. Patients were followed up over 2 years. The outcomes were cardiovascular death, all‐cause death, major adverse cardiovascular events (MACE) defined as a composite of cardiovascular death and HF hospitalization, and HF hospitalization. The mean age of the patients was 75.5 (standard deviation, 12.6) years, and 57% were male. Patients with lower sVEGFR‐2 levels were older and more likely to be female, and had greater proportions of atrial fibrillation and anaemia, and lower proportions of diabetes, dyslipidaemia, and HF with reduced ejection fraction (<40%). During the follow‐up, 113 cardiovascular deaths, 211 all‐cause deaths, 350 MACE, and 309 HF hospitalizations occurred. After adjustment for potential clinical confounders and established biomarkers [N‐terminal B‐type natriuretic peptide (NT‐proBNP), high‐sensitivity cardiac troponin I, and high‐sensitivity C‐reactive protein], a low sVEGFR‐2 level below the 25th percentile was significantly associated with cardiovascular death [hazard ratio (HR), 1.79; 95% confidence interval (CI), 1.16–2.74] and all‐cause death (HR, 1.43; 95% CI, 1.04–1.94), but not with MACE (HR, 1.11; 95% CI, 0.86–1.43) or HF hospitalization (HR, 1.03; 95% CI, 0.78–1.35). The stratified analyses revealed that a low sVEGFR‐2 level below the 25th percentile was significantly associated with cardiovascular death (HR, 1.76; 95% CI, 1.07–2.85) and all‐cause death (HR, 1.49; 95% CI, 1.03–2.15) in the high‐NT‐proBNP group (above the median), but not in the low‐NT‐proBNP group. Notably, the patients with high‐NT‐proBNP and low‐sVEGFR‐2 (below the 25th percentile) had a 2.96‐fold higher risk (95% CI, 1.56–5.85) for cardiovascular death and a 2.40‐fold higher risk (95% CI, 1.52–3.83) for all‐cause death compared with those with low‐NT‐proBNP and high‐sVEGFR‐2.

Conclusions

A low sVEGFR‐2 value was independently associated with cardiovascular death and all‐cause death in patients with chronic HF. These associations were pronounced in those with high NT‐proBNP levels.

Damage to cardiac vasculature may be associated with breast cancer treatment-induced cardiotoxicity

BACKGROUND

Breast cancer is the most common female cancer worldwide. Effective therapies including doxorubicin and trastuzumab have improved survival, but are associated with a substantial risk of cardiovascular disease. Mechanisms underlying cancer treatment-induced cardiotoxicity (CTC) are poorly understood and have largely focused on cardiomyocyte damage, although other cellular populations in the heart such as the cardiac endothelium, may play an important role in cardiac damage. We treated a breast tumor-bearing mouse model with doxorubicin and trastuzumab to investigate the role of the cardiac endothelium in the development of CTC.

METHODS

Immune compromised mice were inoculated in the 4th mammary fat pad with human breast cancer cells overexpressing HER2 (BT474). When tumors were palpable, mice were treated weekly with doxorubicin (5 mg/kg) and trastuzumab (4 mg/kg). The cardiac phenotype of mice was assessed by echocardiography and histological evaluation of the heart. Cardiac vascular damage was assayed by in vivo permeability assays and primary cultures of murine cardiac endothelial cells were used to assay doxorubicin toxicity in vitro.

RESULTS

The growth of BT474 breast tumors in Balb/c Nude mice was suppressed upon treatment with doxorubicin and trastuzumab. Mice treated for 4 months with doxorubicin and trastuzumab maintained body weights, but demonstrated an echocardiographic phenotype consistent with preserved left ventricular (LV) ejection fraction, decreased LV mass and increased filling pressures (E/e'). Histological staining with Masson's trichrome and Picrosirius red showed extensive fibrosis and increased collagen deposition in the ventricular myocardium surrounding blood vessels of treated mice compared to untreated mice. Evans blue permeability assays demonstrated increased cardiac vasculature permeability while primary cardiac endothelial cells exposed to doxorubicin in vitro showed increased cell death as compared to lung or liver endothelial cells.

