The conundrum of patients with obesity, exercise intolerance, elevated ventricular filling pressures and a measured ejection fraction in the normal range

Body mass index and cardiorenal outcomes in the EMPEROR-Preserved trial: Principal findings and meta-analysis with the DELIVER trial

AIMS

Both low and high body mass index (BMI) are associated with poor heart failure outcomes. Whether BMI modifies benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in heart failure with preserved ejection fraction (HFpEF) requires further investigation.

METHODS AND RESULTS

Using EMPEROR-Preserved data, the effects of empagliflozin versus placebo on the risks for the primary outcome (hospitalization for heart failure [HHF] or cardiovascular [CV] death), change in estimated glomerular filtration rate (eGFR) slopes, change in Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS), and secondary outcomes across baseline BMI categories (<25 kg/m2, 25 to <30 kg/m2, 30 to <35 kg/m2, 35 to <40 kg/m2 and ≥40 kg/m2) were examined, and a meta-analysis conducted with DELIVER. Forty-five percent had a BMI of ≥30 kg/m2. For the primary outcome, there was a consistent treatment effect of empagliflozin versus placebo across the BMI categories with no formal interaction (p trend = 0.19) by BMI categories. There was also no difference in the effects on secondary outcomes including total HHF (p trend = 0.19), CV death (p trend = 0.20), or eGFR slope with slower declines with empagliflozin regardless of BMI (range 1.12-1.71 ml/min/1.73 m2 relative to placebo, p trend = 0.85 for interaction), though there was no overall impact on the composite renal endpoint. The difference in weight change between empagliflozin and placebo was -0.59, -1.48, -1.54, -0.87, and - 2.67 kg in the lowest to highest BMI categories (p trend = 0.016 for interaction). A meta-analysis of data from EMPEROR-Preserved and DELIVER showed a consistent effect of SGLT2i versus placebo across BMI categories for the outcome of HHF or CV death. There was a trend toward greater absolute KCCQ-CSS benefit at 32 weeks with empagliflozin at higher BMIs (p = 0.08).

CONCLUSIONS

Empagliflozin treatment resulted in broadly consistent cardiac effects across the range of BMI in patients with HFpEF. SGLT2i treatment yields benefit in patients with HFpEF regardless of baseline BMI.

Obesity-Related High-Output Heart Failure: An Integrative Review

BACKGROUND

High-output heart failure (HF) is a type of HF characterized by signs and symptoms of HF and a cardiac output of 8 L/min or greater or a cardiac index greater than 3.9 L/min/m 2 . High-output HF occurs secondary to an underlying condition that requires high cardiac output due to an increase in oxygen consumption or decreased systemic vascular resistance. Obesity is a major cause of high-output HF, yet there is limited research on obesity-related high-output HF. Thus, the pathophysiologic mechanisms of this syndrome are not fully understood.

OBJECTIVE

The objectives of this integrative review were to describe the current state of the research regarding obesity-related high-output HF and to recommend direction for future research.

METHODS

We conducted an integrative review focusing on the peer-reviewed literature on patients with obesity-related high-output HF using Whittemore and Knafl's methodology. MEDLINE, CINAHL, and EMBASE electronic databases were searched for all publications indexed in the databases as of March 9, 2022. A narrative synthesis of definitions and symptoms, obesity as an underlying condition, pathophysiology, and treatments of obesity-related high-output HF was completed.

RESULTS

A total of 6 articles were included in the integrative review, with 1 nonexperimental, retrospective study and 5 literature reviews. Understanding of obesity-related high-output HF is very limited because of scant empirical evidence in the existing literature. Possible pathophysiologic mechanisms include increased pressure in the upper airways, adipokine dysregulation, increased metabolic activity, and insulin resistance.

CONCLUSION

Additional research is needed on the pathophysiologic mechanisms of obesity-related high-output HF to begin investigations on therapeutic interventions to improve health outcomes.

Right ventricular-pulmonary arterial coupling impairment and exercise capacity in obese adults

Background

Obesity-related exercise intolerance may be associated with pulmonary vascular and right ventricular dysfunction. This study tested the hypothesis that decreased pulmonary vascular reserve and right ventricular (RV)-pulmonary arterial (PA) uncoupling contributes to exercise limitation in subjects with obesity.

