Matchmaking for the optimization of clinical trials of heart failure with preserved ejection fraction: no laughing matter

Exploring the therapeutic potential of tetrahydrobiopterin for heart failure with preserved ejection fraction: A path forward

A large number of patients are affected by classical heart failure (HF) symptomatology with preserved ejection fraction (HFpEF) and multiorgan syndrome. Due to high morbidity and mortality rate, hospitalization and mortality remain serious socioeconomic problems, while the lack of effective pharmacological or device treatment means that HFpEF presents a major unmet medical need. Evidence from clinical and basic studies demonstrates that systemic inflammation, increased oxidative stress, and impaired mitochondrial function are the common pathological mechanisms in HFpEF. Tetrahydrobiopterin (BH4), beyond being an endogenous co-factor for catalyzing the conversion of some essential biomolecules, has the capacity to prevent systemic inflammation, enhance antioxidant resistance, and modulate mitochondrial energy production. Therefore, BH4 has emerged in the last decade as a promising agent to prevent or reverse the progression of disorders such as cardiovascular disease. In this review, we cover the clinical progress and limitations of using downstream targets of nitric oxide (NO) through NO donors, soluble guanylate cyclase activators, phosphodiesterase inhibitors, and sodium-glucose co-transporter 2 inhibitors in treating cardiovascular diseases, including HFpEF. We discuss the use of BH4 in association with HFpEF, providing new evidence for its potential use as a pharmacological option for treating HFpEF.

Understanding heterogeneous mechanisms of heart failure with preserved ejection fraction through cardiorenal mathematical modeling

In contrast to heart failure (HF) with reduced ejection fraction (HFrEF), effective interventions for HF with preserved ejection fraction (HFpEF) have proven elusive, in part because it is a heterogeneous syndrome with incompletely understood pathophysiology. This study utilized mathematical modeling to evaluate mechanisms distinguishing HFpEF and HFrEF. HF was defined as a state of chronically elevated left ventricle end diastolic pressure (LVEDP > 20mmHg). First, using a previously developed cardiorenal model, sensitivities of LVEDP to potential contributing mechanisms of HFpEF, including increased myocardial, arterial, or venous stiffness, slowed ventricular relaxation, reduced LV contractility, hypertension, or reduced venous capacitance, were evaluated. Elevated LV stiffness was identified as the most sensitive factor. Large LV stiffness increases alone, or milder increases combined with either decreased LV contractility, increased arterial stiffness, or hypertension, could increase LVEDP into the HF range without reducing EF. We then evaluated effects of these mechanisms on mechanical signals of cardiac outward remodeling, and tested the ability to maintain stable EF (as opposed to progressive EF decline) under two remodeling assumptions: LV passive stress-driven vs. strain-driven remodeling. While elevated LV stiffness increased LVEDP and LV wall stress, it mitigated wall strain rise for a given LVEDP. This suggests that if LV strain drives outward remodeling, a stiffer myocardium will experience less strain and less outward dilatation when additional factors such as impaired contractility, hypertension, or arterial stiffening exacerbate LVEDP, allowing EF to remain normal even at high filling pressures. Thus, HFpEF heterogeneity may result from a range of different pathologic mechanisms occurring in an already stiffened myocardium. Together, these simulations further support LV stiffening as a critical mechanism contributing to elevated cardiac filling pressures; support LV passive strain as the outward dilatation signal; offer an explanation for HFpEF heterogeneity; and provide a mechanistic explanation distinguishing between HFpEF and HFrEF.

Heart Failure With Preserved Ejection Fraction: An Evolving Understanding

Heart failure (HF) with preserved ejection fraction (HFpEF) is a clinical syndrome in which patients have signs and symptoms of HF due to high left ventricular (LV) filling pressure despite normal or near normal LV ejection fraction. It is more common than HF with reduced ejection fraction (HFrEF), and its diagnosis and treatment are more challenging than HFrEF. Although hypertension is the primary risk factor, coronary artery disease and other comorbidities, such as atrial fibrillation (AF), diabetes, chronic kidney disease (CKD), and obesity, also play an essential role in its formation. This review summarizes current knowledge about HFpEF, its pathophysiology, clinical presentation, diagnostic challenges, current treatments, and promising novel treatments. It is essential to continue to be updated on the latest treatments for HFpEF so that patients always receive the most therapeutic treatments. The use of GnRH agonists in the management of HFpEF, infusion of Apo a-I nanoparticle, low-level transcutaneous vagal stimulation (LLTS), and estrogen only in post-menopausal women are promising strategies to prevent diastolic dysfunction and HFpEF; however, there is still no proven curative treatment for HFpEF yet.

Elucidating the Clinical Implications and Pathophysiology of Pulmonary Hypertension in Heart Failure With Preserved Ejection Fraction: A Call to Action: A Science Advisory From the American Heart Association

This science advisory focuses on the need to better understand the epidemiology, pathophysiology, and treatment of pulmonary hypertension in patients with heart failure with preserved ejection fraction. This clinical phenotype is important because it is common, is strongly associated with adverse outcomes, and lacks evidence-based therapies. Our goal is to clarify key knowledge gaps in pulmonary hypertension attributable to heart failure with preserved ejection fraction and to suggest specific, actionable scientific directions for addressing such gaps. Areas in need of additional investigation include refined disease definitions and interpretation of hemodynamics, as well as greater insights into noncardiac contributors to pulmonary hypertension risk, optimized animal models, and further molecular studies in patients with combined precapillary and postcapillary pulmonary hypertension. We highlight translational approaches that may provide important biological insight into pathophysiology and reveal new therapeutic targets. Last, we discuss the current and future landscape of potential therapies for patients with heart failure with preserved ejection fraction and pulmonary vascular dysfunction, including considerations of precision medicine, novel trial design, and device-based therapies, among other considerations. This science advisory provides a synthesis of important knowledge gaps, culminating in a collection of specific research priorities that we argue warrant investment from the scientific community.

Exercise-induced B-lines in heart failure with preserved ejection fraction occur along with diastolic function worsening

Aims

Pulmonary congestion during exercise assessed by lung ultrasound predicts negative outcome in patients with heart failure with preserved ejection fraction (HFpEF). We aimed at assessing predictors of exercise‐induced pulmonary B‐lines in HFpEF patients.

