Impaired systolic function by strain imaging in heart failure with preserved ejection fraction

Angiotensin receptor neprilysin inhibition in heart failure: mechanistic action and clinical impact

Heart failure (HF) is an increasingly common syndrome associated with high mortality and economic burden, and there has been a paucity over the past decade of new pharmacotherapies that improve outcomes. However, recent data from a large randomized controlled trial compared the novel agent LCZ696, a dual-acting angiotensin receptor blocker and neprilysin inhibitor (ARNi), with the well established angiotensin-converting enzyme (ACE) inhibitor enalapril and found significant reduction in mortality among the chronic reduced ejection fraction HF population. Preclinical and clinical data suggest that neprilysin inhibition provides beneficial outcomes in HF patients by preventing the degradation of natriuretic peptides and thereby promoting natriuresis and vasodilatation and counteracting the negative cardiorenal effects of the up-regulated renin-angiotensin-aldosterone system. Agents such as omapatrilat combined neprilysin and ACE inhibition but had increased rates of angioedema. Goals of an improved safety profile provided the rationale for the development of the ARNi LCZ696. Along with significant reductions in mortality and hospitalizations, clinical trials suggest that LCZ696 may improve surrogate markers of HF severity. In this paper, we review the preclinical and clinical data that led to the development of LCZ696, the understanding of the underlying mechanistic action, and the robust clinical impact that LCZ696 may have in the near future.

Myocardial hypertrophy and its role in heart failure with preserved ejection fraction

Left ventricular hypertrophy (LVH) is the most common myocardial structural abnormality associated with heart failure with preserved ejection fraction (HFpEF). LVH is driven by neurohumoral activation, increased mechanical load, and cytokines associated with arterial hypertension, chronic kidney disease, diabetes, and other comorbidities. Here we discuss the experimental and clinical evidence that links LVH to diastolic dysfunction and qualifies LVH as one diagnostic marker for HFpEF. Mechanisms leading to diastolic dysfunction in LVH are incompletely understood, but may include extracellular matrix changes, vascular dysfunction, as well as altered cardiomyocyte mechano-elastical properties. Beating cardiomyocytes from HFpEF patients have not yet been studied, but we and others have shown increased Ca(2+) turnover and impaired relaxation in cardiomyocytes from hypertrophied hearts. Structural myocardial remodeling can lead to heterogeneity in regional myocardial contractile function, which contributes to diastolic dysfunction in HFpEF. In the clinical setting of patients with compound comorbidities, diastolic dysfunction may occur independently of LVH. This may be one explanation why current approaches to reduce LVH have not been effective to improve symptoms and prognosis in HFpEF. Exercise training, on the other hand, in clinical trials improved exercise tolerance and diastolic function, but did not reduce LVH. Thus current clinical evidence does not support regression of LVH as a surrogate marker for (short-term) improvement of HFpEF.

Patient selection in heart failure with preserved ejection fraction clinical trials

Recent clinical trials in patients with heart failure with preserved ejection fraction (HFpEF) have provided important insights into participant selection strategies. Historically, HFpEF trials have included patients with relatively preserved left ventricular ejection fraction ranging from 40% to 55% and a clinical history of heart failure. Contemporary HFpEF trials have also incorporated inclusion criteria such as hospitalization for HFpEF, altered functional capacity, cardiac structural and functional abnormalities, and abnormalities in neurohormonal status (e.g., elevated natriuretic peptide levels). Careful analyses of the effect of these patient selection criteria on outcomes in prior trials provide valuable lessons for future trial design. We review recent and ongoing HFpEF clinical trials from a patient selection perspective and appraise trial patient selection methodologies in relation to outcomes. This review reflects discussions between clinicians, scientists, trialists, regulators, and regulatory representatives at the 10th Global CardioVascular Clinical Trialists Forum in Paris, France, on December 6, 2013.

