Sex differences on peak oxygen uptake in heart failure

Impact of cardiac structure and function on exercise intolerance in Chagas cardiomyopathy: Insights from CPET and echocardiography

INTRODUCTION

Chronic Chagas cardiomyopathy (CCC), the most severe clinical condition of Chagas disease, often leads to a reduction in functional capacity and the appearance of symptoms such as fatigue and dyspnea on exertion. However, its determinant factors remain unclear. We aimed to evaluate the peak oxygen consumption (VO2peak) in patients with CCC and identify its determining factors.

METHODS

An observational study with 97 CCC patients was conducted. Patients underwent clinical examination, cardiopulmonary exercise test (CPET), and echocardiography as part of the standard clinical evaluation. Multivariate linear regression was used to identify independent clinical and echocardiographic predictors of VO2peak and percentage of predicted VO2.

RESULTS

Mean age of study patients was 55.9 ± 13.4 years, median left ventricle ejection fraction (LVEF) was 40 (26-61.5) % and median VO2peak was 16.1 (12.1-20.8) ml/Kg/min. 36 patients presented preserved LVEF and 61 presented reduced LVEF. There were significant differences in almost all CPET variables (p < 0.05) between these two groups. VO2peak was associated with age, male sex, NYHA functional class, LVEF, left atrium diameter, LV diastolic diameter, E wave, LV mass index, and pulmonary artery systolic pressure (PASP). Age, male sex, LVEF, and E wave remained independently associated with VO2peak in the multivariate analysis (R2 = 0.69), furthermore, only LVEF and E wave were associated with the predicted VO2 percentage (R2 = 0.53).

CONCLUSION

In patients with CCC, disease severity, male sex, LV systolic and diastolic function influence the functional capacity.

Screening of key genes related to M6A methylation in patients with heart failure

OBJECTIVE

This study aims to identify m6A methylation-related and immune cell-related key genes with diagnostic potential for heart failure (HF) by leveraging various bioinformatics techniques.

METHODS

The GSE116250 and GSE141910 datasets were sourced from the Gene Expression Omnibus (GEO) database. Correlation analysis was conducted between differentially expressed genes (DEGs) in HF and control groups, alongside differential m6A regulatory factors, to identify m6A-related DEGs (m6A-DEGs). Subsequently, candidate genes were narrowed down by intersecting key module genes derived from weighted gene co-expression network analysis (WGCNA) with m6A-DEGs. Key genes were then identified through the Least Absolute Shrinkage and Selection Operator (LASSO) analysis. Correlation analyses between key genes and differentially expressed immune cells were performed, followed by the validation of key gene expression levels in public datasets. To ensure clinical applicability, five pairs of blood samples were collected for quantitative real-time fluorescence PCR (qRT-PCR) validation.

RESULTS

A total of 93 m6A-DEGs were identified (|COR| > 0.6, P < 0.05), and five key genes (LACTB2, NAMPT, SCAMP5, HBA1, and PRKAR2A) were selected for further analysis. Correlation analysis revealed that differential immune cells were negatively associated with the expression of LACTB2, NAMPT, and PRKAR2A (P < 0.05), while positively correlated with SCAMP5 and HBA1 (P < 0.05). Subsequent expression validation confirmed significant differences in key gene expression between the HF and control groups, with consistent expression trends observed across both training and validation sets. The expression trends of LACTB2, PRKAR2A, and HBA1 in blood samples from the qRT-PCR assay aligned with the results derived from public databases.

CONCLUSION

This study successfully identified five m6A methylation-related key genes with diagnostic significance, providing a theoretical foundation for further exploration of m6A methylation's molecular mechanisms in HF.

Cardiopulmonary Exercise Testing in Patients with Heart Failure: Impact of Gender in Predictive Value for Heart Transplantation Listing

BACKGROUND

Exercise testing is key in the risk stratification of patients with heart failure (HF). There are scarce data on its prognostic power in women. Our aim was to assess the predictive value of the heart transplantation (HTx) thresholds in HF in women and in men.