Methods and results

Eighty‐one I–II NYHA class HFpEF patients (65.0  ± 8.2 y/o, 56.8% females) underwent standard and strain echocardiography, lung ultrasound, and natriuretic peptide assessment during supine exercise echocardiography (baseline and peak exercise). Peak values and their changes were compared in subgroups according to exercise lung congestion grading (peak B‐lines >10 or ≤10). Exercise elicited significant changes for all echocardiographic parameters in both subgroups [39/81 (48.1%) with peak B‐lines >10; 42/81 (51.9%) with B‐lines ≤10]. Peak values and changes of E‐wave (and its derived indices) were significantly higher in patients with >10 peak B‐lines compared with those with ≤10 B‐line (all P‐values <0.03), showing significant correlation with peak B‐lines for all parameters; concomitantly, global longitudinal strain (GLS) and global strain rate (GSR) during systole (GSRs), early (GSRe) and late (GSRa) diastole, and isovolumic relaxation (GSRivr) were reduced in patients with B‐lines >10 (all P‐values <0.05), showing a negative correlation with peak B‐lines. By adjusted linear regression analysis, peak and change diastolic parameters (E‐wave, E/e′, GSRivr, and E/GSRivr) and peak GLS were individually significantly associated with peak B‐lines. By covariate‐adjusted multivariable model, E/e′ and GSRa at peak exercise were retained as independent predictors of peak B‐lines, with substantial goodness of fit of model (adjusted R² 0.776).

Conclusions

In HFpEF, development of pulmonary congestion upon exercise is mostly concomitant with exercise‐induced worsening of diastolic function.

Maternal myocardial dysfunction after hemolysis, elevated liver enzymes, and low platelets syndrome: a speckle-tracking study

OBJECTIVES

Pregnancy complicated by pre-eclampsia (PE) and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome is associated with an increased risk of cardiovascular (CV) diseases later in life. Subclinical cardiac alterations precede eminent CV diseases. Speckle-tracking echocardiography (STE) is an effective method to assess subclinical myocardial dysfunction. We performed a myocardial speckle tracking study to investigate the prevalence of subclinical myocardial dysfunction in former PE patients (with and without HELLP syndrome) compared to normotensive women affected by HELLP syndrome.

METHODS

In this cross-sectional retrospective study, women with a history of normotensive HELLP (n = 32), PE without HELLP (n = 59), and PE with HELLP (n = 101) underwent conventional and STE as part of the clinical CV work-up after their complicated pregnancies from 6 months to 4 years postpartum. We excluded women with comorbidities, including chronic hypertension, hypercholesterolemia, and obesity.

RESULTS

Women with a history of PE with HELLP syndrome were characterized by a higher prevalence of altered left ventricular circumferential and global longitudinal two-dimensional (2D) strain (74 and 20%, respectively), altered right ventricular longitudinal 2D strain (37%), and left atrial (LA) 2D strain (57%). Moreover, a higher proportion of alterations of biventricular and LA strains was also present in former PE without HELLP as well as in the normotensive HELLP group.

CONCLUSIONS

In the first years after a pregnancy complicated by HELLP syndrome, irrespective of whether there was concomitant PE, a higher rate of abnormal STE myocardial function is observed. Therefore, these women may benefit from CV risk management.

Cardiovascular magnetic resonance predicts all-cause mortality in pulmonary hypertension associated with heart failure with preserved ejection fraction

This study aimed to determine the prognostic value of cardiovascular magnetic resonance (CMR) in patients with heart failure with preserved ejection fraction and associated pulmonary hypertension (pulmonary hypertension-HFpEF). Patients with pulmonary hypertension-HFpEF were recruited from the ASPIRE registry and underwent right heart catheterisation (RHC) and CMR. On RHC, the inclusion criteria was a mean pulmonary artery pressure (MPAP) ≥ 25 mmHg and pulmonary arterial wedge pressure > 15 mmHg and, on CMR, a left atrial volume > 41 ml/m² with left ventricular ejection fraction > 50%. Cox regression was performed to evaluate CMR against all-cause mortality. In this study, 116 patients with pulmonary hypertension-HFpEF were identified. Over a mean follow-up period of 3 ± 2 years, 61 patients with pulmonary hypertension-HFpEF died (53%). In univariate regression, 11 variables demonstrated association to mortality: indexed right ventricular (RV) volumes and stroke volume, right ventricular ejection fraction (RVEF), indexed RV mass, septal angle, pulmonary artery systolic/diastolic area and its relative area change. In multivariate regression, only three variables were independently associated with mortality: RVEF (HR 0.64, P < 0.001), indexed RV mass (HR 1.46, P < 0.001) and IV septal angle (HR 1.48, P < 0.001). Our CMR model had 0.76 area under the curve (P < 0.001) to predict mortality. This study confirms that pulmonary hypertension in patients with HFpEF is associated with a poor prognosis and we observe that CMR can risk stratify these patients and predict all-cause mortality. When patients with HFpEF develop pulmonary hypertension, CMR measures that reflect right ventricular afterload and function predict all-cause mortality.

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

Heart Failure with preserved Ejection Fraction (HFpEF) is an increasingly prevalent clinical condition associated with cardiovascular aging, characterized by different pathophysiological mechanisms and poor outcomes. In this manuscript, we analysed the main differences in terms of updated diagnostic criteria and patients' selection in the most recent HFpEF trials. Recent algorithm purposed for HFpEF diagnosis, does not reflect common criteria adopted in clinical trials. Patients included in the larger studies experienced different characteristics in terms of clinical presentation and echocardiographic features. Current concerns complicate results interpretation and could hypothesize different stages of disease progression, rather than different cardiac phenotypes. Both the lack of diagnostic standardization and the population heterogeneity, might explain why trials investigating the effects of different therapeutic interventions failed to show improved outcomes for patients with HFpEF. Accordingly, we propose to exceed current view mainly based on the morphological adaptations evaluating patients' characterisation, their cardiovascular risk, associated diseases, and structural features consistent with disease progression. Detailed clinical, imaging and biological characterisation of this population, along with the identification of mechanisms linked with disease progression and prognosis, would allow for tailored treatments and provide important mechanistic insights into the complex HFpEF pathophysiology.

Different Pathophysiology and Outcomes of Heart Failure With Preserved Ejection Fraction Stratified by K-Means Clustering

