Design and evaluation of novel natriuretic peptide derivatives with improved pharmacokinetic and pharmacodynamic properties

C-type natriuretic peptide (CNP) and its receptor, natriuretic peptide receptor B (NPR-B), are potent positive regulators of endochondral bone growth, making the CNP pathway one of the most promising therapeutic targets for the treatment of growth failure. However, the administration of exogenous CNP is not fully effective, due to its rapid clearance in vivo. Modification of CNP to potentially druggable derivatives may result in increased resistance to proteolytic degradation, longer plasma half-life (T_1/2), and better distribution to target tissues. In the present study, we designed and evaluated CNP/ghrelin chimeric peptides as novel CNP derivatives. We have previously reported that the ghrelin C-terminus increases peptide metabolic stability. Therefore, we combined the 17-membered, internal disulfide ring portion of CNP with the C-terminal portion of ghrelin. The resultant peptide displayed improved biokinetics compared to CNP, with increased metabolic stability and longer plasma T_1/2. Repeated subcutaneous administration of the chimeric peptide to mice resulted in a significant acceleration in longitudinal growth, whereas CNP(1-22) did not. These results suggest that the ghrelin C-terminus improves the stability of CNP, and the chimeric peptide may be useful as a novel therapeutic agent for growth failure and short stature.

Predictors of clinical outcomes in acute decompensated heart failure: Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure outcome models

BACKGROUND

Patients hospitalized for acute decompensated heart failure (ADHF) are at high risk for early mortality and rehospitalization. Risk stratification of ADHF using clinically available data on admission is increasingly important to integrate with clinical pathways. Our goal was to create a simple method of screening patients upon admission to identify those with increased risk of future adverse events.

METHODS

Using ASCEND-HF, a pragmatic clinical trial conducted in 398 sites globally, we developed and validated logistic regression risk models for (a) 30-day mortality/HF rehospitalization, (b) 30-day mortality/all-cause rehospitalization, (c) 30-day all-cause mortality, and (d) 180-day all-cause mortality. Fifty-one candidate variables were evaluated based on prior publications and clinical review. Final models were selected based on stepwise selection with entry and a staying criterion of P < .01. The 30-day mortality model was externally validated, and coefficients were converted to an additive risk score.

RESULTS

Among 7,141 patients, the median age was 67 years, 34% were female, and 80% had a left ventricular ejection fraction <40%. The models had between 5 and 12 risk factors with c-indices ranging from 0.68 to 0.75. A simplified score, including age, systolic blood pressure, sodium, blood urea nitrogen, and dyspnea at rest, discriminated 30-day mortality risk from 0.5% (score 0) to 53% (score 10).

CONCLUSIONS

Commonly available clinical variables provide simple risk stratification for clinical outcomes among patients with ADHF, and these models may be considered for integration into routine clinical care.

Low-dose dopamine or low-dose nesiritide in acute heart failure with renal dysfunction: the ROSE acute heart failure randomized trial

IMPORTANCE

Small studies suggest that low-dose dopamine or low-dose nesiritide may enhance decongestion and preserve renal function in patients with acute heart failure and renal dysfunction; however, neither strategy has been rigorously tested.

OBJECTIVE

To test the 2 independent hypotheses that, compared with placebo, addition of low-dose dopamine (2 μg/kg/min) or low-dose nesiritide (0.005 μg/kg/min without bolus) to diuretic therapy will enhance decongestion and preserve renal function in patients with acute heart failure and renal dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, double-blind, placebo-controlled clinical trial (Renal Optimization Strategies Evaluation [ROSE]) of 360 hospitalized patients with acute heart failure and renal dysfunction (estimated glomerular filtration rate of 15-60 mL/min/1.73 m2), randomized within 24 hours of admission. Enrollment occurred from September 2010 to March 2013 across 26 sites in North America.

INTERVENTIONS

Participants were randomized in an open, 1:1 allocation ratio to the dopamine or nesiritide strategy. Within each strategy, participants were randomized in a double-blind, 2:1 ratio to active treatment or placebo. The dopamine (n = 122) and nesiritide (n = 119) groups were independently compared with the pooled placebo group (n = 119).

MAIN OUTCOMES AND MEASURES

Coprimary end points included 72-hour cumulative urine volume (decongestion end point) and the change in serum cystatin C from enrollment to 72 hours (renal function end point).

RESULTS

Compared with placebo, low-dose dopamine had no significant effect on 72-hour cumulative urine volume (dopamine, 8524 mL; 95% CI, 7917-9131 vs placebo, 8296 mL; 95% CI, 7762-8830 ; difference, 229 mL; 95% CI, -714 to 1171 mL; P = .59) or on the change in cystatin C level (dopamine, 0.12 mg/L; 95% CI, 0.06-0.18 vs placebo, 0.11 mg/L; 95% CI, 0.06-0.16; difference, 0.01; 95% CI, -0.08 to 0.10; P = .72). Similarly, low-dose nesiritide had no significant effect on 72-hour cumulative urine volume (nesiritide, 8574 mL; 95% CI, 8014-9134 vs placebo, 8296 mL; 95% CI, 7762-8830; difference, 279 mL; 95% CI, -618 to 1176 mL; P = .49) or on the change in cystatin C level (nesiritide, 0.07 mg/L; 95% CI, 0.01-0.13 vs placebo, 0.11 mg/L; 95% CI, 0.06-0.16; difference, -0.04; 95% CI, -0.13 to 0.05; P = .36). Compared with placebo, there was no effect of low-dose dopamine or nesiritide on secondary end points reflective of decongestion, renal function, or clinical outcomes.

CONCLUSION AND RELEVANCE

In participants with acute heart failure and renal dysfunction, neither low-dose dopamine nor low-dose nesiritide enhanced decongestion or improved renal function when added to diuretic therapy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01132846.

Left ventricular responses to acute changes in late systolic pressure augmentation in older adults

BACKGROUND

Changes in the cardiovascular system with age may predispose older persons to development of heart failure with preserved ejection fraction. Vascular stiffening, aortic pressure augmentation, and ventricular-vascular coupling have been implicated. We explored the potential for acute reductions in late systolic pressure augmentation to impact left ventricular relaxation in older persons without heart failure.

METHODS

Sixteen older persons free of known cardiovascular disease with the exception of hypertension had noninvasive tonometry and cardiac ultrasound to evaluate central augmentation index (AI) and diastolic function at baseline and after randomized, blinded administration of intravenous B-type natriuretic peptide (BNP) and hydralazine in a crossover design.

