Utility of natriuretic peptides to assess and manage patients with heart failure receiving angiotensin receptor blocker/neprilysin inhibitor therapy

Angiotensin Receptor-Neprilysin Inhibitors and the Natriuretic Peptide Axis

PURPOSE OF THE REVIEW

The purpose of this review is to describe the effects of angiotensin receptor neprilysin inhibitor (ARNI) therapy on the natriuretic peptide axis (NPA), with a particular focus on B-type natriuretic peptide (BNP), atrial natriuretic peptide (ANP), and C-type natriuretic peptide (CNP) to better understand the biology behind the improved outcomes in patients with heart failure with reduced ejection fraction (HFrEF).

RECENT FINDINGS

BNP, ANP, and CNP are the three main natriuretic peptides (NP); they share a common structure and ultimately mediate their actions by activating cyclic guanosine monophosphate (cGMP). ARNI therapy results in a decrease of N-terminal pro-BNP (NT-proBNP) and increase of BNP levels respectively. It is been questioned whether these changes may result from unique laboratory assays characteristics rather than actual biological implications. It appears to be that the prognostic accuracy of BNP for cardiovascular outcomes remains independent and comparable to that of NT-proBNP while on ARNI therapy. ANP levels also increase with ARNI therapy, but no consistent change has been described for CNP levels. There is evidence that the changes in BNP and NT-proBNP correlate with improvement in echocardiographic parameters of volume and function. The dual effect of neprilysin inhibition and angiotensin receptor blockade has substantial implications on the natriuretic peptide axis (NPA). The changes seen in BNP and NT-proBNP specifically have shown to correlate with improvement in echocardiographic parameters. Further results exploring the biologic effects of ARNI therapy on other NPs are still pending and likely will provide further insights in the mechanisms behind the improvement in cardiac function and clinical outcomes.

Effects of Guanxinshutong Capsules as Complementary Treatment in Patients With Chronic Heart Failure: Study Protocol for a Randomized Controlled Trial

Chronic heart failure (CHF) is a common cardiovascular disease with high mortality and a poor prognosis, which places heavy burdens upon society and families. Traditional Chinese medicine (TCM) has been used extensively as complementary treatment for CHF. Guanxinshutong (GXST) capsules are used commonly for the treatment of coronary heart disease (CHD). Experimental research and small-sample clinical trials have shown that GXST can attenuate CHF. However, the effects of GXST as complementary medicine in CHF treatment lack high-quality clinical evidence. We have designed a multicenter, randomized, double-blind, placebo-controlled clinical trial that explores the efficacy and safety of using GXST compared with placebo for patients with CHF with reduced left ventricular ejection fraction (LVEF). A total of 480 participants will be assigned randomly to the GXST group or placebo group at a 2:1 ratio. GXST and placebo will be added to standard treatment for 12 weeks, and then followed up for another 40 weeks. The primary outcome is the improvement value of 6-min walk distance, and the secondary outcomes include plasma levels of N-terminal pro-B-type natriuretic peptide, New York Heart Association classification, Minnesota Living with Heart Failure Questionnaire scores, echocardiographic parameters, and clinical endpoint events. Adverse events will be monitored throughout the trial. Data will be analyzed following a predefined statistical analysis plan. This study will show the effects of the specific use of GXST in CHF patients with reduced LVEF. The Research Ethics Committee of the Second Affiliated Hospital of Zhejiang Chinese Medical University has approved this study (2019-Y-003-02). Written informed consent of patients will be required. This trial is registered in the Chinese Clinical Trial Registry (ChiCTR1900023877). Our results will be disseminated to the public through peer-reviewed journals, academic conferences, and the Internet.

Inappropriate use of laboratory tests: How availability triggers demand - Examples across Europe

INTRODUCTION

The appropriate use of laboratory diagnostics is increasingly at stake. The aim of this study was to depict some paradigmatic examples of under- and overutilization, as well as possible solutions across Europe.

METHODS

We collected six examples from five European countries where a rise or decline of orders for specific laboratory parameters was observed after organizational changes but without evidence of changes in patient collective characteristics as source of this variation.