Background: Stratified medicine may enable the development of effective treatments for particular groups of patients with heart failure with preserved ejection fraction (HFpEF); however, the heterogeneity of this syndrome makes it difficult to group patients together by common disease features. The aim of the present study was to find new subgroups of HFpEF using machine learning. Methods: K-means clustering was used to stratify patients with HFpEF. We retrospectively enrolled 350 outpatients with HFpEF. Their clinical characteristics, blood sample test results and hemodynamic parameters assessed by echocardiography, electrocardiography and jugular venous pulse, and clinical outcomes were applied to k-means clustering. The optimal k was detected using Hartigan's rule. Results: HFpEF was stratified into four groups. The characteristic feature in group 1 was left ventricular relaxation abnormality. Compared with group 1, patients in groups 2, 3, and 4 had a high mean mitral E/e' ratio. The estimated glomerular filtration rate was lower in group 2 than in group 3 (median 51 ml/min/1.73 m² vs. 63 ml/min/1.73 m² p < 0.05). The prevalence of less-distensible right ventricle and atrial fibrillation was higher, and the deceleration time of mitral inflow was shorter in group 3 than in group 2 (93 vs. 22% p < 0.05, 95 vs. 1% p < 0.05, and median 167 vs. 223 ms p < 0.05, respectively). Group 4 was characterized by older age (median 85 years) and had a high systolic pulmonary arterial pressure (median 37 mmHg), less-distensible right ventricle (89%) and renal dysfunction (median 54 ml/min/1.73 m²). Compared with group 1, group 4 exhibited the highest risk of the cardiac events (hazard ratio [HR]: 19; 95% confidence interval [CI] 8.9-41); group 2 and 3 demonstrated similar rates of cardiac events (group 2 HR: 5.1; 95% CI 2.2-12; group 3 HR: 3.7; 95%CI, 1.3-10). The event-free rates were the lowest in group 4 (p for trend < 0.001). Conclusions: K-means clustering divided HFpEF into 4 groups. Older patients with HFpEF may suffer from complication of RV afterload mismatch and renal dysfunction. Our study may be useful for stratified medicine for HFpEF.

Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction

Background

Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise.

Methods and Results

Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08).

Conclusions

Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients.

20th Annual Feigenbaum Lecture: Echocardiography for Precision Medicine-Digital Biopsy to Deconstruct Biology

Heart failure with preserved ejection fraction (HFpEF) is a complex, heterogeneous syndrome in need of improved classification given its high morbidity and mortality and few effective treatment options. HFpEF represents an ideal setting to examine the utility and feasibility of a precision medicine approach. This article (based on the 20th annual Feigenbaum Lecture, presented at the 2019 American Society of Echocardiography Scientific Sessions) describes the utility of echocardiography as a "digital biopsy" and how deep quantitative echocardiographic phenotyping, coupled with machine learning, can be used to identify novel HFpEF phenotypes. The cellular and ultrastructural basis of abnormal speckle-tracking echocardiography- (STE-) based measurements of cardiac mechanics can provide a window into cardiomyocyte calcium homeostasis. STE-based measurements of longitudinal strain can thus inform the extent of myocardial involvement in patients with HFpEF, which may help to determine responsiveness to cardiac-specific HF medications. However, classifying the complex, systemic, multiorgan nature of HFpEF appropriately likely requires more advanced methods. Using unsupervised machine learning, HFpEF can be classified into three distinct phenogroups with differing clinical and echocardiographic characteristics and outcomes: (1) natriuretic peptide deficiency syndrome; (2) extreme cardiometabolic syndrome; and (3) right ventricle-cardio-abdomino-renal syndrome. Each can be probed to determine their biological basis. The goal of improved classification of HFpEF is to match the right patient with the right treatment, with the hope of improving the track record of HFpEF clinical trials. This article emphasizes the central role of echocardiography in advancing precision medicine and illustrates the integration of basic, translational, clinical, and population research in echocardiography with the goal of better understanding the pathobiology of a complex cardiovascular syndrome.

[Mechanisms of exercise intolerance in patients with heart failure and preserved ejection fraction. Part II: The role of right heart chambers, vascular system and skeletal muscles]

The main clinical manifestation of heart failure with preserved ejection fraction is poor exercise tolerance. In addi-tion to the dysfunction of the left heart chambers, which were presented in the first part of this review, many other disorders are involved in poor exercise tolerance in such patients: impairments of the right heart, vascular system and skeletal muscle. The second part of this review presents the mechanisms for the development of these disorders, as well as possible ways to correct them.

Prominent 'Y' descent is an ominous sign of a poorer prognosis in heart failure with preserved ejection fraction

AIMS

The heterogeneity of heart failure with preserved ejection fraction (HFpEF) represents different pathophysiological paths by which individual patients develop heart failure. The deterioration mechanisms are considered to be mainly left ventricular diastolic dysfunction, right ventricular (RV) systolic function, and RV afterload. It is unclear whether RV distensibility affects the deterioration of HFpEF. Our study aimed to clarify whether impaired RV distensibility is associated with the deterioration of HFpEF.

METHODS AND RESULTS

We retrospectively enrolled 322 patients with HFpEF and examined their echocardiography results, electrocardiograms, phonocardiograms, and jugular venous pulse waves. Using signal-processing techniques, the prominent 'Y' descent of the jugular venous waveform was detected as an established haemodynamic sign of a less-distensible right ventricle. We defined cardiovascular events of HFpEF as follows: sudden death, death from heart failure, or hospitalization for HFpEF. During a mean follow-up period of 33 ± 20 months, 73 patients had cardiovascular events of HFpEF. The prevalence of a less-distensible right ventricle and the variables of RV systolic pressure were independent risk factors for cardiovascular events (hazard ratio, 2.046, P = 0.005, and hazard ratio, 1.032 per 1 mmHg, P = 0.002, respectively). The event-free rate of HFpEF was the lowest for HFpEF with a less-distensible right ventricle and elevated RV systolic pressure (≥35 mmHg) (P for trend <0.001).

CONCLUSIONS

A less-distensible right ventricle and elevated RV systolic pressure were found to be closely associated with the deterioration of HFpEF. Assessment of a less-distensible right ventricle may help to stratify patients and improve therapeutic strategies for HFpEF.

Randomized Evaluation of Heart Failure With Preserved Ejection Fraction Patients With Acute Heart Failure and Dopamine: The ROPA-DOP Trial

OBJECTIVES

This study sought to compare a continuous infusion diuretic strategy versus an intermittent bolus diuretic strategy, with the addition of low-dose dopamine (3 μg/kg/min) in the treatment of hospitalized patients with heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

HFpEF patients are susceptible to development of worsening renal function (WRF) when hospitalized with acute heart failure; however, inpatient treatment strategies to achieve safe and effective diuresis in HFpEF patients have not been studied to date.

METHODS

In a prospective, randomized, clinical trial, 90 HFpEF patients hospitalized with acute heart failure were randomized within 24 h of admission to 1 of 4 treatments: 1) intravenous bolus furosemide administered every 12 h; 2) continuous infusion furosemide; 3) intermittent bolus furosemide with low-dose dopamine; and 4) continuous infusion furosemide with low-dose dopamine. The primary endpoint was percent change in creatinine from baseline to 72 h. Linear and logistic regression analyses with tests for interactions between diuretic and dopamine strategies were performed.

