The natriuretic peptides in heart failure: diagnostic and therapeutic potentials

Examination of the in vivo cardiac electrophysiological effects of nesiritide (human brain natriuretic peptide) in conscious dogs

BACKGROUND

Human brain natriuretic peptide (hBNP) is a new therapeutic agent, nesiritide, indicated in patients with decompensated congestive heart failure, a group at significant risk of developing cardiac arrhythmias. Whether hBNP has cardiac electrophysiologic effects has not been reported.

METHODS AND RESULTS

In 9 healthy, chronically instrumented, conscious dogs, hemodynamic and electrophysiologic parameters were assessed at baseline and during recombinant hBNP (nesiritide) infusion at 0.03 and 0.09 microg/kg/min after 1 hour at each dose. Infusion of hBNP produced dose-related increases (P <.001) in hBNP and cyclic GMP plasma levels and reductions (P <.05) in mean arterial pressure. Mean central venous pressure and sinus cycle length did not change significantly. Infusion of hBNP produced no significant changes in any of the electrophysiologic parameters including no change in surface ECG variables (P wave duration, PR interval, QRS duration, and QTc interval), corrected sinus node recovery time, atrioventricular nodal Wenckebach cycle length, and atrial and ventricular effective refractory periods measured at a 400 ms cycle length. Spontaneous or induced arrhythmias were not observed during hBNP infusion.

CONCLUSIONS

In conscious, healthy dogs, short-term infusion of recombinant hBNP has no significant effects on atrial or ventricular electrophysiologic parameters.

Plasma brain natriuretic peptide concentration: impact of age and gender

OBJECTIVES

We wished to examine the effects of age and gender on plasma brain natriuretic peptide (BNP) concentration in a population-based study.

BACKGROUND

Measurement of BNP concentration is approved for use in the diagnosis of heart failure and may aid in the detection of left ventricular dysfunction. Although BNP is approved for clinical use, there are few data regarding the range of BNP observed in persons without cardiovascular disease or cardiac dysfunction. These data are essential for the interpretation of BNP.

METHODS

In 2,042 randomly selected residents of Olmsted County, Minnesota, >44 years old, BNP (Shionogi and Biosite assays), Doppler echocardiography, and medical record review were performed. A normal subset of subjects (n = 767) in sinus rhythm without cardiovascular, renal, or pulmonary disease or diabetes; on no cardiovascular medications; and with normal systolic, diastolic, and valvular function was identified.

RESULTS

Within the normal subset, the distribution of BNP differed by age, gender, and assay system. With both assays, BNP increased significantly with age and was significantly higher in women than men, leading to age-, gender-, and assay-specific reference ranges. Receiver operating characteristic analysis for the ability of BNP to detect an ejection fraction < or = 40% was performed in each age/gender stratum in the entire cohort (n = 2,042) and confirmed that discriminatory values for BNP for detection of reduced ejection fraction were higher in women and older persons and were different between the two assays.

CONCLUSIONS

Interpretation of BNP should include consideration of age-, gender-, and assay-specific partition values.

Brain natriuretic peptide: role in cardiovascular and volume homeostasis

The identification of natriuretic peptides as key regulators of natriuresis and vasodilatation, and the appreciation that their secretion is under the control of cardiac hemodynamic and neurohumoral factors, has caused wide interest. The natriuretic peptides are structurally similar, but genetically distinct peptides that have diverse actions on cardiovascular, renal, and endocrine homeostasis. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are of myocardial cell origin, while cardiac natriuretic peptide (CNP) is of endothelial origin. ANP and BNP bind to the natriuretic peptide receptor (NPR-A) which, via 3' 5'-cyclic guanosine monophosphate (cGMP), mediates natriuresis, vasodialation, renin inhibition, and antimitogenic properties. CNP lacks natriuretic action but possesses vasodilating and growth inhibiting effects via the guanyl cyclase linked natriuretic peptide-B (NPR-B) receptor. All three peptides are cleared by natriuretic peptide-C receptor (NPR-C) and degraded by neutral endopeptidase, both of which are widely expressed in kidney, lung, and vascular wall. Recently, a fourth member of the natriuretic peptide, dendroaspsis natriuretic peptide (DNP) has been reported to be present in human plasma and atrial myocardium.

