Current gaps in HFpEF trials: Time to reconsider patients' selection and to target phenotypes

Risk Factors and Cellular Differences in Heart Failure: The Key Role of Sex Hormones

Patients with heart failure are conventionally stratified into phenotypic groups based on their ejection fraction. The aim of this stratification is to improve disease management with a more targeted therapeutic approach. A further subdivision based on patient gender is justified. It is recognized that women are underrepresented in randomized controlled clinical trials, resulting in limited clinical and molecular differentiation between males and females. However, many observational studies show that the onset, development, and clinical course of the disease may substantially differ between the two sexes. According to the emerging concept of precision medicine, investigators should further explore the mechanisms responsible for the onset of heart failure due to sex differences. Indeed, the synergistic or opposing effects of sex hormones on the cardiovascular system and underlying heart failure mechanisms have not yet been clarified. Sex hormones, risk factors impact, and cardiovascular adaptations may be relevant for a better understanding of the intrinsic pathophysiological mechanisms in the two sexes. Despite the differences, treatment for HF is similar across the whole population, regardless of sex and gender. In our review, we describe the main differences in terms of cardiovascular dysfunction, risk factors, and cellular signaling modifications related to the hormonal pattern.

Myocardial RNA Sequencing Reveals New Potential Therapeutic Targets in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) represents a global health challenge, with limited therapies proven to enhance patient outcomes. This makes the elucidation of disease mechanisms and the identification of novel potential therapeutic targets a priority. Here, we performed RNA sequencing on ventricular myocardial biopsies from patients with HFpEF, prospecting to discover distinctive transcriptomic signatures. A total of 306 differentially expressed mRNAs (DEG) and 152 differentially expressed microRNAs (DEM) were identified and enriched in several biological processes involved in HF. Moreover, by integrating mRNA and microRNA expression data, we identified five potentially novel miRNA-mRNA relationships in HFpEF: the upregulated hsa-miR-25-3p, hsa-miR-26a-5p, and has-miR4429, targeting HAPLN1; and NPPB mRNA, targeted by hsa-miR-26a-5p and miR-140-3p. Exploring the predicted miRNA-mRNA interactions experimentally, we demonstrated that overexpression of the distinct miRNAs leads to the downregulation of their target genes. Interestingly, we also observed that microRNA signatures display a higher discriminative power to distinguish HFpEF sub-groups over mRNA signatures. Our results offer new mechanistic clues, which can potentially translate into new HFpEF therapies.

Does the Measurement of Ejection Fraction Still Make Sense in the HFpEF Framework? What Recent Trials Suggest

Left ventricular ejection fraction (LVEF) is universally accepted as a cardiac systolic function index and it provides intuitive interpretation of cardiac performance. Over the last two decades, it has erroneously become the leading feature used by clinicians to characterize the left ventricular function in heart failure (HF). Notably, LVEF sets the basis for structural and functional HF phenotype classification in current guidelines. However, its diagnostic and prognostic role in patients with preserved or mildly reduced contractile function is less clear. This is related to several concerns due to intrinsic technical, methodological and hemodynamic limitations entailed in LVEF measurement that do not describe the chamber's real contractile performance as expressed by pressure volume loop relationship. In patients with HF and preserved ejection fraction (HFpEF), it does not reflect the effective systolic function because it is prone to preload and afterload variability and it does not account for both longitudinal and torsional contraction. Moreover, a repetitive measurement could be assessed over time to better identify HF progression related to natural evolution of disease and to the treatment response. Current gaps may partially explain the causes of negative or neutral effects of traditional medical agents observed in HFpEF. Nevertheless, recent pooled analysis has evidenced the positive effects of new therapies across the LVEF range, suggesting a potential role irrespective of functional status. Additionally, a more detailed analysis of randomized trials suggests that patients with higher LVEF show a risk reduction strictly related to overall cardiovascular (CV) events; on the other hand, patients experiencing lower LVEF values have a decrease in HF-related events. The current paper reports the main limitations and shortcomings in LVEF assessment, with specific focus on patients affected by HFpEF, and it suggests alternative measurements better reflecting the real hemodynamic status. Future investigations may elucidate whether the development of non-invasive stroke volume and longitudinal function measurements could be extensively applied in clinical trials for better phenotyping and screening of HFpEF patients.

Laboratory and Metabolomic Fingerprint in Heart Failure with Preserved Ejection Fraction: From Clinical Classification to Biomarker Signature

Heart failure with preserved ejection fraction (HFpEF) remains a poorly characterized syndrome with many unknown aspects related to different patient profiles, various associated risk factors and a wide range of aetiologies. It comprises several pathophysiological pathways, such as endothelial dysfunction, myocardial fibrosis, extracellular matrix deposition and intense inflammatory system activation. Until now, HFpEF has only been described with regard to clinical features and its most commonly associated risk factors, disregarding all biological mechanisms responsible for cardiovascular deteriorations. Recently, innovations in laboratory and metabolomic findings have shown that HFpEF appears to be strictly related to specific cells and molecular mechanisms' dysregulation. Indeed, some biomarkers are efficient in early identification of these processes, adding new insights into diagnosis and risk stratification. Moreover, recent advances in intermediate metabolites provide relevant information on intrinsic cellular and energetic substrate alterations. Therefore, a systematic combination of clinical imaging and laboratory findings may lead to a 'precision medicine' approach providing prognostic and therapeutic advantages. The current review reports traditional and emerging biomarkers in HFpEF and it purposes a new diagnostic approach based on integrative information achieved from risk factor burden, hemodynamic dysfunction and biomarkers' signature partnership.