RESULTS

Compared to intermittent bolus strategy, the continuous infusion strategy was associated with higher percent increase in creatinine (continuous infusion: 16.01%; 95% confidence interval [CI]: 8.58% to 23.45% vs. intermittent bolus: 4.62%; 95% CI: -1.15% to 10.39%; p = 0.02). Low-dose dopamine had no significant effect on percent change in creatinine (low-dose dopamine: 12.79%; 95% CI: 5.66% to 19.92%, vs. no-dopamine: 8.03%; 95% CI: 1.44% to 14.62%; p = 0.33). Continuous infusion was also associated with greater risk of WRF than intermittent bolus (odds ratio [OR]: 4.32; 95% CI: 1.26 to 14.74; p = 0.02); no differences in WRF risk were seen with low-dose dopamine. No significant interaction was seen between diuretic strategy and low-dose dopamine (p > 0.10).

CONCLUSIONS

In HFpEF patients hospitalized with acute heart failure, low-dose dopamine had no significant impact on renal function, and a continuous infusion diuretic strategy was associated with renal impairment. (Diuretics and Dopamine in Heart Failure With Preserved Ejection Fraction [ROPA-DOP]; NCT01901809).

Importance of combined left atrial size and estimated pulmonary pressure for clinical outcome in patients presenting with heart failure with preserved ejection fraction

Aims

Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome with various phenotypes and outcomes. The prognostic relevance of echocardiography and the E/e' ratio has previously been reported. We sought to study in addition, the value of estimated pulmonary pressure and left atrial size for diagnosing and determining a prognosis for HFpEF-patients in a prospective multi-centric cohort.

Methods and results

Patients with an acute-HF event accompanied with NT-proBNP >300 pg/mL (BNP >100 pg/mL) and LVEF >45% were included (n = 237) and clinically reassessed using echo-Doppler after 4-8 weeks of HF treatment as part of the prospective KaRen HFpEF study. A core-centre performed the echocardiographic analyses. A combined primary endpoint of either HF hospitalizations and mortality over a span of 18-month, or simply mortality (secondary endpoint) were used. The mean LVEF was 62 ± 7%, E/e':12.9 ± 6.0, left atrial volume index (LAVI): 48.1 ± 15.9 ml/m2, TR: 2.9 ± 0.9 m/s. Patients with both LAVI > 40 ml/m2 and TR > 3.1 m/s had a significantly greater risk of death or heart failure related hospitalization than others (P = 0.014 after adjustment).

Conclusion

The combination of enlarged LA and elevated estimated pulmonary pressure has a strong prognostic impact in patients suffering from HFpEF. Our results indicate that such patients constitute a risk group in HFpEF which requires dedicated medical attention.

ClinicalTrials.gov

NCT00774709.

Reduced Myocardial Flow Reserve Is Associated With Diastolic Dysfunction and Decreased Left Atrial Strain in Patients With Normal Ejection Fraction and Epicardial Perfusion

INTRODUCTION

Coronary microvascular dysfunction (MVD) may contribute to the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Using myocardial flow reserve (MFR) measured by positron emission tomography (PET) as an assessment of microvascular function, we hypothesized that abnormal MFR is associated with LV diastolic dysfunction (DD) and reduced LV and LA strain in patients with risk factors for HFpEF and normal epicardial perfusion on cardiac PET.

METHODS AND RESULTS

Retrospective study of patients without heart failure who underwent cardiac rubidium-82 PET and echocardiography. Global MFR was calculated as the ratio of global stress to rest myocardial blood flow. Echocardiographic measures of diastolic function were recorded. Global longitudinal LA and LV strain were measured with a 2-dimensional speckle-tracking technique. Relationships among MFR and echocardiographic measures were assessed with linear regression, analysis of variance, and test for trend. Seventy-three patients (age 64 ± 11 years, 52% male) were identified with no epicardial perfusion defect on cardiac PET and an ejection fraction ≥50%. Decreased MFR was associated with LV DD (P = .02) and increased E/e', an estimation of LV filling pressure (low E/e' [<8] vs. high E/e' [>15], P < .001). MFR was associated with LA strain independent of age, gender, and common comorbidities (adjusted β = 2.6% per unit MFR, P = 0.046); however, MFR was only marginally related to LV strain.

CONCLUSIONS

In patients with risk factors for HFpEF, MVD assessed with MFR was associated with DD, increased estimated LV filling pressure, and abnormal LA strain.

Murine Models of Heart Failure with Preserved Ejection Fraction: a "Fishing Expedition"

Heart failure with preserved ejection fraction (HFpEF) is characterized by signs and symptoms of HF in the presence of a normal left ventricular (LV) ejection fraction (EF). Despite accounting for up to 50% of all clinical presentations of HF, the mechanisms implicated in HFpEF are poorly understood, thus precluding effective therapy. The pathophysiological heterogeneity in the HFpEF phenotype also contributes to this disease and likely to the absence of evidence-based therapies. Limited access to human samples and imperfect animal models that completely recapitulate the human HFpEF phenotype have impeded our understanding of the mechanistic underpinnings that exist in this disease. Aging and comorbidities such as atrial fibrillation, hypertension, diabetes and obesity, pulmonary hypertension and renal dysfunction are highly associated with HFpEF. Yet, the relationship and contribution between them remains ill-defined. This review discusses some of the distinctive clinical features of HFpEF in association with these comorbidities and highlights the advantages and disadvantage of commonly used murine models, used to study the HFpEF phenotype.

How to Develop and Implement a Specialized Heart Failure with Preserved Ejection Fraction Clinical Program

Heart failure with preserved ejection fraction (HFpEF), a highly prevalent and complex clinical syndrome with high morbidity and mortality, is often unrecognized and not optimally treated. Clinical trials for HFpEF have been plagued by low enrollment, and clinicians often approach HFpEF patients with "therapeutic nihilism" given the perceived lack of available therapies based on the disappointing results of these prior trials. Due to these challenges, we have pioneered the successful creation of dedicated, specialized HFpEF clinical programs. Here, we discuss (1) the rationale for the development of a specialized HFpEF clinical program; (2) strategies for the systematic identification of HFpEF patients; (3) a standardized diagnostic and therapeutic approach; (4) validation of the HFpEF clinical program paradigm; (5) staffing and reimbursement considerations; (6) HFpEF clinical trial enrollment; and (7) challenges and future directions for HFpEF clinical programs. We conclude that it is feasible to create HFpEF clinical programs that fulfill the major unmet need of identifying and caring for patients with HFpEF. These clinics are essential for confirming the HFpEF diagnosis, providing standardized treatment, and facilitating clinical trial enrollment. It is our hope that the information provided here will encourage others to establish their own specialized HFpEF programs, thereby allowing for comprehensive care for these complex patients.