Brain natriuretic peptide (nesiritide) in the treatment of heart failure

Over the last decade brain natriuretic peptide (BNP) emerged as a cardiac hormone of clinical interest in diagnosis, prognosis and treatment of patients with Heart Failure (HF). The diagnostic potential of BNP is now well established both in patients with suspected HF as well as in patients with asymptomatic left ventricular systolic dysfunction. The prognostic information obtained from BNP levels in HF and acute myocardial infarction patients seems even more promising. Nesiritide is a synthetic peptide, homologous to endogenous BNP. It is a balanced vasodilator with diuretic and natriuretic properties. It decreases the elevated levels of neurohormones resulting from activation of the sympathetic and renin-aldosterone systems in HF. The results of clinical trials involving more than 2000 patients with decompensated HF are now available. In these trials nesiritide was administered by single or repeated bolus injections, as well as by sustained infusions. Nesiritide has been shown to produce a potent, dose-related vasodilator effect that is rapid in onset and sustained during infusion. Balanced vasodilation is reflected by decreases in systemic vascular resistance, pulmonary artery wedge pressure and right atrial pressure. No tachyphylaxis has been observed in these trials. Efficacy of nesiritide in the treatment of decompensated HF has been demonstrated. Trials comparing nesiritide with conventional treatment of decompensated HF showed that nesiritide compares favorably to standard agents. The safety profile has been excellent with a dose-dependent hypotension as the major side effect. Ventricular arrhythmia was not more frequent in patients treated with nesiritide than with placebo. Thus, nesiritide appears to be useful as a first-line agent in the treatment of patients with decompensated HF.

Cloning and characterization of feline brain natriuretic peptide

Brain (B-type) natriuretic peptide (BNP) is a cardiac hormone involved in regulation of fluid balance and blood pressure homeostasis of mammalian species. BNP sequence is species-specific and considered to be a significant prognostic and diagnostic marker for cardiac dysfunction. Using conventional polymerase chain reaction and amplification of cDNA 3'- and 5'-ends, a total of 1500 nucleotides encompassing the entire feline BNP gene were characterized. The feline BNP gene is organized in three exons separated by two introns. The complete transcript of 736 nucleotides was characterized, including 396 nucleotides encoding feline preproBNP. The preproBNP consisted of a signal peptide of 26 amino acids and a proBNP of 106 residues. The predicted mature BNP comprised 35 amino acids with likely 26- and 29-aa isomers, including a histidine residue at the C-terminus. Based on the similarity of BNP prepropeptide sequences, a phylogenetic relationship is presented for mammalian species including human, cat, cattle, dog, mouse, rat, sheep and swine.

Divergent effects of ANP and BNP in acute heart failure: evidence for a putative BNP-selective receptor?

OBJECTIVE

Since the pathophysiology of natriuretic peptides in chronic heart failure (HF) is not uniform, we hypothesized that atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) may also have differential effects in acute HF. Our aim was to compare the haemodynamic actions of ANP with BNP, using a classical vasodilator as the control, in greyhound dogs with acute pacing-induced HF.

DESIGN AND METHODS

The right ventricles of eight anaesthetized dogs were paced (193 +/- 4 bpm) until pulmonary capillary pressure (PCP) increased to approximately 15 mmHg. In each animal, according to a randomized within-animal design, haemodynamic responses to equimolar (10 pmol/kg per min) infusions of ANP and BNP were compared with those to sodium nitroprusside (SNP).

RESULTS

Acute pacing alone increased PCP from 6.6 +/- 0.7 to 15.7 +/- 0.3 mmHg, right atrial pressure (RAP) from 1.9 +/- 0.5 to 4.0 +/- 0.6 mmHg, and systemic vascular resistance (SVR) from 1706 +/- 110 to 2179 +/- 106 dyne s/cm5, and reduced cardiac output (CO) from 4.1 +/- 0.4 to 2.5 +/- 0.2 l/min and arterial pressure from 86.1 +/- 2.4 to 74.5 +/- 2.1 mmHg (all P < 0.01). BNP and SNP improved haemodynamics similarly (CO +13 +/- 3% and +9 +/- 5%; PCP -12 +/- 2% and -12 +/- 2%; RAP -28 +/- 9% and -34 +/- 6%, SVR -15 +/- 3% and -11 +/- 3%, all P < 0.01, except CO with SNP, not significant), but effects of BNP on preload outlasted those of SNP. By contrast, ANP did not improve the haemodynamics. Haematocrit was significantly higher during BNP infusion than with ANP (P < 0.05) or with SNP (P < 0.001).

