Nesiritide: a review of its use in acute decompensated heart failure

Uncovering hidden therapeutic indications through drug repurposing with graph neural networks and heterogeneous data

Drug repurposing has gained the attention of many in the recent years. The practice of repurposing existing drugs for new therapeutic uses helps to simplify the drug discovery process, which in turn reduces the costs and risks that are associated with de novo development. Representing biomedical data in the form of a graph is a simple and effective method to depict the underlying structure of the information. Using deep neural networks in combination with this data represents a promising approach to address drug repurposing. This paper presents BEHOR a more comprehensive version of the REDIRECTION model, which was previously presented. Both versions utilize the DISNET biomedical graph as the primary source of information, providing the model with extensive and intricate data to tackle the drug repurposing challenge. This new version's results for the reported metrics in the RepoDB test are 0.9604 for AUROC and 0.9518 for AUPRC. Additionally, a discussion is provided regarding some of the novel predictions to demonstrate the reliability of the model. The authors believe that BEHOR holds promise for generating drug repurposing hypotheses and could greatly benefit the field.

A Comparison of Network-Based Methods for Drug Repurposing along with an Application to Human Complex Diseases

Drug repurposing strategy, proposing a therapeutic switching of already approved drugs with known medical indications to new therapeutic purposes, has been considered as an efficient approach to unveil novel drug candidates with new pharmacological activities, significantly reducing the cost and shortening the time of de novo drug discovery. Meaningful computational approaches for drug repurposing exploit the principles of the emerging field of Network Medicine, according to which human diseases can be interpreted as local perturbations of the human interactome network, where the molecular determinants of each disease (disease genes) are not randomly scattered, but co-localized in highly interconnected subnetworks (disease modules), whose perturbation is linked to the pathophenotype manifestation. By interpreting drug effects as local perturbations of the interactome, for a drug to be on-target effective against a specific disease or to cause off-target adverse effects, its targets should be in the nearby of disease-associated genes. Here, we used the network-based proximity measure to compute the distance between the drug module and the disease module in the human interactome by exploiting five different metrics (minimum, maximum, mean, median, mode), with the aim to compare different frameworks for highlighting putative repurposable drugs to treat complex human diseases, including malignant breast and prostate neoplasms, schizophrenia, and liver cirrhosis. Whilst the standard metric (that is the minimum) for the network-based proximity remained a valid tool for efficiently screening off-label drugs, we observed that the other implemented metrics specifically predicted further interesting drug candidates worthy of investigation for yielding a potentially significant clinical benefit.

Insights of Worsening Renal Function in Type 1 Cardiorenal Syndrome: From the Pathogenesis, Biomarkers to Treatment

Type-1 cardiorenal syndrome refers to acute kidney injury induced by acute worsening cardiac function. Worsening renal function is a strong and independent predictive factor for poor prognosis. Currently, several problems of the type-1 cardiorenal syndrome have not been fully elucidated. The pathogenesis mechanism of renal dysfunction is unclear. Besides, the diagnostic efficiency, sensitivity, and specificity of the existing biomarkers are doubtful. Furthermore, the renal safety of the therapeutic strategies for acute heart failure (AHF) is still ambiguous. Based on these issues, we systematically summarized and depicted the research actualities and predicaments of the pathogenesis, diagnostic markers, and therapeutic strategies of worsening renal function in type-1 cardiorenal syndrome.

Nesiritide in patients with acute myocardial infarction and heart failure: a meta-analysis

Objective

This meta-analysis evaluated the efficacy and safety of nesiritide in patients with acute myocardial infarction (AMI) and heart failure.

Methods

PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception through December 2018. Studies including patients with AMI and heart failure who received nesiritide were identified.

Results

Ten trials involving 870 participants were included in this meta-analysis. Nesiritide treatment significantly increased left ventricular ejection fraction, cardiac index, and 24- and 72-hour urine volumes. Additionally, pulmonary capillary wedge pressure, right atrial pressure, and brain natriuretic peptide and N-terminal brain natriuretic peptide levels were significantly decreased in patients treated with nesiritide compared with those treated with control drugs. However, patients treated with nesiritide did not have an increased risk of mortality compared with those treated with control drugs. There were no differences between the two groups with respect to heart rate or the risk of readmission, hypotension, or renal dysfunction.

Conclusions

Nesiritide appears to be safe for patients with AMI and heart failure, and it improves global cardiac and systemic function.

Beneficial effects of early administration of recombinant human B-type natriuretic peptide in ST-elevation myocardial infarction patients receiving percutaneous coronary intervention treatment

INTRODUCTION

We aimed to evaluate the clinical performance of early administration of recombinant human B-type natriuretic peptide (rhBNP) to ST-elevation myocardial infarction (STEMI) patients receiving percutaneous coronary intervention (PCI) treatment.

METHODS

In total, 185 patients diagnosed with STEMI were enrolled and randomised into either the placebo-treated (n = 88) or rhBNP-treated (n = 97) group. Patients were given either saline or rhBNP ten minutes before PCI and monitored with various cardiac parameters, including accelerated idioventricular rhythm, frequent ventricular premature beat (FVPB), ventricular tachycardia, systolic blood pressure, thrombolysis in myocardial infarction (TIMI) 3 gradation, corrected TIMI frame count (cTFC) and myocardial blush grade (MBG) 3 classification.

RESULTS

Our results revealed no difference in accelerated idioventricular rhythm between the two groups. However, FVPB and ventricular tachycardia were significantly decreased in rhBNP-treated patients compared to placebo-treated patients (p < 0.05). Moreover, the occurrence ratio of reperfusion-associated low blood pressure in rhBNP-treated patients was lower than in placebo-treated patients (p = 0.03), while no difference was observed in infarction-related arteries TIMI 3 blood flow between the two groups (p = 0.23). Importantly, measurement of post-reperfusion blood flow velocity via cTFC suggested that rhBNP treatment could significantly increase blood circulation (p = 0.003). After stent implantation, the acquisition rate of MBG 3 was higher in rhBNP-treated patients compared to placebo-treated patients (p = 0.071), although the difference was not significant.

CONCLUSION

We concluded that early administration of rhBNP can ameliorate the severity of reperfusion injury for STEMI patients receiving PCI treatment.