Innovative Clinical Trial Designs for Precision Medicine in Heart Failure with Preserved Ejection Fraction

A major challenge in the care of patients with heart failure and preserved ejection fraction (HFpEF) is the lack of proven therapies due to disappointing results from randomized controlled trials (RCTs). The heterogeneity of the HFpEF syndrome and the use of conventional RCT designs are possible reasons underlying the failure of these trials. There are several factors-including the widespread adoption of electronic health records, decreasing costs of obtaining high-dimensional data, and the availability of a wide variety of potential therapeutics-that have evolved to enable more innovative clinical trial designs in HFpEF. Here, we review the current landscape of HFpEF RCTs and present several innovative RCT designs that could be implemented in HFpEF, including enrichment trials, adaptive trials, umbrella trials, basket trials, and machine learning-based trials (including examples for each). Our hope is that the description of the aforementioned innovative trial designs will stimulate new approaches to clinical trials in HFpEF.

Developing New Treatments for Heart Failure: Focus on the Heart

Compared with heart failure (HF) care 20 to 30 years ago, there has been tremendous advancement in therapy for ambulatory HF with reduced ejection fraction with the use of agents that block maladaptive neurohormonal pathways. However, during the past decade, with few notable exceptions, the frequency of successful drug development programs has fallen as most novel therapies have failed to offer incremental benefit or raised safety concerns (ie, hypotension). Moreover, no therapy has been approved specifically for HF with preserved ejection fraction or for worsening chronic HF (including acutely decompensated HF). Across the spectrum of HF, preliminary results from many phase II trials have been promising but are frequently followed by unsuccessful phase III studies, highlighting a disconnect in the translational process between basic science discovery, early drug development, and definitive clinical testing in pivotal trials. A major unmet need in HF drug development is the ability to identify homogeneous subsets of patients whose underlying disease is driven by a specific mechanism that can be targeted using a new therapeutic agent. Drug development strategies should increasingly consider therapies that facilitate reverse remodeling by directly targeting the heart itself rather than strictly focusing on agents that unload the heart or target systemic neurohormones. Advancements in cardiac imaging may allow for more focused and direct assessment of drug effects on the heart early in the drug development process. To better understand and address the array of challenges facing current HF drug development, so that future efforts may have a better chance for success, the Food and Drug Administration facilitated a meeting on February 17, 2015, which was attended by clinicians, researchers, regulators, and industry representatives. The following discussion summarizes the key takeaway dialogue from this meeting.

Precision Medicine for Heart Failure with Preserved Ejection Fraction: An Overview

There are few proven therapies for heart failure with preserved ejection fraction (HFpEF). The lack of therapies, along with increased recognition of the disorder and its underlying pathophysiology, has led to the acknowledgement that HFpEF is heterogeneous and is not likely to respond to a one-size-fits-all approach. Thus, HFpEF is a prime candidate to benefit from a precision medicine approach. For this reason, we have assembled a compendium of papers on the topic of precision medicine in HFpEF in the Journal of Cardiovascular Translational Research. These papers cover a variety of topics relevant to precision medicine in HFpEF, including automated identification of HFpEF patients; machine learning, novel molecular approaches, genomics, and deep phenotyping of HFpEF; and clinical trial designs that can be used to advance precision medicine in HFpEF. In this introductory article, we provide an overview of precision medicine in HFpEF with the hope that the work described here and in the other papers in this special theme issue will stimulate investigators and clinicians to advance a more targeted approach to HFpEF classification and treatment.

Assessing the Eligibility Criteria in Phase III Randomized Controlled Trials of Drug Therapy in Heart Failure With Preserved Ejection Fraction: The Critical Play-Off Between a "Pure" Patient Phenotype and the Generalizability of Trial Findings

AIMS

To investigate the effect of the different eligibility criteria used by phase III clinical studies in heart failure with preserved ejection fraction (HFpEF) on patient selection, phenotype, and survival.

METHODS AND RESULTS

We applied the key eligibility criteria of 7 phase III HFpEF studies (Digitalis Investigation Group Ancillary, Candesartan in Patients With Chronic Heart Failure and Preserved Left-Ventricular Ejection Fraction, Perindopril in Elderly People With Chronic Heart Failure, Irbesartan in Heart Failure With Preserved Systolic Function, Japanese Diastolic Heart Failure, Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist, and Efficacy and Safety of LCZ696 Compared to Valsartan, on Morbidity and Mortality in Heart Failure Patients With Preserved Ejection Fraction [PARAGON-HF; ongoing]) to a typical and well-characterized HFpEF population (n = 557) seen in modern European cardiological practice. Follow-up was available for a minimum of 24 months in each patient. Increasing the number of study eligibility criteria identifies a progressively smaller group of patients from real-life practice suitable for recruitment into clinical trials; using the J-DHF criteria, 81% of our clinic patients would have been eligible, whereas the PARAGON-HF criteria significantly reduced this proportion to 32%. The patients identified from our clinical population had similar mortality rates using the different criteria, which were consistently higher than those reported in the actual clinic trials.

CONCLUSIONS

Trial eligibility criteria have become stricter with time, which reduces the number of eligible patients, affecting both generalizability of any findings and feasibility of completing an adequately powered trial. We could not find evidence that the additional criteria used in more recent randomized trials in HFpEF have identified patients at higher risk of all-cause mortality.

Drug Development for Heart Failure With Preserved Ejection Fraction: What Pieces Are Missing From the Puzzle?

Despite the growing number of patients with heart failure with preserved ejection fraction (HFpEF) and event rates comparable with many cancers, there remain no pharmacologic agents definitively proven to improve patient outcomes. Although phase II trials have intermittently yielded encouraging results, none have translated into successful achievement of a phase III primary end point. Thus, because of the urgent need to discover proven therapies, it is prudent to reevaluate our current approach to HFpEF drug development. In this review, we comment on key areas of uncertainty and importance relevant to successful drug discovery for HFpEF. These areas include the need to: clarify and homogenize the HFpEF definition; better understand the role of comorbidities and varying HFpEF etiology; use the heart failure hospitalization as the prime opportunity for trial enrollment; classify HFpEF patients within discrete clinicopathologic phenotypes for selected study; discover novel molecular drug targets; and determine predictors of specific causes of death to allow optimal matching of pharmacologic mechanisms with HFpEF subgroups most likely to benefit. Recognizing that the study of HFpEF is inherently challenging and complex, addressing these specific areas and overcoming their respective hurdles might maximize the chances of discovering a beneficial therapy.

Advances in the pharmacotherapy of chronic heart failure with preserved ejection fraction: an ideal opportunity for precision medicine

INTRODUCTION

Heart failure with preserved ejection fraction (HFpEF), which comprises approximately 50% of all heart failure patients, is a challenging and complex clinical syndrome that is often thought to lack effective treatments. Areas covered: Despite the common mantra that HFpEF has no effective treatments, closer inspection of HFpEF clinical trials reveals that several of the drugs tested are associated with benefits in exercise capacity and quality of life, and reduction in heart failure hospitalization. Here we review major randomized controlled trials in HFpEF, focusing on renin-angiotensin-aldosterone system antagonists, organic nitrates, digoxin, beta-blockers, and phosphodiesterase-5 inhibitors. In addition, we review several classes of drugs currently in development for HFpEF such as neprilysin inhibitors, inorganic nitrates (nitrites), and soluble guanylate cyclase stimulators. Expert opinion: HFpEF should not be viewed as lacking effective treatments. While there have been no breakthrough clinical trials showing a reduction in mortality, several existing medications are likely to benefit specific subgroups of HFpEF patients. HFpEF is now well known to be a heterogeneous syndrome; thus, the clinical management of HFpEF patients and future HFpEF clinical trials will both likely require a nuanced, phenotype-specific approach instead of a one-size-fits-all tactic. Drug development for HFpEF therefore represents an exciting opportunity for personalized medicine.