CONCLUSIONS

An orthotopic mouse model of human breast cancer in Nude mice treated with doxorubicin and trastuzumab resulted in a cardiac vascular defect accompanied by preserved LV ejection fraction, decreased LV mass, suggesting mild diastolic dysfunction and cardiac remodeling consistent with subclinical cardiotoxicity. Our data suggest that cardiac endothelium is more sensitive to doxorubicin therapy as compared to other organ endothelium and cardiac endothelial damage may correlate with breast cancer treatment-induced cardiotoxicity.

Mast Cells Are the Trigger of Small Vessel Disease and Diastolic Dysfunction in Diabetic Obese Mice

[Figure: see text].

Sacubitril-valsartan improves conduit vessel function and functional capacity and reduces inflammation in heart failure with reduced ejection fraction

The Prospective comparison of ARNI with angiotensin-converting enzyme inhibitor to Determine Impact on Global Mortality and morbidity in Heart Failure trial identified a marked reduction in the risk of death and hospitalization for heart failure in patients with heart failure with reduced ejection fraction (HFrEF) treated with sacubitril-valsartan (trade name Entresto), but the physiological processes underpinning these improvements are unclear. We tested the hypothesis that treatment with sacubitril-valsartan improves peripheral vascular function, functional capacity, and inflammation in patients with HFrEF. We prospectively studied patients with HFrEF (n = 11, 10 M/1 F, left ventricular ejection fraction = 27 ± 8%) on optimal, guideline-directed medical treatment who were subsequently prescribed sacubitril-valsartan (open-label, uncontrolled, and unblinded). Peripheral vascular function [brachial artery flow-mediated dilation (FMD, conduit vessel function) and reactive hyperemia (RH, microvascular function)], functional capacity [six-minute walk test (6MWT) distance], and the proinflammatory biomarkers tumor necrosis factor-α (TNF-α) and interleukin-18 (IL-18) were obtained at baseline and at 1, 2, and 3 mo of treatment. %FMD improved after 1 mo of treatment, and this favorable response persisted for months 2 and 3 (baseline: 3.25 ± 1.75%; 1 mo: 5.23 ± 2.36%; 2 mo: 5.81 ± 1.79%; 3 mo: 6.35 ± 2.77%), whereas RH remained unchanged. 6MWT distance increased at months 2 and 3 (baseline: 420 ± 92 m; 1 mo: 436 ± 98 m; 2 mo: 465 ± 115 m; 3 mo: 460 ± 110 m), and there was a sustained reduction in TNF-α (baseline: 2.38 ± 1.35 pg/mL; 1 mo: 2.06 ± 1.52 pg/mL; 2 mo: 1.95 ± 1.34 pg/mL; 3 mo: 1.92 ± 1.37 pg/mL) and a reduction in IL-18 at month 3 (baseline: 654 ± 150 pg/mL; 1 mo: 595 ± 140 pg/mL; 2 mo: 601 ± 176 pg/mL; 3 mo: 571 ± 127 pg/mL). This study provides new evidence for the potential of this new drug class to improve conduit vessel function, functional capacity, and inflammation in patients with HFrEF.NEW & NOTEWORTHY We observed an approximately twofold improvement in conduit vessel function (brachial artery FMD), increased functional capacity (6MWT distance), and a reduction in inflammation (TNF-α and IL-18) following 3 mo of sacubitril-valsartan therapy. These findings provide important new information concerning the physiological mechanisms by which this new drug class provokes favorable changes in HFrEF pathophysiology.

Heart Failure With Preserved Ejection Fraction in Hypertension Patients: A Myocardial MR Strain Study

BACKGROUND

Despite current recommendations for heart failure with preserved ejection fraction (HFpEF), few studies have demonstrated the ability of MRI to identify subtle functional differences between HFpEF with essential hypertension (HFpEF-HTN) patients and hypertension patients (HTN).

PURPOSE

This study aimed to detect and evaluate HFpEF in patients with HTN using feature-tracking (FT) and to ascertain optimal strain cutoffs for the diagnosis of HFpEF-HTN.

STUDY TYPE

Retrospective study.

POPULATION

Three groups (84 with HFpEF-HTN; 72 with HTN; and 70 healthy controls).