RESULTS

AI was significantly reduced after BNP (11.4±8.9 to -0.2±14.7%; P = 0.02) and nonsignificantly reduced after hydralazine (14.7±8.4% to 11.5±8.8%; P = 0.39). With decreased AI during BNP, a trend toward worsened myocardial relaxation by tissue Doppler imaging occurred (E' velocity pre- and post-BNP: 10.0±2.5 and 8.8±2.0cm/s, respectively; P = 0.06). There was a significant fall in stroke volume with BNP (68.5±18.3 to 60.9±18.1ml; P = 0.02), suggesting that changes in preload overwhelmed effects of afterload reduction on ventricular performance. With hydralazine, neither relaxation nor stroke volume changed.

CONCLUSIONS

Acute changes in late systolic aortic pressure augmentation do not necessarily lead to improved systolic or diastolic function in older people. Preload may be a more important determinant of cardiac performance than afterload in older people with compensated ventricular function. The potential for changes in preload to impair rather than enhance left ventricular systolic and diastolic function in older people warrants further study.

CLINICAL TRIALS REGISTRATION

This study is registered at clinicaltrials.gov as NCT00204984.

B-type natriuretic peptide (BNP) affects the initial response to intravenous glucose: a randomised placebo-controlled cross-over study in healthy men

AIMS/HYPOTHESIS

B-type natriuretic peptide (BNP) is a hormone released from cardiomyocytes in response to cell stretching and elevated in heart failure. Recent observations indicate a distinct connection between chronic heart failure and diabetes mellitus. This study investigated the role of BNP on glucose metabolism.

METHODS

Ten healthy volunteers (25 ± 1 years; BMI 23 ± 1 kg/m(2); fasting glucose 4.6 ± 0.1 mmol/l) were recruited to a participant-blinded investigator-open placebo-controlled cross-over study, performed at a university medical centre. They were randomly assigned (sequentially numbered opaque sealed envelopes) to receive either placebo or 3 pmol kg(-1) min(-1) BNP-32 intravenously during 4 h on study day 1 or 2. One hour after beginning the BNP/placebo infusion, a 3 h intravenous glucose tolerance test (0.33 g/kg glucose + 0.03 U/kg insulin at 20 min) was performed. Plasma glucose, insulin and C-peptide were frequently measured.

RESULTS

Ten volunteers per group were analysed. BNP increased the initial glucose distribution volume (13 ± 1% body weight vs 11 ± 1%, p < 0.002), leading to an overall reduction in glucose concentration (p < 0.001), particularly during the initial 20 min of the test (p = 0.001), accompanied by a reduction in the initial C-peptide levels (1.42 ± 0.13 vs 1.62 ± 0.10 nmol/l, p = 0.015). BNP had no impact on beta cell function, insulin clearance or insulin sensitivity and induced no adverse effects.

CONCLUSIONS/INTERPRETATION

Intravenous administration of BNP increases glucose initial distribution volume and lowers plasma glucose concentrations following a glucose load, without affecting beta cell function or insulin sensitivity. These data support the theory that BNP has no diabetogenic properties, but improves metabolic status in men, and suggest new questions regarding BNP-induced differences in glucose availability and signalling in various organs/tissues.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01324739

FUNDING

The study was funded by Jubilée Fonds of the Austrian National Bank (OeNB-Fonds).

B-type natriuretic peptide and glycaemia: an emerging cardiometabolic pathway?

There is emerging evidence of cross-talk between the myocardium and systemic metabolic pathways. In particular, there is interest in the potential metabolic effects of A-type and B-type natriuretic peptides (ANP and BNP), produced in the myocardial tissue in response to ventricular stretch and cardiac overload. This commentary provides an overview of the evidence that natriuretic peptides promote lipolysis and enhance adiponectin production. In addition, we review new and existing evidence that BNP may directly improve glucose control, or else lower glucose indirectly via enhanced capillary permeability or greater renal excretion. Further investigation of the links between natriuretic peptide and glycaemia would seem important given the potential to reveal novel mechanisms to treat diabetes.

Potentiated effect of systemic administration of oxytocin on hypertonic NaCl intake in food-deprived male rats

Subcutaneous administration of oxytocin (OT) increases water intake and sodium/urine excretion in food-deprived male rats. This study analyzes the effect of OT administration (at 0830 and 1430h) on the consumption of water and hypertonic NaCl (1.5%). In the first experiment, injections of OT increased the intake of hypertonic NaCl (but not of water) in food-deprived rats but not in ad lib-fed animals during the second 12 h (2030 to 0830) of the treatment day. The net concentration of the fluid consumed by OT/deprived animals was close to isotonic. In the second experiment, the initial effect of OT administration was an increase in urine volume and urinary sodium excretion and concentration by food-deprived animals during the first 12 h (0830 to 2030). These findings suggest that in food-deprived animals, systemic administration of OT induces NaCl intake as a consequence of previous urine loss and urinary sodium excretion.

Renal and anti-aldosterone actions of vasopressin-2 receptor antagonism and B-type natriuretic peptide in experimental heart failure

BACKGROUND

Hemodynamic and neurohumoral function can affect the efficacy of diuretic therapy in congestive heart failure. Arginine vasopressin increases water reabsorption through the V(2) receptor in the collecting duct, whereas B-type natriuretic peptide (BNP) decreases sodium reabsorption in the collecting duct. We hypothesized that combining BNP to the V(2)-receptor antagonist tolvaptan (TLV) would enhance renal excretory function by augmenting sodium excretion together with aquaresis without adversely affecting renal hemodynamics in experimental congestive heart failure.

METHODS AND RESULTS

Congestive heart failure was induced in 3 groups (n=6 per group) of dogs by tachypacing. A acute experiment was done after 10 days. After baseline measurements, study groups received a 0.1 mg/kg IV bolus of TLV alone (TLV), TLV in combination with BNP (TLV+BNP; 50 ng/[kg . min]), or BNP alone (BNP). Mean arterial pressure increased with TLV, remained unchanged with TLV+BNP, and decreased with BNP (+5+/-1mm Hg versus -1+/-1 mm Hg versus -15+/-1 mm Hg; P<0.05). Renal blood flow and glomerular filtration rate were preserved with all regimens. Urine flow increased in all 3 groups but significantly more so with TLV+BNP (TLV: +0.4+/-0.1 mL/min versus TLV+BNP: +2.4+/-0.5 mL/min versus BNP: +0.8+/-0.3 mL/min; P<0.05). Only TLV+BNP and BNP were natriuretic (P<0.05), whereas only TLV and TLV+BNP increased electrolyte-free water excretion (P<0.05). Compared with TLV alone, TLV+BNP prevented an increase in aldosterone (P<0.05).