Pedal Edema as an Indicator of Early Heart Failure in the Community: Prevalence and Associations With Cardiac Structure/Function and Natriuretic Peptides (MESA [Multiethnic Study of Atherosclerosis])

BACKGROUND

The prevalence of pedal edema (PE) and its associations with abnormal cardiac structure/function, natriuretic peptides, and incident heart failure (HF) is unknown, especially in community-dwelling adults without a history of cardiovascular disease.

METHODS AND RESULTS

Out of 5004 MESA (Multiethnic Study of Atherosclerosis) participants who had cardiac magnetic resonance imaging, 4196 had complete data and were included in this analysis (3501 for the right ventricle analysis). Logistic regression and Cox proportional hazard analyses were used to assess the associations among self-reported PE, 2-pillow orthopnea, paroxysmal nocturnal dyspnea, left and right ventricular structure and function, natriuretic peptide levels, and incident HF. PE was present in 28% of the participants. PE was not associated with overt left or right ventricular systolic dysfunction (ejection fraction <50%). PE was associated with 2-pillow orthopnea (odds ratio 1.66; 95% confidence interval [CI], 1.30-2.12), paroxysmal nocturnal dyspnea (odds ratio 1.95; 95% CI, 1.55-2.44), and abnormal N-terminal pro-B-type natriuretic peptide levels (defined as >400 pg/mL; odds ratio 1.80; 95% CI, 1.21-2.68) in adjusted models. After a mean of 10.2 years of follow-up, 184/4196 (4.4%) participants had an adjudicated incident HF hospitalization. PE was associated with incident HF hospitalization in models adjusted for age, sex, and race (hazard ratio 1.44; 95% CI, 1.05-1.97). This association persisted after adding additional covariates, including comorbidities, baseline left ventricular ejection fraction, and antecedent myocardial infarction (hazard ratio 1.43; 95% CI, 1.02-1.99). The association of PE with incident HF was attenuated by further adjustment for N-terminal pro-B-type natriuretic peptide.

CONCLUSIONS

PE is prevalent in community-dwelling adults without clinically recognized cardiovascular disease and associated with future hospitalized HF.

Advances in the management of heart failure: the role of ivabradine

A high resting heart rate (≥70–75 b.p.m.) is a risk factor for patients with heart failure (HF) with reduced ejection fraction (EF), probably in the sense of accelerated atherosclerosis, with an increased morbidity and mortality. Beta-blockers not only reduce heart rate but also have negative inotropic and blood pressure-lowering effects, and therefore, in many patients, they cannot be given in the recommended dose. Ivabradine specifically inhibits the pacemaker current (funny current, I_f) of the sinoatrial node cells, resulting in therapeutic heart rate lowering without any negative inotropic and blood pressure-lowering effect. According to the European Society of Cardiology guidelines, ivabradine should be considered to reduce the risk of HF hospitalization and cardiovascular death in symptomatic patients with a reduced left ventricular EF ≤35% and sinus rhythm ≥70 b.p.m. despite treatment with an evidence-based dose of beta-blocker or a dose below the recommended dose (recommendation class “IIa” = weight of evidence/opinion is in favor of usefulness/efficacy: “should be considered”; level of evidence “B” = data derived from a single randomized clinical trial or large nonrandomized studies). Using a heart rate cutoff of ≥ 75 b.p.m., as licensed by the European Medicines Agency, treatment with ivabradine 5–7.5 mg b.i.d. reduces cardiovascular mortality by 17%, HF mortality by 39% and HF hospitalization rate by 30%. A high resting heart rate is not only a risk factor in HF with reduced EF but also at least a risk marker in HF with preserved EF, in acute HF and also in special forms of HF. In this review, we discuss the proven role of ivabradine in the validated indication “HF with reduced EF” together with interesting preliminary findings, and the potential role of ivabradine in further, specific forms of HF.

Burden of Recurrent Hospitalizations Following an Admission for Acute Heart Failure: Preserved Versus Reduced Ejection Fraction

INTRODUCTION AND OBJECTIVES

Heart failure with preserved ejection fraction and reduced ejection fraction share a high mortality risk. However, differences in the rehospitalization burden over time between these 2 entities remains unclear.

METHODS

We prospectively included 2013 consecutive patients discharged for acute heart failure. Of these, 1082 (53.7%) had heart failure with preserved ejection fraction and 931 (46.2%) had heart failure with reduced ejection fraction. Cox and negative binomial regression methods were used to evaluate the risks of death and repeat hospitalizations, respectively.

RESULTS

At a median follow-up of 2.36 years (interquartile range: 0.96-4.65), 1018 patients (50.6%) died, and 3804 readmissions were registered in 1406 patients (69.8%). Overall, there were no differences in mortality between heart failure with preserved ejection fraction and heart failure with reduced ejection fraction (16.7 vs 16.1 per 100 person-years, respectively; P=0794), or all-cause repeat hospitalization rates (62.1 vs 62.2 per 100 person-years, respectively; P=.944). After multivariable adjustment, and compared with patients with heart failure with reduced ejection fraction, patients with heart failure with preserved ejection fraction exhibited a similar risk of all-cause readmissions (incidence rate ratio=1.04; 95%CI, 0.93-1.17; P=.461). Regarding specific causes, heart failure with preserved ejection fraction showed similar risks of cardiovascular and heart failure-related rehospitalizations (incidence rate ratio=0.93; 95%CI, 0.82-1.06; P=.304; incidence rate ratio=0.96; 95% confidence interval, 0.83-1.13; P=.677, respectively), but had a higher risk of noncardiovascular readmissions (incidence rate ratio=1.24; 95%CI, 1.04-1.47; P=.012).

CONCLUSIONS

Following an admission for acute heart failure, patients with heart failure with preserved ejection fraction have a similar rehospitalization burden to those with heart failure with reduced ejection fraction. However, patients with heart failure with preserved ejection fraction are more likely to be readmitted for noncardiovascular causes.