Methods

Seventeen subjects with obesity were matched to normo-weighted healthy controls. All subjects underwent; exercise echocardiography, lung diffusing capacity (DL) for nitric oxide (NO) and carbon monoxide (CO) and an incremental cardiopulmonary exercise test. Cardiac output (Q), PA pressure (PAP) and tricuspid annular plane systolic excursion (TAPSE) were recorded at increasing exercise intensities. Pulmonary vascular reserve was assessed by multipoint mean PAP (mPAP)/Q relationships with more reserve defined by lesser increase in mPAP at increased Q, and RV-PA coupling was assessed by the TAPSE/systolic PAP (sPAP) ratio.

Results

At rest, subjects with obesity displayed lower TAPSE/sPAP ratios (1.00 ± 0.26 vs. 1.19 ± 0.22 ml/mmHg, P &lt; 0.05), DLCO and pulmonary capillary blood volume (52 ± 11 vs. 64 ± 13 ml, P &lt; 0.01) compared to controls. Exercise was associated with steeper mPAP-Q slopes, decreased TAPSE/sPAP and lower peak O2 uptake (VO2peak). The changes in TAPSE/sPAP at exercise were correlated to the body fat mass (R = 0.39, P = 0.01) and VO2peak (R = 0.44, P &lt; 0.01).

Conclusion

Obesity is associated with a decreased pulmonary vascular and RV-PA coupling reserve which may impair exercise capacity.

The Impact of Obesity in Heart Failure

Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Epidemiologic studies have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with leaner patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean mass as well as weight loss and improvements in quality of diet for the prevention and treatment of heart failure and concomitant obesity to improve cardiorespiratory fitness.

Heart failure with preserved ejection fraction based on aging and comorbidities

Heart failure (HF) with preserved ejection fraction (HFpEF) is a leading cause of hospitalizations and mortality when diagnosed at the age of ≥ 65 years. HFpEF represents multifactorial and multisystemic syndrome and has different pathophysiology and phenotypes. Its diagnosis is difficult to be established based on left ventricular ejection fraction and may benefit from individually tailored approaches, underlying age-related changes and frequent comorbidities. Compared with the rapid development in the treatment of heart failure with reduced ejection fraction, HFpEF presents a great challenge and needs to be addressed considering the failure of HF drugs to improve its outcomes. Further extensive studies on the relationships between HFpEF, aging, and comorbidities in carefully phenotyped HFpEF subgroups may help understand the biology, diagnosis, and treatment of HFpEF. The current review summarized the diagnostic and therapeutic development of HFpEF based on the complex relationships between aging, comorbidities, and HFpEF.

Subclinical cardiac dysfunction in obesity patients is linked to autonomic dysfunction: findings from the CARDIOBESE study

Aims

Obesity doubles the lifetime risk of developing heart failure. Current knowledge on the role of obesity in causing cardiac dysfunction is insufficient for optimal risk stratification. The aim of this study was first to estimate the prevalence of subclinical cardiac dysfunction in obesity patients and second to investigate the underlying pathophysiology.

Methods and results

The CARDIOBESE study is a cross‐sectional multicentre study of 100 obesity patients [body mass index (BMI) ≥ 35 kg/m²] without known cardiovascular disease and 50 age‐matched and gender‐matched non‐obese controls (BMI ≤ 30 kg/m²). Echocardiography was performed, blood samples were collected, and a Holter monitor was affixed. Fifty‐nine obesity patients [48 (42–50) years, 70% female] showed subclinical cardiac dysfunction: 57 patients had decreased global longitudinal strain (GLS), and two patients with normal GLS had either diastolic dysfunction or increased brain natriuretic peptide (BNP). Only one non‐obese control had diastolic dysfunction, and none had another sign of cardiac dysfunction. Multivariable logistic analysis identified male gender and standard deviation of all NN intervals (SDNN) index, which is a measure of autonomic dysfunction, as independent significant risk factors for subclinical cardiac dysfunction in obesity patients.