CONCLUSIONS

Coadministration of TLV and BNP in experimental HF resulted in a beneficial profile of renal, neurohumoral, and hemodynamic actions, specifically potent diuresis with natriuresis, neutral effect on mean arterial pressure, and lack of aldosterone activation.

Managing acute renal failure in patients with acute decompensated heart failure: the cardiorenal syndrome

In patients with acute decompensated heart failure, worsening renal function during conventional decongestive therapy (cardiorenal syndrome) affects prognosis and the initiation of therapies with known benefit in chronic heart failure. Potential strategies for decongestion in patients who develop cardiorenal syndrome include invasive hemodynamic monitoring to guide therapy, use of continuous diuretic infusions, ultrafiltration, or novel therapy with adenosine or vasopressin receptor antagonists. Clinical trials by the National Heart, Lung, and Blood Institute's Heart Failure Network are currently underway to validate such therapies in patients with acute decompensated heart failure with worsening renal function and to establish novel biomarkers for the early identification of patients who develop cardiorenal syndrome.

Usefulness of BNP-administration in cardiac surgery: animal model

OBJECTIVE

The pharmacologic properties of Brain natriuretic peptide make it a favourable substance to use after cardiac operations. The goal of this study was to evaluate the effect of BNP following cardio-pulmonary bypass (CPB).

METHOD

Nineteen pigs were operated on using CPB. One group received BNP and the control group received placebo. A 30-minute ischemic episode was simulated. Following declamping, BNP was administered by an IV bolus, followed by an infusion for 60 minutes. Hemodynamic and clinical chemistry parameters were documented, as well as the amount of catecholamines.

RESULTS

The Cardiac output and Cardiac Index in the BNP group were significantly higher 60 minutes after ending CPB. Seven of ten animals in the control group needed catecholamines at the end of the experiment, whereas none of the animals in the BNP group did at this juncture. Creatine kinase and Lactate were significantly lower.

CONCLUSION

BNP is a well-tolerated agent that could present a new treatment option for heart failure following cardiac surgery. Hemodynamics are greatly improved with almost no need for pharmacological support.

B-type natriuretic peptide infusions in acute myocardial infarction

BACKGROUND

Natriuretic peptides have actions likely to ameliorate cardiac dysfunction. B-type natriuretic peptide (BNP) is indicated as treatment for decompensated cardiac failure.

OBJECTIVE

To determine the utility of BNP in acute myocardial infarction (MI).

DESIGN

Double-blind randomised placebo-controlled trial.

SETTING

Tertiary hospital coronary care unit.

PATIENTS

28 patients with acute MI with delayed or failed reperfusion and moderate left ventricular dysfunction.

INTERVENTIONS

Infusion of BNP or placebo for 60 hours after MI.

MAIN OUTCOME MEASURES

Neurohormonal activation and renal function in response to BNP infusion, secondary end points of echocardiographic measures of left ventricular function and dimension.

RESULTS

BNP infusion resulted in a significant rise in BNP (276 pg/l vs 86 pg/l, p = 0.001). NT-proBNP levels were suppressed by BNP infusion (p = 0.002). Atrial natriuretic peptide (ANP) and NT-proANP levels fell with a significant difference in the pattern between BNP infusion and placebo during the first 5 days (p<0.005). C-type natriuretic peptide (CNP) and NT-proCNP levels rose during the infusion with higher levels than placebo at all measurements during the first 3 days (p<0.01). Cyclic guanosine monophosphate (cGMP) was raised during the infusion period showing a peak of 23 pmol/l on day 2 (placebo 8.9 pmol/l, p = 0.002), with a correlation between BNP and cGMP levels (p<0.001). Glomerular filtration rate (GFR) fell with BNP infusion but was not significantly lower than with placebo (71.0 (5.6) vs 75.8 (5.4) ml/min/1.73 m2, p = 0.62). Patients receiving nesiritide exhibited favourable trends in left ventricular remodelling.

CONCLUSIONS

Nesiritide, given soon after MI, induced increments in plasma cGMP and CNP and decrements in other endogenous cardiac peptides with a neutral effect on renal function and a trend towards favourable ventricular remodelling.

Hemolytic-uremic syndrome and myocardial dysfunction in a 9-month-old boy

Cardiovascular dysfunction in patients with hemolytic-uremic syndrome (HUS) may be related to secondary issues such as volume overload, hypertension or electrolyte disturbances including hyperkalemia. Additionally, primary myocardial involvement has been increasingly recognized as a potential comorbid feature of HUS. We report a 9-month-old child with HUS who developed clinical signs of poor myocardial function with depressed myocardial function noted by echocardiography. Supportive care including mechanical ventilation and inotropic agents were necessary for approximately 10 days. Follow-up echocardiography revealed return of normal ventricular function. Previous reports of primary cardiac involvement with HUS have included thrombotic microangiopathy of the coronary vasculature resulting in myocardial ischemia, myocardial infarction or depressed myocardial function, myocarditis, congestive heart failure with dilated cardiomyopathy and pericardial effusion with tamponade. Given the potential for morbidity and mortality during the preoperative period in patients with HUS, anesthesiologists involved in the care of such patients should be aware of the potential for myocardial involvement in this disease process. Preoperatively, the routine evaluation of myocardial function may be indicated.

Controversy and Conflict in the Treatment of Acute Decompensated Heart Failure: Nesiritide as Evidence-Based Treatment

Acute decompensated heart failure poses a complex clinical challenge for the health care community. Evolving concepts of the pathophysiology and lack of consensus on appropriate outcome measures for drug approval underlie some of the current controversies about nesiritide. We outline the major controversies from the viewpoint that nesiritide should continue to be used judiciously by following its package insert recommendations and the Heart Failure Society of America's 2006 Comprehensive Heart Failure Practice Guidelines.

The Second Follow-up Serial Infusions of Nesiritide (FUSION II) trial for advanced heart failure: study rationale and design

BACKGROUND

Patients with persistently symptomatic advanced heart failure have limited treatment options after appropriate use of standard evidence-based therapies. Current recommendations from the American College of Cardiology/American Heart Association guidelines for treatment of stage C/D heart failure beyond standard therapy include ventricular replacement, investigational agents, and palliative interventions. Given the elevated risk of this patient population, additional treatment options seem warranted. Natriuretic peptides are protean compounds that provoke vasodilation, natriuresis, neurohormonal antagonism, and reverse remodeling, but they have an uncertain risk-benefit profile affecting serum creatinine and clinical events. In the pilot, open-label FUSION I trial, the adjunctive administration of nesiritide with standard therapy for patients with advanced heart failure, was demonstrated to have a neutral effect on outcomes with no evidence of increased risk. Within a prespecified subset of high-risk patients, a potential signal of benefit on a combined end point of mortality and cardiovascular hospitalization was identified.