RESULTS

The collected examples were the following: 1-Germany) Switch from a Brain-Natriuretic-Peptide assay to NT-pro Brain-Natriuretic-Peptide assay, resulting in a 374% increase in these analytics; 2-Spain) Implementation of a gatekeeping strategy in tumor marker diagnostics, resulting in a 15-61% reduction of these diagnostics; 3-Croatia) Stepwise elimination of creatine-kinase-MB assay from the laboratory portfolio; 4-UK) Removal of γ-glutamyl transferase from a "liver function" profile, resulting in 82% reduction of orders; 5-Austria) Implementation of a new device for rapid Influenza-RNA detection, resulting in a 450% increase of Influenza testing; 6-Spain) Insourcing of 1,25-(OH)₂-Vitamin D measurements, leading to a 378% increase of these analyses.

CONCLUSION

The six paradigmatic examples described in this manuscript show that availability of laboratory resources may considerably catalyze the demand, thus underscoring that inappropriate use of laboratory resources may be commonplace in routine laboratories all across Europe and most probably beyond. They also demonstrate that the application of simple strategies may assist in overcoming this issue. We believe that laboratory specialists need to refocus on the extra-analytical parts of the testing process and engage more in interdisciplinary patient-care.

Cardiorenal Syndrome: Classification, Pathophysiology, Diagnosis, and Treatment Strategies: A Scientific Statement From the American Heart Association

Cardiorenal syndrome encompasses a spectrum of disorders involving both the heart and kidneys in which acute or chronic dysfunction in 1 organ may induce acute or chronic dysfunction in the other organ. It represents the confluence of heart-kidney interactions across several interfaces. These include the hemodynamic cross-talk between the failing heart and the response of the kidneys and vice versa, as well as alterations in neurohormonal markers and inflammatory molecular signatures characteristic of its clinical phenotypes. The mission of this scientific statement is to describe the epidemiology and pathogenesis of cardiorenal syndrome in the context of the continuously evolving nature of its clinicopathological description over the past decade. It also describes diagnostic and therapeutic strategies applicable to cardiorenal syndrome, summarizes cardiac-kidney interactions in special populations such as patients with diabetes mellitus and kidney transplant recipients, and emphasizes the role of palliative care in patients with cardiorenal syndrome. Finally, it outlines the need for a cardiorenal education track that will guide future cardiorenal trials and integrate the clinical and research needs of this important field in the future.

Detection of Neprilysin-Derived BNP Fragments in the Circulation: Possible Insights for Targeted Neprilysin Inhibition Therapy for Heart Failure

BACKGROUND

Entresto™ is a new heart failure (HF) therapy that includes the neprilysin (NEP) inhibitor sacubitril. One of the NEP substrates is B-type natriuretic peptide (BNP); its augmentation by NEP inhibition is considered as a possible mechanism for the positive effects of Entresto. We hypothesized that the circulating products of BNP proteolysis by NEP might reflect NEP impact on the metabolism of active BNP. We suggest that NEP-based BNP cleavage at position 17–18 results in BNP ring opening and formation of a novel epitope with C-terminal Arg-17 (BNP-neo17 form). In this study, we use a specific immunoassay to explore BNP-neo17 in a rat model and HF patient plasma.

METHODS

We injected BNP into rats, with or without NEP inhibition with sacubitril. BNP-neo17 in plasma samples at different time points was measured with a specific immunoassay with neglectable cross-reactivity to intact forms. BNP-neo17 and total BNP were measured in EDTA plasma samples of HF patients.

RESULTS

BNP-neo17 generation in rat circulation was prevented by NEP inhibition. The maximum 13.2-fold difference in BNP-neo17 concentrations with and without sacubitril was observed at 2 min after injection. BNP-neo17 concentrations in 32 HF patient EDTA plasma samples ranged from 0 to 37 pg/mL (median, 5.4; interquartile range, 0–9.1). BNP-neo17/total BNP had no correlation with total BNP concentration (with r = −0.175, P = 0.680) and showed variability among individuals.