Management of heart failure with preserved ejection fraction: from neurohormonal antagonists to empagliflozin

Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with multifaceted pathophysiology. All approaches to neurohormonal modulation were shown not to improve survival in HFpEF, despite their well-established efficacy in heart failure with reduced ejection fraction (HFrEF). This might be attributed to suboptimal study design, inadequate diagnostic criteria, or statistical power, but is also likely to reflect a lack of consideration for its clinical heterogeneity. The attention then shifted to the phenotypic heterogeneity of HFpEF, with the ultimate goal of developing therapies tailored to individual patient phenotypes. Recently, the sodium-glucose co-transporter-2 inhibitor (SGLT2i) empagliflozin has been found to reduce the combined risk of cardiovascular death or hospitalization for HF in patients with HFpEF, a result driven by a reduction in HF hospitalizations. This paper recapitulates the journey from the failure of trials on neurohormonal antagonists to the attempts of personalized approaches and the new perspectives of SGLT2i therapy for HFpEF.

The Conundrum of HFpEF Definition: Non-Invasive Assessment Uncertainties and Alternative Diagnostic Strategies

Heart failure (HF) with preserved ejection fraction (HFpEF) is a heterogeneous syndrome including several morphological phenotypes and varying pathophysiological mechanisms. The conventional classification of HF based on left ventricular ejection fraction (LVEF) has created an oversimplification in diagnostic criteria. Although LVEF is a standardized parameter easy to calculate and broadly applied in the large clinical trials, but it is erroneously considered an index of left ventricular (LV) systolic function. Indeed,  it is affected by preload and afterload and it has limitations related to reproducibility, reduced sensitivity and scarce prognostic values especially when above 50%. Notably, additional diagnostic parameters have been recently proposed in order to improve diagnostic accuracy and to homogenise the different HFpEF populations. Unfortunately, these algorithms comprise sophisticated measurements that are difficult to apply in the daily clinical practice. Additionally, the scarce diffusion of these diagnostic criteria may have led to neutral or negative results in interventional phase 3 trials . We propose changes to the current HFpEF diagnostic approach mainly based on LVEF stratification measurement aiming towards a more inclusive model taking into consideration an integrative approach starting from the main diseases responsible for cardiac dysfunction  through to cardiac structural and functional alterations. Accordingly, with recent universal HF definitions, a stepwise model could be helpful in recognizing patients with early vs. overt HFpEF by the appraisal of specific Doppler echocardiographic variables. Thus, we would encourage the application of new criteria in order to better identify the different phenotypes and to move towards more personalized medicine.

Heart failure during the COVID-19 pandemic: clinical, diagnostic, management, and organizational dilemmas

The coronavirus 2019 (COVID-19) infection pandemic has affected the care of patients with heart failure (HF). Several consensus documents describe the appropriate diagnostic algorithm and treatment approach for patients with HF and associated COVID-19 infection. However, few questions about the mechanisms by which COVID can exacerbate HF in patients with high-risk (Stage B) or symptomatic HF (Stage C) remain unanswered. Therefore, the type of HF occurring during infection is poorly investigated. The diagnostic differentiation and management should be focused on the identification of the HF phenotype, underlying causes, and subsequent tailored therapy. In this framework, the relationship existing between COVID and onset of acute decompensated HF, isolated right HF, and cardiogenic shock is questioned, and the specific management is mainly based on local hospital organization rather than a standardized model. Similarly, some specific populations such as advanced HF, heart transplant, patients with left ventricular assist device (LVAD), or valve disease remain under investigated. In this systematic review, we examine recent advances regarding the relationships between HF and COVID-19 pandemic with respect to epidemiology, pathogenetic mechanisms, and differential diagnosis. Also, according to the recent HF guidelines definition, we highlight different clinical profile identification, pointing out the main concerns in understudied HF populations.