CONCLUSIONS

The haemodynamic responses to exogenous BNP and ANP in acute heart failure were strikingly different. Whereas ANP actions were blunted, BNP response was preserved. Hypothetically, the presence of a putative BNP receptor may explain this finding.

The potential of brain natriuretic peptide as a biomarker for New York Heart Association class during the outpatient treatment of heart failure

BACKGROUND

Plasma C-terminal atrial natriuretic peptide (C-ANP), N-terminal ANP (N-ANP), and brain natriuretic peptide (BNP) have diagnostic utility in detecting left ventricular dysfunction. Their relative value in monitoring symptom status during the chronic treatment of congestive heart failure (CHF) remains undefined.

METHODS AND RESULTS

Ninety-eight subjects with CHF were evaluated. Baseline natriuretic peptides were measured by radioimmunoassay, left ventricular ejection fraction (LVEF) was estimated with echocardiography, and New York Heart Association (NYHA) class was determined independently by attending heart failure specialists. Forty-one subjects were restudied during a 6- to 12-month follow-up period after optimizing therapy. At baseline, all natriuretic peptides and LVEF correlated positively with NYHA class (P <.005). Plasma BNP, however, correlated best with NYHA class. At follow-up, only changes of BNP correlated to changes of NYHA class (P =.04). BNP decreased (-45% +/- 12%, N = 14, P =.002) in subjects whose NYHA class improved whereas BNP remained unchanged (-1% +/- 10%, N = 25, P =.95) in those whose NYHA class was stable.

CONCLUSIONS

This investigation demonstrates the superiority of plasma BNP as compared to ANP and LVEF in objectively assessing NYHA class during the chronic treatment of CHF. Given that clinical assessment of CHF is subjective, plasma BNP is a useful objective biomarker in monitoring human CHF in the outpatient setting.

B-type natriuretic peptide predicts sudden death in patients with chronic heart failure

BACKGROUND

Given the high incidence of sudden death in patients with chronic heart failure (CHF) and the efficacy of implantable cardioverter-defibrillators, an appropriate tool for the prediction of sudden death is desirable. B-type natriuretic peptide (BNP) has prognostic significance in CHF, and the stimuli for its production cause electrophysiological abnormalities. This study tests BNP levels as a predictor of sudden death.

METHODS AND RESULTS

BNP levels, in addition to other neurohormonal, clinical, and hemodynamic variables, were obtained from 452 patients with a left ventricular ejection fraction (LVEF) < or =35%. For prediction of sudden death, only survivors without heart transplantation (HTx) or a mechanical assist device and patients who died suddenly were analyzed. Up to 3 years, 293 patients survived without HTx or a mechanical assist device, 89 patients died, and 65 patients underwent HTx. Mode of death was sudden in 44 patients (49%), whereas 31 patients (35%) had pump failure and 14 patients (16%) died from other causes. Univariate risk factors of sudden death were log BNP (P=0.0006), log N-terminal atrial natriuretic peptide (P=0.003), LVEF (P=0.005), log N-terminal BNP (P=0.006), systolic blood pressure (P=0.01), big endothelin (P=0.03), and NYHA class (P=0.04). In the multivariate model, log BNP level was the only independent predictor of sudden death (P=0.0006). Using a cutoff point of log BNP <2.11 (130 pg/mL), Kaplan-Meier sudden death-free survival rates were significantly higher in patients below (99%) compared with patients above (81%) this cutoff point (P=0.0001).

CONCLUSION

BNP levels are a strong, independent predictor of sudden death in patients with CHF.

