Zooming in on the Microvasculature in Heart Failure With Preserved Ejection Fraction

Nonpharmacological Approaches to Managing Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a common subtype of heart failure marked by impaired left ventricular diastolic function and decreased myocardial compliance. Given the limited availability of evidence-based pharmacological treatments for HFpEF, there is a growing interest in nonpharmacological interventions as viable therapeutic alternatives. This review aims to explore the pathophysiology of HFpEF and present recent advancements in nonpharmacological management approaches, encompassing noninvasive therapies, invasive procedures and targeted treatments for comorbidities. An extensive literature review was undertaken to identify and synthesize emerging nonpharmacological treatment options for HFpEF, assessing their potential to enhance patient outcomes. Nonpharmacological strategies, such as vagus nerve stimulation, percutaneous pulmonary artery denervation, renal denervation, transcatheter insertion of atrial shunts and pericardial resection, demonstrate promising potential for alleviating HFpEF symptoms and improving patient prognosis. Moreover, addressing comorbidities, such as hypertension and diabetes, may offer additional therapeutic benefits. These cutting-edge techniques, in conjunction with well-established exercise therapies, pave the way for future research and clinical applications in the field. Nonpharmacological interventions hold promise for advancing HFpEF patient care and fostering a deeper understanding of these treatment approaches, which will facilitate new clinical applications and contribute to the development of more targeted therapies.

Supervised Exercise Training for Chronic Heart Failure With Preserved Ejection Fraction: A Scientific Statement From the American Heart Association and American College of Cardiology

Heart failure with preserved ejection fraction (HFpEF) is one of the most common forms of heart failure; its prevalence is increasing, and outcomes are worsening. Affected patients often experience severe exertional dyspnea and debilitating fatigue, as well as poor quality of life, frequent hospitalizations, and a high mortality rate. Until recently, most pharmacological intervention trials for HFpEF yielded neutral primary outcomes. In contrast, trials of exercise-based interventions have consistently demonstrated large, significant, clinically meaningful improvements in symptoms, objectively determined exercise capacity, and usually quality of life. This success may be attributed, at least in part, to the pleiotropic effects of exercise, which may favorably affect the full range of abnormalities-peripheral vascular, skeletal muscle, and cardiovascular-that contribute to exercise intolerance in HFpEF. Accordingly, this scientific statement critically examines the currently available literature on the effects of exercise-based therapies for chronic stable HFpEF, potential mechanisms for improvement of exercise capacity and symptoms, and how these data compare with exercise therapy for other cardiovascular conditions. Specifically, data reviewed herein demonstrate a comparable or larger magnitude of improvement in exercise capacity from supervised exercise training in patients with chronic HFpEF compared with those with heart failure with reduced ejection fraction, although Medicare reimbursement is available only for the latter group. Finally, critical gaps in implementation of exercise-based therapies for patients with HFpEF, including exercise setting, training modalities, combinations with other strategies such as diet and medications, long-term adherence, incorporation of innovative and more accessible delivery methods, and management of recently hospitalized patients are highlighted to provide guidance for future research.

Predictors of adverse diastolic remodeling in non-diabetic patients presenting with ST-elevation myocardial infarction

BACKGROUND

Adverse systolic remodeling after ST-elevation myocardial infarction (STEMI) is associated with poor clinical outcomes. However, little is known about diastolic remodeling. The purpose of this study was to identify the factors leading to diastolic remodeling.

METHODS

Echocardiography was performed during hospitalization and at 4 months follow-up in 267 non-diabetic STEMI patients from the GIPS-III trial. As parameters of diastolic remodeling we used (1.) the E/e' at 4 months adjusted for the E/e' at hospitalization and (2.) the change in E/e' between hospitalization and 4 months. Multivariable regression models correcting for age and sex were constructed to identify possible association of clinical and angiographic variables as well as biomarkers with diastolic remodeling.

RESULTS

Older age, female gender, hypertension, multi vessel disease, higher glucose and higher peak CK were independent predictors of higher E/e' at 4 months in a multivariable model (R2:0.20). After adjustment for E/e' during hospitalization only female gender, multivessel disease and higher glucose remained predictors of E/e' at four months (R2:0.40). Lower myocardial blush grade, AST and NT-proBNP were independent predictors of a higher increase of E/e' between hospitalization and at 4 months in a multivariable model (R2:0.08).

CONCLUSIONS

Our data supports the hypothesis that female gender, multivessel coronary artery disease, and microvascular damage are important predictors of adverse diastolic remodeling after STEMI. In addition, our data suggests that older age and hypertension prior to STEMI may have contributed to worse pre-existing diastolic function.