Prognostic Impact of the HFA-PEFF Score in Patients with Acute Myocardial Infarction and an Intermediate to High HFA-PEFF Score

This study aimed to investigate the efficacy of the HFA-PEFF score in predicting the long-term risks in patients with acute myocardial infarction (AMI) and an HFA-PEFF score ≥ 2. The subjects were divided according to their HFA-PEFF score into intermediate (2−3 points) and high (4−6 points) score groups. The primary outcome was all-cause mortality. Of 1018 patients with AMI and an HFA-PEFF score of ≥2, 712 (69.9%) and 306 (30.1%) were classified into the intermediate and high score groups, respectively. Over a median follow-up of 4.8 (3.2, 6.5) years, 114 (16.0%) and 87 (28.4%) patients died in each group. Multivariate Cox regression identified a high HFA-PEFF score as an independent predictor of all-cause mortality [hazard ratio (HR): 1.53, 95% CI: 1.15−2.04, p = 0.004]. The predictive accuracies for the discrimination and reclassification were significantly improved (C-index 0.750 [95% CI 0.712−0.789]; p = 0.049 and NRI 0.330 [95% CI 0.180−0.479]; p < 0.001) upon the addition of a high HFA-PEFF score to clinical risk factors. The model was better at predicting combined events of all-cause mortality and heart failure readmission (C-index 0.754 [95% CI 0.716−0.791]; p = 0.033, NRI 0.372 [95% CI 0.227−0.518]; p < 0.001). In the AMI cohort, the HFA-PEFF score can effectively predict the prognosis of patients with an HFA-PEFF score of ≥2.

Mitochondrial bioenergetics and D-ribose in HFpEF: a brief narrative review

Objective

In this review article, we briefly describe the status of treatment options for HFpEF and the role of mitochondrial dysfunction in the pathogenesis of HFpEF as an alternative therapeutic target. We also examine the mechanisms of D-ribose in cellular energy production and discuss the potential disadvantages and benefits of supplemental use of D-ribose in patients with HFpEF.

Background

Heart failure is a major cardiovascular disease that impacts over 6 million Americans and is one of the leading causes for morbidity and mortality. Patients with heart failure often experience shortness of breath and fatigue along with impaired physical capacity, all leading to poor quality of life. As a subtype of heart failure, heart failure with preserved ejection fraction (HFpEF) is characterized with impaired diastolic function. Currently, there are no effective treatments specifically for HFpEF, thus clinicians and researchers are searching for therapies to improve cardiac function. Emerging evidence indicate that mitochondrial dysfunction and impaired cardiac bioenergetics are among the underlying mechanisms for HFpEF. There is increased interest in investigating the use of supplements such as D-ribose to enhance mitochondrial function and improve production of adenosine triphosphate (ATP).

Methods

For this narrative review, more than 100 relevant scientific articles were considered from various databases (e.g., PubMed, Web of Science, CINAHL, and Google Scholar) using the keywords “Heart Failure”, “HFpEF”, “D-ribose”, “ATP”, “Mitochondria”, Bioenergetics”, and “Cellular Respiration”.

Conclusions

It is essential to find potential targeted therapeutic treatments for HFpEF. Since there is evidence that the HFpEF is related to impaired myocardial bioenergetics, enhancing mitochondrial function could augment cardiac function. Using a supplement such as D-ribose could improve mitochondrial function by increasing ATP and enhancing cardiac performance for patients with HFpEF. There is a recently completed clinical trial with HFpEF patients that indicates D-ribose increases ATP production and improves cardiac ejection fraction.

Predictive Value of HFA-PEFF Score in Patients With Heart Failure With Preserved Ejection Fraction

Aims: HFA-PEFF score has been proposed for diagnosing heart failure with preserved ejection fraction (HFpEF). Currently, there are only a limited number of tools for predicting the prognosis. In this study, we evaluated whether the HFA-PEFF score can predict mortality in patients with HFpEF.

Methods: This single-center, retrospective observational study enrolled patients diagnosed with HFpEF at the First Affiliated Hospital of Dalian Medical University between January 1, 2015, and April 30, 2018. The subjects were divided according to their HFA-PEFF score into low (0–2 points), intermediate (3–4 points), and high (5–6 points) score groups. The primary outcome was all-cause mortality.

Results: A total of 358 patients (mean age: 70.21 ± 8.64 years, 58.1% female) were included. Of these, 63 (17.6%), 156 (43.6%), and 139 (38.8%) were classified into the low, intermediate, and high score groups, respectively. Over a mean follow-up of 26.9 months, 46 patients (12.8%) died. The percentage of patients who died in the low, intermediate, and high score groups were 1 (1.6%), 18 (11.5%), and 27 (19.4%), respectively. A multivariate Cox regression identified HFA-PEFF score as an independent predictor of all-cause mortality [hazard ratio (HR):1.314, 95% CI: 1.013–1.705, P = 0.039]. A Cox analysis demonstrated a significantly higher rate of mortality in the intermediate (HR: 4.912, 95% CI 1.154–20.907, P = 0.031) and high score groups (HR: 5.291, 95% CI: 1.239–22.593, P = 0.024) than the low score group. A receiver operating characteristic (ROC) analysis indicated that the HFA-PEFF score can effectively predict all-cause mortality after adjusting for age and New York Heart Association (NYHA) class [area under the curve (AUC) 0.726, 95% CI 0.651–0.800, P = 0.000]. With an HFA-PEFF score cut-off value of 3.5, the sensitivity and specificity were 78.3 and 54.8%, respectively. The AUC on ROC analysis for the biomarker component of the score was similar to that of the total score.

Conclusions: The HFA-PEFF score can be used both to diagnose HFpEF and predict the prognosis. The higher scores are associated with higher all-cause mortality.