CONCLUSIONS

BNP-neo17 formation is NEP dependent. Considering that BNP-neo17 is generated from the active form of BNP by NEP, we speculate that BNP-neo17 may reflect both the NEP activity and natriuretic potential and serve for HF therapy guidance.

An update on the use and discovery of prognostic biomarkers in acute decompensated heart failure

Introduction: Acute decompensated heart failure (ADHF) remains a significant health care burden as evidenced by high readmission rates and mortality. Over the years, the care of patients with ADHF has been transformed by the use of biomarkers, specifically to aid in the diagnosis and prognosis. Patients with HF follow a variable course given the complex and heterogenous pathophysiological processes, thus it is imperative for clinicians to have tools to predict short and long-term outcomes in order to educate patients and optimize management. Areas Covered: The natriuretic peptides, including B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, are considered the gold standard biomarkers. Yet, other emerging biomarkers such as suppression of tumerogenicity-2, cardiac troponin, galectin-2, mid-regional pro-adrenomedullin, copeptin, cystatin, and neutrophil gelatinase-associated lipocalin have increasingly shown promise in evaluating prognosis in patients with ADHF. This article reviews the pathophysiology and utility of both established and emerging biomarkers for the prognostication of patients with ADHF. Expert Opinion: As of 2019, the most validated biomarkers for use in decompensated heart failure include natriuretic peptides, high sensitivity troponin, and sST2. These biomarkers are involved in the underlying pathophysiology of disease and as such provide added information to that of exam, x-ray, and echocardiography.

Effects of sacubitril/valsartan on B-type natriuretic peptide circulating levels and loop diuretic dose in a case series of stabilized heart failure patients with left ventricular ejection fraction ≤35

Sacubitril/valsartan, an angiotensin receptor neprilysin inhibitor, was shown to improve outcome in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). There are reasons for believing that the concept that the lower the B-type natriuretic peptide (BNP) circulating level the better the prognosis may no longer be correct in patients treated with sacubitril/valsartan, since sacubitril may interfere with BNP clearance. We reported a case series of ten patients with stable chronic HF and LVEF ≤35% (mean age: 64 ± 8 years; 30% female), referred to our outpatient HF clinic, treated with sacubitril/valsartan, in whom the global amelioration of NYHA class and LVEF was coupled with a clinically significant decrease in BNP levels and a reduction of loop diuretic dose. Average sacubitril/valsartan daily dose was 220 mg. The median duration of treatment was 15 months (range: 6-21 months). Seventy percent of patients exhibited an improvement in exercise tolerance, as indicated by the change in NYHA class. There was also an improvement in LVEF from 28 ± 5% to 39 ± 7%. Clinically significant reductions in BNP levels were evident, with a median change from 181 pg/ml to 70 pg/ml. Furosemide daily dose decreased from a median of 43.3 mg to 12.5 mg. This case series suggests that BNP may still be valuable for the assessment of ambulatory HF patients, after the optimization of sacubitril/valsartan therapy.

Pathophysiological Mechanisms in Cardiorenal Syndrome

Cardiorenal syndrome represents the confluence of intricate hemodynamic, neurohormonal, and inflammatory pathways that initiate and propagate the maladaptive cross talk between the heart and kidneys. Several of these pathophysiological principles were described in older historical experiments. The last decade has witnessed major efforts in streamlining its definition, clinical phenotypes, and classification to improve diagnostic accuracy and deliver optimal goal-directed medical therapies. The ability to characterize the various facets of cardiorenal syndrome based on its pathophysiology is poised in an exciting vantage point, in the backdrop of several advanced diagnostic strategies, notably cardiorenal biomarkers that may help with accurate delineation of clinical phenotype, prognosis, and delivery of optimal medical therapies in future studies. This promises to help integrate precision medicine into the clinical diagnosis and treatment strategies for cardiorenal syndrome and, through a heightened understanding of its pathophysiology, to deliver appropriate therapies that will reduce its associated morbidity and mortality.