TRIAL REGISTRATION

NIH, NCT01217307. Prospectively registered on October 8th 2010, https://clinicaltrials.gov/ct2/show/NCT01217307 .

Endothelial-cell-mediated mechanism of coronary microvascular dysfunction leading to heart failure with preserved ejection fraction

Although the prevalence of heart failure with preserved ejection fraction (HFpEF) is growing worldwide, its complex pathophysiology has yet to be fully elucidated, and multiple hypotheses have all failed to produce a viable target for therapeutic action or provide effective treatment. Cardiac remodeling has long been considered an important mechanism of HFpEF. Strong evidence has been reported over the past years that coronary microvascular dysfunction (CMD), manifesting as structural and functional abnormalities of coronary microvasculature, also contributes to the evolution of HFpEF. However, the mechanisms of CMD are still not well understood and need to be studied further. Coronary microvascular endothelial cells (CMECs) are one of the most abundant cell types in the heart by number and active players in cardiac physiology and pathology. CMECs are not only important cellular mediators of cardiac vascularization but also play an important role in disease pathophysiology by participating in the inception and progression of cardiac remodeling. CMECs are also actively involved in the pathogenesis of CMD. Numerous studies have confirmed that CMD is closely related to cardiac remodeling. ECs may serve a critical function in mediating the connection between CMD and HFpEF. It follows that CMECs participate in the mechanism of CMD leading to HFpEF. In this review article, we focus on the role of CMD in the pathogenesis of HFpEF resulting from cardiac remodeling and highlight the subsequent complexity of the EC-mediated correlation between CMD and HFpEF.

Prognostic implications of coronary artery disease and stress tests in patients with elevated left ventricular filling pressure and preserved ejection fraction

Background

The prognostic role of myocardial ischemia in patients with heart failure with preserved ejection fraction (HFpEF) has not been fully elucidated. Therefore, we investigated the change in echocardiographic parameters and clinical outcomes based on the presence of epicardial coronary artery disease (CAD) and positive stress tests in HFpEF patients.

Methods

Symptomatic patients with left ventricular end diastolic pressure ≥15 mmHg who underwent coronary angiography were analyzed between January 2000 and August 2019 after exclusion of patients with acute coronary syndrome.

Results

A total of 555 HFpEF patients were invasively confirmed, 285 (51%) had angiographically-proven CAD. HFpEF patients with CAD displayed greater deterioration in left ventricular ejection fraction (p = 0.002) over time but this was not observed in those without CAD (p = 0.99) on follow-up echocardiography; however, the mitral annulus early diastolic velocity (e') was significantly decreased in both groups (p < 0.001 and p = 0.003, respectively). Among 274 patients that received stress tests, those with positive stress tests showed a decline in e' (p 0.001), but this was not found in subjects with negative stress tests (p = 0.44). There was no significant difference in all-cause mortality between patients with CAD and without CAD (p = 0.26) with a median follow-up of 10.6 years.

Conclusion

In HFpEF patients, CAD was associated with greater deterioration in the left ventricular systolic function but not with mortality during the follow-up. In addition, myocardial ischemia with a positive stress test may contribute to greater deterioration of diastolic dysfunction.

Transmural Distribution of Coronary Perfusion and Myocardial Work Density Due to Alterations in Ventricular Loading, Geometry and Contractility

Myocardial supply changes to accommodate the variation of myocardial demand across the heart wall to maintain normal cardiac function. A computational framework that couples the systemic circulation of a left ventricular (LV) finite element model and coronary perfusion in a closed loop is developed to investigate the transmural distribution of the myocardial demand (work density) and supply (perfusion) ratio. Calibrated and validated against measurements of LV mechanics and coronary perfusion, the model is applied to investigate changes in the transmural distribution of passive coronary perfusion, myocardial work density, and their ratio in response to changes in LV contractility, preload, afterload, wall thickness, and cavity volume. The model predicts the following: (1) Total passive coronary flow varies from a minimum value at the endocardium to a maximum value at the epicardium transmurally that is consistent with the transmural distribution of IMP; (2) Total passive coronary flow at different transmural locations is increased with an increase in either contractility, afterload, or preload of the LV, whereas is reduced with an increase in wall thickness or cavity volume; (3) Myocardial work density at different transmural locations is increased transmurally with an increase in either contractility, afterload, preload or cavity volume of the LV, but is reduced with an increase in wall thickness; (4) Myocardial work density-perfusion mismatch ratio at different transmural locations is increased with an increase in contractility, preload, wall thickness or cavity volume of the LV, and the ratio is higher at the endocardium than the epicardium. These results suggest that an increase in either contractility, preload, wall thickness, or cavity volume of the LV can increase the vulnerability of the subendocardial region to ischemia.