Cardiovascular monitoring and therapy for HIV-infected patients

Cardiovascular complications are important contributors to morbidity and mortality in HIV-infected patients. These complications can usually be detected at subclinical levels with monitoring, which can help guide targeted interventions. This article reviews available data on types and frequency of cardiovascular manifestations in HIV+ patients and proposes monitoring strategies aimed at early subclinical detection. In particular, we recommend routine echocardiography for HIV+ patients, even those with no evidence of cardiovascular disease. We also review preventive and therapeutic cardiovascular interventions. For procedures that have not been studied in HIV+ patients, we extrapolate from evidence-based guidelines for the general population.

Canine idiopathic dilated cardiomyopathy. Part II: pathophysiology and therapy

Dilated cardiomyopathy (DCM) in dogs is characterized by ventricular and atrial enlargement, and systolic and diastolic dysfunction, with congestive heart failure (CHF) often developing at some stage. With greater understanding of the impact of neuroendocrine stimulation in heart disease, the understanding of the pathophysiology for CHF has changed considerably. It is no longer considered only to be a simple haemodynamic consequence of pump dysfunction, but is now characterized as a complex clinical syndrome with release of many neurohormones, which are believed to have impact on the progression of disease. This change in our understanding of the pathophysiology of CHF has important therapeutic implications. There are strong indications, although not yet proven, that drugs designed to influence the neuroendocrine activity, such as Angiotensin Converting Enzyme (ACE) inhibitors and beta-receptors antagonists, are efficacious as adjunct therapy of heart failure attributable to DCM in dogs. The benefits of drugs designed to influence the myocardial contractile state (positive inotropes) have not been fully evaluated. However, evidence has emerged in recent years indicating that new types of positive inotropes may be beneficial in dogs with DCM. This review focuses on the neuroendocrine aspects of DCM and their possible therapeutic implications and the place for long-term inotropic support in dogs with DCM.

Mediators of chronic heart failure: how drugs work

OBJECTIVE

To critically review the pathophysiology of chronic heart failure at the neurohormonal level, and discuss the effect of present and future therapeutic options on these neurohormones.

DATA SOURCES

A MEDLINE search (1986-November 2000) was used to identify important primary literature and reviews. Additional references were obtained from these articles.

DATA SYNTHESIS

Chronic heart failure is a common, progressive disorder with high morbidity and mortality. Progression is due in large part to several redundant neurohormonal responses. The neurohormones include angiotensin II, norepinephrine, aldosterone, endothelin-1, arginine vasopressin, and tumor necrosis factor. These responses are initially adaptive, but become maladaptive in the long term, impairing the function of the heart, vasculature, and kidneys. Counter-regulatory hormones, such as bradykinin and natriuretic peptides, are insufficient to offset the adverse effects of the other neurohormones. Most drugs used to treat chronic heart failure, such as angiotensin-converting enzyme inhibitors, beta-adrenergic antagonists, and spironolactone, achieve their benefits through altering the neurohormonal pathways. New agents that affect more or different neurohormones may soon be available.

CONCLUSIONS

Multiple agents are required for treatment of chronic heart failure, as no single agent can counteract all of the various adverse pathways. The appropriate prescription and use of such inherently complex regimens require significant physician and patient education.

Cardiac phosphodiesterase 5 (cGMP-specific) modulates beta-adrenergic signaling in vivo and is down-regulated in heart failure

Recent studies implicate increased cGMP synthesis as a postreceptor contributor to reduced cardiac sympathetic responsiveness. Here we provide the first evidence that modulation of this interaction by cGMP-specific phosphodiesterase PDE5A is also diminished in failing hearts, providing a novel mechanism for blunted beta-adrenergic signaling in this disorder. In normal conscious dogs chronically instrumented for left ventricular pressure-dimension analysis, PDE5A inhibition by EMD82639 had modest basal effects but markedly blunted dobutamine-enhanced systolic and diastolic function. In failing hearts (tachypacing model), however, EMD82639 had negligible effects on either basal or dobutamine-stimulated function. Whole myocardium from failing hearts had 50% lower PDE5A protein expression and 30% less total and EMD92639-inhibitable cGMP-PDE activity. Although corresponding myocyte protein and enzyme activity was similar among groups, the proportion of EMD82639-inhibitable activity was significantly lower in failure cells. Immunohistochemistry confirmed PDE5A expression in both the vasculature and myocytes of normal and failing hearts, but there was loss of z-band localization in failing myocytes that suggested altered intracellular localization. Thus, PDE5A regulation of cGMP in the heart can potently modulate beta-adrenergic stimulation, and alterations in enzyme localization and reduced synthesis may blunt this pathway in cardiac failure, contributing to dampening of the beta-adrenergic response.