Global longitudinal two-dimensional systolic strain is associated with hemodynamic alterations in arterial hypertension

Arterial hypertension can lead to the progressive deterioration of the left ventricular (LV) performance. The aim of this study was to estimate the relation of global longitudinal systolic strain (GLSS) with central and systemic hemodynamics assessed by applanation tonometry and impedance cardiography in 125 hypertensive patients. Those with more impaired GLSS characterized with 1/worse diastolic function (mitral inflow early phase (E) to mitral septal annulus early diastolic velocity (e') ratio, 8.0 vs. 7.0, P = .014); 2/lower LV performance (cardiac index, 3.14 vs. 3.64 l/min/m(2); P = .007), and 3/higher afterload (systemic vascular resistance index, 2506 vs. 2107 dyn s m(2)/cm(5); P = .008). No relevant differences in, that is, gender, age, blood pressure, LV mass index, left chambers dimensions, and central blood pressure characteristics were identified. The results revealed that impaired GLSS is related to LV diastolic dysfunction and altered hemodynamics which may be markers of early systolic LV dysfunction related to arterial hypertension.

Functional Organ Damage in Cardiovascular Low Risk Patients with High Central Aortic Pressure

BACKGROUND

The loss of the viscoelastic properties of central arteries independently of blood pressure loads could stimulate the development of left ventricular hypertrophy and dysfunction, renal failure, or cerebral vascular injury.

OBJECTIVE

The aim of the present study is to determine if an elevated systolic aortic pressure is a marker of more frequent target organ damage (TOD) in hypertensive low cardiovascular risk (CVR) patients.

METHODS

Hypertensive non treated consecutive patients (p) assisted at first visit in a specialized center with a CVR according to WHO Americas B area score less than 10 % were included. Left ventricular mass index (LVMI) and tissue Doppler diastolic and systolic function were measured as Lang et al. (J Am Soc Echocardiogr 18:1440-1463, 2005) and Nagueh et al. (J Am Soc Echocardiogr 22:107-133, 2009). Cardiac TOD was considered according to 2013 European Society of Hypertension/European Society of Cardiology. Glomerular filtration rate (GFR) was calculated by MDRD formula, a value <60 ml/min/1.73 m(2) was considered TOD. Systolic aortic pressured (CAoP) was measured by radial tonometry and classified according to criteria proposed by Herbert et al. (Eur Heart J 35:3100-3132, 2014). Continue variables are reported as means with standard deviation and discrete variables as absolute values and percentages. Statistical analysis was performed with Students t test, significant differences were considered with a p value < 0.05 RESULTS: 155 p were included; 23 p (14.8 %) had elevated CAoP while 132 p (85.2 %) had normal CAoP. Sample mean age was 54.1 + 12.9 years; 85 p (54.8 %) were males. Dyslipidemia was detected in 44 p (28.4 %), and 18 p (11.6 %) were smokers. Mean blood pressure was 143.7 + 17.1 mmHg/86.4 + 12.3 mmHg in p with normal (n) CAoP and 140.3 + 12 mmHg/81.9 + 6.8 mmHg in p with CAoP elevated e (p = NS). Mean CAoP in p with normal values was 117.4 + 10.9 mmHg and 116.9 + 10.7 in p with elevated values (p = NS). The average s wave was 7.42 + 1 cm/sec in n CAoP p vs 6.6 + 1 cm/sec in e CAoP p (p < 0.05) while and E/e' ratio >13 was detected in 14.4 % n CAoP p vs 8.7 % e CAoP p (p = NS). Mean GFR was 105.4 + 40.5 ml/min/1.73 m(2) in n CAoP p vs 103.9 + 45.6 ml/min/1.73 m(2) in e CAoP p (p = NS) and GFR <60 ml/min/1.73 m(2) was present in 4.5 % n CAoP p vs 26.1 % e CAoP p (p < 0.0125).

CONCLUSIONS

At the same level of CVR according to WHO Americas B score patients with elevated CAoP had lower longitudinal left ventricular systolic function and renal function was more deteriorated.

Imaging Techniques in Acute Heart Failure

In recent years, imaging techniques have revolutionized the diagnosis of heart failure. In patients with a clinical picture of acute decompensation, prognosis is largely determined by early implementation of general measures and treatment of the underlying cause. Given its diagnostic yield and portability, ultrasound has become an essential tool in the setting of acute heart failure, and is currently found in all medical departments involved in the care of the critically ill patient. Cardiac magnetic resonance and computed tomography allow detailed characterization of multiple aspects of cardiac structure and function that were previously unavailable. This helps guide and monitor many of the treatment decisions in the acute heart failure population in an entirely noninvasive way. This article aims to review the usefulness of the imaging techniques that are clinically relevant in the context of an episode of acute heart failure. We discuss the indications and limitations of these techniques in detail and describe the general principles for the appropriate interpretation of results.

