Current Understanding of Molecular Pathophysiology of Heart Failure With Preserved Ejection Fraction

High-sensitivity C-reactive protein in heart failure with preserved ejection fraction: Findings from TOPCAT

BACKGROUND

Inflammation plays a central role in the genesis and progression of heart failure with preserved ejection fraction (HFpEF). C-reactive protein (CRP) is widely used as means to assess systemic inflammation, and elevated levels of CRP have been associated with poor HF prognosis. Identification of chronic low-grade inflammation in outpatients can be performed measuring high-sensitivity CRP (hsCRP). The clinical characteristics and outcome associations of a pro-inflammatory state among outpatients with HFpEF requires further study.

AIMS

Using a biomarker subset of TOPCAT-Americas (NCT00094302), we aim to characterize HFpEF patients according to hsCRP levels and study the prognostic associations of hsCRP.

METHODS

hsCRP was available in a subset of 232 participants. Comparisons were performed between patients with hsCRP <2 mg/L and ≥ 2 mg/L. Cox regression models were used to study the association between hsCRP and the study outcomes.

RESULTS

Compared to patients with hsCRP <2 mg/L (n = 89, 38%), those with hsCRP ≥2 mg/L (n = 143, 62%) had more frequent HF hospitalizations prior to randomization, chronic obstructive pulmonary disease, orthopnea, higher body mass index, and worse health-related quality-of-life. A hsCRP level ≥ 2 mg/L was associated with an increased risk of cardiovascular death and HF hospitalizations: hsCRP ≥2 mg/L vs <2 mg/L adjusted HR 2.36, 95%CI 1.27-4.38, P = 0.006. Spironolactone did not influence hsCRP levels from baseline to month 12: gMean ratio = 1.11, 95%CI 0.87-1.42, P = 0.39.

CONCLUSIONS

A hsCRP ≥2 mg/L identified HFpEF patients with a high risk of HF events and cardiovascular mortality. Spironolactone did not influence hsCRP levels at 12 months.

Current Insights and Future Directions in the Treatment of Heart Failure with Preserved Ejection Fraction

Heart failure is a clinical syndrome associated with poor quality of life, substantial healthcare resource utilization, and premature mortality, in large part related to high rates of hospitalizations. The clinical manifestations of heart failure are similar regardless of the ejection fraction. Unlike heart failure with reduced ejection fraction, there are few therapeutic options for treating heart failure with preserved ejection fraction. Molecular therapies that have shown reduced mortality and morbidity in heart failure with reduced ejection have not been proven to be effective for patients with heart failure and preserved ejection fraction. The study of pathophysiological processes involved in the production of heart failure with preserved ejection fraction is the basis for identifying new therapeutic means. In this narrative review, we intend to synthesize the existing therapeutic means, but also those under research (metabolic and microRNA therapy) for the treatment of heart failure with preserved ejection fraction.

Locomotor and respiratory muscle abnormalities in HFrEF and HFpEF

Heart failure (HF) is a chronic and progressive syndrome affecting worldwide billions of patients. Exercise intolerance and early fatigue are hallmarks of HF patients either with a reduced (HFrEF) or a preserved (HFpEF) ejection fraction. Alterations of the skeletal muscle contribute to exercise intolerance in HF. This review will provide a contemporary summary of the clinical and molecular alterations currently known to occur in the skeletal muscles of both HFrEF and HFpEF, and thereby differentiate the effects on locomotor and respiratory muscles, in particular the diaphragm. Moreover, current and future therapeutic options to address skeletal muscle weakness will be discussed focusing mainly on the effects of exercise training.

Artificial intelligence and heart failure: A state-of-the-art review

Heart failure (HF) is a heterogeneous syndrome affecting more than 60 million individuals globally. Despite recent advancements in understanding of the pathophysiology of HF, many issues remain including residual risk despite therapy, understanding the pathophysiology and phenotypes of patients with HF and preserved ejection fraction, and the challenges related to integrating a large amount of disparate information available for risk stratification and management of these patients. Risk prediction algorithms based on artificial intelligence (AI) may have superior predictive ability compared to traditional methods in certain instances. AI algorithms can play a pivotal role in the evolution of HF care by facilitating clinical decision making to overcome various challenges such as allocation of treatment to patients who are at highest risk or are more likely to benefit from therapies, prediction of adverse outcomes, and early identification of patients with subclinical disease or worsening HF. With the ability to integrate and synthesize large amounts of data with multidimensional interactions, AI algorithms can supply information with which physicians can improve their ability to make timely and better decisions. In this review, we provide an overview of the AI algorithms that have been developed for establishing early diagnosis of HF, phenotyping HF with preserved ejection fraction, and stratifying HF disease severity. This review also discusses the challenges in clinical deployment of AI algorithms in HF, and the potential path forward for developing future novel learning-based algorithms to improve HF care.