Waist to height ratio is associated with an increased risk of mortality in Chinese patients with heart failure with preserved ejection fraction

Background

Abdominal obesity as a predominant comorbidity has played a key role in the incidence and worsening of heart failure with preserved ejection fraction (HFpEF), and waist-to-height ratio (WHtR) behaves better than waist circumference or body mass index in evaluating abdominal obesity. While the association between WHtR and all-cause death in Chinese patients with HFpEF remains unclear.

Methods

Patients with stable HFpEF (N = 2041) who presented to our hospital from January 2008 to July 2019 were divided into low-WHtR (< 0.5, N = 378) and high-WHtR (≥ 0.5, N = 1663). Multivariable Cox proportional-hazard models were used to examine the association of WHtR with all-cause death.

Results

The average age was 76.63 ± 11.44 years, and the mean follow-up was 4.53 years. During follow-up, 185 patients (9.06%) reached the primary outcome of all-cause death. As for the secondary outcome, 79 patients (3.87%) experienced cardiovascular death, 106 (5.19%) had non-cardiovascular death, and 94 (4.61%) had heart failure rehospitalization. After multivariable adjustment, a higher WHtR was significantly associated with the increased risks of all-cause death [adjusted hazard ratios (HR) 1.91, 95% confidence interval (CI) 1.06–3.45, p = 0.032], cardiovascular death (adjusted HR 2.58; 95% CI 1.01–6.67, p = 0.048), and HF rehospitalization (adjusted HR 3.04; 95% CI 1.26–7.31, p = 0.013).

Conclusions

Higher WHtR is an independent risk factor for all-cause death in Chinese patients with HFpEF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02080-9.

Myocardial ischemia and coronary disease in heart failure

Heart failure is a complex clinical syndrome and represents the final path of numerous heart diseases. Coronary artery disease is recognized as the primary risk factor for heart failure development, being the main etiological factor in more than 50% of heart failure patients in North America and Europe. Regardless of overt coronary artery disease, myocardial ischemia is a common finding in failing hearts, likely due to structural or functional coronary circulation alterations. Ischemia is a self-propagating process which irreversibly impairs the cardiac function and negatively impacts prognosis. Thus, a better and thorough understanding of myocardial ischemia pathophysiology in heart failure would likely lead to significantly improved outcomes in these patients. This review aims to describe the mechanisms of myocardial ischemia and coronary artery disease in heart failure, focusing on coronary circulation dysfunctions due to increased parietal stress or non-obstructive coronary disease, and discussing the association and management of coronary artery disease in patients with heart failure.

Myocardial blush grade: a determinant of left ventricular ejection fraction and adverse outcomes in STEMI

BACKGROUND AND AIMS

Despite restoration of blood flow, subtle microvascular obstruction can occur. This obstruction can be graded using myocardial blush grade. We aimed to investigate the role of myocardial blush grade in ejection fraction and adverse outcomes, after percutaneous intervention.

METHODS

A prospective, observational study was conducted at our institute with a calculated sample size. Variables such as age, gender, and ejection fraction were noted before the intervention. The patients were followed for 3 months to determine the outcomes. The data was analyzed using IBM SPSS software version 26.0. P-value of less than 0.05 was considered significant for the statistical tests.

RESULTS

There were 74 male and 36 female participants in the study. The mean age was 52.20 ± 10.02 years. The most common adverse outcome was heart failure (18%). There was a significant Pearson's correlation between myocardial blush grade and improvement in ejection fraction (p < 0.05). Improvement in myocardial blush grade was significantly related to a decrease in adverse outcomes (p < 0.05). Regression analysis proved myocardial blush grade and diabetes status as independent predictors of percentage increase in ejection fraction (p < 0.05).

CONCLUSION

High myocardial blush grade is one of the independent predictors of better outcomes in ST-elevation myocardial infarction.