Alterations of left ventricular deformation and cardiac sympathetic derangement in patients with systolic heart failure: a 3D speckle tracking echocardiography and cardiac ¹²³I-MIBG study

PURPOSE

Myocardial contractile function is under the control of cardiac sympathetic activity. Three-dimensional speckle tracking echocardiography (3D-STE) and cardiac imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) are two sophisticated techniques for the assessment of left ventricular (LV) deformation and sympathetic innervation, respectively, which offer important prognostic information in patients with heart failure (HF). The purpose of this investigation was to explore, in patients with systolic HF, the relationship between LV deformation assessed by 3D-STE and cardiac sympathetic derangement evaluated by (123)I-MIBG imaging.

METHODS

We prospectively studied 75 patients with systolic HF. All patients underwent a 3D-STE study (longitudinal, circumferential, area and radial) and (123)I-MIBG planar and SPECT cardiac imaging.

RESULTS

3D-STE longitudinal, circumferential and area strain values were correlated with (123)I-MIBG late heart to mediastinum (H/M) ratio and late SPECT total defect score. After stratification of the patients according to ischaemic or nonischaemic HF aetiology, we observed a good correlation of all 3D-STE measurements with late H/M ratio and SPECT data in the ischaemic group, but in patients with HF of nonischaemic aetiology, no correlation was found between LV deformation and cardiac sympathetic activity. At the regional level, the strongest correlation between LV deformation and adrenergic innervation was found for the left anterior descending coronary artery distribution territory for all four 3D-STE values. In multivariate linear regression analyses, including age, gender, LV ejection fraction, NYHA class, body mass index, heart rate and HF aetiology, only 3D-STE area and radial strain values significantly predicted cardiac sympathetic derangement on (123)I-MIBG late SPECT.

CONCLUSION

This study indicated that 3D-STE measurements are correlated with (123)I-MIBG planar and SPECT data. Furthermore, 3D-STE area and radial strain values, but not LVEF, predict cardiac sympathetic derangement in human postischaemic HF.

Left ventricular ejection fraction is determined by both global myocardial strain and wall thickness

Objectives

The purpose of this study was to determine the mathematical relationship between left ventricular ejection fraction and global myocardial strain. A reduction in myocardial strain would be expected to cause a fall in ejection fraction. However, there is abundant evidence that abnormalities of myocardial strain can occur with a normal ejection fraction. Explanations such as a compensatory increase in radial or circumferential strain are not supported by clinical studies. We set out to determine the biomechanical relationship between ejection fraction, wall thickness and global myocardial strain.

Methods

The study used an established abstract model of left ventricular contraction to examine the effect of global myocardial strain and wall thickness on ejection fraction. Equations for the relationship between ejection fraction, wall thickness and myocardial strain were obtained using curve fitting methods.

Results

The mathematical relationship between ejection fraction, ventricular wall thickness and myocardial strain was derived as follows: φ = e^{(0.14Ln(ε) + 0.06)ω + (0.9Ln(ε) + 1.2)}, where φ is ejection fraction (%), ω is wall thickness (cm) and ε is myocardial strain (−%).

Conclusion

The findings of this study explain the coexistence of reduced global myocardial strain and normal ejection fraction seen in clinical observational studies. Our understanding of the pathophysiological processes in heart failure and associated conditions is substantially enhanced. These results provide a much better insight into the biophysical inter-relationship between myocardial strain and ejection fraction. This improved understanding provides an essential foundation for the design and interpretation of future clinical mechanistic and prognostic studies.

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Ejection fraction has a limited value in predicting mortality and functional capacity.

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Myocardial mechanics including the relationship between myocardial strain and ejection fraction are currently poorly understood.

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We showed that there is biophysical relationship between end-diastolic wall thickness, myocardial strain and ejection fraction.

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Such a relationship explains the poor correlation of ejection fraction with prognosis and functional capacity.

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The study provides the foundation for determining the relationship between ventricular hypertrophy, ejection fraction and prognosis.