STUDY DESIGN

FUSION II is a 900-patient randomized, placebo-controlled, double-blind, phase IIb trial designed to further assess the safety, efficacy, and optimal dosing frequency of outpatient nesiritide for advanced heart failure. The primary end point is a composite of all-cause mortality and cardiorenal hospitalization.

CONCLUSIONS

If a confirmatory signal of benefit is identified in FUSION II, a definitive phase III mortality/quality of life trial will be warranted. Additional issues related to the influence of disease management, the logistics of outpatient parenteral therapy administration, and future iterations of natriuretic peptide therapy will need to be investigated.

CNP infusion attenuates cardiac dysfunction and inflammation in myocarditis

Myocarditis is an acute inflammatory disease of the myocardium for which there is currently no specific therapy. We investigated the therapeutic potential of C-type natriuretic peptide (CNP) in acute experimental autoimmune myocarditis. One week after injection of porcine myosin into male Lewis rats, CNP (0.05 microg/kg/min) was continuously administered for 2 weeks. CNP infusion significantly increased maximum dP/dt, decreased left ventricular end-diastolic pressure, and improved fractional shortening compared with vehicle administration. In vehicle-treated hearts, severe necrosis and marked infiltration of CD68-positive inflammatory cells were observed. Myocardial and serum levels of monocyte chemoattractant protein-1 were elevated in myocarditis. However, these changes were attenuated by CNP infusion. In addition, treatment with CNP significantly increased myocardial capillary density. Guanylyl cyclase-B, a receptor for CNP, was expressed in myocarditic heart, and cyclic guanosine monophosphate was elevated by CNP infusion. In conclusion, CNP infusion attenuated cardiac function in acute myocarditis through anti-inflammatory and angiogenic effects.

Nesiritide for the Treatment of Diastolic Dysfunction

Despite advances in the treatment of left ventricular diastolic dysfunction, therapy is still primarily empiric and readmission rates remain high, with up to half of patients discharged with the diagnosis of congestive heart failure being rehospitalized within 6 months due to recurrent decompensation. Even with this high economic burden, no effective, long-term therapies have been developed. The authors present a patient with recurrent hospitalizations for decompensated congestive heart failure due to left ventricular diastolic dysfunction becoming refractory to parenteral diuretic therapy. The patient exhibited a dramatic response to a 96-hour intravenous infusion of nesiritide and experienced prolonged clinical benefit, remaining in New York Heart Association functional class I for more than 6 months after the infusion.

Oral Brain Natriuretic Peptide: A Novel Strategy for Chronic Protein Therapy for Cardiovascular Disease

In 1956, secretory granules were detected via electron microscopy in the mammalian atria by Kisch. This remarkable discovery signaled the beginning of a new field of research that decades later has lead to the concept of the heart as an endocrine organ and the establishment of the natriuretic peptide (NP) system. In 1981, deBold and colleagues identified from the atrial myocardium the first member of the NP family, atrial NP. Thereafter, new members of this growing family of cardiac hormones were identified and investigated. The successful story of B-type or brain NP (BNP), from its discovery to its use in the diagnosis and prognosis of cardiovascular diseases and later as a tool in the treatment of acute congestive heart failure, have since taken place. However, the use of peptides as chronic therapies has been limited by enzymatic degradation. Chronic administration of BNP, particularly in disease states like hypertension and early heart failure, could be effective as an antihypertensive therapy and in delaying progression of cardiac disease. To date, the use of BNP is limited to patients with acute decompensated heart failure, but new strategies are under investigation to extend the use of chronic BNP in less severe stages of cardiovascular diseases. Innovative technologies have been recently developed that allow protection of proteins from enzymatic degradation, making feasible oral administration of small proteins such as BNP. This review will focus on the potential role of BNP as a new chronic therapeutic strategy in the treatment of cardiovascular diseases and will summarize our recent report of the development and in vivo evaluation of orally active human BNP.

The rise and fall of natriuretic peptides in acute kidney injury: a misunderstood relationship?

The vasodilatory, natriuretic, and diuretic properties of natriuretic peptides (NPs) make them attractive agents in the treatment of acute kidney injury (AKI). However, there is conflicting evidence of their beneficial effects. This article examines the reasons for the differences, and provides insight that the reported outcomes may be related to the unique physiologic effects and mechanisms of action of NPs, the designs and cohorts of the trials, and the characteristic renal hemodynamics associated with AKI. NPs are effective in the prevention of AKI when applied prophylactically, in lower doses, for prolonged duration, in patients with mild to moderate impairment in renal function, and in predictable clinical settings with clearly defined outcome measurements.

Effects of standard heart failure therapy and concomitant treatment with intravenous furosemide or inotropes (dobutamine, dopamine, and/or milrinone) on renal function and mortality in patients treated with nesiritide

The safety and efficacy of the concomitant use of intravenous diuretics and positive inotropes with nesiritide have not been well studied. There is also a paucity of data examining whether the type of medical therapy before treatment with nesiritide has an effect on outcomes. Data from 167 patients with heart failure and reduced left ventricular ejection fractions (34 +/- 17%) treated with nesiritide were analyzed retrospectively. Baseline oral medications were continued, diuretic regimens were modified, and nitrates were discontinued. Forty-three patients (26%) received intravenous furosemide with nesiritide. The glomerular filtration rate before and after nesiritide infusion was not different in patients treated with versus without furosemide (0.7 +/- 8.8 vs 0.7 +/- 11.0 ml/min/1.73 m(2), p = 0.71). Change in urine output from before to during nesiritide infusion was greater with concomitant furosemide (41 +/- 57 vs 10 +/- 58 m/hour, p = 0.006). There was no significant difference in survival with furosemide (90% vs 89% at 30 days, 62% vs 57% at 12 months, p = 0.63). Thirty-nine patients (23%) received inotrope support with nesiritide. The glomerular filtration rate tended to improve when inotropes were used with nesiritide (3.3 +/- 13.1 vs -0.1 +/- 9.4, ml/min/1.73 m(2), p = 0.17). No significant changes in serum creatinine or urine output were observed with inotrope use. Survival was not worsened in those receiving inotropes (p = 0.51). Also, there were no significant differences in serum creatinine, glomerular filtration rate, or urine output in patients who continued to receive angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta blockers, or digoxin therapy during nesiritide infusion. In conclusion, there were no observed adverse affects of baseline medical therapy, intravenous diuretics, or intravenous inotropes on renal functions or mortality when used in conjunction with nesiritide in the treatment of decompensated chronic heart failure.