Hemodynamic assessment in heart failure

Hemodynamics play a central role in the pathophysiology of heart failure (HF), yet their proper assessment and optimization remains challenging. Heart failure is defined as the inability of the heart to deliver adequate perfusion (cardiac output) to the body at rest or exercise, or to require an elevation in cardiac filling pressures in order to do this. This bedrock definition is important because it relies on measurable quantities (filling pressures and output) that are readily assessed in the cardiac catheterization laboratory. Here we present three cases to illustrate how better understanding of the determinants of cardiac output and stroke volume: preload, afterload, contractility, and lusitropy, as well as the determinants of congestion (high filling pressures) may be used to guide optimization of hemodynamic status. The goal is that the readers will be able to think more critically when evaluating the hemodynamics of their patient in HF and recognize the complex interplay that determines the complex balance between cardiac ejection and filling capabilities, and how this alters symptoms and outcomes for patients with HF. KEY POINTS: Careful assessment of hemodynamics in the catheterization laboratory allows for actionable insight to a patient's volume status, cardiac function and can help prognosticate outcomes. Exercise hemodynamics in heart failure is a powerful tool to better understand the cause of symptoms and predict outcomes. Clinicians should aim to decrease biventricular filling pressures to normal values to improve morbidity and reduce risk for readmission. In patients with heart failure and reduced ejection fraction, clinicians should aim to decrease afterload as much as can be tolerated by the renal function and patient's symptoms. Low cardiac output can often be improved by optimizing preload and afterload rather than initiating inotropes, which should be reserved until needed. In advanced heart failure, the right heart function becomes a key determinant of symptoms and outcomes.

Endothelium-dependent and independent coronary microvascular dysfunction in patients with heart failure with preserved ejection fraction

BACKGROUND

Coronary microvascular inflammation is hypothesized to play a fundamental role in the pathophysiology of heart failure with preserved ejection fraction (HFpEF). No study has directly evaluated both endothelium-dependent and independent coronary microvascular function in HFpEF.

METHODS AND RESULTS

Consecutive patients with HFpEF undergoing invasive coronary physiologic testing and echocardiography were examined. Endothelial function was quantified by the increase in coronary blood flow in response to intracoronary infusion of acetylcholine (10^-6 -10^-4  mol/L) using a Doppler flow wire with quantitative angiography. Endothelium-independent coronary microvascular function was assessed by the hyperaemic increase in coronary flow reserve in response to adenosine infusion. Among 162 HFpEF patients (67% women), coronary microvascular function was abnormal in 117 (72%). Isolated endothelium-dependent microvascular dysfunction was present in 47 patients (29%), isolated endothelium-independent microvascular dysfunction in 53 patients (33%), and combined microvascular dysfunction in 17 patients (10%). The presence of coronary microvascular dysfunction was not identifiable from medical co-morbidities or other clinical characteristics. As compared to patients with normal endothelium-independent function, HFpEF patients with endothelium-independent coronary microvascular dysfunction displayed lower diastolic relaxation velocities (7.0 ± 1.8 vs. 8.4 ± 2.9 cm/s, P = 0.002) and higher estimated filling pressures (E/e' 13.1 ± 4.1 vs. 9.6 ± 3.4, P < 0.001). There were no relationships between left ventricular structure, function, or haemodynamics and endothelium-dependent coronary vasodilatation. Endothelium-independent microvascular dysfunction was associated with increased mortality.

CONCLUSIONS

Coronary microvascular dysfunction is common in patients with HFpEF and is caused equally by endothelium-dependent and independent mechanisms, but the presence of microvascular dysfunction cannot be identified from clinical markers and co-morbidities alone. Patients with HFpEF and endothelium-independent microvascular dysfunction display worse diastolic dysfunction and outcomes.

Reappraisal of Ischemic Heart Disease

In recent years, it has become apparent that coronary microvascular dysfunction plays a pivotal pathogenic role in angina pectoris. Functional and structural mechanisms can affect the physiological function of the coronary microvasculature and lead to myocardial ischemia in people without coronary atheromatous disease and also in individuals with obstructive coronary artery disease. Abnormal dilatory responses of the coronary microvessels, coronary microvascular spasm, and extravascular compressive forces have been identified as pathogenic mechanisms in both chronic and acute forms of ischemic heart disease. The condition characterized by anginal symptoms and evidence of myocardial ischemia triggered by coronary microvascular dysfunction, in the absence of obstructive coronary disease, is known as microvascular angina. The concept of microvascular angina, however, may extend further to include patients with obstructive coronary artery disease and individuals with angina after coronary revascularization or heart transplantation because coronary microvascular dysfunction contributes to myocardial ischemia in many such patients. Patients with microvascular angina constitute a sizeable proportion of all cases of stable angina undergoing diagnostic coronary angiography and of those with persisting angina after successful coronary revascularization. Coronary microvascular dysfunction is also often responsible for angina in individuals with cardiomyopathy and heart valve disease as well as acute coronary syndrome cases such as Takotsubo syndrome and myocardial infarction with no obstructive coronary artery disease. Patients with stable microvascular angina present typically with effort or rest chest pain and a reduced coronary flow reserve or microvascular spasm. This condition, which affects women and men, can markedly impair quality of life and prognosis and represents a substantial cost burden to healthcare systems and individuals alike. In recent years, progress in the diagnosis of myocardial ischemia and the use of tests to investigate functional and structural causes for a reduced coronary flow reserve and microvascular spasm have allowed the identification of an increased number of cases of microvascular angina in everyday clinical practice. Although some of the available anti-anginal drugs may be helpful, treatment of coronary microvascular dysfunction remains a major challenge. The present article discusses the fundamental role that coronary microvascular dysfunction plays in the pathogenesis of ischemic heart disease, the clinical characteristics of patients presenting with microvascular angina, and possible diagnostic and therapeutic strategies.