Conclusions

There was a high prevalence (61%) of subclinical cardiac dysfunction in obesity patients without known cardiovascular disease, which appeared to be best identified by GLS. Subclinical cardiac dysfunction in obesity was linked to autonomic dysfunction and male gender, and not to the presence of traditional cardiac risk factors, increased C‐reactive protein, increased BNP, increased high‐sensitivity troponin I, or increased left ventricular mass.

Characterization of the inflammatory-metabolic phenotype of heart failure with a preserved ejection fraction: a hypothesis to explain influence of sex on the evolution and potential treatment of the disease

Accumulating evidence points to the existence of an inflammatory-metabolic phenotype of heart failure with a preserved ejection fraction (HFpEF), which is characterized by biomarkers of inflammation, an expanded epicardial adipose tissue mass, microvascular endothelial dysfunction, normal-to-mildly increased left ventricular volumes and systolic blood pressures, and possibly, altered activity of adipocyte-associated inflammatory mediators. A broad range of adipogenic metabolic and systemic inflammatory disorders - e.g. obesity, diabetes and metabolic syndrome as well as rheumatoid arthritis and psoriasis - can cause this phenotype, independent of the presence of large vessel coronary artery disease. Interestingly, when compared with men, women are both at greater risk of and may suffer greater cardiac consequences from these systemic inflammatory and metabolic disorders. Women show disproportionate increases in left ventricular filling pressures following increases in central blood volume and have greater arterial stiffness than men. Additionally, they are particularly predisposed to epicardial and intramyocardial fat expansion and imbalances in adipocyte-associated proinflammatory mediators. The hormonal interrelationships seen in inflammatory-metabolic phenotype may explain why mineralocorticoid receptor antagonists and neprilysin inhibitors may be more effective in women than in men with HFpEF. Recognition of the inflammatory-metabolic phenotype may improve an understanding of the pathogenesis of HFpEF and enhance the ability to design clinical trials of interventions in this heterogeneous syndrome.

Epidemiology of heart failure

The heart failure syndrome has first been described as an emerging epidemic about 25 years ago. Today, because of a growing and ageing population, the total number of heart failure patients still continues to rise. However, the case mix of heart failure seems to be evolving. Incidence has stabilized and may even be decreasing in some populations, but alarming opposite trends have been observed in the relatively young, possibly related to an increase in obesity. In addition, a clear transition towards heart failure with a preserved ejection fraction has occurred. Although this transition is partially artificial, due to improved recognition of heart failure as a disorder affecting the entire left ventricular ejection fraction spectrum, links can be made with the growing burden of obesity‐related diseases and with the ageing of the population. Similarly, evidence suggests that the number of patients with heart failure may be on the rise in low‐income countries struggling under the double burden of communicable diseases and conditions associated with a Western‐type lifestyle. These findings, together with the observation that the mortality rate of heart failure is declining less rapidly than previously, indicate we have not reached the end of the epidemic yet. In this review, the evolving epidemiology of heart failure is put into perspective, to discern major trends and project future directions.

The Impact of Obesity in Heart Failure

Obesity has reached worldwide epidemic proportions, adversely impacting health on a global scale. Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Studies and meta-analyses have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with lean patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean and muscle mass, and weight loss, for the prevention and treatment of compared with in patients with concomitant obesity.

Do most patients with obesity or type 2 diabetes, and atrial fibrillation, also have undiagnosed heart failure? A critical conceptual framework for understanding mechanisms and improving diagnosis and treatment

Obesity and diabetes can lead to heart failure with preserved ejection fraction (HFpEF), potentially because they both cause expansion and inflammation of epicardial adipose tissue and thus lead to microvascular dysfunction and fibrosis of the underlying left ventricle. The same process also causes an atrial myopathy, which is clinically evident as atrial fibrillation (AF); thus, AF may be the first manifestation of HFpEF. Many patients with apparently isolated AF have latent HFpEF or subsequently develop HFpEF. Most patients with obesity or diabetes who have AF and exercise intolerance have increased left atrial pressures at rest or during exercise, even in the absence of diagnosed HFpEF. Among patients with AF, those who also have latent HFpEF have increased risk for systemic thromboembolism and death. The identification of HFpEF in patients with obesity or diabetes alters the risk-to-benefit relationship of commonly prescribed treatments. Bariatric surgery and statins can ameliorate AF and reduce the risk for HFpEF. Conversely, antihyperglycaemic drugs that promote adipogenesis or cause sodium retention (insulin and thiazolidinediones) may increase the risk for heart failure in patients with an underlying ventricular myopathy. Patients with obesity and diabetes who undergo catheter ablation for AF are at increased risk for AF recurrence and for post-ablation increases in pulmonary venous pressures and worsening heart failure, especially if HFpEF coexists. Therefore, AF may be the earliest indicator of HFpEF in patients with obesity or type 2 diabetes, and recognition of HFpEF alters the management of these patients.