Bronchodilator effect of infused B-type natriuretic peptide in asthma

STUDY OBJECTIVE

To determine the bronchodilator effect of recombinant human B-type natriuretic peptide (BNP; nesiritide) on patients with asthma.

DESIGN

A prospective, open-label study.

SETTING

Outpatient setting.

PATIENTS

Eight adult patients with asthma confirmed by > 12% and > 200 mL increase in FEV1 after bronchodilator inhalation.

INTERVENTIONS

An IV nesiritide bolus, 2 microg/kg, followed by continuous infusion for a total of 3 h at escalating doses of 0.01, 0.02, and 0.03 microg/kg/min for 1 h each as tolerated.

MEASUREMENTS

Spirometry and forced oscillation technique (FOT) measurements were both obtained at baseline and every 30 min during the infusion. Two doses of albuterol, 90 microg, inhalation via metered-dose inhaler were then administered at the end of nesiritide infusion, followed by repeat spirometry and FOT measurements after 30 min. Primary end points were FEV1 and FVC changes after the nesiritide infusion for 3 h. Wilcoxon signed-ranks tests were used to compare the effects of nesiritide and albuterol.

RESULTS

Baseline measurements (mean +/- SD) were as follows: FEV1, 1.89 +/- 0.87 L; FVC, 3.02 +/- 0.99 L; respiratory resistance at 5 Hz (Rrs5), 10.3 +/- 3.85 cm H2O . s/L; and mean respiratory resistance at 5 to 20 Hz, 7.56 +/- 1.92 cm H2O/L/s. Mean baseline serum BNP level was 27 +/- 27 pg/mL. After 180 min of nesiritide infusion, the following measurements showed significant changes: FEV1 increased to 2.41 +/- 0.78 L (mean increase, 520 mL), p = 0.012; FVC increased to 3.65 +/- 1.05 L (mean increase, 630 mL), p = 0.017; and Rrs5 decreased to 8.24 +/- 4.02 cm H2O/L/s, p = 0.017. After albuterol, there were no further significant changes in these measurements.

CONCLUSION

IV nesiritide is an effective bronchodilator in patients with asthma.

Potential applications of outpatient nesiritide infusions in patients with advanced heart failure and concomitant renal insufficiency (from the Follow-Up Serial Infusions of Nesiritide [FUSION I] trial)

This retrospective substudy of the Follow-Up Serial Infusions of Nesiritide trial (FUSION I) assessed the feasibility of outpatient administration of nesiritide in 138 patients with co-morbid advanced heart failure and renal insufficiency (estimated creatinine clearance<60 ml/min). Patients received 1 of 3 treatments once weekly for 12 weeks: standard care (SC), SC plus nesiritide 0.005 microg/kg/min, or SC plus nesiritide 0.010 microg/kg/min. The addition of nesiritide to SC was well tolerated, with no evidence of worsening renal function, compared with SC only and was associated with a reduction in the rate of all-cause hospitalization or mortality through week 12, with hazard ratios of 2.027 (95% confidence interval 1.165 to 3.525) and 2.219 (95% confidence interval 1.233 to 3.992) for the SC-only group compared with the SC plus 0.005 microg/kg/min and SC plus 0.010 microg/kg/min nesiritide groups, respectively. These findings raise the hypothesis that adjunctive therapy with nesiritide on an outpatient basis may be beneficial for patients with advanced heart failure and renal insufficiency. Further study is warranted to test the validity of this finding.

Diuretic potential of energy drinks

Recent literature suggests that both caffeine and taurine can induce diuresis and natriuresis in rat and man. Although they act via different cellular mechanisms, their diuretic actions might be additive. This is of considerable interest, as several commercially available energy drinks contain both substances. In this study we examined the possible diuretic effects of caffeine and taurine in a cross-over-design in which 12 healthy male volunteers received each of 4 different test drinks (750 ml of energy drink containing 240 mg caffeine and 3 g taurine, the three other test drinks either lacked caffeine, taurine or both) after restraining from fluids for 12 h. Mixed model analyses demonstrated that urinary output and natriuresis were significantly increased by caffeine (mean differences 243 ml and 27 mmol; both p < 0.001) and that there were no such effects of taurine (mean differences 59 ml and -4 mmol). Additionally, urinary osmolarity at baseline was significantly related to the urinary output (p < 0.001). Urine osmolarity values at baseline and in the 6 h urine collection did not differ significantly between treatments. Taken together, our study demonstrates that diuretic and natriuretic effects of the tested energy drink were largely mediated by caffeine. Taurine played no significant role in the fluid balance in moderately dehydrated healthy young consumers. Consequently, the diuretic potential of energy drinks will not differ significantly from other caffeine containing beverages.

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.

[Medical and ventilatory treatment of acute heart failure]

BACKGROUND

Traditional medical treatment of acute heart failure has remained unchanged for many years. It has been based on oxygen supplementation and mechanical ventilatory support as well as the administration of morphine, diuretics, nitrates and inotropic agents. In 2005 the European Society of Cardiology published new guidelines on diagnosis and treatment. Also, new therapies have been introduced recently, giving rise to changes in therapeutic concepts.

MATERIAL AND METHOD

The article is based on these new guidelines and recent studies selected from the literature.

RESULTS

Mechanical ventilatory support reduces the number of patients who require endotracheal intubation. Nitrates in higher dosages than employed today appear to be beneficial to patients with pulmonary congestion, probably because of the pronounced afterload reducing effect. Nesiritide has shown better haemodynamic effects than common nitrate dosages in patients with congestive heart failure. Tezosentan was tested in the biggest trial ever which, however, was terminated prematurely, because of futility with regard to the endpoints dyspnoea and death. Dobutamine and milrinone are associated with increased mortality in patients with pronounced chronic and acute congestive heart failure. Levosimendan has shown lower mortality compared to dobutamine in patients with acute congestive heart failure.

INTERPRETATION

New concepts have finally emerged, including the application of old drugs such as nitrates in new (i.e., higher) dosages, as well as the novel compound levosimendan, and hypoperfused organs without severe hypotension. The new European Society of Cardiology classification provides a valuable and long-awaited guideline to diagnosis and treatment.