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words

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.

Clinical outcomes and cardiovascular responses to exercise training in heart failure patients with preserved ejection fraction: a systematic review and meta-analysis

Exercise training induces physical adaptations for heart failure patients with systolic dysfunction, but less is known about those patients with preserved ejection fraction. To establish whether exercise training produces changes in peak V̇o2 and related measures, quality of life, general health, and diastolic function in heart failure patients with preserved ejection fraction. We conducted a MEDLINE search (1985 to October 10, 2014), for exercise-based rehabilitation trials in heart failure, using search terms "exercise training, heart failure with preserved ejection fraction, heart failure with normal ejection fraction, peak V̇o₂, and diastolic heart dysfunction". Seven intervention studies were included providing a total of 144 exercising subjects and 114 control subjects, a total of 258 participants. Peak V̇o₂ increased by a mean difference (MD) 2.13 ml·kg(-1)·min(-1) [95% confidence interval (CI) 1.54 to 2.71, P < 0.00001] in exercise training vs. sedentary control, equating to a 17% improvement from baseline. The corresponding data are provided for the following exercise test variables: V̇e/V̇co₂ slope, MD 0.85 ml·kg(-1)·min(-1) (95% CI 0.05 to 1.65, P = 0.04); maximum heart rate, MD 5.60 beats per minute (95% CI 3.95 to 7.25, P < 0.00001); Six-Minute Walk Test, MD 32.1 m (95% CI 17.2 to 47.1, P < 0.0001); and indices of diastolic function: E/A ratio, MD 0.07 (95% CI 0.02 to 0.12, P = 0.005); E/E' ratio MD -2.31 (95% CI -3.44 to -1.19, P < 0.0001); deceleration time (DT), MD -13.2 ms (95% CI -19.8 to -6.5, P = 0.0001); and quality of life: Minnesota Living with Heart Failure Questionnaire, MD -6.50 (95% CI -9.47 to -3.53, P < 0.0001); and short form-36 health survey (physical dimension), MD 15.6 (95% CI 7.4 to 23.8, P = 0.0002). In 3,744 h patient-hours of training, not one death was directly attributable to exercise. Exercise training appears to effect several health-related improvements in people with heart failure and preserved ejection fraction.

Prognostic significance of semiautomatic quantification of left ventricular long axis shortening in systemic light-chain amyloidosis

AIMS

To assess left ventricular long axis shortening (LAS) in patients with AL amyloidosis as a potential predictor for outcome.

METHODS AND RESULTS

We performed a de novo echocardiographic analysis of LAS in 120 patients with biopsy-proven AL amyloidosis evaluated at first presentation before specific treatment. Additionally, 47 control subjects were analyzed retrospectivly. LAS was measured using a semiautomatic tissue motion annular displacement software algorithm (TMAD). LAS was significantly better than ejection fraction (EF) (p < 0.0001) and M-mode-derived mitral annular plane systolic excursion (MAPSE) (p < 0.05) discriminating AL patients from control subjects, while being non-inferior compared to tissue Doppler-derived peak systolic mitral annular velocity. One year outcome analysis in patients with AL amyloidosis showed that LAS remained the only significant echocardiographic parameter (HR:0.76; p < 0.005) in a multivariable Cox regression model of echocardiographic values. In a comprehensive clinical model, LAS (HR:0.72, p < 0.0001), cardiac troponin-T (HR:2.86, p < 0.01) and free light chain difference (HR:1.00; p < 0.05) were independently associated with the outcome. Assessment of LAS led to a significant integrated discrimination improvement and offered incremental information compared to EF and biomarkers. The cut-off value for LAS discriminating the endpoint was 5.8%.

CONCLUSION

LAS was an independent predictor of survival within the first year and offers incremental information in patients with AL amyloidosis evaluated prior to specific treatment.

Heart failure with preserved ejection fraction: current understandings and challenges

Heart failure (HF) is the leading cause of hospitalization among older adults and the prevalence is growing with the aging populations in western countries. Approximately one-half of patients with HF have preserved ejection fraction (HFpEF). In contrast to HF with reduced EF (HFrEF), there is no proven effective treatment for HFpEF. The pathophysiology of HFpEF is complex, and the dominant mechanisms leading to symptoms of HF often vary between afflicted patients, confounding efforts to apply "one-size fits all" types of therapeutic approaches. Current treatment strategies focus on control of volume status and comorbidities, but future research aimed at individualized therapies holds promise to improve outcomes in this increasingly prevalent form of cardiac failure.