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.

Evaluation of the effects of sodium-glucose co-transporter 2 inhibition with empagliflozin on morbidity and mortality in patients with chronic heart failure and a preserved ejection fraction: rationale for and design of the EMPEROR-Preserved Trial

BACKGROUND

The principal biological processes that characterize heart failure with a preserved ejection fraction (HFpEF) are systemic inflammation, epicardial adipose tissue accumulation, coronary microcirculatory rarefaction, myocardial fibrosis and vascular stiffness; the resulting impairment of left ventricular and aortic distensibility (especially when accompanied by impaired glomerular function and sodium retention) causes increases in cardiac filling pressures and exertional dyspnoea despite the relative preservation of left ventricular ejection fraction. Independently of their actions on blood glucose, sodium-glucose co-transporter 2 (SGLT2) inhibitors exert a broad range of biological effects (including actions to inhibit cardiac inflammation and fibrosis, antagonize sodium retention and improve glomerular function) that can ameliorate the pathophysiological derangements in HFpEF. Such SGLT2 inhibitors exert favourable effects in experimental models of HFpEF and have been found in large-scale trials to reduce the risk for serious heart failure events in patients with type 2 diabetes, many of whom were retrospectively identified as having HFpEF.

STUDY DESIGN

The EMPEROR-Preserved Trial is enrolling ≈5750 patients with HFpEF (ejection fraction >40%), with and without type 2 diabetes, who are randomized to receive placebo or empagliflozin 10 mg/day, which is added to all appropriate treatments for HFpEF and co-morbidities.

STUDY AIMS

The primary endpoint is the time-to-first-event analysis of the combined risk for cardiovascular death or hospitalization for heart failure. The trial will also evaluate the effects of empagliflozin on renal function, cardiovascular death, all-cause mortality and recurrent hospitalization events, and will assess a wide range of biomarkers that reflect important pathophysiological mechanisms that may drive the evolution of HFpEF. The EMPEROR-Preserved Trial is well positioned to determine if empagliflozin can have a meaningful impact on the course of HFpEF, a disorder for which there are currently few therapeutic options.

Obesity paradox in cardiovascular disease: where do we stand?

Obesity is associated with an increased risk of developing cardiovascular disease (CVD), particularly heart failure (HF) and coronary heart disease (CHD). The mechanisms through which obesity increases CVD risk involve changes in body composition that can affect hemodynamics and alters heart structure. Pro-inflammatory cytokines produced by the adipose tissue itself which can induce cardiac dysfunction and can promote the formation of atherosclerotic plaques. When obesity and HF or CHD coexist, individuals with class I obesity present a more favorable prognosis compared to individuals who are normal or underweight. This phenomenon has been termed the “obesity paradox.” Obesity is defined as an excess fat mass (FM), but individuals with obesity typically also present with an increased amount of lean mass (LM). The increase in LM may explain part of the obesity paradox as it is associated with improved cardiorespiratory fitness (CRF), a major determinant of clinical outcomes in the general population, but particularly in those with CVD, including HF. While increased LM is a stronger prognosticator in HF compared to FM, in patients with CHD excess FM can exert protective effects particularly when not associated with increased systemic inflammation. In the present review, we discuss the mechanisms through which obesity may increase the risk for CVD, and how it may exert protective effects in the setting of established CVD, with a focus on body composition. We also highlight the importance of measuring or estimating CRF, including body composition-adjusted measures of CRF (ie, lean peak oxygen consumption) for an improved risk status stratification in patients with CVD and finally, we discuss the potential non-pharmacologic therapeutics, such as exercise training and dietary interventions, aimed at improving CRF and perhaps clinical outcomes.