FIELD STRENGTH

1.5T, steady-state free precession (SSFP), and half-Fourier single-shot turbo spin-echo (HASTE) sequences.

ASSESSMENT

All patients underwent laboratory testing and imaging protocols (echocardiography and MRI). FT-derived left ventricular (LV) strain and strain rate (SR) were measured and compared among the three groups with adjustment for confounding factors.

STATISTICAL TESTS

Kolmogorov-Smirnov's test, independent-sample t-tests, one-way analysis of variance (ANOVA), Pearson's correlation coefficient, area under the receiver-operator characteristic (ROC) curve (AUC), and logistic regression.

RESULTS

Compared to 72 HTN patients and 70 healthy controls, HFpEF-HTN patients (84 patients) demonstrated significantly impaired LV strains (except for global peak systolic radial strain, GRS, P < 0.05 for all). Only LV global peak systolic longitudinal strain (GLS) was significantly impaired in HTN patients vs. controls (P < 0.05). The global peak systolic circumferential SR (sGCSR) showed the highest diagnostic value for the differentiation of HFpEF-HTN patients from HTN patients (AUC, 0.731; cutoff value, -1.11/s; sensitivity, 56.0%; specificity, 84.7%). Only global peak early diastolic longitudinal SR (eGLSR) remained independently associated with a diagnosis of HFpEF-HTN in multilogistic analysis. The major strain parameters significantly correlated with LV ejection fraction, end-systolic volume index, and N-terminal pro-brain natriuretic peptide (P < 0.05 for all) and also demonstrated differences between NYHA functional class.

DATA CONCLUSION

HFpEF-HTN patients suffer from both systolic and diastolic cardiac dysfunction. FT-derived strain parameters have potential value for the diagnosis and risk stratification of HFpEF-HTN patients. Level of Evidence 3. Technical Efficacy Stage 2.

Heart Failure with Preserved Ejection Fraction-a Concise Review

Purpose of Review

Heart failure with preserved ejection fraction (HFpEF) is a relatively new disease entity used in medical terminology; however, both the number of patients and its clinical significance are growing. HFpEF used to be seen as a mild condition; however, the symptoms and quality of life of the patients are comparable to those with reduced ejection fraction. The disease is much more complex than previously thought. In this article, information surrounding the etiology, diagnosis, prognosis, and possible therapeutic options of HFpEF are reviewed and summarized.

Recent Findings

It has recently been proposed that heart failure (HF) is rather a heterogeneous syndrome with a spectrum of overlapping and distinct characteristics. HFpEF itself can be distilled into different phenotypes based on the underlying biology. The etiological factors of HFpEF are unclear; however, systemic low-grade inflammation and microvascular damage as a consequence of comorbidities associated with endothelial dysfunction, oxidative stress, myocardial remodeling, and fibrosis are considered to play a crucial role in the pathogenesis of a disease. The H₂FPEF score and the HFpEF nomogram are recently validated highly sensitive tools employed for risk assessment of subclinical heart failure.

Summary

Despite numerous studies, there is still no evidence-based pharmacotherapy for HFpEF and the mortality and morbidity associated with HFpEF remain high. A better understanding of the etiological factors, the impact of comorbidities, the phenotypes of the disease, and implementation of machine learning algorithms may play a key role in the development of future therapeutic strategies.

Heart failure with preserved ejection fraction: an update on pathophysiology, diagnosis, treatment, and prognosis

Heart failure (HF) with preserved ejection fraction (HFpEF) is a clinical syndrome in which patients have symptoms and signs of HF with normal or near-normal left ventricular ejection fraction (LVEF ≥50%). Roughly half of all patients with HF worldwide have an LVEF ≥50% and nearly half have an LVEF <50%. Thanks to the increased scientific attention about the condition and improved characterization and diagnostic tools, the incidence of HF with reduced ejection fraction (HFrEF) dropped while that of HFpEF has increased by 45%. HFpEF has no single guideline for diagnosis or treatment, the patient population is heterogeneously and inconsistently described, and longitudinal studies are lacking. To better understand and overcome the disease, in this review, we updated the latest knowledge of HFpEF pathophysiology, introduced the existing promising diagnostic methods and treatments, and summarized its prognosis by reviewing the most recent cohort studies.