A rapid reporter assay for recombinant human brain natriuretic peptide (rhBNP) by GloSensor technology

Accurate determination of biological activity is essential in quality control of recombinant human brain natriuretic peptide (rhBNP). In previous study, we successfully developed a genetically modified cell line 293GCAC3-based ELISA assay for rhBNP. But ELISA procedure is still tedious, so this study was aimed to develop a rapid and simple bioassay for rhBNP using GloSensor technology, which provides a platform of flexible luciferase-based biosensors for real-time detection of signaling events in live cells, including cGMP production. A reporter cell line 293GCAGlo-G1 was constructed by transfecting pGloSensor™ 40 F plasmid into 293GCAC3. The reporter assay based on 293GCAGlo-G1 showed high precision with intra-assay CV being 8.3% and inter-assay CV being 14.1%; high accuracy with 80%, 100% and 120% recovery rate being 99.2%, 102.4% and 99.0% respectively; and great linearity with R² of linear fitting equation being 0.99. Besides, no significant difference was found in test results of reporter assay and 293GCAC3-based ELISA assay (paired t test, p = 0.630). All these results suggested that the reporter assay was a viable assay for biological determination of rhBNP.

The multifaceted role of natriuretic peptides in metabolic syndrome

Due to globalization and sophisticated western and sedentary lifestyle, metabolic syndrome has emerged as a serious public health challenge. Obesity is significantly increasing worldwide because of increased high calorie food intake and decreased physical activity leading to hypertension, dyslipidemia, atherosclerosis, and insulin resistance. Thus, metabolic syndrome constitutes cardiovascular disease, type 2 diabetes, obesity, and nonalcoholic fatty liver disease (NAFLD) and recently some cancers are also considered to be associated with this syndrome. There is increasing evidence of the involvement of natriuretic peptides (NP) in the pathophysiology of metabolic diseases. The natriuretic peptides are cardiac hormones, which are produced in the cardiac atrium, ventricles of the heart and the endothelium. These peptides are involved in the homeostatic control of body water, sodium intake, potassium transport, lipolysis in adipocytes and regulates blood pressure. The three known natriuretic peptide hormones present in the natriuretic system are atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and c-type natriuretic peptide (CNP). These three peptides primarily function as endogenous ligands and mainly act via their membrane receptors such as natriuretic peptide receptor A (NPR-A), natriuretic peptide receptor B (NPR-B) and natriuretic peptide receptor C (NPR-C) and regulate various physiological and metabolic functions. This review will shed light on the structure and function of natriuretic peptides and their receptors and their role in the metabolic syndrome.

Effect of recombinant human brain natriuretic peptide (rhBNP) versus nitroglycerin in patients with heart failure: A systematic review and meta-analysis

BACKGROUND

This study was the first to evaluate the therapeutic outcomes of recombinant human brain natriuretic peptide (rhBNP) versus nitroglycerin (NIT) in patients with heart failure (HF).

METHODS

The electronic databases were systematically searched to identify available studies. The pooled odds ratios (ORs) and their 95% confidence intervals (95% CIs) were analyzed to assess the mortality, readmission, hypotension, and renal dysfunction in the comparison of rhBNP and NIT therapies.

RESULTS

Final 5 randomized controlled trials (RCTs) involving 782 patients with HF were carried out in our study. The pooled OR of mortality, readmission, and hypotension showed that no significant difference was found in both drugs (P > 0.05), with the absence of heterogeneity. The incidence of renal dysfunction was not significant difference in both groups (P = 0.85). The pooled OR from 2 studies of Asian population using multivariate analysis demonstrated that the use of rhBNP was correlated with a significantly decreased risk of renal dysfunction (I = 0.0%, OR = 0.19, P = 0.001). Possible publication bias was not detected using Egger's test (P > 0.05).

CONCLUSIONS

The results suggested that rhBNP and NIT therapies were not significant difference in mortality, readmission, and hypotension. The use of rhBNP may become a useful predictor of renal dysfunction in Asian patients with HF. Additional studies are needed for Caucasian population with HF.

Diuretic response in acute heart failure-an analysis from ASCEND-HF

BACKGROUND

Diuretic unresponsiveness often occurs during hospital admission for acute heart failure (AHF) and is associated with adverse outcome. This study aims to investigate determinants, clinical outcome, and the effects of nesiritide on diuretic response early after admission for AHF.

METHODS

Diuretic response, defined as weight loss per 40 mg of furosemide or equivalent, was examined from hospital admission to 48 hours in 4,379 patients from the ASCEND-HF trial. As an additional analysis, a urinary diuretic response metric was investigated in 5,268 patients using urine volume from hospital admission to 24 hours per 40 mg of furosemide or equivalent.

RESULTS

Mean diuretic response was -0.42 kg/40 mg of furosemide (interquartile range -1.0, -0.05). Poor responders had lower blood pressure, more frequent diabetes, long-term use of loop diuretics, poorer baseline renal function, and lower urine output (all P < .01). Randomized nesiritide treatment was not associated with diuretic response (P = .987). Good diuretic response was independently associated with a significantly decreased risk of 30-day all-cause mortality or heart failure rehospitalization (odds ratio 0.44, 95% CI 0.29-0.65, highest vs lowest quintile, P < .001). Diuretic response based on urine output per 40 mg of furosemide showed similar results in terms of clinical predictors, association with outcome, and the absence of an effect of nesiritide.

CONCLUSIONS

Poor diuretic response early after hospital admission for AHF is associated with low blood pressure, renal impairment, low urine output, and an increased risk of death or rehospitalization early after discharge. Nesiritide had a neutral effect on diuretic response.

A novel bioassay for the activity determination of therapeutic human brain natriuretic peptide (BNP)

Background

Recombinant human brain natriuretic peptide (rhBNP) is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A.

Methodology/Principal Findings

An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA). Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision.

Conclusion/Significance

The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis.