Increased extracellular volume and altered mechanics are associated with LVH in hypertensive heart disease, not hypertension alone

OBJECTIVES

The goal of this study was to assess the relationship among extracellular volume (ECV), native T1, and systolic strain in hypertensive patients with left ventricular hypertrophy (HTN LVH), hypertensive patients without LVH (HTN non-LVH), and normotensive controls.

BACKGROUND

Diffuse myocardial fibrosis in HTN LVH patients, as reflected by increased ECV and native T1, may be an underlying mechanism contributing to increased cardiovascular risk compared with HTN non-LVH subjects and controls. Furthermore, increased diffuse fibrosis in HTN LVH subjects may be associated with reduced peak systolic and early diastolic strain rate compared with the other 2 groups.

METHODS

T1 mapping was performed in 20 HTN LVH (mean age, 55 ± 11 years), 23 HTN non-LVH (mean age, 61 ± 12 years), and 22 control subjects (mean age, 54 ± 7 years) on a Siemens 1.5-T Avanto (Siemens Healthcare, Erlangen, Germany) using a previously validated modified look-locker inversion-recovery pulse sequence. T1 was measured pre-contrast and 10, 15, and 20 min after injection of 0.15 mmol/kg gadopentetate dimeglumine, and the mean ECV and native T1 were determined for each subject. Measurement of circumferential strain parameters were performed using cine displacement encoding with stimulated echoes.

RESULTS

HTN LVH subjects had higher native T1 compared with controls (p < 0.05). HTN LVH subjects had higher ECV compared with HTN non-LVH subjects and controls (p < 0.05). Peak systolic circumferential strain and early diastolic strain rates were reduced in HTN LVH subjects compared with HTN non-LVH subjects and controls (p < 0.05). Increased levels of ECV and native T1 were associated with reduced peak systolic and early diastolic circumferential strain rate across all subjects.

CONCLUSIONS

HTN LVH patients had higher ECV, longer native T1 and associated reduction in peak systolic circumferential strain, and early diastolic strain rate compared with HTN non-LVH and control subjects. Measurement of ECV and native T1 provide a noninvasive assessment of diffuse fibrosis in hypertensive heart disease.

Left ventricular diastolic function and dysfunction: Central role of echocardiography

Comprehensive and precise assessment of left ventricular (LV) systolic and diastolic function is necessary to establish, or exclude, heart failure as a cause or component of dyspnea. Echocardiography with Doppler readily assesses LV diastolic function; advantages include that echocardiography is non-invasive, does not require radiation, is portable, rapid, readily available, and in competent hands, can provide an accurate and comprehensive assessment of LV systolic and diastolic function. Correct assessment of LV diastolic function is relevant in patients with both depressed and preserved LV ejection fraction (EF ≥ 50%, and < 50%, respectively). Tissue Doppler (TD) imaging has been useful in demonstrating impaired LV relaxation in the setting of preserved LVEF, which, in the setting of increased cardiac volume, can result in elevated LV filling pressures, and dyspnea due to diastolic heart failure. TD imaging is not always critical in patients with depressed LVEF, since such patients by definition have impaired LV relaxation, and thus significant increases in volume will result in increases in LV filling pressure due to impaired LV compliance. Thus, in depressed LVEF, transmitral flow velocities (E and A, and E/A) and deceleration time, pulmonary venous Doppler, left atrial volume, and pulmonary artery (PA) pressures suffice for the accurate assessment of LV filling pressures. Overall, diastolic assessment by echo-Doppler can be readily achieved in by using a comprehensive diastolic assessment—incorporating many 2-dimensional, conventional and tissue Doppler variables—as opposed to relying on any single, diastolic parameter, which can lead to errors.