Cardiac natriuretic peptides are related to left ventricular mass and function and predict mortality in dialysis patients

This study was designed to investigate the relationship among brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) and left ventricular mass (LVM), ejection fraction, and LV geometry in a large cohort of dialysis patients without heart failure (n = 246) and to test the prediction power of these peptides for total and cardiovascular mortality. In separate multivariate models of LVM, BNP and ANP were the strongest independent correlates of the LVM index. In these models, the predictive power of BNP was slightly stronger than that of ANP. Both natriuretic peptides also were the strongest independent predictors of ejection fraction, and again BNP was a slightly better predictor of ejection fraction than ANP. In separate multivariate Cox models, the relative risk of death was significantly higher in patients of the third tertile of the distribution of BNP and ANP than in those of the first tertile (BNP, 7.14 [95% confidence interval (CI), 2.83 to 18.01, P = 0.00001]; ANP, 4.22 [95% CI, 1.79 to 9.92, P = 0.001]), and a similar difference was found for cardiovascular death (BNP, 6.72 [95% CI, 2.44 to 18.54, P = 0.0002]; ANP, 3.80 [95% CI, 1.44 to 10.03, P = 0.007]). BNP but not ANP remained as an independent predictor of death in a Cox's model including LVM and ejection fraction. Cardiac natriuretic peptides are linked independently to LVM and function in dialysis patients and predict overall and cardiovascular mortality. The measurement of the plasma concentration of BNP and ANP may be useful for risk stratification in these patients.

Heart failure in blacks: etiologic and epidemiologic differences

Heart failure in black Americans has become a cardiovascular conundrum of increasing clinical significance. Over 60% of black patients with heart failure have an antecedent history of hypertension as a putative cause of left ventricular (LV) dysfunction, whereas only 30% have coronary artery disease as the suspected cause of LV dysfunction. Once affected with heart failure, the natural history of the disease becomes worrisome: LV dysfunction is more advanced, the severity of the disease is worse, the hospitalization rate is higher, and the mortality rate is at least 30% higher than that of white Americans. When treated in a conventional manner, available data have been inconsistent, and reliable drug efficacy has not been demonstrated. These differences do not appear to be due to socioeconomic factors. It is quite possible that unique pertubations in the neurohormonal environment may explain differences in the natural history of heart failure in blacks and yield new targets of therapy.

An update on nesiritide for treatment of decompensated heart failure

In the July 1999 issue of this publication, we described the chemical properties, pharmacology and clinical trials involving nesiritide as a therapeutic agent for patients with decompensated heart failure (Exp. Opin. Invest. Drugs) (1999) 8(7):1063--1072). At the time of publication, the US Food and Drug Administration reviewed the clinical experience with the compound and did not approve the drug for clinical use. More data were requested regarding safety issues, comparison with nitroglycerine, onset of effects, need for invasive haemodynamic monitoring and symptomatic improvement. The VMAC Study was designed to address these issues. A dosing regimen, 0.2 microgram/kg bolus followed by 0.01 microg/kg/min continuous infusion, was chosen to provide rapid onset of actions and haemodynamic improvement without a high incidence of symptomatic hypotension. Nesiritide was superior to iv. nitroglycerine in its haemodynamic effects, easier to administer without the need for dose titration and better tolerated overall. The drug could be administered safely without the need for invasive haemodynamic monitoring. Symptomatic hypotension occurred in 4% of patients. Beneficial haemodynamic effects correlated with symptomatic improvement in heart failure patients. Nesiritide appears to be an ideal first-line agent for treatment of patients with acutely decompensated heart failure.