Diuretics: a review

Diuretics, in one form or another, have been around for centuries and this review sets out to chart their development and clinical use. Starting with the physiology of the kidney, it progresses to explain how diuretics actually work, via symports on the inside of the renal tubules. The different classes of diuretics are characterized, along with their mode of action. The clinical use of diuretics in conditions like congestive cardiac failure and hypertension, as well as some rarer, but clinically important, conditions is then examined. An account is given of the adverse effects of diuretics and how they come about. Common adverse effects like hypokalaemia and hyponatraemia are examined in some detail, and other electrolyte disturbances like hypomagnesaemia also gain a mention. Diuretic use in chronic kidney disease is examined and new guidelines that have been introduced are presented. A section on diuretic abuse is included as this is becoming an all too common clinical scenario, and the sometimes tragic consequences of this abuse are emphasized. Diuretics also find a role in the diagnosis of forms of renal tubular acidosis and this role is explored. Finally, a selection of some of the newer approaches to diuretic therapy are presented, often the consequence of the increasing development of molecular biology, and some of the novel compounds – which may be in drug formularies of the future – are revealed.

Fluid overload assessment and management in heart failure patients

Heart failure is a syndrome in which myocardial function is incapable of providing for normal physiologic needs. In the acute care setting, cardiac dysfunction primarily manifests with volume perturbations and presents with signs and symptoms of vascular congestion. Thus, in acute heart failure volume assessment is crucial in diagnosing and improving the prognosis. Also, goal-directed therapy relies on accurate volume assessment to minimize the adverse outcomes of inappropriate, ineffective, or excessive diuresis. Currently, in most institutions clinical methods of volume assessment are the mainstay. However, these methods are highly dependent on the practitioners' skill level. In fact, there is a high variability between experienced physicians when assessing volume. As adjuncts, objective methods of volume assessment are being developed and used such as natriuretic peptides, bioimpedance analysis, and imaging.

Natriuretic peptides in therapy for decompensated heart failure

Congestive heart failure (CHF) is the most frequent cause of hospitalization for patients >65 years of age and continues to be a major public health burden among the ageing population. Unlike therapy for chronic CHF, there has been only modest progress in medical treatment for acutely decompensated CHF over the past several decades. Moreover, current treatment-consisting generally of diuretic, inotropic, and vasodilatory agents-is associated with many limitations in clinical practice. Natriuretic peptides provide a promising mechanism of action in the pathophysiologic background for CHF treatment based on their vasodilatory and diuretic properties and effective inhibition of the renin-angiotensin-aldosterone system, which is activated early in the course of CHF. Nesiritide (Natrecor® or Noratak®) is a recombinant natriuretic peptide that has the same 32 amino-acid sequence as human B-type natriuretic peptide. Nesiritide has been shown to improve dyspnea and hemodynamic parameters in patients with decompensated heart failure. Ularitide is a synthetic form of urodilatin, a natriuretic peptide hormone secreted by the kidney. Recent clinical studies suggest that ularitide may play a role in managing decompensated heart failure. This review provides an update on natriuretic peptides and their therapeutic potential in advanced CHF.

Catecholamines, cardiac natriuretic peptides and chromogranin A: evolution and physiopathology of a 'whip-brake' system of the endocrine heart

In the past 50 years, extensive evidence has shown the ability of vertebrate cardiac non-neuronal cells to synthesize and release catecholamines (CA). This formed the mindset behind the search for the intrinsic endocrine heart properties, culminating in 1981 with the discovery of the natriuretic peptides (NP). CA and NP, co-existing in the endocrine secretion granules and acting as major cardiovascular regulators in health and disease, have become of great biomedical relevance for their potent diagnostic and therapeutic use. The concept of the endocrine heart was later enriched by the identification of a growing number of cardiac hormonal substances involved in organ modulation under normal and stress-induced conditions. Recently, chromogranin A (CgA), a major constituent of the secretory granules, and its derived cardio-suppressive and antiadrenergic peptides, vasostatin-1 and catestatin, were shown as new players in this framework, functioning as cardiac counter-regulators in 'zero steady-state error' homeostasis, particularly under intense excitatory stimuli, e.g. CA-induced myocardial stress. Here, we present evidence for the hypothesis that is gaining support, particularly among human cardiologists. The actions of CA, NP and CgA, we argue, may be viewed as a hallmark of the cardiac capacity to organize 'whip-brake' connection-integration processes in spatio-temporal networks. The involvement of the nitric oxide synthase (NOS)/nitric oxide (NO) system in this configuration is discussed. The use of fish and amphibian paradigms will illustrate the ways that incipient endocrine-humoral agents have evolved as components of cardiac molecular loops and important intermediates during evolutionary transitions, or in a distinct phylogenetic lineage, or under stress challenges. This may help to grasp the old evolutionary roots of these intracardiac endocrine/paracrine networks and how they have evolved from relatively less complicated designs. The latter can also be used as an intellectual tool to disentangle the experimental complexity of the mammalian and human endocrine hearts, suggesting future investigational avenues.

Risk and safety assessment of exogenous human brain natriuretic peptide in cynomolgus monkeys (Macaca fascicularis)--a subchronic study

Safety evaluation of synthetic human brain natriuretic peptide (shBNP) was carried out in cynomolgus monkeys (Macaca fascicularis) by 2-week intravenous toxicity studies. System exposure was also assessed throughout the whole administration. Three test groups received doses of 432, 1440 and 4320 microg/kg/day of shBNP, with a high infusion rate of 36 mL/kg/hr for 30 min compared to the clinical protocol of continuous infusion over 24h. Commercially available recombinant human brain natriuretic peptide (rhBNP) of 1440 microg/kg/day was used as positive control. The 2-week repeated intravenous doses of shBNP resulted in reversible increased serum LDH and CPK in monkeys receiving 1440 and 4320 microg/kg/day dose with no pertinent histopathological changes. Some changes related to the pharmacologic effects of BNP including hypotension was observed after administration. No treatment-related mortalities or renal dysfunction were found. Controversy about the safety issue of BNP as an exogenous hormone concerning ventricular remodeling and myocardial cell apoptosis, coupled with our results, were also discussed. The no-observed-adverse-effect level (NOAEL) was considered to be 432 microg/kg /day, which is about 20 times higher than the commonly used clinical dose. The results of the present study advocate the safety of shBNP in cynomolgus monkeys at levels used in the study.

