Response by Obokata and Borlaug to Letters Regarding Article, "Evidence Supporting the Existence of a Distinct Obese Phenotype of Heart Failure With Preserved Ejection Fraction"

Atrial Fibrillation and Semaglutide Effects in Obesity-Related Heart Failure With Preserved Ejection Fraction: STEP-HFpEF Program

BACKGROUND

Obesity is a key factor in the development and progression of both heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF). In the STEP-HFpEF Program (comprising the STEP-HFpEF [Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity] and STEP-HFpEF DM [Research Study to Look at How Well Semaglutide Works in People Living With Heart Failure, Obesity and Type 2 Diabetes] trials), once-weekly semaglutide 2.4 mg improved HF-related symptoms, physical limitations, and exercise function and reduced body weight in patients with obesity-related HFpEF. Whether the effects of semaglutide in this patient group differ in participants with and without AF (and across various AF types) has not been fully examined.

OBJECTIVES

The goals of this study were: 1) to evaluate baseline characteristics and clinical features of patients with obesity-related HFpEF with and without a history of AF; and 2) to determine if the efficacy of semaglutide across all key trial outcomes are influenced by baseline history of AF (and AF types) in the STEP-HFpEF Program.

METHODS

This was a secondary analysis of pooled data from the STEP-HFpEF and STEP-HFpEF DM trials. Patients with heart failure, left ventricular ejection fraction ≥45%, body mass index ≥30 kg/m2, and Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score (KCCQ-CSS) <90 points were randomized 1:1 to receive once-weekly semaglutide 2.4 mg or matching placebo for 52 weeks. Dual primary endpoints (change in KCCQ-CSS and percent change in body weight), confirmatory secondary endpoints (change in 6-minute walk distance; hierarchical composite endpoint comprising all-cause death, HF events, thresholds of change in KCCQ-CSS, and 6-minute walk distance; and C-reactive protein [CRP]), and exploratory endpoint (change in N-terminal pro-B-type natriuretic peptide [NT-proBNP]) were examined according to investigator-reported history of AF (yes/no). Responder analyses examined the proportions of patients who experienced a ≥5-, ≥10, ≥15, and ≥20-point improvement in KCCQ-CSS per history of AF.

RESULTS

Of the 1,145 participants, 518 (45%) had a history of AF (40% paroxysmal, 24% persistent AF, and 35% permanent AF) and 627 (55%) did not. Participants with (vs without) AF were older, more often male, had higher NT-proBNP levels, included a higher proportion of those with NYHA functional class III symptoms, and used more antithrombotic therapies, beta-blockers, and diuretics. Semaglutide led to larger improvements in KCCQ-CSS (11.5 points [95% CI: 8.3-14.8] vs 4.3 points [95% CI: 1.3-7.2]; P interaction = 0.001) and the hierarchal composite endpoint (win ratio of 2.25 [95% CI: 1.79-2.83] vs 1.30 [95% CI: 1.06-1.59]; P interaction < 0.001) in participants with AF vs without AF, respectively. The proportions of patients receiving semaglutide vs those receiving placebo experiencing ≥5-, ≥10-, ≥15-, and ≥20-point improvement in KCCQ-CSS were also higher in those with (vs without) AF (all P interaction values <0.05). Semaglutide consistently reduced CRP, NT-proBNP, and body weight regardless of AF status (all P interaction values not significant). There were fewer serious adverse events and serious cardiac disorders in participants treated with semaglutide vs placebo irrespective of AF history.

CONCLUSIONS

In the STEP-HFpEF Program, AF was observed in nearly one-half of patients with obesity-related HFpEF and was associated with several features of more advanced HF. Treatment with semaglutide led to significant improvements in HF-related symptoms, physical limitations, and exercise function, as well as reductions in weight, CRP, and NT-proBNP in people with and without AF and across AF types. The magnitude of semaglutide-mediated improvements in HF-related symptoms and physical limitations was more pronounced in those with AF vs without AF at baseline. (Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity [STEP-HFpEF; NCT04788511]; Research Study to Look at How Well Semaglutide Works in People Living With Heart Failure, Obesity and Type 2 Diabetes [STEP-HFpEF DM; NCT04916470]).

Hyperlactataemia is a marker of reduced exercise capacity in heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is associated with an array of central and peripheral haemodynamic and metabolic changes. The exact pathogenesis of exercise limitation in HFpEF remains uncertain. Our aim was to compare lactate accumulation and central haemodynamic responses to exercise in patients with HFpEF, non-cardiac dyspnoea (NCD), and healthy volunteers.