METHODS

Prospective evaluation of HF patients who underwent cardiopulmonary exercise testing (CPET) from 2009 to 2018 for the composite endpoint of cardiovascular mortality and urgent HTx.

RESULTS

A total of 458 patients underwent CPET, with a composite endpoint frequency of 10.5% in females vs. 16.0% in males in 36-month follow-up. Peak VO2 (pVO2), VE/VCO2 slope and percent of predicted pVO2 were independent discriminators of the composite endpoint, particularly in women. The International Society for Heart Lung Transplantation recommended values of pVO2 ≤ 12 mL/kg/min or ≤14 if the patient is intolerant to β-blockers, VE/VCO2 slope > 35, and percent of predicted pVO2 ≤ 50% showed a higher diagnostic effectiveness in women. Specific pVO2, VE/VCO2 slope and percent of predicted pVO2 cut-offs in each sex group presented a higher prognostic power than the recommended thresholds.

CONCLUSION

Individualized sex-specific thresholds may improve patient selection for HTx. More evidence is needed to address sex differences in HF risk stratification.

Age Differences in Cardiopulmonary Exercise Testing Parameters in Heart Failure with Reduced Ejection Fraction

Background and Objectives: Cardiopulmonary exercise testing (CPET) is a cornerstone of risk stratification in heart failure with reduced ejection fraction (HFrEF). However, there is a paucity of evidence on its predictive power in older patients. The aim of this study was to evaluate the prognostic power of current heart transplantation (HTx) listing criteria in HFrEF stratified according to age groups. Materials and Methods: Consecutive patients with HFrEF undergoing CPET between 2009 and 2018 were followed-up for cardiac death and urgent HTx. Results: CPET was performed in 458 patients with HFrEF. The composite endpoint occurred in 16.8% of patients ≤50 years vs. 14.1% of patients ≥50 years in a 36-month follow-up. Peak VO2 (pVO2), VE/VCO2 slope and percentage of predicted pVO2 were strong independent predictors of outcomes. The International Society for Heart and Lung Transplantation thresholds of pVO2 ≤ 12 mL/kg/min (≤14 if intolerant to β-blockers), VE/VCO2 slope > 35 and percentage of predicted pVO2 ≤ 50% presented a higher overall diagnostic effectiveness in younger patients (≤50 years). Specific thresholds for each age subgroup outperformed the traditional cut-offs. Conclusions: Personalized age-specific thresholds may contribute to an accurate risk stratification in HFrEF. Further studies are needed to address the gap in evidence between younger and older patients.

Sex-Related Differences in Mortality Following Admission for Acute Heart Failure Across the Left Ventricular Ejection Fraction Spectrum

Background

Following a heart failure (HF)‐decompensation, there is scarce data about sex‐related prognostic differences across left ventricular ejection fraction (LVEF) status. We sought to evaluate sex‐related differences in 6‐month mortality risk across LVEF following admission for acute HF.

Methods and Results

We retrospectively evaluated 4812 patients consecutively admitted for acute HF in a multicenter registry from 3 hospitals. Study end points were all‐cause, cardiovascular, and HF‐related mortality at 6‐month follow‐up. Multivariable Cox regression models were fitted to investigate sex‐related differences across LVEF. A total of 2243 (46.6%) patients were women, 2569 (53.4%) were men, and 2608 (54.2%) showed LVEF≥50%. At 6‐month follow‐up, 645 patients died (13.4%), being 544 (11.3%) and 416 (8.6%) cardiovascular and HF‐related deaths, respectively. LVEF was not independently associated with mortality (HR, 1.02; 95% CI 0.99–1.05; P=0.135). After multivariable adjustment, we found no sex‐related differences in all‐cause mortality (P value for interaction=0.168). However, a significant interaction between sex and cardiovascular and HF mortality risks was found across LVEF (P value for interaction=0.030 and 0.007, respectively). Compared with men, women had a significantly lower risk of cardiovascular and HF‐mortality at LVEF<25% and <43%, respectively. On the contrary, women showed a higher risk of HF‐mortality at the upper extreme of LVEF (>80%).