Relation of adiponectin and high-sensitivity C-reactive protein to pulse-wave velocity and N-terminal pro-B-type natriuretic peptide in the general population

The roles of metabolic syndrome and chronic subclinical inflammation in arterial stiffening and the development of heart failure remain to be elucidated. Whether adiponectin and high-sensitivity C-reactive protein (hs-CRP) were independently related to brachial-ankle pulse-wave velocity (ba-PWV) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) in the general population were investigated. Eligible study subjects were 445 Chinese residents aged > or =40 years who participated in a community-based survey, underwent examination of ba-PWV, and had complete data of serum adiponectin, hs-CRP (<10 mg/L), and NT-pro-BNP. Adiponectin, but not hs-CRP, was independently related to ba-PWV (standardized regression parameter -0.107, p <0.05) when age, gender, body mass index, and number of metabolic syndrome components were accounted for. On the other hand, ba-PWV, adiponectin, and hs-CRP were independently related to NT-pro-BNP (standardized regression parameters 0.116, 0.188, and 0.094, respectively; all p <0.05) when age, gender, body mass index, number of metabolic syndrome components, and renal function were accounted for. In conclusion, adiponectin, but not hs-CRP, is independently associated with both ba-PWV and NT-pro-BNP in the general population. Because adiponectin, hs-CRP, ba-PWV, and NT-pro-BNP may represent markers for metabolic syndrome, chronic subclinical inflammation, arterial stiffness, and ventricular dysfunction, respectively, our results suggest that adiponectin may directly modulate both arterial stiffening and ventricular dysfunction. In contrast, hs-CRP may independently contribute to ventricular dysfunction, but not arterial stiffening.

Nesiritide improves hemodynamics in children with dilated cardiomyopathy: a pilot study

BACKGROUND

This study aimed to obtain hemodynamic measurements of nesiritide in children with dilated cardiomyopathy.

METHODS

A prospective, randomized, double-blinded, placebo-controlled pilot study was conducted in the pediatric intensive care unit at the University of California, Los Angeles. All subjects younger than 21 years admitted to the pediatric intensive care unit with a diagnosis of dilated cardiomyopathy and submitted to cardiac catheterization were randomized to receive either nesiritide or placebo. Right heart catheterization with Swan-Ganz catheter placement was performed. Nesiritide was infused over 24 h. Hemodynamic data were obtained before, during, and after the 24-h nesiritide infusion. The measures obtained included pulmonary capillary wedge pressure (PCWP), central venous pressure, mean pulmonary arterial pressure (MPAP), systolic arterial blood pressure (SBP), cardiac index, and systemic vascular resistance.

RESULTS

The study included 20 children: 9 randomized to nesiritide and 11 to placebo. At 24 h, the mean decreases in PCWP, MPAP, and SBP were significantly greater for nesiritide than for placebo: PCWP (-5.3 vs. 1.2 mmHg; p = 0.02), MPAP (-8.0 vs. 0.4 mmHg; p = 0.006), SBP (-7.9 vs. 2.6 mmHg; p = 0.04).

CONCLUSIONS

Nesiritide significantly decreases PCWP, MPAP, and SBP in children with dilated cardiomyopathy.

Structural and electrical remodeling as therapeutic targets in heart failure

Heart failure is a progressive clinical syndrome that is characterized by remodeling of the myocardium in response to various stress signals. The past several years has seen remarkable progress in unraveling the molecular and cellular mechanisms of structural and electrical remodeling in HF. Improved understanding of the molecular mechanism of myocardial remodeling has resulted in improved HF therapies and revealed potentially novel therapeutic targets. This review discusses the mechanisms of myocardial remodeling in HF and their clinical manifestations. Current and investigational HF therapies targeting these mechanisms also will be discussed.

Natriuretic peptides in vascular physiology and pathology

Four major natriuretic peptides have been isolated: atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and Dendroaspis-type natriuretic peptide (DNP). Natriuretic peptides play an important role in the regulation of cardiovascular homeostasis maintaining blood pressure and extracellular fluid volume. The classical endocrine effects of natriuretic peptides to modulate fluid and electrolyte balance and vascular smooth muscle tone are complemented by autocrine and paracrine actions that include regulation of coronary blood flow and, therefore, myocardial perfusion; modulation of proliferative responses during myocardial and vascular remodeling; and cytoprotective anti-ischemic effects. The actions of natriuretic peptides are mediated by the specific binding of these peptides to three cell surface receptors: type A natriuretic peptide receptor (NPR-A), type B natriuretic peptide receptor (NPR-B), and type C natriuretic peptide receptor (NPR-C). NPR-A and NPR-B are guanylyl cyclase receptors that increase intracellular cGMP concentration and activate cGMP-dependent protein kinases. NPR-C has been presented as a clearance receptor and its activation also results in inhibition of adenylyl cyclase activity. The wide range of effects of natriuretic peptides might be the base for the development of new therapeutic strategies of great benefit in patients with cardiovascular problems including coronary artery disease or heart failure. This review summarizes current literature concerning natriuretic peptides, their receptors and their effects on fluid/electrolyte balance, and vascular and cardiac physiology and pathology, including primary hypertension and myocardial infarction. In addition, we will attempt to provide an update on important issues regarding natriuretic peptides in congestive heart failure.

Safety and efficacy of nesiritide in pediatric heart failure

BACKGROUND

We hypothesized that recombinant B-type natriuretic peptide (BNP) (nesiritide) could improve urine output and neurohormonal markers of heart failure without worsening renal function in pediatric patients.

METHODS AND RESULTS

We analyzed our experience involving 140 nesiritide infusions in 63 consecutive children. Serum levels of BNP and electrolytes were measured before and after therapy. Dosing was begun at 0.01 mcg.kg.min without a bolus and titrated to a maximum of 0.03 mcg.kg.min, in 0.005-mcg.kg.min increments. Blood pressure, heart rate, and heart rhythm were monitored. In a substudy, 20 patients with decompensated cardiomyopathy-related heart failure received 72 hours of nesiritide with prospective assessment of aldosterone, norepinephrine, plasma renin, and endothelin-1 levels before and after therapy. The heart rate decreased significantly (P = .001). Urine output increased significantly on Days 1 and 3 (P < or = .001 and .004, respectively). The mean serum creatinine level decreased from 1.135 to 1.007 mg/dL (P < or = .001). In the substudy, aldosterone levels decreased from 37.5 +/- 57.1 to 20.5 +/- 41.9 ng/dL (P = .005). Plasma renin, norepinephrine, and endothelin-1 levels decreased nonsignificantly. Two infusions were discontinued because of hypotension.