Misconceptions and facts about 'diastolic' heart failure

Heart failure with preserved ejection fraction has become a fashionable diagnosis. An increasing number of elderly patients with dyspnea carry this diagnosis. Evaluation and management of these patients typically labeled as having "diastolic" heart failure are challenging, and misconceptions are common. No drug class has been shown to consistently provide outcome benefit. Therapeutic strategies based on the predominant pathophysiologic mechanism and stage of the disease currently remain the best option in tackling the perplexing syndrome of heart failure with preserved ejection fraction.

Left ventricular long-axis performance during exercise is an important prognosticator in patients with heart failure and preserved ejection fraction

BACKGROUND

Although many prognostic variables have been reported, the risk stratification of patients with heart failure and preserved ejection fraction (HFPEF) has long been controversial due to considerable discordance. Ergometry stress echocardiography may provide a more clinical relevant evaluation in HFPEF. We aimed at evaluating the prognostic value of echocardiographic parameters during exercise in HFPEF patients.

METHODS

Comprehensive echocardiographic examination with symptom-limited exercise testing on a semi-recumbent and tilting bicycle Ergometer (Lode BV, Groningen, the Netherlands) was performed on 80 consecutive HFPEF patients (aged 66±8years; 64% male). The exercise images for two-dimensional (2D) speckle tracking analysis were acquired with heart rate of 90-100bpm, while exercise images for tissue Doppler imaging (TDI) and M-mode echocardiography were stored with attainment of >85% of maximal age-predicted heart rate. All patients were followed up for 3years after stress echocardiography for all-cause mortality and/or heart failure (HF) hospitalization.

RESULTS

During the follow-up, 43 (54%) patients reached the combined end point: 5 (6%) patients died, and another 38 (48%) patients experienced HF hospitalizations. Univariate predictors were: decreased resting left atrial ejection fraction (LAEF), lower peak heart rate, elevated E/e' ratio, reduced TDI myocardial velocities, and impaired 2D global longitudinal strain (GLS) during exercise. Only impaired GLS (hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.67 to 0.91) remained independent after multivariate analysis (p=0.008).

CONCLUSIONS

More than half of the HFPEF patients died or were hospitalized for HF at 3-year follow-up and this was significantly related to impaired left ventricular long-axis function during exercise.

New strategies for heart failure with preserved ejection fraction: the importance of targeted therapies for heart failure phenotypes

The management of heart failure with reduced ejection fraction (HF-REF) has improved significantly over the last two decades. In contrast, little or no progress has been made in identifying evidence-based, effective treatments for heart failure with preserved ejection fraction (HF-PEF). Despite the high prevalence, mortality, and cost of HF-PEF, large phase III international clinical trials investigating interventions to improve outcomes in HF-PEF have yielded disappointing results. Therefore, treatment of HF-PEF remains largely empiric, and almost no acknowledged standards exist. There is no single explanation for the negative results of past HF-PEF trials. Potential contributors include an incomplete understanding of HF-PEF pathophysiology, the heterogeneity of the patient population, inadequate diagnostic criteria, recruitment of patients without true heart failure or at early stages of the syndrome, poor matching of therapeutic mechanisms and primary pathophysiological processes, suboptimal study designs, or inadequate statistical power. Many novel agents are in various stages of research and development for potential use in patients with HF-PEF. To maximize the likelihood of identifying effective therapeutics for HF-PEF, lessons learned from the past decade of research should be applied to the design, conduct, and interpretation of future trials. This paper represents a synthesis of a workshop held in Bergamo, Italy, and it examines new and emerging therapies in the context of specific, targeted HF-PEF phenotypes where positive clinical benefit may be detected in clinical trials. Specific considerations related to patient and endpoint selection for future clinical trials design are also discussed.

Elevation in high-sensitivity troponin T in heart failure and preserved ejection fraction and influence of treatment with the angiotensin receptor neprilysin inhibitor LCZ696

BACKGROUND

Elevated high-sensitivity troponin is associated with increasing disease severity in patients with stable heart failure with reduced ejection fraction, but less is known about the association in heart failure with preserved ejection fraction.