Combining three independent pathological stressors induces a heart failure with preserved ejection fraction phenotype

Heart failure (HF) with preserved ejection fraction (HFpEF) is defined as HF with an ejection fraction (EF) ≥ 50% and elevated cardiac diastolic filling pressures. The underlying causes of HFpEF are multifactorial and not well-defined. A transgenic mouse with low levels of cardiomyocyte (CM)-specific inducible Cavβ2a expression (β2a-Tg mice) showed increased cytosolic CM Ca2+, and modest levels of CM hypertrophy, and fibrosis. This study aimed to determine if β2a-Tg mice develop an HFpEF phenotype when challenged with two additional stressors, high-fat diet (HFD) and Nω-nitro-l-arginine methyl ester (l-NAME, LN). Four-month-old wild-type (WT) and β2a-Tg mice were given either normal chow (WT-N, β2a-N) or HFD and/or l-NAME (WT-HFD, WT-LN, WT-HFD-LN, β2a-HFD, β2a-LN, and β2a-HFD-LN). Some animals were treated with the histone deacetylase (HDAC) (hypertrophy regulators) inhibitor suberoylanilide hydroxamic acid (SAHA) (β2a-HFD-LN-SAHA). Echocardiography was performed monthly. After 4 mo of treatment, terminal studies were performed including invasive hemodynamics and organs weight measurements. Cardiac tissue was collected. Four months of HFD plus l-NAME treatment did not induce a profound HFpEF phenotype in FVB WT mice. β2a-HFD-LN (3-Hit) mice developed features of HFpEF, including increased atrial natriuretic peptide (ANP) levels, preserved EF, diastolic dysfunction, robust CM hypertrophy, increased M2-macrophage population, and myocardial fibrosis. SAHA reduced the HFpEF phenotype in the 3-Hit mouse model, by attenuating these effects. The 3-Hit mouse model induced a reliable HFpEF phenotype with CM hypertrophy, cardiac fibrosis, and increased M2-macrophage population. This model could be used for identifying and preclinical testing of novel therapeutic strategies.NEW & NOTEWORTHY Our study shows that three independent pathological stressors (increased Ca2+ influx, high-fat diet, and l-NAME) together produce a profound HFpEF phenotype. The primary mechanisms include HDAC-dependent-CM hypertrophy, necrosis, increased M2-macrophage population, fibroblast activation, and myocardial fibrosis. A role for HDAC activation in the HFpEF phenotype was shown in studies with SAHA treatment, which prevented the severe HFpEF phenotype. This "3-Hit" mouse model could be helpful in identifying novel therapeutic strategies to treat HFpEF.

Effects of treatment of non-alcoholic fatty liver disease on heart failure with preserved ejection fraction

In the past few decades, non-alcoholic fatty liver disease (NAFLD) and heart failure with preserved ejection fraction (HFpEF) have become the most common chronic liver disease and the main form of heart failure (HF), respectively. NAFLD is closely associated with HFpEF by sharing common risk factors and/or by boosting systemic inflammation, releasing other secretory factors, and having an expansion of epicardial adipose tissue (EAT). Therefore, the treatments of NAFLD may also affect the development and prognosis of HFpEF. However, no specific drugs for NAFLD have been approved by the Food and Drug Administration (FDA) and some non-specific treatments for NAFLD are applied in the clinic. Currently, the treatments of NAFLD can be divided into non-pharmacological and pharmacological treatments. Non-pharmacological treatments mainly include dietary intervention, weight loss by exercise, caloric restriction, and bariatric surgery. Pharmacological treatments mainly include administering statins, thiazolidinediones, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, and metformin. This review will mainly focus on analyzing how these treatments may affect the development and prognosis of HFpEF.

Vascular compliance and left ventricular compliance cross talk: Implications for using long-term heat acclimation in cardiac care

1) The first evidence of the beneficial impact of Long-Term-Heat-Acclimation (LTHA) on cardio-vascular compliance was the positive inotropic response and improved left ventricular (LV) compliance noted when isolated hearts from LTHA rats were studied. Human echo study demonstrates that passive HA affects the right ventricle and the atria as well. 2) There is a cross-talk between vascular and cardiac compliance. Vascular compliance per se is defined by central venous pressure-Blood volume relationship-Global Vascular Compliance (GVC). It is determined by the sum of the vascular compliance of the vessels in every organ in any physiological state, varies with LTHA and thus influences cardiac performance. LTHA improves endothelial function, increases NO (nitric oxide) production, in-turn stimulating alterations in ECM (extracellular matrix) via the TGF β1-SMAD pathway. 3) LTHA is associated with transformation from fast to slow myosin, heat acclimation ischemic/hypoxic cross-tolerance and alterations in the extracellular matrix. 4) A human translational study demonstrated improved LV compliance following bypass surgery in LTHA subjects compared to controls. 5) Diastolic dysfunction and the impact of comorbidities with vascular and non- vascular origins are major contributors to the syndrome of heart failure with preserved ejection function (HFPEF). Unfortunately, there is a paucity of treatment modalities that improve diastolic dysfunction. 6) In the current mini-review we suggest that LTHA may be beneficial to HFPEF patients by remodeling cardiac compliance and vascular response.

Heart Failure in Menopause: Treatment and New Approaches

Aging is an important risk factor for the development of heart failure (HF) and half of patients with HF have preserved ejection fraction (HFpEF) which is more common in elderly women. In general, sex differences that lead to discrepancies in risk factors and to the development of cardiovascular disease (CVD) have been attributed to the reduced level of circulating estrogen during menopause. Estrogen receptors adaptively modulate fibrotic, apoptotic, inflammatory processes and calcium homeostasis, factors that are directly involved in the HFpEF. Therefore, during menopause, estrogen depletion reduces the cardioprotection. Preclinical menopause models demonstrated that several signaling pathways and organ systems are closely involved in the development of HFpEF, including dysregulation of the renin-angiotensin system (RAS), chronic inflammatory process and alteration in the sympathetic nervous system. Thus, this review explores thealterations observed in the condition of HFpEF induced by menopause and the therapeutic targets with potential to interfere with the disease progress.