Amphiphilic Conjugates of Human Brain Natriuretic Peptide Designed for Oral Delivery: In Vitro Activity Screening

Congestive heart failure (CHF) is a complex syndrome involving altered neurohormonal levels and impaired cardiac and renal function. In recent years, intravenous administration of exogenous human brain-type natriuretic peptide (hBNP) has become an important therapy in treating patients with acutely decompensated CHF. However, reports during the past year suggest that hBNP could play a prominent role in the chronic treatment of CHF patients as well. We are currently developing conjugates of hBNP suitable for oral delivery to provide a patient-friendly treatment option for chronic heart failure patients. In this report, we present in vitro activity results obtained from hBNP conjugates featuring a variety of rationally designed amphiphilic oligomers. Mapping studies revealed that the hydrophobic/hydrophilic balance of the oligomer impacted the regioselectivity of conjugation. Additionally, the regiochemistry and extent of conjugation had a significant impact on activity. Many monoconjugates retained activity comparable to native peptide and are currently under evaluation in subsequent in vivo screens.

Administration of a Large Nesiritide Bolus Dose in a Pediatric Patient: Case Report and Review of Nesiritide Use in Pediatrics

Nesiritide (recombinant B-type natriuretic peptide) is often given for symptomatic relief of acute decompensated heart failure in adults. The literature describing the safety or efficacy of nesiritide in children is minimal, and we know of no data that describe the effects of a nesiritide overdose in adults or children. A 3-year-old, 10.9-kg girl was admitted to the pediatric intensive care unit with the diagnosis of dilated cardiomyopathy and acute decompensated heart failure. She received several vasoactive infusions during her admission, including nesiritide. On hospital day 47 (day 45 of nesiritide therapy), the patient received an 18-fold overdose of nesiritide, with no hemodynamic, cardiac, or renal sequelae. She subsequently underwent successful cardiac transplantation. The nesiritide treatment duration was longer for this patient than the 45 days previously reported in a pediatric patient. No hemodynamic instability or cardiac or renal sequelae were associated with the large, inadvertent bolus in our patient. This case report demonstrates the lack of adverse events in a pediatric patient administered nesiritide beyond the recommended dosing parameters. Increased vigilance is always advised when administering drugs not commonly given to pediatric patients.

Effects of intravenous nesiritide on pulmonary vascular hemodynamics in pulmonary hypertension

BACKGROUND

Nesiritide is effective in the treatment of decompensated heart failure (HF). We evaluated the acute hemodynamic effects of nesiritide, a recombinant B-type natriuretic peptide, in patients with HF and pulmonary hypertension (PH).

METHODS AND RESULTS

Twenty patients with HF and PH (mean pulmonary arterial [PA] pressure >25 mm Hg) were enrolled: 10 with postpulmonary capillary wedge (PCW) >15 mm Hg and 10 with precapillary PH (PCW) < or =15. The pulmonary and systemic hemodynamics were determined by right heart catheterization at baseline and at 15 and 30 minutes after an intravenous nesiritide infusion (2 mcg/kg bolus and 0.01 mcg.kg.min). For the patients with postcapillary PH, the mean left ventricular ejection fraction was 28 +/- 15%. After the 30-minute nesiritide infusion, right atrial (RA) pressure decreased 48% (P < .0001), mean PA pressure decreased 29% (P < .0001), PCW pressure decreased 40% (P < .0001), cardiac index (CI) increased 35% (P = .009), pulmonary vascular resistance index (PVRI) decreased 35% (P = .01), and arteriovenous oxygen difference (AVDO(2)) decreased 27% (P = .0003). For precapillary PH patients, there was no change in RA, PA, or PCW pressure, nor any change in CI, PVRI, or AVDO(2).

CONCLUSIONS

Nesiritide acutely and significantly reduced PA pressure, PVRI, and biventricular filling pressures in patients with postcapillary PH. However, for patients with precapillary PH, nesiritide had no significant acute hemodynamic effect on the pulmonary hemodynamics. The lack of acute beneficial effects of nesiritide in patients with advanced precapillary PH may be related to their relatively fixed remodeling of the pulmonary vasculature.

New cardioprotective agent K201 is natriuretic and glomerular filtration rate enhancing

BACKGROUND

K201 (JTV519) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It functions via stabilization of the ryanodine receptor-calcium release channel in the heart (RyR2). This receptor has been identified in the kidney, and in vitro studies suggest a role in the control of renal hemodynamics. To date, the in vivo function of this receptor is undefined. We hypothesized that this new drug, which is being developed for the treatment of heart failure for its myocardial actions, also possesses renal hemodynamic enhancing and excretory properties. We also used immunohistochemistry to identify RyR2 in the normal canine kidney.

METHODS AND RESULTS

We investigated the renal actions of K201 during intrarenal infusion in normal anesthetized dogs. K201 was infused after baseline measurements at 2 doses (0.1 and 0.5 mg.kg(-1).min(-1)). Immunohistochemistry was used to identify RyR2 presence in the kidney not exposed to K201. K201 was potently natriuretic and diuretic, with glomerular filtration rate- and renal blood flow-enhancing actions. The excretory responses to K201 administration were associated with decreases in distal tubular reabsorption of sodium despite a mild decrease in mean arterial pressure, which returned to baseline levels after K201 discontinuation. Immunohistochemistry of the normal canine kidney revealed the presence of RyR2 in the medullary collecting duct cells.

CONCLUSIONS

We report for the first time that the newly developed cardioprotective drug K201 possesses natriuretic, diuretic, glomerular filtration rate-enhancing, and vasodilating properties that go beyond myocardial actions and may support its therapeutic role in treatment of heart failure.

Observation unit treatment of heart failure with nesiritide: results from the proaction trial

This was a multicenter, randomized, double-blind, placebo-controlled pilot study, evaluating the safety and efficacy of a standard care treatment regimen with the addition of either nesiritide or placebo (SCP) in 237 Emergency Department (ED)/Observation Unit (OU) patients with decompensated heart failure (HF). Efficacy measures included initial admission, length of hospital stay (LOS), and inpatient rehospitalization through 30 days. Compared to the standard care group, patients who also received nesiritide had 11% fewer inpatient hospital admissions at the index ED visit (55% SCP, 49% nesiritide, p = 0.436), and 57% fewer inpatient hospitalizations within 30 days after discharge from the index hospitalization (23% SCP, 10% nesiritide, p = 0.058). The duration of rehospitalization was shorter for nesiritide patients (median LOS 2.5 vs. 6.5 days, p = 0.032). The incidence of symptomatic hypotension was low and did not differ between the groups. This study showed that nesiritide is safe when used in the emergency department, observation units, or similar settings.

C-type natriuretic peptide inhibits constrictive remodeling without compromising re-endothelialization in balloon-dilated renal arteries

PURPOSE

To investigate the long-term effect of local, liposome-mediated gene transfer of C-type natriuretic peptide (CNP) plasmid versus CNP protein on restenosis in porcine renal arteries following balloon angioplasty.