METHODS AND RESULTS

We examined the prevalence of elevated high-sensitivity troponin T (hs-TnT) in 298 patients with heart failure with preserved ejection fraction enrolled in the Prospective comparison of angiotensin receptor neprilysin inhibitor with angiotensin receptor blocker on Management Of heart failUre with preserved ejectioN fracTion (PARAMOUNT) trial, in which the angiotensin receptor neprilysin inhibitor LCZ696 reduced markers of heart failure severity compared with valsartan. We assessed the association between hs-TnT and cardiac structure and function, and the effect of LCZ696, compared with valsartan, on hs-TnT over 36 weeks. Elevated hs-TnT in the myocardial injury range (>0.014 μg/L) was found in 55% of patients and was associated with older age, history of diabetes mellitus, higher N-terminal pro-brain natriuretic peptide, lower estimated glomerular filtration rate, and larger left atrial size, left ventricular volume, and mass. LCZ696 treatment reduced hs-TnT to a greater extent at 12 weeks (12% reduction; P=0.05) and at 36 weeks (14% reduction; P=0.03) compared with valsartan.

CONCLUSIONS

Troponin T was elevated in a substantial number of patients enrolled in a heart failure with preserved ejection fraction clinical trial and was associated with abnormalities of cardiac structure, function, and elevated baseline N-terminal pro-brain natriuretic peptide. Decreases in hs-TnT with LCZ696 in parallel with improvement in N-terminal pro-brain natriuretic peptide and left atrial size suggest that the angiotensin receptor neprilysin inhibitor LCZ696 may reduce this measure of myocardial injury in heart failure with preserved ejection fraction.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00887588.

Pulmonary capillary wedge pressure during exercise and long-term mortality in patients with suspected heart failure with preserved ejection fraction

AIMS

In patients with suspected heart failure with preserved ejection fraction (HFpEF), invasive exercise testing may be considered when measurements at rest are inconclusive. However, the prognostic impact of invasive exercise testing is uncertain, so far.

METHODS AND RESULTS

We retrospectively analysed mortality in 355 patients [mean age 61.2 ± 11.3 years, 235 (66.2%) women] with unexplained dyspnoea and suspected HFpEF. During an invasive haemodynamic stress test pulmonary capillary wedge pressure (PCWP) at rest and the PCWP response to exercise, expressed as the ratio of PCWP at peak exercise to workload normalized to body weight [PCWL (mmHg/W/kg)], were recorded. Both PCWP at rest and PCWL were significant and independent predictors of long-term mortality. Adding PCWL to PCWP at rest improved reclassification of patients into survivors or non-survivors with a net reclassification improvement (NRI) of 0.56 (95% CI: 0.29-0.83; P < 0.001). Ten-year mortality was 6.6% in subjects with low PCWP at rest (≤ 12 mmHg) and low PCWL (≤ 25.5 mmHg/W/kg); 28.2% in patients with low PCWP and high PCWL and 35.2% in those with high PCWP and high PCWL. Compared with patients with low PCWP and low PCWL, the adjusted hazard ratio for mortality was 2.37 (95% CI: 1.09-5.17; P = 0.029) for the low-PCWP/high-PCWL group and 4.75 (95% CI: 1.90-11.84; P < 0.001) for patients with high PCWP/high PCWL.

CONCLUSION

In patients with suspected HFpEF, invasive exercise testing substantially improves prediction of long-term mortality. An excessive rise of PCWP during exercise despite normal PCWP at rest is associated with increased mortality and may be considered as early HFpEF.

Impaired left atrial function in heart failure with preserved ejection fraction

AIMS

Left atrial (LA) enlargement is present in the majority of heart failure with preserved ejection fraction (HFpEF) patients and is a marker of risk. However, the importance of LA function in HFpEF is less well understood.

METHODS AND RESULTS

The PARAMOUNT trial enrolled HFpEF patients (LVEF ≥45%, NT-proBNP >400 pg/mL). We assessed LA reservoir, conduit, and pump function using two-dimensional volume indices and speckle tracking echocardiography in 135 HFpEF patients in sinus rhythm at the time of echocardiography and 40 healthy controls of similar age and gender. Systolic LA strain was related to clinical characteristics and measures of cardiac structure and function. Compared with controls, HFpEF patients had worse LA reservoir, conduit, and pump function. The differences in systolic LA strain (controls 39.2 ± 6.6% vs. HFpEF 24.6 ± 7.3%) between groups remained significant after adjustments and even in the subsets of HFpEF patients with normal LA size or without a history of AF. Among HFpEF patients, lower systolic LA strain was associated with higher prevalence of prior HF hospitalization and history of AF, as well as worse LV systolic function, and higher LV mass and LA volume. However, NT-proBNP and E/E' were similar across the quartiles of LA function.