CONCLUSIONS

Nesiritide safely treated decompensated heart failure in children. Increased urine output reflected improving renal function. Improved neurohormonal markers were seen after 72 hours of therapy, and complications were uncommon.

Natriuretic peptides and therapeutic applications

Since the discovery of atrial natriuretic factor by de Bold et al., there has been tremendous progress in our understanding of the physiologic, diagnostic and therapeutic roles of the natriuretic peptides (NPs) in health and disease. Natriuretic peptides are endogenous hormones that are released by the heart in response to myocardial stretch and overload. Three mammalian NPs have been identified and characterized, including atrial natriuretic peptide (ANP or atrial natriuretic factor), B-type natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). In addition, Dendroaspis natriuretic peptide (DNP) has been isolated from the venom of Dendroaspis angusticeps (the green mamba snake), and urodilatin from human urine. These peptides are structurally similar and they consist of a 17-amino-acid core ring and a cysteine bridge. Both ANP and BNP bind to natriuretic peptide receptor A (NPR-A) that are expressed in the heart and other organs. Activation of NPR-A generates an increase in cyclic guanosine monophosphate, which mediates natriuresis, inhibition of renin and aldosterone, as well as vasorelaxant, anti-fibrotic, anti-hypertrophic, and lusitropic effects. The NP system thus serves as an important compensatory mechanism against neurohumoral activation in heart failure. This provides a strong rationale for the use of exogenous NPs in the management of acutely decompensated heart failure. In this article, the therapeutic applications of NPs in the acute heart failure syndromes are reviewed. Emerging therapeutic agents and areas for future research are discussed.

Benefit-Risk Assessment of Nesiritide in the Treatment of Acute Decompensated Heart Failure

Nesiritide is a recombinant form of human B-type natriuretic peptide, a naturally occurring endogenous hormone released by cardiac ventricles in response to an increase in ventricular wall stress. Its use in the treatment of acute decompensated heart failure (ADHF) has been evaluated in a series of randomised controlled clinical trials. It is currently approved in the US for the treatment of ADHF. Nesiritide induces a balanced vasodilation and an indirect increase in cardiac output, but has no actual inotropic effects and exerts a neutral effect on heart rate. In addition, it inhibits adverse neurohormonal activation and, in some individuals, promotes natriuresis and diuresis. In adults with ADHF, nesiritide reduces pulmonary capillary wedge pressure, right atrial pressure and systemic vascular resistance; decreases symptoms of heart failure; and enhances global clinical status. Important questions regarding the risks of nesiritide therapy have recently been raised, and resolution of the safety of nesiritide is a process that remains in evolution. The most frequently reported adverse effect is dose-related hypotension. In addition, nesiritide may cause an acute increase in serum creatinine concentration. This increase seems to be a haemodynamic response to a combination of volume depletion, vasodilation and neurohormonal inhibition. Nesiritide-induced changes in renal function have not been definitively shown to negatively affect mortality. The effect of nesiritide on all-cause mortality is currently unresolved. Recent meta-analyses of existing databases have raised concerns regarding adverse effects of the drug on 30-day mortality. However, reviews of large, observational, registry databases do not suggest an adverse inpatient mortality effect compared with other vasodilator therapies. Further resolution of the mortality question awaits completion of pending randomised controlled clinical trials. When used for approved indications and according to recommended dosage and administration regimens, nesiritide represents a reasonable treatment adjunct for ADHF.

Characterization of the snake venom ligand [125I]-DNP binding to natriuretic peptide receptor-A in human artery and potent DNP mediated vasodilatation

BACKGROUND AND PURPOSE

The natriuretic peptides, ANP and BNP, modulate vascular smooth muscle tone in human conduit arteries. Surprisingly, the natriuretic peptide receptor-A (NPR-A) has not been visualized using radioligand binding in these vessels. A new member of this peptide family, Dendroaspis natriuretic peptide (DNP) identified from snake venom, has been proposed to be present in human plasma and endothelial cells. Also, recently a novel radioligand, [(125)I]-DNP, has been characterized as selective for NPR-A in human heart.

EXPERIMENTAL APPROACH

Our aims were to investigate expression and function of NPR-A receptors in human mammary artery using [(125)I]-DNP to quantify receptor density, immunocytochemistry to delineate the cellular distribution of the receptor and in vitro pharmacology to compare DNP induced vasodilatation to that of ANP.

KEY RESULTS

Saturable, sub-nanomolar affinity [(125)I]-DNP binding was detected to smooth muscle of mammary artery, with receptor density of approximately 2 fmol mg(-1) protein, comparable to that of other vasoactive peptides. NPR-A immunoreactivity was localised to vascular smooth muscle cells and this was confirmed with fluorescence dual labelling. NPR-A expression was not detected in the endothelium. Like ANP, DNP fully reversed the constrictor response to ET-1 in endothelium intact or denuded mammary artery, with comparable nanomolar potencies.

CONCLUSIONS AND IMPLICATIONS

This is the first characterization of NPR-A in human mammary artery using [(125)I]-DNP and we provide evidence for the presence of receptor protein on vascular smooth muscle cells, but not endothelial cells. This implies that the observed vasodilatation is predominantly mediated via direct activation of smooth muscle NPR-A.

Impact of Early Initiation of Intravenous Therapy for Acute Decompensated Heart Failure on Outcomes in ADHERE

BACKGROUND

Since most acute decompensated heart failure (ADHF) patients present for hospital care via the emergency department (ED), we sought to determine the impact of early ED initiation of ADHF-specific therapy, as indicated by nesiritide use, on subsequent outcomes.

METHODS

We queried the Acute Decompensated Heart Failure National Registry (ADHERE) to identify patients with initial systolic blood pressure >90 mm Hg and negative cardiac biomarkers, hospitalized after presentation to the ED, who received nesiritide but no other intravenous vasoactive drugs. Intensive care unit use and total hospital length of stay were compared based on the hospital unit where nesiritide therapy was initiated after multivariate adjustment for baseline differences in study populations.