The Role of Cardiovascular Magnetic Resonance Imaging in Heart Failure

Cardiovascular imaging is key for the assessment of patients with heart failure. Today, cardiovascular magnetic resonance imaging plays an established role in the assessment of patients with suspected and confirmed heart failure syndromes, in particular identifying aetiology. Its role in informing prognosis and guiding decisions around therapy are evolving. Key strengths include its accuracy; reproducibility; unrestricted field of view; lack of radiation; multiple abilities to characterise myocardial tissue, thrombus and scar; as well as unparalleled assessment of left and right ventricular volumes. T2* has an established role in the assessment and follow-up of iron overload cardiomyopathy and a role for T1 in specific therapies for cardiac amyloid and Anderson-Fabry disease is emerging.

Serum insulin-like growth factor-1 and its binding protein-7: potential novel biomarkers for heart failure with preserved ejection fraction

Background

Insulin-like growth factor binding protein-7 (IGFBP-7) modulates the biological activities of insulin-like growth factor-1 (IGF-1). Previous studies demonstrated the prognostic value of IGFBP-7 and IGF-1 among patients with systolic heart failure (HF). This study aimed to evaluate the IGF1/IGFBP-7 axis in HF patients with preserved ejection fraction (HFpEF).

Methods

Serum IGF-1 and IGFBP-7 levels were measured in 300 eligible consecutive patients who underwent comprehensive cardiac assessment. Patients were categorized into 3 groups including controls with normal diastolic function (n = 55), asymptomatic left ventricular diastolic dysfunction (LVDD, n = 168) and HFpEF (n = 77).

Results

IGFBP-7 serum levels showed a significant graded increase from controls to LVDD to HFpEF (median 50.30 [43.1-55.3] vs. 54.40 [48.15-63.40] vs. 61.9 [51.6-69.7], respectively, P < 0.001), whereas IGF-1 levels showed a graded decline from controls to LVDD to HFpEF (120.0 [100.8-144.0] vs. 112.3 [88.8-137.1] vs. 99.5 [72.2-124.4], p < 0.001). The IGFBP-7/IGF-1 ratio increased from controls to LVDD to HFpEF (0.43 [0.33-0.56] vs. 0.48 [0.38-0.66] vs. 0.68 [0.55-0.88], p < 0.001). Patents with IGFB-7/IGF1 ratios above the median demonstrated significantly higher left atrial volume index, E/E’ ratio, and NT-proBNP levels (all P ≤ 0.02).

Conclusion

In conclusion, this hypothesis-generating pilot study suggests the IGFBP-7/IGF-1 axis correlates with diastolic function and may serve as a novel biomarker in patients with HFpEF. A rise in IGFBP-7 or the IGFBP-7/IGF-1 ratio may reflect worsening diastolic function, adverse cardiac remodeling, and metabolic derangement.

Current and projected burden of heart failure in the Australian adult population: a substantive but still ill-defined major health issue

BACKGROUND

Comprehensive epidemiological data to describe the burden of heart failure (HF) in Australia remain lacking despite its importance as a major health issue. Herewith, we estimate the current and future burden of HF in Australia using best available data.

METHODS

Australian-specific and the most congruent international epidemiological and health utilisation data were applied to the Australian population (adults aged ≥ 45 years, 8.9 of 22.7 million total population in 2014) on an age and sex-specific basis. We estimated the current incident and prevalent cases of clinically overt/symptomatic HF (predominately those with reduced ejection fraction), hospital activity (diagnosis of HF as a primary or secondary reason for admission) and health care costs in 2014 and future prevalence and burden of HF projected to 2030.

RESULTS

We estimated that over 61,000 (6.9 per 1000 person-years) adult Australians aged ≥ 45 years (58 % women) are diagnosed with HF with clinically overt signs and symptoms every year. On a conservative basis, 480,000 (6.3 %, 95 % CI 2.6 to 10.0 %) Australians (66 % men) are now affected by the syndrome with > 150,000 hospitalisations in excess of 1 million days in hospital per annum. The annual cost of managing HF in the community is approximately $900 million and nearly $2.7 billion ($1.5 versus $1.2 billion, men versus women) when considering the additional cost of in-patient care. We predict that the prevalence and future burden of HF will continue to increase over the next 10-15 years to nearly 750,000 people with an estimated annual health care cost of $3.8 billion.

CONCLUSIONS

Australia is not immune to the growing magnitude and implications of a sustained epidemic of HF in an ageing population. However, its public health and economic burden will remain ill-defined until more definitive Australian-specific data are generated.

Influence of Clinical Trial Site Enrollment on Patient Characteristics, Protocol Completion, and End Points

Background—

Most international acute heart failure trials have failed to show benefit with respect to key end points. The impact of site enrollment and protocol execution on trial performance is unclear.

Methods and Results—

We assessed the impact of varying site enrollment volume among all 7141 acute heart failure patients from the ASCEND-HF trial (Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure). Overall, 398 sites enrolled ≥1 patient, and median enrollment was 12 patients (interquartile range, 5–23). Patients from high enrolling sites (>60 patients/site) tended to have lower ejection fraction, worse New York Heart Association functional class, and lower utilization of guideline-directed medical therapy but fewer comorbidities and lower B-type natriuretic peptide level. Every 10 patient increase (up to 100 patients) in site enrollment correlated with lower likelihood of protocol noncompletion (odds ratio, 0.93; 95% confidence interval [CI], 0.89–0.98). After adjustment, increasing site enrollment predicted higher risk of persistent dyspnea at 6 hours (per 10 patient increase: odds ratio 1.02; 95% CI, 1.01–1.03) but not at 24 hours (odds ratio, 0.99; 95% CI, 0.98–1.00). Higher site enrollment was independently associated with lower risk of 30-day death or rehospitalization (per 10 patient increase: odds ratio, 0.98, 95% CI, 0.96–0.99) but not 180-day mortality (hazard ratio, 0.99; 95% CI, 0.98–1.01). The influence of increasing site enrollment on clinical end points varied across geographic regions with strongest associations in Latin America and Asia-Pacific (all interaction P <0.01).

Conclusions—

In this large, acute heart failure trial, site enrollment correlated with protocol completion and was independently associated with trial end points. Individual and regional site performance present challenges to be considered in design of future acute heart failure trials.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00475852.

QRS Duration Is a Predictor of Adverse Outcomes in Heart Failure With Preserved Ejection Fraction

OBJECTIVES

This study examined the relationship between baseline QRS duration and clinical outcomes in subjects enrolled in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial.

BACKGROUND

Heart failure with preserved ejection fraction (HFPEF) is a heterogeneous clinical syndrome. Whether QRS duration identifies HFPEF subjects at an increased risk of adverse outcomes has not been well studied.

METHODS

QRS duration was analyzed as a dichotomous variable (≥120 ms or <120 ms) and as a continuous variable to determine its relation to the primary outcome (composite of cardiovascular death, aborted cardiac arrest, or HF hospitalization [HFH]) and to each component of the primary outcome. Multivariate analyses were conducted in the entire study cohort as well as in separate analyses for subjects enrolled only from North and South America, or from Russia and Georgia.