Conclusions

Following an admission for acute HF, no sex‐related differences were found in all‐cause mortality risk. However, when compared with men, women showed a lower risk of cardiovascular and HF‐mortality at the lower extreme of LVEF. On the contrary, they showed a higher risk of HF death at the upper extreme.

Determinants of Functional Capacity in Patients with Chagas Disease

BACKGROUND

Chagas disease leads to reduced functional capacity. However, the stage at which functional impairment is detectable remains unclear.

OBJECTIVES

The present study was addressed to compare the functional capacity of patients at different stages of Chagas disease and healthy individuals and to verify the determinants of peak oxygen uptake (VO2peak).

METHODS

In a cross-sectional study, 160 individuals were selected, 35 healthy and 125 with Chagas disease. In the Chagasic group, 61 (49%) were in the indeterminate form of the disease, 45 (36%) with Chagas cardiomyopathy (ChC) and preserved cardiac function and 19 (15%) with cardiac dysfunction and dilated ChC. The data were analyzed using univariate and multivariate regression analysis. Statistical significance was set at 5%.

RESULTS

Patients in the indeterminate form of disease showed similar functional capacity to healthy individuals (p>0.05). Patients with ChC and preserved cardiac function had lower VO2peak than patients in the indeterminate form (p<0.05), but showed similar VO2peak values than dilated ChC (p=0.46). The age, male sex, NYHA functional class, diastolic blood pressure, ratio of the early diastolic transmitral flow velocity to early diastolic mitral annular velocity, left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter were associated with functional capacity. However, only age, male sex, LVEF and NYHA functional class, remained associated with VO2peak in the final model (adjusted R2=0.60).

CONCLUSION

Patients with ChC had lower functional capacity than patients in the indeterminate form. LVEF, age, male sex and NYHA functional class were determinants with VO2peak in patients with Chagas disease.

Heart failure in the last year: progress and perspective

Research about heart failure (HF) has made major progress in the last years. We give here an update on the most recent findings. Landmark trials have established new treatments for HF with reduced ejection fraction. Sacubitril/valsartan was superior to enalapril in PARADIGM-HF trial, and its initiation during hospitalization for acute HF or early after discharge can now be considered. More recently, new therapeutic pathways have been developed. In the DAPA-HF and EMPEROR-Reduced trials, dapagliflozin and empagliflozin reduced the risk of the primary composite endpoint, compared with placebo [hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.65-0.85; P < 0.001 and HR 0.75; 95% CI 0.65-0.86; P < 0.001, respectively]. Second, vericiguat, an oral soluble guanylate cyclase stimulator, reduced the composite endpoint of cardiovascular death or HF hospitalization vs. placebo (HR 0.90; 95% CI 0.82-0.98; P = 0.02). On the other hand, both the diagnosis and treatment of HF with preserved ejection fraction, as well as management of advanced HF and acute HF, remain challenging. A better phenotyping of patients with HF would be helpful for prognostic stratification and treatment selection. Further aspects, such as the use of devices, treatment of arrhythmias, and percutaneous treatment of valvular heart disease in patients with HF, are also discussed and reviewed in this article.

Sex differences on peak oxygen uptake in heart failure

Women represent nearly half of the adult heart failure (HF) population and they remain underrepresented in HF studies. We aimed to evaluate the evidence about peak oxygen uptake (peak VO₂) for clinical stratification in women with HF. This narrative review summarizes (i) the evidence endorsing the value of cardiopulmonary exercise testing for clinical stratification and phenotyping HF population; (ii) the determinants of a person's functional aerobic capacity to understand predicted values for patients with chronic HF; and (iii) sex differences on peak VO₂ data in different forms of HF. Lastly, based on existing data in patients with HF, we provide a perspective on how to improve existing gaps about the utility of peak VO₂ in clinical stratification in women. Peak VO₂ provides prognosis information in patients with HF; however, its use has been limited for a reduced number of patients excluding women, elderly, and HF patients with preserved ejection fraction. Further studies will help to fill the wide gender gap about the utility of cardiopulmonary exercise testing in the risk assessment and management in women with HF.