RESULTS

Nesiritide was started in the ED in 1,613 patients (EDN group) and after admission to an inpatient unit in 2,687 patients (INN group). EDN patients had higher baseline systolic and diastolic blood pressure (both p < 0.001); while INN patients were more likely to be male and have baseline renal dysfunction (both p < 0.001). Nesiritide was initiated a median of 2.8 and 15.5 h after presentation in EDN and INN patients, respectively (p < 0.001). Compared to INN, EDN patients had a shorter adjusted mean total hospital length of stay (5.4 vs. 6.9 days; p < 0.001), were less likely to require transfer to the intensive care unit from another inpatient unit (odds ratio [OR]: 0.301; 95% confidence interval [CI]: 0.206-0.440), and were more likely to be discharged home (OR: 1.154; 95% CI: 1.005-1.325).

CONCLUSIONS

Initiation of ADHF-specific therapy early, while the patient is in the ED, is associated with improved clinical outcomes.

Pharmacoeconomic Modeling of Nesiritide versus Dobutamine for Decompensated Heart Failure

STUDY OBJECTIVE

To model the cost-effectiveness of nesiritide compared with dobutamine in patients with decompensated heart failure.

DESIGN

Cost-effectiveness analysis.

MEASUREMENTS AND MAIN RESULTS

A decision tree model was derived from randomized clinical trial data and data from a previously published economic study. Four cost-effectiveness analyses were performed: analysis 1 -- full probabilistic analysis, repeatedly sampled probabilities for 6-month mortality and hospital readmission from distributions based on 95% confidence intervals (CIs); analysis 2 -- best-case nesiritide analysis, used the limiting values of the 95% CI favorable to nesiritide; analysis 3 -- best-case dobutamine analysis, used the limiting values of the 95% CI favorable to dobutamine; and analysis 4 -- replicated the previously published cost-effectiveness study and served as a methodologic control. Fifty-one consecutive Monte Carlo simulations for cohorts of 1000 hypothetical patients were performed for each analysis. Incremental cost, incremental effectiveness, and incremental cost-effectiveness ratios (ICERs) were calculated for nesiritide versus dobutamine. Analysis 1 showed a mean ICER of 767 US dollars/life-year gained for nesiritide versus dobutamine (incremental cost 251 US dollars +/- 290 US dollars, incremental effectiveness 0.33 +/- 0.22 yr). The 95% confidence region surrounding this point estimate spanned all four quadrants of the incremental cost-effectiveness scatterplot, suggesting inconclusive results. Nesiritide was the dominant treatment strategy in analysis 2 (incremental cost -734 US dollars+/- 106 US dollars, incremental effectiveness 1.19 +/- 0.07 yrs), whereas dobutamine was dominant in analysis 3 (incremental cost 1242 +/- 73 US dollars, incremental effectiveness -0.57 +/- 0.05 yr). Analysis 4 was comparable to the previously published cost-effectiveness analysis (incremental cost -77 +/- 87 US dollars, incremental effectiveness 0.48 +/- 0.05 yr).

CONCLUSIONS

Based on available randomized clinical trial data, nesiritide did not exhibit robust economic superiority over dobutamine. When incorporating the uncertainty (i.e., 95% CIs) in clinical effectiveness as reported in available clinical trial data into the economic analysis, either nesiritide or dobutamine may be the dominant treatment (i.e., more effective at lower cost) for the studied population. Economic analyses of nesiritide and any comparator must account for uncertainty in estimates of cost as well as in clinical effectiveness.

BNP--Considering a heartfelt message

The natriuretic hormones have been discovered as mediators of the cardiac response to volume overload and mechanical dysfunction. Although there are some physiological differences between atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), it is BNP that has been found to be most useful as a clinical test. BNP is secreted along with an N terminal proBNP cleavage product (NT-proBNP). The similarities between these two tests are far greater than the differences. They are both probably useful in the diagnosis of high-risk patients (e.g. dyspnoeic) and may be useful in monitoring cardiac failure treatment. Although BNP levels in the normal range predict the risk of cardiac events and mortality, there is little evidence to promote their use as a screening test. In such an important condition as cardiac failure we should consider any messages that are likely to be of value, particularly those that are heartfelt.

Determinants of Natriuretic Peptide Production by the Heart

The cardiac natriuretic peptides (NPs) atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) are polypeptide hormones synthesized, stored, and secreted by cardiac muscle cells (cardiocytes). The NPs modulate extracellular fluid volume and blood pressure and have potent growth-regulating properties, which make them of great interest for cardiac remodeling in acute myocardial infarction and congestive heart failure. We have observed that the production of NP can be coordinately or discoordinately regulated. In the former type, muscle stretch-elicited secretion triggers signals mediated by Gi/o protein, whereas agonists such as endothelin 1 independently signal through Gq. Discoordinated regulation is observed following stimulations by some cytokines, which selectively up-regulate BNP. This regulation takes place at the translational and transcriptional levels and is dependent on a p38 signaling pathway. Further details of processes regulating NP secretion need to be defined to develop a comprehensive view of the endocrine function of the heart. Nevertheless, translational research in the area of NPs has demonstrated the usefulness of these hormones as a marker of disease and as potential therapeutic agents. The latter application of NP is particularly attractive given that ANF and BNP possess pharmacologic actions that require polypharmacy in the treatment of acute myocardial infarction and congestive heart failure.