METHODS

The renal arteries of 15 pigs were dilated and the adventitia at the site of balloon injury injected with CNP protein, pCR3.1 plasmid encoding CNP, or the beta-galactosidase gene (control) via a needle injection catheter. Five animals receiving the CNP and control genes in dilated arteries were sacrificed after 3 weeks to analyze re-endothelialization, proliferation, and early CNP expression. Ten animals designated for the long-term experiments (3 months) were treated with the CNP gene versus CNP protein (n=3), the CNP gene versus the control gene (n=3), and the CNP protein versus the control gene (n=3). One animal served as a dilated non-treated control. Transfection and expression of CNP and beta-galactosidase were measured by polymerase chain reaction (PCR) and reverse transcription PCR. Renal arterial lumen narrowing was measured with angiography and histology. Endothelialization was assessed using Evans blue stain; vWF, CD31, factor VIII, and Ki67 were markers for immunohistochemical analysis.

RESULTS

An intact endothelial layer was seen at 3 weeks following angioplasty in all transfected arteries. Three months following treatment, computer-assisted morphometric analysis revealed significant enlargement of the arterial cross-sectional areas in CNP plasmid- treated vessels compared to dilated but untreated arteries (CNP plasmid +34.8%+/-13.9% versus CNP protein -1.75%+/-19.9% versus beta-galactosidase -47.0%+/-13.9%, p<0.01). Angiographic analysis showed significant enlargement of the arterial diameter compared to dilated, untreated arteries (CNP plasmid +20.8%+/-6.8% versus CNP protein +5.7%+/-6.0% versus beta-galactosidase -24.5%+/-10.2%, p<0.01).

CONCLUSIONS

Local application of CNP plasmid proved superior to CNP protein in producing rapid re-endothelialization and significantly enlarging the renal arterial lumen following dilation.

The Pilot Randomized Study of Nesiritide Versus Dobutamine in Heart Failure (PRESERVD-HF)

Acute heart failure syndromes (AHFS) are related to several diseases affecting not only the heart but also the kidneys and blood vessels. Emerging evidence indicates that myocardial injury may also play a role in the pathophysiology of AHFS, as suggested by increased levels of markers of injury, such as cardiac troponin (cTn). Although cTn is a known prognostic marker, the release of cTn during hospitalization has not been evaluated prospectively with serial measures. We prospectively evaluated patterns of cTn release by conducting serial measures of cTnI and cTnT in patients hospitalized for AHFS. This study enrolled 51 patients with AHFS who were admitted with worsening heart failure (HF) and a history of coronary artery disease (CAD) in whom an acute coronary event was not suspected. Levels of cTnI and cTnT were measured at 8, 32, 56, and 80 hours after study entry. At baseline, 73.9% of patients had detectable cTnI, and 43.5% had detectable cTnT levels. The median concentrations of cTnI and cTnT were unchanged from 0 to 32 hours, increased from 32 to 56 hours, then either plateaued (cTnT) or decreased to baseline (cTnI). Of the 26 patients who had no detectable cTn levels at baseline, 2 (7.7%) developed detectable cTnT and 5 (41.7%) developed detectable cTnI release during hospitalization. Detectable levels of cTn at baseline were related to short-term clinical events. In this study of patients with CAD in whom an acute coronary event was not suspected, most had detectable levels of cTn present at admission, and some patients developed cTn release during hospitalization. Because cTn release may be a marker for myocardial injury, this study raises the possibility that injury occurred in most patients admitted with AHFS. Therefore, the goal of therapy for AHFS should be not only to improve symptoms and hemodynamics but also to salvage myocardium. Accordingly, therapies for AHFS that are aimed at improving hemodynamics may affect long-term prognosis by either injuring or salvaging myocardium.

Reliability of nesiritide infusion via non-primed tubing and heparin-coated catheters

BACKGROUND

Prescribing information for nesiritide mandates priming of intravenous tubing prior to connecting to the patient's intravenous access because the drug may adsorb to the line. As of this writing, no published study has quantified the binding effect of nesiritide to intravenous tubing.

OBJECTIVE

To investigate whether priming of peripheral intravenous tubing is necessary and whether nesiritide can be reliably delivered through central intravenous lines, including heparin-coated catheters, where priming cannot occur.

METHODS

A 23.3-mL bolus of nesiritide followed by a 7-mL/h 2-hour infusion were run through (1) polyvinylchloride (PVC) peripheral intravenous tubing primed with nesiritide, (2) non-primed PVC peripheral intravenous tubing, (3) non-primed polyethylene peripheral intravenous tubing, (4) non-primed PVC peripheral intravenous tubing connected to a central intravenous polyurethane catheter, and (5) non-primed PVC peripheral intravenous tubing connected to a heparin-coated pulmonary artery PVC catheter. Nesiritide concentrations were measured in the intravenous bags and in samples collected from the 5 intravenous settings.

RESULTS

Priming of intravenous tubing with nesiritide did not increase drug recovery: at least 94% of the bolus dose and 96% of the total drug were recovered from all intravenous sets.

CONCLUSIONS

Infusion of nesiritide via non-primed peripheral and central intravenous tubing, including heparin-coated pulmonary catheter, is reliable. Changes in nesiritide labeling appear to be warranted.

Nesiritide in infants and children with congestive heart failure

OBJECTIVES

Nesiritide (synthetic B-type natriuretic peptide) has been shown to be effective in the management of acute decompensated heart failure in adults. The role of nesiritide in pediatric heart failure has not been examined. In the present study, we reviewed our initial experience with nesiritide in children with primary heart failure or low cardiac output after heart surgery.

METHODS

Nesiritide was administered in an open-label fashion to patients with heart failure who were already receiving inotropic and diuretic therapy. Between July 2003 and August 2004, 30 patients aged 5 days to 16.7 yrs (median age, 4.6 months) received nesiritide therapy. Diagnoses included single-ventricle congenital defect (n = 5), two-ventricle congenital defect (n = 13), heart transplant (n = 5), and dilated cardiomyopathy (n = 7). Sixteen patients were started on nesiritide within 2 wks of corrective or palliative heart surgery. The majority of subjects (n = 24) received an initial bolus dose. Continuous infusion dosage ranged between 0.005 and 0.02 microg.kg.min. Nesiritide was discontinued for possible side effects in two patients (arrhythmia and hypotension). Duration of therapy ranged from 1 to 24 days (median, 4 days).