CONCLUSIONS

In this HFpEF cohort, we observed impairment in all phases of LA function, and systolic LA strain was decreased independent of LA size or history of AF. LA dysfunction may be a marker of severity and play a pathophysiological role in HFpEF.

TRIAL REGISTRATION

NCT00887588.

A pilot study of angiogenin in heart failure with preserved ejection fraction: a novel potential biomarker for diagnosis and prognosis?

Characteristics of heart failure with preserved ejection fraction (HFPEF) have not yet been fully understood. The objectives of this pilot study are to detect protein expression profile in the sera of HFPEF patients, and to identify potential biomarkers for the disease. Five hundred and seven proteins were detected in the sera of healthy volunteers and patients with either HFPEF or hypertension using antibody microarrays (three in each group). The results showed that the serum concentrations of 17 proteins (e.g. angiogenin, activin A and artemin) differed considerably between HFPEF and non-HFPEF patients (hypertensive patients and healthy controls), while a protein expression pattern distinct from that in non-HFPEF patients was associated with HFPEF patients. The up-regulation of angiogenin in both HFPEF patients with LVEF ≥50% (P = 0.004) and a subset of HFPEF patients with LVEF = 41–49% (P < 0.001) was further validated in 16 HFPEF patients and 16 healthy controls. Meanwhile, angiogenin distinguished HFPEF patients from controls with a mean area under the receiver operating characteristic curve of 0.88 (P < 0.001) and a diagnostic cut-off point of 426 ng/ml. Moreover, the angiogenin levels in HFPEF patients were positively correlated with Lg(N-terminal pro-B-type natriuretic peptide, NT-proBNP) (P < 0.001). In addition, high angiogenin level (≥426 ng/ml) was a predictor of all-cause death within a short-term follow-up duration, but not in the longer term of 36 months. This pilot study indicates that the aforementioned 17 potential biomarkers, such as angiogenin, may hold great promise for both diagnosis and prognosis assessment of HFPEF.

Heart failure with preserved ejection fraction: mechanisms, clinical features, and therapies

The clinical syndrome comprising heart failure (HF) symptoms but with a left ventricular ejection fraction (EF) that is not diminished, eg, HF with preserved EF, is increasingly the predominant form of HF in the developed world, and soon to reach epidemic proportions. It remains among the most challenging of clinical syndromes for the practicing clinician and scientist alike, with a multitude of proposed mechanisms involving the heart and other organs and complex interplay with common comorbidities. Importantly, its morbidity and mortality are on par with HF with reduced EF, and as the list of failed treatments continues to grow, HF with preserved EF clearly represents a major unmet medical need. The field is greatly in need of a more unified approach to its definition and view of the syndrome that engages integrative and reserve pathophysiology beyond that related to the heart alone. We need to reflect on prior treatment failures and the message this is providing, and redirect our approaches likely with a paradigm shift in how the disease is viewed. Success will require interactions between clinicians, translational researchers, and basic physiologists. Here, we review recent translational and clinical research into HF with preserved EF and give perspectives on its evolving demographics and epidemiology, the role of multiorgan deficiencies, potential mechanisms that involve the heart and other organs, clinical trials, and future directions.

Accurate high-resolution measurements of 3-D tissue dynamics with registration-enhanced displacement encoded MRI

Displacement fields are important to analyze deformation, which is associated with functional and material tissue properties often used as indicators of health. Magnetic resonance imaging (MRI) techniques like DENSE and image registration methods like Hyperelastic Warping have been used to produce pixel-level deformation fields that are desirable in high-resolution analysis. However, DENSE can be complicated by challenges associated with image phase unwrapping, in particular offset determination. On the other hand, Hyperelastic Warping can be hampered by low local image contrast. The current work proposes a novel approach for measuring tissue displacement with both DENSE and Hyperelastic Warping, incorporating physically accurate displacements obtained by the latter to improve phase characterization in DENSE. The validity of the proposed technique is demonstrated using numerical and physical phantoms, and in vivo small animal cardiac MRI.