Heart Failure with Preserved Ejection Fraction

Heart failure (HF) is a clinical syndrome of diverse etiologies and can be associated with preserved, reduced, or mid-range ejection fraction (EF). In the community, heart failure with preserved ejection fraction (HFpEF) is emerging as the most common form of HF. There remains considerable uncertainty regarding its pathogenesis, diagnosis, and optimal therapeutic approach. Hypotheses have been advanced to explain the underlying pathophysiology responsible for HFpEF, but to date, no specific therapy based on these hypotheses has been proven to improve outcomes in HFpEF. We provide a clinically focused review of the epidemiology, clinical presentation, diagnostic approach, pathophysiology, and treatment of HFpEF.

Prognostic significance of high-sensitivity cardiac troponin in patients with heart failure with preserved ejection fraction

The aim of this study was to investigate the prognostic significance of high-sensitivity troponin T (hs-TnT) in patients with heart failure (HF) with preserved ejection fraction (HFpEF). We enrolled consecutive patients admitted to Shinshu University Hospital for HF treatment between July 2014 and March 2017 and stratified them into HF with reduced ejection fraction and HFpEF groups (left ventricular ejection fraction, < 50% and  ≥ 50%, respectively). Hs-TnT was evaluated at discharge, and patients were prospectively monitored for all-cause mortality, non-fatal myocardial infarction, stroke, and HF hospitalization. In 155 enrolled patients (median age 76 years), during a median follow-up of 449 days, 60 experienced an adverse event. Hs-TnT was significantly higher in patients with adverse events than in those without in HFpEF (p = 0.003). Hs-TnT did not significantly correlate with age, sex, hemoglobin, albumin, eGFR, or BNP. In Kaplan–Meier analysis, high hs-TnT predicted a poor prognosis in HFpEF (p = 0.003). In multivariate Cox regression analysis, hs-TnT levels independently predicted adverse events in HFpEF (p = 0.003) after adjusting for age and eGFR [HR, 1.015 (95% CI, 1.005–1.025), p = 0.004], and age and BNP [HR 1.016 (95% CI 1.005–1.027), p = 0.005]. Elevated hs-TnT at discharge predicted adverse events in HFpEF.

The Role of Echocardiography in Heart Failure with Preserved Ejection Fraction: What Do We Want from Imaging?

Noninvasive imaging, particularly echocardiography, plays a central role in the evaluation for heart failure with preserved ejection fraction (HFpEF). Echocardiography helps to rule in HFpEF among patients with unexplained dyspnea when the diagnosis is uncertain. In established HFpEF, echocardiography provides important insights into pathophysiology and phenotyping, such as isolated left ventricular diastolic dysfunction, left atrial dysfunction, abnormal right ventricular-pulmonary artery coupling, ischemia, or obesity phenotypes. In addition, imaging enables risk stratification for HFpEF. This article provides a critical appraisal of the role of echocardiography in the diagnosis and evaluation of HFpEF.

Associations and prognostic significance of diffuse myocardial fibrosis by cardiovascular magnetic resonance in heart failure with preserved ejection fraction

BACKGROUND

Increased myocardial fibrosis may play a key role in heart failure with preserved ejection fraction (HFpEF) pathophysiology. The study aim was to evaluate the presence, associations, and prognostic significance of diffuse fibrosis in HFpEF patients compared to age- and sex-matched controls.

METHODS

We prospectively included 118 consecutive HFpEF patients. Diffuse myocardial fibrosis was estimated by extracellular volume (ECV) quantified by cardiovascular magnetic resonance with the modified Look-Locker inversion recovery sequence. We determined an ECV age- and sex-adjusted cutoff value (33%) in 26 controls.