Effects of natriuretic peptides on ventricular myocyte contraction and role of cyclic GMP signaling

Natriuretic peptides, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) act through different receptors and at different potencies to affect cardiac myocyte function. We tested the hypothesis that these three peptides would differentially reduce cardiomyocyte function through their effects on the cyclic GMP signaling pathway. Rabbit ventricular myocytes were isolated and stimulated by electrical field stimulation. Cell function was measured using a video edge detector. ANP BNP or CNP at 10(-9), 10(-8), 10(-7) M were added to the myocytes. Intracellular cyclic GMP was determined using a radioimmunoassay in the absence or presence of ANP, BNP or CNP. All natriuretic peptides decreased myocyte contractility in a similar concentration dependent manner. Myocyte percentage shortening was significantly decreased with all peptides at 10(-7) M compared with baseline (ANP from 5.4+/-0.4 to 3.9+/-0.2%; BNP from 5.0+/-0.2 to 3.5+/-0.1%; CNP from 5.6+/-0.3 to 4.0+/-0.3%). Maximum rate of shortening and relaxation were also decreased similarly and significantly. Intracellular cyclic GMP was significantly increased in myocytes treated with ANP, BNP or CNP (Baseline 1.0+/-0.2, ANP 2.1+/-0.2, BNP 2.3+/-0.3, CNP 2.0+/-0.2 pmol/10(5) myocytes). Furthermore, inhibition of the cyclic GMP protein kinase with KT5823 caused a reversal in the functional effects of CNP. We concluded that all natriuretic peptides had similar negative effects on ventricular myocyte function and their effects were accompanied by increased cyclic GMP. Blockade the effect of CNP by a cyclic GMP protein kinase inhibitor demonstrated that effects were mediated through the cyclic GMP signaling pathway.

Natriuretic Peptides in ESRD

Natriuretic peptides are involved in the regulation of volume homeostasis. Their levels generally are increased in the setting of volume expansion and act on multiple effector systems to cause vasodilation and natriuresis in an effort to return volume status back to normal. In patients with end-stage renal disease, the natriuretic capabilities of these peptides are limited. However, there has been much interest in the potential applicability of measurement of these peptides as a surrogate marker of volume status and in the determination of dry weight. Furthermore, atrial natriuretic peptide and brain natriuretic peptide can serve as markers of left ventricular dysfunction and may have utility in determining cardiac prognosis in patients on long-term dialysis therapy.

AlbuBNP, a recombinant B-type natriuretic peptide and human serum albumin fusion hormone, as a long-term therapy of congestive heart failure

PURPOSE

B-type natriuretic peptide (BNP) has been in clinical use for the treatment of decompensated congestive heart failure. However, BNP has a very short half-life in circulation, which limits its application to acute CHF and requires continuous i.v. infusion. To provide superior pharmacological benefits of BNP to other stages of chronic congestive heart failure and to eliminate problems associated with drug delivery via continuous i.v. infusion, we have designed and evaluated AlbuBNP, a long-acting form of BNP by recombinant fusion to human serum albumin for use in chronic congestive heart failure, post-acute follow-up, and postmyocardial infarction.

METHODS

Human BNP (1-32) was seamlessly fused to mature human serum albumin at N-terminus to create AlbuBNP. The bioactivities of AlbuBNP were evaluated by natriuretic peptide receptor-A mediated cGMP activation assay, hemodynamic responses, and plasma cGMP elevation. The pharmacokinetic properties were determined after single i.v. or s.c. bolus injection in C57/BL6 mice.

RESULTS

AlbuBNP had approxiamtely the same maximal bioactivity as BNP to activate cGMP in the in vitro NPRA/cGMP assay. The EC50s were 28.4+/-1.2 and 0.46+/-1.1 nM for AlbuBNP and BNP, respectively. In spontaneously hypertensive rats, AlbuBNP lowered both systolic and diastolic blood pressure, having sustainable mean arterial pressure reduction for more than 2 days. Six nmol/kg AlbuBNP i.v. bolus in mice increased plasma cGMP level 5.6-fold over the baseline. The elimination half-life in mice was dramatically increased from 3 min for BNP to 12-19 h for AlbuBNP.

CONCLUSIONS

AlbuBNP is bioactive and has desired pharmacokinetic properties for long-term use. It has the potential to be further developed as a new therapeutic option for chronic, acute, and post-acute CHF to alleviate symptoms, improve clinical status, and slow the disease progression by sustained drug exposure via infrequent simple subcutaneous injections.

B-type natriuretic peptide in heart failure: diagnostic, prognostic, and therapeutic use

Chronic heart failure affects nearly 5 million people living in the United States, and the majority of economic burden is the result of hospitalizations for acute decompensated congestive heart failure. Patient history and symptom assessment, physical examination, and chest radiography remain the cornerstones of diagnosis and prognostic assessment. Evaluation of endogenous B-type natriuretic peptide (BNP) has emerged as a useful addition to standard methods for diagnosis and risk stratification of suspected congestive heart failure, and final diagnosis requires integration of BNP assays with traditional methods. BNP levels >500 pg/mL are more likely to be comfirmative of a primary diagnosis of heart failure and are also important predictors for long-term adverse prognosis; >100 pg/mL but <500 pg/mL suggests a reasonable likelihood for the diagnosis of heart failure but does require thoughtful exclusion of other potential confounders such as pulmonary disease resulting in right heart failure; and <100 indicates that heart failure is very unlikely. Positive physiological effects of BNP, including improvements in hemodynamics, suppression of neurohormonal activity, preservation of renal function, diuresis and natriuresis, and balanced arterial and venous dilatation have suggested that this peptide also may have therapeutic use in congestive heart failure. In clinical trials, treatment of patients with acute decompensated congestive heart failure with nesiritide, a recombinant form of human BNP, was shown to significantly reduce pulmonary capillary wedge pressure versus placebo plus standard care, as well as provide a significant improvement in dyspnea versus placebo. Diagnostic, prognostic, and therapeutic applications of BNP can be integrated easily with standard methods to provide physicians with a useful evaluation and treatment algorithm that may result in faster identification of patients likely to benefit from early therapy, including nesiritide, thereby leading to the potential for more favorable patient outcomes.

Cardiac natriuretic peptides for cardiac health

The cardiac natriuretic peptides, ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide), are secreted by the heart in proportion to cardiac transmural pressures. They possess a wide range of effects in multiple tissues facilitating overall pressure/volume homoeostasis. The close relationship between plasma concentrations of these peptides and 'cardiac load' has led to their use as biomarkers of cardiac health with diagnostic and prognostic applications in a variety of disorders affecting the cardiovascular system. BNP and its N-terminal fragment (NT-BNP) are especially sensitive indicators of cardiac dysfunction and remodelling, and correlate strongly with severity. Given that cardiac ischaemia is also an important trigger for the release of these ventricular peptides, they may likewise play a role in the detection of coronary artery disease. Measurement of BNP/NT-BNP shows particular promise as a 'rule out' test for suspected cases of HF (heart failure) in both emergency care and outpatient settings, and may assist in identifying individuals with asymptomatic ventricular impairment who will benefit from therapy preventing progression to overt HF. The BNP peptides also predict subsequent haemodynamic deterioration and adverse events in cardiovascular disease, and can therefore be used to monitor those at high risk and act as a guide to optimization of treatment. The favourable biological properties of the natriuretic peptides have also led to their use as therapeutic agents.