Obesity, Hypertension, and Cardiac Dysfunction: Novel Roles of Immunometabolism in Macrophage Activation and Inflammation

Obesity and hypertension, which often coexist, are major risk factors for heart failure and are characterized by chronic, low-grade inflammation, which promotes adverse cardiac remodeling. While macrophages play a key role in cardiac remodeling, dysregulation of macrophage polarization between the proinflammatory M1 and anti-inflammatory M2 phenotypes promotes excessive inflammation and cardiac injury. Metabolic shifting between glycolysis and mitochondrial oxidative phosphorylation has been implicated in macrophage polarization. M1 macrophages primarily rely on glycolysis, whereas M2 macrophages rely on the tricarboxylic acid cycle and oxidative phosphorylation; thus, factors that affect macrophage metabolism may disrupt M1/M2 homeostasis and exacerbate inflammation. The mechanisms by which obesity and hypertension may synergistically induce macrophage metabolic dysfunction, particularly during cardiac remodeling, are not fully understood. We propose that obesity and hypertension induce M1 macrophage polarization via mechanisms that directly target macrophage metabolism, including changes in circulating glucose and fatty acid substrates, lipotoxicity, and tissue hypoxia. We discuss canonical and novel proinflammatory roles of macrophages during obesity-hypertension-induced cardiac injury, including diastolic dysfunction and impaired calcium handling. Finally, we discuss the current status of potential therapies to target macrophage metabolism during heart failure, including antidiabetic therapies, anti-inflammatory therapies, and novel immunometabolic agents.

Risks of incident heart failure with preserved ejection fraction in Chinese patients hospitalized for cardiovascular diseases

Background

Endogenous aldehyde damages DNA and potentiates an ageing phenotype. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism has a prevalence of 30%–50% in Asian populations. In this study, we aimed to analyze risk factors contributing to the development of heart failure with preserved ejection fraction (HFpEF) along with the genetic exposure in Chinese patients hospitalized with cardiovascular diseases (CVD).

Methods

From July 2017 to October 2018, a total of 770 consecutive Chinese patients with normal left ventricular ejection fractions (LVEF) and established CVD (hypertension, coronary heart diseases, or diabetes) were enrolled in this prospective cross-sectional study. HFpEF was defined by the presence of at least one of symptom (dyspnoea and fatigue) or sign (rales and ankle swelling) related to heart failure; N-terminal pro-B-Type natriuretic peptide (NT pro-BNP ≥ 280 pg/mL); LVEF ≥ 50%; and at least one criterion related to elevated ventricular filling pressure or diastolic dysfunction (left atrial diameter > 40 mm, E/E' ≥ 13, E'/A' < 1 or concurrent atrial fibrillation). Logistic regression was performed to yield adjusted odds ratios (ORs) for HFpEF incidence associated with traditional and/or genetic exposures.

Results

Finally, among 770 patients with CVD, 92 (11.9%) patients were classified into the HFpEF group according to the diagnostic criteria. The mean age of the participants was 67 ± 12 years, and 278 (36.1%) patients were females. A total of 303 (39.4%) patients were ALDH2*2 variant carriers. In the univariate analysis, eight exposures were found to be associated with HFpEF: atrial fibrillation, ALDH2*2 variants, hypertension, age, anaemia, smoking, alcohol consumption and sex. Multivariable logistic regression showed that 4 ‘A’ variables (atrial fibrillation, ALDH2*2 variants, age and anaemia) were significantly associated with an increased risk of HFpEF. Atrial fibrillation was associated with a 3.8-fold increased HFpEF risk (95% CI: 2.21–6.61, P < 0.001), and the other three exposures associated with increased HFpEF risk were the ALDH2*2 variant (OR = 2.41, 95% CI: 1.49–3.87, P < 0.001), age (OR = 2.14, 95% CI: 1.27–3.60, P = 0.004), and anaemia (OR = 1.79, 95% CI: 1.05–3.03, P = 0.032). These four variables predicted HFpEF incidence in Chinese CVD patients (C-statistic = 0.745, 95% CI: 0.691–0.800, P < 0.001).