RESULTS

Mean ECV was significantly higher in HFpEF patients versus healthy controls (32.9 ± 4.8% vs 28.2 ± 2.4%, P <  0.001). Multivariate logistic regression showed that body mass index (BMI) (odds ratio (OR) =0.92 [0.86-0.98], P = 0.011), diabetes (OR = 2.62 [1.11-6.18], P = 0.028), and transmitral peak E wave velocity (OR = 1.02 [1.00-1.03], P = 0.022) were significantly associated with abnormal ECV value. During a median follow-up of 11 ± 6 months, the primary outcome (all-cause mortality or first heart failure hospitalization) occurred in 38 patients. In multivariate Cox regression analysis, diabetes (hazard ratio (HR) =1.98 [1.04; 3.76], P = 0.038) and hemoglobin level (HR = 0.81 [0.67; 0.98], P = 0.028) were significant predictors of composite outcome. The ECV ability to improve this model added significant prognostic information. We then developed a risk score including diabetes, hemoglobin and ECV > 33% demonstrating significant prediction of risk and validated this score in a validation cohort of 53 patients. Kaplan-Meier curves showed a significant difference according to tertiles of the probability score (P <  0.001).

CONCLUSION

Among HFpEF patients, high ECV, likely reflecting abnormal diffuse myocardial fibrosis, was associated with a higher rate of all-cause death and first HF hospitalization in short term follow up.

TRIAL REGISTRATION

Characterization of Heart Failure With Preserved Ejection Fraction.

TRIAL REGISTRATION NUMBER

NCT03197350 . Date of registration: 20/06/2017. This trial was retrospectively registered.

Myocardial Injury and Cardiac Reserve in Patients With Heart Failure and Preserved Ejection Fraction

BACKGROUND

Cardiac reserve is depressed in patients with heart failure and preserved ejection fraction (HFpEF). The mechanisms causing this are poorly understood.

OBJECTIVES

The authors hypothesized that myocardial injury might contribute to the hemodynamic derangements and cardiac reserve limitations that are present in HFpEF. Markers of cardiomyocyte injury, central hemodynamics, ventricular function, and determinants of cardiac oxygen supply-demand balance were measured.

METHODS

Subjects with HFpEF (n = 38) and control subjects without heart failure (n = 20) underwent cardiac catheterization, echocardiography, and expired gas analysis at rest and during exercise. Central venous blood was sampled to measure plasma high-sensitivity troponin T levels as an index of cardiomyocyte injury.

RESULTS

Compared with control subjects, troponins were more than 2-fold higher in subjects with HFpEF at rest and during exercise (p < 0.0001). Troponin levels were directly correlated with left ventricular (LV) filling pressures (r = 0.52; p < 0.0001) and diastolic dysfunction (r = -0.43; p = 0.002). Although myocardial oxygen demand was similar, myocardial oxygen supply was depressed in HFpEF, particularly during exercise (coronary perfusion pressure-time integral; 44 ± 9 mm Hg × s × min-1 × l × dl-1 vs. 30 ± 9 mm Hg × s × min-1 × l × dl-1; p < 0.0001), and reduced indices of supply were correlated with greater myocyte injury during exercise (r = -0.44; p = 0.0008). Elevation in troponin with exercise was directly correlated with an inability to augment LV diastolic (r = -0.40; p = 0.02) and systolic reserve (r = -0.57; p = 0.0003), greater increases in LV filling pressures (r = 0.55; p < 0.0001), blunted cardiac output response (r = -0.44; p = 0.002), and more severely depressed aerobic capacity in HFpEF.

CONCLUSIONS

Limitations in LV functional reserve and the hemodynamic derangements that develop secondary to these limitations during exercise in HFpEF are correlated with the severity of cardiac injury, assessed by plasma levels of troponin T. Further study is warranted to determine the mechanisms causing myocyte injury in HFpEF and the potential role of ischemia, and to identify and test novel interventions targeted to these mechanisms. (EXEC [Study of Exercise and Heart Function in Patients With Heart Failure and Pulmonary Vascular Disease]; NCT01418248).

Abdominal Obesity Is Associated With an Increased Risk of All-Cause Mortality in Patients With HFpEF

BACKGROUND

There is a lack of studies that evaluate the association between abdominal obesity and subsequent outcomes in patients with heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

The present study aimed to assess the association between abdominal obesity and risk of all-cause mortality in patients with HFpEF.

METHODS

The present study used data from the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist) trial. The primary outcome was all-cause mortality. We analyzed and compared the hazard ratios (HRs) in patients with abdominal obesity and those without abdominal obesity using multivariable Cox proportional hazard models. Abdominal obesity was defined as a waist circumference of ≥102 cm in men and ≥88 cm in women.