METHODS AND RESULTS

Right heart catheterization with mixed venous blood gas and lactate measurements was performed at rest and during symptom-limited supine exercise. Multivariable analyses were conducted to determine the relationship between haemodynamic and biochemical parameters and their association with exercise capacity. Of 362 subjects, 198 (55%) had HFpEF, 103 (28%) had NCD, and 61 (17%) were healthy volunteers. This included 139 (70%) females with HFpEF, 77 (75%) in NCD (P = 0.41 HFpEF vs. NCD), and 31 (51%) in healthy volunteers (P < 0.001 HFpEF vs. volunteers). The median age was 71 (65, 75) years in HFpEF, 66 (57, 72) years in NCD, and 49 (38, 65) years in healthy volunteers (HFpEF vs. NCD or volunteer, both P < 0.001). Peak workload was lower in HFpEF compared with healthy volunteers [52 W (interquartile range 31-73), 150 W (125-175), P < 0.001], but not NCD [53 W (33, 75), P = 0.85]. Exercise lactate indexed to workload was higher in HFpEF at 0.08 mmol/L/W (0.05-0.11), 0.06 mmol/L/W (0.05-0.08; P = 0.016) in NCD, and 0.04 mmol/L/W (0.03-0.05; P < 0.001) in volunteers. Exercise cardiac index was 4.5 L/min/m2 (3.7-5.5) in HFpEF, 5.2 L/min/m2 (4.3-6.2; P < 0.001) in NCD, and 9.1 L/min/m2 (8.0-9.9; P < 0.001) in volunteers. Oxygen delivery in HFpEF was lower at 1553 mL/min (1175-1986) vs. 1758 mL/min (1361-2282; P = 0.024) in NCD and 3117 mL/min (2667-3502; P < 0.001) in the volunteer group during exercise. Predictors of higher exercise lactate levels in HFpEF following adjustment included female sex and chronic kidney disease (both P < 0.001).

CONCLUSIONS

HFpEF is associated with reduced exercise capacity secondary to both central and peripheral factors that alter oxygen utilization. This results in hyperlactataemia. In HFpEF, plasma lactate responses to exercise may be a marker of haemodynamic and cardiometabolic derangements and represent an important target for future potential therapies.

Epicardial Fat Expansion in Diabetic and Obese Patients With Heart Failure and Preserved Ejection Fraction-A Specific HFpEF Phenotype

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome with diverse etiologies and pathophysiological factors. Obesity and type 2 diabetes mellitus (T2DM), conditions that coexist frequently, induce a cluster of metabolic and non-metabolic signaling derangements which are in favor to induce inflammation, fibrosis, myocyte stiffness, all hallmarks of HFpEF. In contrast to other HFpEF risk factors, obesity and T2DM are often associated with the generation of enlarged epicardial adipose tissue (EAT). EAT acts as an endocrine tissue that may exacerbate myocardial inflammation and fibrosis via various paracrine and vasocrine signals. In addition, an abnormally large EAT poses mechanical stress on the heart via pericardial restrain. HFpEF patients with enlarged EAT may belong to a unique phenotype that can benefit from specific EAT-targeted interventions, including life-style modifications and pharmacologically via statins and fat modifying anti-diabetics drugs; like metformin, sodium-glucose cotransporter 2 inhibitors, or glucagon-like peptide-1 receptor agonists, respectively.

Sarcopenic Obesity in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a public health epidemic that is projected to double over the next two decades. Despite the high prevalence of HFpEF, there are currently no FDA approved therapies for health-related outcomes in this clinical syndrome making it one the greatest unmet needs in cardiovascular medicine. Aging and obesity are hallmarks of HFpEF and therefore there is a high incidence of sarcopenic obesity (SO) associated with this syndrome. The presence of SO in HFpEF patients is noteworthy as it is associated with co-morbidities, worsened cardiovascular health, hospitalizations, quality of life, and mortality. Furthermore, SO plays a central role in exercise intolerance, the most commonly reported clinical symptom of this condition. The aim of this review is to provide insights into the current knowledge pertaining to the contributing pathophysiological mechanisms and clinical outcomes associated with HFpEF-related SO. Current and prospective therapies to address SO in HFpEF, including lifestyle and pharmaceutical approaches, are discussed. The urgent need for future research aimed at better understanding the multifaceted physiological contributions to SO in HFpEF and implementing interventional strategies to specifically target SO is highlighted.