Conclusions

4 A traits (atrial fibrillation, ALDH2*2 variants, age and anaemia) were associated with an increased risk of HFpEF in Chinese CVD patients. Our results provide potential clues to the aetiology, pathophysiology and therapeutic targets of HFpEF.

The vasculature in HFpEF vs HFrEF: differences in contractile protein expression produce distinct phenotypes

Both heart failure with reduced (HFrEF) and preserved (HFpEF) ejection fraction are associated with abnormalities of the vasculature, including a resting vasoconstriction and a decrease in sensitivity to nitric oxide (NO) mediated vasodilation. Vascular tone is controlled by the expression and activation of both smooth muscle (SM) and nonmuscle (NM) myosin, and NO mediated vasodilation is regulated by the expression of the leucine zipper positive (LZ+) isoform of the myosin targeting subunit (MYPT1) of myosin light chain phosphatase (MLCP). This study was designed to determine the expression of these contractile proteins in humans with HFrEF and HFpEF vs normal controls. We isolated tertiary mesenteric vessels from remnant biospecimens of patients undergoing partial or total colectomy at Mayo Clinic Rochester from August 2017 to December 2018, and examined the expression of MYPT1 and the LZ + MYPT1 isoform with immunoblots, while 2D SDS-PAGE was used to resolve the phosphorylated and nonphosphorylated regulatory light chains of NM and SM myosin. Our data show that NM myosin expression, as a percentage of total myosin, was 12 ± 3% (controls, n = 6), 7 ± 5% (HFpEF, n = 4) and 37 ± 18% (HFrEF, n = 5, p < 0.05). Total MYPT1 expression was significantly reduced (p < 0.05) in both HFpEF (70 ± 11%) and HFrEF (48 ± 6%); and in HFrEF, LZ + MYPT1 was also depressed (62 ± 19%, <0.05). These results demonstrate that HFrEF and HFpEF are distinct vascular entities, and the changes in protein expression contribute to the vascular abnormalities associated with these diseases. Further in HFpEF, the decrease in MYPT1 would explain why pharmacologic therapies that are designed to activate the NO/cGMP/PKG signaling pathway do not produce a clinical benefit.

Microvascular Dysfunction in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is an increasingly studied entity accounting for 50% of all diagnosed heart failure and that has claimed its own dignity being markedly different from heart failure with reduced EF in terms of etiology and natural history (Graziani et al., 2018). Recently, a growing body of evidence points the finger toward microvascular dysfunction as the major determinant of the pathological cascade that justifies clinical manifestations (Crea et al., 2017). The high burden of comorbidities such as metabolic syndrome, hypertension, atrial fibrillation, chronic kidney disease, obstructive sleep apnea, and similar, could lead to a systemic inflammatory state that impacts the physiology of the endothelium and the perivascular environment, engaging complex molecular pathways that ultimately converge to myocardial fibrosis, stiffening, and dysfunction (Paulus and Tschope, 2013). These changes could even self-perpetrate with a positive feedback where hypoxia and locally released inflammatory cytokines trigger interstitial fibrosis and hypertrophy (Ohanyan et al., 2018). Identifying microvascular dysfunction both as the cause and the maintenance mechanism of this condition has opened the field to explore specific pharmacological targets like nitric oxide (NO) pathway, sarcomeric titin, transforming growth factor beta (TGF-β) pathway, immunomodulators or adenosine receptors, trying to tackle the endothelial impairment that lies in the background of this syndrome (Graziani et al., 2018;Lam et al., 2018). Yet, many questions remain, and the new data collected still lack a translation to improved treatment strategies. To further elaborate on this tangled and exponentially growing topic, we will review the evidence favoring a microvasculature-driven etiology of this condition, its clinical correlations, the proposed diagnostic workup, and the available/hypothesized therapeutic options to address microvascular dysfunction in the failing heart.

Left ventricular systolic dysfunction potentially contributes to the symptoms in heart failure with preserved ejection fraction

AIMS

Left ventricular diastolic dysfunction (LVDD) is considered a key factor associated with heart failure (HF) symptoms in patients with preserved ejection fraction (HFpEF). However, LV systolic performance, including LV systolic function and synchrony, has not been well characterized in these patients. The aims of this study were to assess to investigate the underlying relationship and differences between subclinical LVDD and HFpEF.