Opportunities for improvement in the cardiovascular care of patients with end-stage renal disease

Cardiovascular disease accounts for the majority of morbidity and mortality in patients with end-stage renal disease (ESRD). Studies have identified several explanations for this observation, such as high rates of cardiovascular risk factors, lesser use of cardioprotective strategies, adverse outcomes with cardiovascular drugs and procedures, and accelerated atherosclerosis and myocardial disease in ESRD. Based on these findings, this article addresses the critical opportunities for improvement in cardiovascular outcomes in patients with ESRD. These improvements include prevention of cardiovascular events, management of acute coronary syndromes and heart failure, and the prevention of sudden death.

Autocrine and paracrine actions of natriuretic peptides in the heart

The natriuretic peptides, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), are a family of polypeptide mediators exerting numerous actions in cardiovascular homeostasis. ANP and BNP are cardiac derived, being secreted and up-regulated in myocardium in response to many pathophysiological stimuli. CNP is an endothelium-derived mediator. The classical endocrine effects of ANP and BNP on fluid homeostasis and blood pressure, especially in conditions characterised by left ventricular dysfunction, are well recognised and extensively researched. However, there is accumulating evidence that, in addition to endocrine actions, ANP and BNP exhibit important autocrine and paracrine functions within the heart and coronary circulation. These include regulation of myocyte growth, inhibition of fibroblast proliferation and extracellular matrix deposition, a cytoprotective anti-ischaemic (preconditioning-like) function, and influences on coronary endothelium and vascular smooth muscle proliferation and contractility. Most if not all of these actions can be ascribed to particulate guanylyl cyclase activation because the ANP/BNP receptor, natriuretic peptide receptor (NPR)-A, has an intracellular guanylyl cyclase domain. Subsequent elevation of the intracellular second messenger cGMP may exert diverse physiological effects through activation of cGMP-dependent protein kinases (cGK), predominantly cGK-I. However, there appear to be other contributory mechanisms in several of these actions, including the augmentation of nitric oxide synthesis. These diverse actions may represent counterregulatory mechanisms in the pathophysiology of many cardiovascular diseases, not just those typified by left ventricular dysfunction. Ultimately, insights from the autocrine/paracrine actions of natriuretic peptides may provide routes to therapeutic application in cardiac diseases of natriuretic peptides and drugs that modify their availability.

Pharmacological therapy of acute cardiogenic pulmonary oedema in the emergency department

This paper critically reviews the major drug types that are currently used in the management of acute cardiogenic pulmonary oedema. As decompensated heart failure becomes an increasingly common problem in emergency departments in the developed world, optimization of emergency drug therapy for these critically ill patients is essential. The evidence base for 'routine therapy' in the ED is considered. The review also briefly considers emerging pharmacological therapies that may have an impact on future management of cardiogenic pulmonary oedema.

Perioperative Pharmacotherapy in Patients with Left Ventricular Assist Devices

Heart failure remains the leading cause of death in Western countries, affecting 4.9 million individuals and causing >300 000 deaths annually in the US alone. The disease is highly prevalent in the elderly population and often follows a course of progressive disability and deterioration. An estimated 15 000 patients with end-stage heart failure could benefit from heart transplant each year. Yet, as a result of a significant shortage of donor organs, only 2500 hearts are donated annually, and approximately one-third of patients awaiting heart transplant die each year. Mechanical circulatory support, primarily in the form of left ventricular assist devices (LVADs), has come to the forefront of treatment for severe congestive heart failure by providing a feasible alternative to patients who might otherwise die awaiting heart transplant. The arrival of LVADs has resulted in a dramatic shift in the management of heart failure, one that will undoubtedly affect and include a vast proportion of elderly patients. While LVADs represent a surgical approach to a disease that has traditionally been managed medically, the pharmacological application throughout the perioperative period remains of critical importance. Five primary classes of drugs bear specific application to the LVAD population: (i) drugs that provide haemodynamic support; (ii) antimicrobials; (iii) anticoagulants and antiplatelets; (iv) agents that promote myocardial recovery; and (v) miscellaneous other medications. Drugs that provide haemodynamic support are subdivided into inotropes, vasopressors and pulmonary vasodilators. Some combination of these medications is usually administered within the perioperative period in order to maintain stable patient haemodynamics and assure proper LVAD function. Antimicrobials are of paramount importance in the pre-, intra- and postoperative periods to minimise the risk of infection, an unfortunately common complication of LVAD therapy that can have potentially morbid consequences. Anticoagulants and antiplatelet medications are necessary for certain types of LVADs and serve to curb the incidence of device thrombus formation and associated embolic phenomena. Pharmacotherapeutic agents that facilitate myocardial recovery are being investigated as adjuncts to LVAD support so that bridge to recovery can become a realistic outcome for a growing number of LVAD patients. The miscellaneous class of medications used with LVADs includes those that minimise the risk of bleeding in select patients and those that enhance proper vitamin and nutrient status in the postoperative period, the attainment of which may serve vital to a successful recovery.

Science or fiction: use of nesiritide as a first-line agent?

Nesiritide is an effective agent for the treatment of decompensated CHF. However, the VMAC trial shows that the agent's efficacy and safety are actually more similar than dissimilar to those of nitroglycerin. Indeed, objective reviews have placed nesiritide as a second-line agent behind current standard drug therapy. Finally, nesiritide is approximately 40 times the purchase price of standard agents such as nitroglycerin. For these reasons, we feel that nesiritide should not be considered as first-line therapy. Reflecting this notion, one institution has implemented a protocol that recommends administration of nitroglycerin and intravenous diuretics (using > or = 2 times the usual daily diuretic dose) before using nesiritide. In light of the existing data, we feel that this approach appears to be an appropriate and prudent one for nesiritide's place in therapy.