RESULTS

The QRS duration of ≥120 ms was independently associated with an increased risk of the primary outcome (p = 0.009) and HFH (p = 0.003) in the entire study cohort and in the subset enrolled in the Americas. There was a linear relation of QRS duration with risk of the primary outcome and HFH. No interaction was observed between treatment with spironolactone and QRS duration. The risk of adverse outcomes was increased independently of the type of conduction abnormality underlying prolonged QRS duration.

CONCLUSIONS

This post hoc analysis demonstrated that prolonged QRS duration identifies HFPEF subjects at a higher risk of adverse clinical outcomes and that spironolactone had a similar effect on outcomes independent of QRS duration. (Aldosterone Antagonist Therapy for Adults With Heart Failure and Preserved Systolic Function [TOPCAT]; NCT00094302).

Advances in the pathophysiology and treatment of heart failure with preserved ejection fraction

PURPOSE OF REVIEW

With the failure of multiple trials to identify a successful therapy for heart failure with preserved ejection fraction (HFpEF), attention has shifted to defining specific phenotypes within the HFpEF spectrum in an effort to develop a targeted approach to treatment. Here we summarize the most recent studies investigating the pathophysiology and clinical features of HFpEF, and discuss recent clinical trials in the context of developing treatments that look toward the underlying cause of this disorder.

RECENT FINDINGS

Advances in basic science and clinical research have further characterized HFpEF, identifying multiple pathophysiological mechanisms that ultimately lead to exercise intolerance and volume overload. The success of small studies focused on specific subsets of the HFpEF population has promoted the concept that there may not be one treatment strategy that can universally be applied to HFpEF.

SUMMARY

HFpEF is associated with significant morbidity and mortality and accounts for approximately half of patients with chronic heart failure. HFpEF is a complex disease, encompassing a diverse cohort of patients and marked by the presence of multiple etiological mechanisms. The failure to develop successful therapies for the management of HFpEF may be because of inadequate standardization of the HFpEF diagnosis, overly broad inclusion criteria and inadequate differentiation of disease subtypes. Given the heterogeneity among patients with HFpEF, much of the current research is focused on understanding of pathophysiology and identifying disease phenotypes that may respond to a targeted treatment approach. Several newer approaches, including neprilysin inhibition and device therapy, offer promise for a new era of HFpEF treatment.

Outcomes and worsening renal function in patients hospitalized with heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) has been described as a disease of elderly subjects with female predominance and hypertension. Our clinical experience suggests patients with HFpEF from an urban population are far more heterogenous, with greater co-morbidities and significant inhospital morbidity. There are limited data on the hospitalization course and outcomes in acute decompensated HFpEF. Hospitalizations for acute heart failure at our institution from July 2011 to June 2012 were identified by International Classification of Diseases, Ninth Revision, codes and physician review for left ventricular ejection fraction ≥50% and were reviewed for patient characteristics and clinical outcomes. Worsening renal function (WRF) was defined as creatinine increase of ≥0.3 mg/dl by 72 hours after admission. Hospital readmission and mortality data were captured from electronic medical records and the Social Security Death Index. Of 434 heart failure admissions, 206 patients (47%) with HFpEF were identified. WRF developed in 40%, the highest reported in HFpEF to date, and was associated with higher blood pressure and lower volume of diuresis. Compared to previous reports, hospitalized patients with HFpEF were younger (mean age 63.2 ± 13.6 years), predominantly black (74%), and had more frequent and severe co-morbidities: hypertension (89%), diabetes (56%), and chronic kidney disease (55%). There were no significant differences in 1- and 12-month outcomes by gender, race, or WRF. In conclusion, we found hospitalized patients with HFpEF from an urban population develop a high rate of WRF are younger than previous cohorts, often black, and have greater co-morbidities than previously described.

Challenging aspects of treatment strategies in heart failure with preserved ejection fraction: "Why did recent clinical trials fail?"

Heart failure (HF) is the leading cause of hospitalization among older adults and the prevalence is growing with the aging populations in the Western countries. Epidemiologic reports suggest that approximately 50% of patients who have signs or symptoms of HF have preserved left ventricular ejection fraction. This HF type predominantly affects women and the elderly with other co-morbidities, such as diabetes, hypertension, and overt volume status. Most of the current treatment strategies are based on morbidity benefits such as quality of life and reduction of clinical HF symptoms. Treatment of patients with HF with preserved ejection fraction displayed disappointing results from several large randomized controlled trials. The heterogeneity of HF with preserved ejection fraction, understood as complex syndrome, seems to be one of the primary reasons. Here, we present an overview of the current management strategies with available evidence and new therapeutic approach from drugs currently in clinical trials, which target diastolic dysfunction, chronotropic incompetence, and risk factor management. We provide an outline and interpretation of recent clinical trials that failed to improve outcome and survival in patients with HF with preserved ejection fraction.

Invasive hemodynamic characterization of heart failure with preserved ejection fraction

Recent hemodynamic studies have advanced our understanding of heart failure with preserved ejection fraction (HFpEF). Despite improved pathophysiologic insight, clinical trials have failed to identify an effective treatment for HFpEF. Invasive hemodynamic assessment can diagnose or exclude HFpEF, making it invaluable in understanding the basis of the disease. This article reviews the hemodynamic mechanisms underlying HFpEF and how they manifest clinically, discusses invasive hemodynamic assessment as a diagnostic tool, and explores how invasive hemodynamic profiling may allow understanding of pathophysiological differences and inform the design and entry criteria for future trials.

Heart failure with preserved ejection fraction in the elderly: scope of the problem

Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults, particularly women, and is increasing in prevalence as the population ages. With morbidity and mortality on par with HF with reduced ejection fraction, it remains a most challenging clinical syndrome for the practicing clinician and basic research scientist. Originally considered to be predominantly caused by diastolic dysfunction, more recent insights indicate that HFpEF in older persons is typified by a broad range of cardiac and non-cardiac abnormalities and reduced reserve capacity in multiple organ systems. The globally reduced reserve capacity is driven by: 1) inherent age-related changes; 2) multiple, concomitant co-morbidities; 3) HFpEF itself, which is likely a systemic disorder. These insights help explain why: 1) co-morbidities are among the strongest predictors of outcomes; 2) approximately 50% of clinical events in HFpEF patients are non-cardiovascular; 3) clinical drug trials in HFpEF have been negative on their primary outcomes. Embracing HFpEF as a true geriatric syndrome, with complex, multi-factorial pathophysiology and clinical heterogeneity could provide new mechanistic insights and opportunities for progress in management. This article is part of a Special Issue entitled CV Aging.