METHODS

Eighty-six patients with LVDD were recruited (58 with HFpEF and 28 with subclinical LVDD). Systolic left ventricular (LV) longitudinal strain (LS), systolic longitudinal strain rate (LSrS), early diastolic longitudinal strain rate (LSrE), and late diastolic longitudinal strain rate (LSrA) were measured using speckle tracking echocardiography. LV diastolic and systolic dyssynchrony (Te-SD and Ts-SD) were calculated. Forty age- and sex-matched healthy individuals were enrolled as a control group.

RESULTS

LV global LS and LSrS were decreased in patients with HFpEF than in normal controls and subclinical LVDD patients (P < .05). Te-SD and Ts-SD were significantly more prolonged in subclinical LVDD and HFpEF patients than in the control group (P < .05). Reduced LS was associated with HF symptoms in LVDD patients, and a cutoff value of -18% for LS could differentiate HFpEF from subclinical LVDD with 73% sensitivity and 69% specificity.

CONCLUSION

LV systolic function and mechanical dyssynchrony were impaired in HFpEF patients. Deteriorated LV longitudinal systolic function was likely correlated with the symptoms of HFpEF.

Diastology for the clinician

Diastolic filling of the heart is a complex sequence of multiple inter-related events consisting of processes such as ventricular relaxation, erectile coronary effect, visco-elastic forces of the myocardium, ventricular interaction, myocardial stress strain relationships, pericardial restraint, passive filling, and atrial contraction. However, in order to understand diastolic filling from a clinical aspect, a simplified foundation can be used which divides the cardiac cycle into contraction, relaxation, passive filling, and filling at atrial contraction. The mitral flow velocity curves are representative of the relative driving pressure between left atrium and left ventricle and allow one to grade the progression of diastolic dysfunction which occurs in disease states. Doppler tissue imaging is necessary as a surrogate of ventricular relaxation to further determine the stages of diastolic dysfunction in patients with preserved ejection fraction. These Doppler flow velocity curves can be applied to understanding diastolic filling of the heart in patients with both reduced ejection fraction and preserved ejection fraction.

ALDH2 rs671 polymorphism and the risk of heart failure with preserved ejection fraction (HFpEF) in patients with cardiovascular diseases

Aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism is an established genetic risk of hypertension, diabetes, and coronary heart diseases in Asian population. Previous experimental data showed ALDH2 regulated inflammation, a potential mechanism of heart failure with preserved ejection fraction (HFpEF). However, clinically, the association between ALDH2 polymorphism and incidence of HFpEF remains unknown. In this prospective cross-sectional study, ALDH2 genotyping was performed in 613 consecutive patients enrolled with cardiovascular diseases (CVDs), including hypertension, coronary heart diseases, and/or diabetes mellitus, with normal left ventricular ejection fraction (LVEF). HFpEF was diagnosed according to symptoms and/or signs of dyspnea, fatigue or ankle swelling, N-terminal pro-B-Type natriuretic peptide (NT pro-BNP ≥ 280 pg/mL), LVEF ≥ 50%, and at least one additional criterion: left atrial enlargement (left atrial diameter > 40 mm), diastolic dysfunction (E/E' ≥ 13 or E'/A' < 1) or concurrently with atrial fibrillation. Finally, of 613 patients with CVD, 379 patients (61.8%) were assigned to the wild-type ALDH2*1/*1 group and 234 patients (38.2%) to the mutation-type ALDH2*2 group according to genotyping results. Sixty-nine patients (11.3%) were diagnosed with HFpEF. In ALDH2*2 group, the occurrence of HFpEF was higher (15.4% vs. 8.7%, p = 0.011) than that in ALDH2*1/*1 group. Leukocyte count, the indicator of systemic inflammation, was significantly higher (6.9 ± 2.4 × 10⁹/L vs. 6.5 ± 1.9 × 10⁹/L, p = 0.010) in ALDH2*2 group compared to ALDH2*1/*1 group. In conclusion, ALDH2*2 variant is associated with the risk of HFpEF in patients with CVD. Increased systemic inflammation probably involved in this disease process.