RESULTS

The present study included 3,310 patients with HFpEF: 2,413 patients with abdominal obesity and 897 without abdominal obesity. The mean follow-up was 3.4 ± 1.7 years. During follow-up, 500 patients died. All-cause mortality rates in patients with and without abdominal obesity were 46.1 and 40.7 events per 1,000 person-years, respectively. After multivariable adjustment, the risk of all-cause mortality was significantly higher in patients with abdominal obesity than in those without abdominal obesity (adjusted HR: 1.52; 95% confidence interval [CI]: 1.16 to 1.99; p = 0.002). The risk of cardiovascular and noncardiovascular mortality was also significantly higher in patients with abdominal obesity than in those without abdominal obesity (adjusted HR: 1.50; 95% CI: 1.08 to 2.08; p = 0.01 and adjusted HR: 1.58; 95% CI: 1.00 to 2.51; p = 0.04, respectively).

CONCLUSIONS

The risk of all-cause mortality was significantly higher in patients with HFpEF with abdominal obesity than in those without abdominal obesity.

Gender and cardiovascular disease: are sex-biased microRNA networks a driving force behind heart failure with preserved ejection fraction in women?

Cardiovascular disease (CVD) is the primary cause of death among men and women worldwide. Nevertheless, our comprehension of how CVD progresses in women and elicits clinical outcomes is lacking, leading CVD to be under-diagnosed and under-treated in women. A clear example of this differential presentation of CVD pathophysiologies in females is the strikingly higher prevalence of heart failure with preserved ejection fraction (HFpEF). Women with a history of pre-eclampsia or those who present with co-morbidities such as obesity, hypertension, and diabetes mellitus are at increased risk of developing HFpEF. Long understood to be a critical CVD risk factor, our understanding of how gender differentially affects the development of CVD has been greatly expanded by extensive genomic and transcriptomic studies. These studies uncovered a pivotal role for differential microRNA (miRNA) expression in response to systemic inflammation, where their co-ordinated expression forms a post-transcriptional regulatory network that instigates microcirculation defects. Importantly, the potential sex-biased expression of the given miRNAs may explain sex-specific cardiovascular pathophysiologies in women, such as HFpEF. Sex-biased miRNAs are regulated by oestrogen (E2) in their transcription and processing or are expressed from loci on the X-chromosome due to incomplete X-chromosome inactivation. Interestingly, while E2-induced miRNAs predominantly appear to serve protective functions, it could be argued that many X-linked miRNAs have been found to challenge microvascular and myocardial integrity. Therefore, menopausal E2 deficiency, resulting in protective miRNA loss, and the augmentation of X-linked miRNA expression, may well contribute to the molecular mechanisms that underlie the female-specific cardiovascular aetiology in HFpEF.

Percutaneous Pericardial Resection: A Novel Potential Treatment for Heart Failure With Preserved Ejection Fraction

BACKGROUND

People with heart failure and preserved ejection fraction develop increases in left ventricular (LV) end-diastolic pressures during exercise that contribute to dyspnea. In normal open-chest animal preparations, the pericardium restrains LV filling when central blood volume increases. We hypothesized that resection of the pericardium using a minimally invasive epicardial approach would mitigate the increase in LV end-diastolic pressure that develops during volume loading in normal and diseased hearts with the chest intact.

METHODS AND RESULTS

Invasive hemodynamic assessment was performed at baseline and after saline load before and after pericardial resection in normal canines with open (n=3) and closed chest (n=5) and in a pig model with features of human heart failure and preserved ejection fraction with sternum intact (n=4). In closed-chest animals, pericardiotomy was performed using a novel subxiphoid procedure. In both experimental preparations of normal dogs, pericardiotomy blunted the increase in LV end-diastolic pressure with saline infusion, while enhancing the saline-mediated increase in LV end-diastolic volume. With chest intact in the pig model, percutaneous pericardial resection again blunted the increase in LV end-diastolic pressure secondary to volume expansion (+4±3 versus +13±5 mm Hg; P=0.014), while enhancing the saline-mediated increase in LV end-diastolic volume (+17±1 versus +10±2 mL; P=0.016).

CONCLUSIONS

This proof of concept study demonstrates that pericardial resection through a minimally invasive percutaneous approach mitigates the elevation in LV filling pressures with volume loading in both normal animals and a pig model with diastolic dysfunction. Further study is warranted to determine whether this method is safe and produces similar acute and chronic hemodynamic benefits in people with heart failure and preserved ejection fraction.