RESULTS

Administration of nesiritide was associated with improvement in fluid balance from positive 0.8 +/- 1.9 mL.kg.hr at baseline to negative 0.3 +/- 1.8 mL.kg.hr after 24 hrs of therapy (p = .02). There was a nonsignificant trend toward a reduction in right atrial pressure (9.2 +/- 3.9 vs. 11.2 +/- 4.1, p = .08).

CONCLUSIONS

Nesiritide is well tolerated in children with heart failure and is associated with improved diuresis. Further prospective studies will be needed to compare nesiritide with other vasoactive agents and examine the cost-efficacy of this therapy.

Treatment with B-Type Natriuretic Peptide for Chronic Decompensated Heart Failure: Insights Learned from the Follow-Up Serial Infusion of Nesiritide (FUSION) Trial

Several evidence-based treatment regimens are modestly effective in patients with moderately severe to severe heart failure, but truly effective therapies that improve symptoms, reduce hospitalizations, and extend meaningful survival do not exist for these patients. Only ventricular replacement therapy, with either heart transplantation or left ventricular assist devices, has been shown to significantly improve outcomes. Nesiritide, a recombinant B-type natriuretic peptide, is associated with significant reductions in filling pressure, with corresponding relief of symptoms, and diminished neurohormonal levels and has no inotropic effects and no evidence of proarrhythmia when given to patients with decompensated acute heart failure. Results of the Follow-Up Serial Infusion of Nesiritide (FUSION) trial suggest that a regimen incorporating nesiritide can be accomplished with a reasonable assurance of safety and tolerability; pre-study concerns regarding hypotension were not realized. A qualified look at outcomes data within FUSION I suggests that further study of this paradigm is reasonable, especially if the studied patient population includes patients with a low left ventricular ejection fraction and New York Heart Association (NYHA) class III disease with renal insufficiency, or patients with low left ventricular ejection fraction and NYHA class IV heart failure. Therefore, FUSION II, a double-blind, placebo-controlled trial, will randomly assign approximately 900 such patients to treatment with usual care plus nesiritide or usual care plus placebo and will use mortality/cardiorenal hospitalization as a composite end point. If positive data emerge from FUSION II that either confirm or strengthen the data in FUSION I, a new therapeutic option may be available for patients with chronic decompensated heart failure.

Interaction Between Nesiritide and a Heparin-Coated Pulmonary Artery Line During an Infusion for Decompensated Heart Failure

STUDY OBJECTIVE

Because it is known that intravenous nesiritide is not compatible with unfractionated heparin, we sought to determine the effect that heparin coating on a pulmonary artery catheter may have on the efficacy of a nesiritide infusion.

METHODS

The efficacy of a nesiritide infusion given through a heparin-coated pulmonary artery line was compared with that of a nesiritide infusion administered in the same patient through a heparin-free peripheral line.

RESULTS

The rate of infusion was titrated to maintain consistent hemodynamic parameters. When nesiritide was administered through a heparin-coated line, the infusion rate escalated from 0.01 microg/kg/minute to 0.07 microg/kg/minute. After the route of administration was switched to a heparin-free line, the same hemodynamic parameters were maintained. The heparin-free line made it possible to reduce the infusion rate by 57.1% over the next 24 hours to 0.03 microg/kg/minute.

CONCLUSION

The interaction of nesiritide with heparin-coated pulmonary artery lines has the potential to be clinically significant. Clinicians should be educated about this potential interaction. Nesiritide should be infused only through heparin-free lines.

Safety and feasibility of using serial infusions of nesiritide for heart failure in an outpatient setting (from the FUSION I trial)

The Follow-Up Serial Infusions of Nesiritide pilot study was designed to assess the safety and tolerability of outpatient serial infusions of nesiritide in 210 patients with decompensated heart failure who were randomly assigned to usual care only or usual care plus weekly infusions of nesiritide at dosages of 0.005 or 0.01 microg/kg/min for 12 weeks. The mean age +/- SD of the entire population was 67 +/- 13 years; 70% were men, and 80% were white. Mean baseline serum creatinine levels were 1.8 +/- 0.7 mg/dl, and mean left ventricular ejection fraction was 0.28 +/- 0.15%. Diabetes mellitus was present in 106 patients (50%), and atrial arrhythmias were present in 100 patients (48%). A totalof 1,645 nesiritide infusions was administered; 11 (< 1%) were discontinued due to an adverse event. All treatment groups had a similar frequency of adverse events and experienced improvements in quality of life. Administration of nesiritide resulted in acute decreases in aldosterone and endothelin-1 concentrations. Although there were no statistically significant differences among groups by outcome, prospectively defined higher risk subgroups demonstrated significant decreases in cardiovascular events. These results demonstrate the safety and feasibility of administering nesiritide in an outpatient setting. Additional studies are needed to determine the effect of outpatient serial infusions of nesiritide on rates of morbidity and mortality in advanced heart failure.

Use of noninvasive hemodynamics to aid decision making in the initiation and titration of neurohormonal agents

Angiotensin-converting enzyme inhibitors, beta adrenergic blockers, and nesiritide are pharmacologic agents for heart failure with both short- and long-term neurohormonal and hemodynamic effects. Angiotensin-converting enzyme inhibitors and beta adrenergic blockers reduce morbidity and mortality in chronic heart failure. Higher doses may result in better outcomes than lower doses, but concern about hemodynamic tolerance is a major barrier to the initiation and up-titration of these agents. Nesiritide is a newer neurohormonal agent with proven efficacy and safety for use in decompensated heart failure, but appropriate patient selection has been challenging for clinicians. Like vasodilators, nesiritide may be underutilized in heart failure treatment. Impedance cardiography is a newer, noninvasive monitoring technology that can accurately measure hemodynamic parameters. Impedance cardiography is being used with increasing frequency by clinicians to guide therapy in patients with heart failure and has been proposed in heart failure treatment algorithms. Three case reports are presented to illustrate how hemodynamic data using impedance cardiography can be utilized in the initiation and titration of neurohormonal agents.

Comparison of effects on left ventricular filling pressure of intravenous nesiritide and high-dose nitroglycerin in patients with decompensated heart failure

The results of this study showed an advantage of nesiritide compared with high-dose nitroglycerin in the treatment of patients with decompensated heart failure. Nesiritide resulted in an early decrease in pulmonary capillary wedge pressure (< or =15 minutes), which was sustained throughout the study period (24 hours) without the need for up-titration. In contrast, the onset of the nitroglycerin-mediated hemodynamic effect was delayed, and despite aggressive up-titration, the decrease in pulmonary capillary wedge pressure was gradually attenuated because of the early development of tolerance.