Experimental cardiac radiation exposure induces ventricular diastolic dysfunction with preserved ejection fraction

Breast cancer radiotherapy increases the risk of heart failure with preserved ejection fraction (HFpEF). Cardiomyocytes are highly radioresistant, but radiation specifically affects coronary microvascular endothelial cells, with subsequent microvascular inflammation and rarefaction. The effects of radiation on left ventricular (LV) diastolic function are poorly characterized. We hypothesized that cardiac radiation exposure may result in diastolic dysfunction without reduced EF. Global cardiac expression of the sodium-iodide symporter (NIS) was induced by cardiotropic gene (adeno-associated virus serotype 9) delivery to 5-wk-old rats. SPECT/CT (¹²⁵I) measurement of cardiac iodine uptake allowed calculation of the ¹³¹I doses needed to deliver 10- or 20-Gy cardiac radiation at 10 wk of age. Radiated (Rad; 10 or 20 Gy) and control rats were studied at 30 wk of age. Body weight, blood pressure, and heart rate were similar in control and Rad rats. Compared with control rats, Rad rats had impaired exercise capacity, increased LV diastolic stiffness, impaired LV relaxation, and elevated filling pressures but similar LV volume, EF, end-systolic elastance, preload recruitable stroke work, and peak +dP/dt Pathology revealed reduced microvascular density, mild concentric cardiomyocyte hypertrophy, and increased LV fibrosis in Rad rats compared with control rats. In the Rad myocardium, oxidative stress was increased and in vivo PKG activity was decreased. Experimental cardiac radiation exposure resulted in diastolic dysfunction without reduced EF. These data provide insight into the association between cardiac radiation exposure and HFpEF risk and lend further support for the importance of inflammation-related coronary microvascular compromise in HFpEF.NEW & NOTEWORTHY Cardiac radiation exposure during radiotherapy increases the risk of heart failure with preserved ejection fraction. In a novel rodent model, cardiac radiation exposure resulted in coronary microvascular rarefaction, oxidative stress, impaired PKG signaling, myocardial fibrosis, mild cardiomyocyte hypertrophy, left ventricular diastolic dysfunction, and elevated left ventricular filling pressures despite preserved ejection fraction.

Risk of Heart Failure With Preserved Ejection Fraction in Older Women After Contemporary Radiotherapy for Breast Cancer

BACKGROUND

Cardiomyocytes are resistant to radiation. However, cardiac radiation exposure causes coronary microvascular endothelial inflammation, a perturbation implicated in the pathogenesis of heart failure (HF) and particularly HF with preserved ejection fraction (HFpEF). Radiotherapy for breast cancer results in variable cardiac radiation exposure and may increase the risk of HF.

METHODS

We conducted a population-based case-control study of incident HF in 170 female residents of Olmsted County, Minnesota (59 cases and 111 controls), who underwent contemporary (1998-2013) radiotherapy for breast cancer with computed tomography-assisted radiotherapy planning. Controls were matched to cases for age, tumor side, chemotherapy use, diabetes mellitus, and hypertension. Mean cardiac radiation dose (MCRD) in each patient was calculated from the patient's computed tomography images and radiotherapy plan.

RESULTS

Mean age at radiotherapy was 69±9 years. Of HF cases, 38 (64%) had EF≥50% (HFpEF), 18 (31%) had EF<50% (HF with reduced EF), and 3 (5%) did not have EF measured. The EF was ≥40% in 50 of the 56 HF cases (89%) with an EF measurement. The mean interval from radiotherapy to HF was 5.8±3.4 years. The odds of HF was higher in patients with a history of ischemic heart disease or atrial fibrillation. The MCRD was 2.5 Gy (range, 0.2-13.1 Gy) and higher in cases (3.3±2.7 Gy) than controls (2.1±2.0 Gy; P=0.004). The odds ratio (95% confidence interval) for HF per log MCRD was 9.1 (3.4-24.4) for any HF, 16.9 (3.9-73.7) for HFpEF, and 3.17 (0.8-13.0) for HF with reduced EF. The increased odds of any HF or HFpEF with increasing MCRD remained significant after adjustment for HF risk factors and in sensitivity analyses matching by cancer stage rather than tumor side. Only 18.6% of patients experienced new or recurrent ischemic events between radiotherapy and the onset of HF.

CONCLUSIONS

The relative risk of HFpEF increases with increasing cardiac radiation exposure during contemporary conformal breast cancer radiotherapy. These data emphasize the importance of radiotherapy techniques that limit MCRD during breast cancer treatment. Moreover, these data provide further support for the importance of coronary microvascular compromise in the pathophysiology of HFpEF.