Diagnostic potential of cardiac natriuretic peptides in dialysis patients

BACKGROUND

In the general population, the plasma concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are useful to predict left ventricular hypertrophy (LVH) and LV systolic dysfunction. Whether these cardiac hormones have a similar diagnostic potential in dialysis patients is unknown.

METHODS

We studied the diagnostic value of ANP and BNP for alterations in LV mass and function in a cohort of 246 dialysis patients without clinical evidence of heart failure.

RESULTS

Both ANP and BNP were independently related to left ventricular mass (P < 0.0001) as well as to ejection fraction (P < 0.0001). In an analysis based on a prospectively defined threshold (95th percentile of the normal range), BNP had a significantly higher (P < 0.01) sensitivity (88%) than ANP (51%) for the diagnosis of LVH, but the positive predictive value of the two peptides was very similar (92 and 87%, respectively, P = NS). However, the negative predictive value of BNP for excluding LVH was 22% higher than that of ANP (53 vs. 31%, P = 0.05). Both natriuretic peptides had a high sensitivity for the detection of LV dysfunction (87 and 94%), but their positive predictive value was low (25 and 15%). Importantly, both ANP and BNP proved to be very useful for excluding this alteration (negative predictive value 97 and 96%, respectively). An analysis based on the "best cut-offs" of each peptide as identified on the basis of the ROC curves augmented the positive and negative prediction values of BNP for the diagnosis of LVH to 95 and 61%, respectively. This approach also raised the BNP-positive prediction value for the identification of LV dysfunction to 31% but did not modify the diagnostic potential of ANP (either for LVH or for LV dysfunction).

CONCLUSIONS

Measuring the plasma concentration of cardiac natriuretic hormones, particularly BNP, may be useful for the identification of dialysis patients with LVH or for excluding systolic dysfunction.

Effects of intravenous brain natriuretic peptide on regional sympathetic activity in patients with chronic heart failure as compared with healthy control subjects

OBJECTIVES

We sought to assess the effects of brain natriuretic peptide (BNP) on systemic and regional sympathetic nervous activity (SNA) in both patients with congestive heart failure (CHF) and healthy control subjects.

BACKGROUND

Although the response of SNA to atrial natriuretic peptide (ANP) has been well documented, the response of SNA to BNP is largely unknown.

METHODS

We assessed cardiac and whole-body SNA using the norepinephrine (NE) tracer dilution method before and after infusion of two doses of BNP (3 and 15 ng/kg body weight per min) in 11 patients with stable CHF (ejection fraction 24 +/- 2%) and 12 age-matched healthy control subjects. In addition, renal SNA and hemodynamic variables were assessed at baseline and after the higher BNP dose.

RESULTS

Low dose BNP did not change blood pressure or whole-body NE spillover, but reduced cardiac NE spillover in both groups by 32 +/- 13 pmol/min (p < 0.05). In both groups, high dose BNP reduced pulmonary capillary pressure by 5 +/- 1 mm Hg (p < 0.001) and mean arterial pressure by 6 +/- 3 mm Hg (p < 0.05), without a concomitant increase in whole-body NE spillover; however, cardiac NE spillover returned to baseline levels. Renal NE spillover remained virtually unchanged in healthy control subjects (501 +/- 120 to 564 +/- 115 pmol/min), but was reduced in patients with CHF (976 +/- 133 to 656 +/- 127 pmol/min, p < 0.01).

CONCLUSIONS

Our results demonstrate a sympathoinhibitory effect of BNP. Cardiac sympathetic inhibition was observed at BNP concentrations within the physiologic range, whereas high dose BNP, when arterial and filling pressures fell and reflex sympathetic stimulation was expected, systemic and cardiac SNA equated to baseline values. There was inhibition of renal SNA in patients with CHF, but not in healthy control subjects. Whether this effect is specific to BNP or related to reduced filling pressure remains to be determined.

Circulating atrial natriuretic peptide plasma levels as a marker for cardiac damage after radiotherapy

PURPOSE

To investigate whether plasma concentrations of atrial natriuretic peptide (ANP) could be used to identify patients with radiation mediated cardiac dysfunction.

MATERIALS AND METHODS

Circulating levels of ANP were measured in patients who have been irradiated on a large part of the heart (50-80%; Hodgkin's disease) or smaller part of the heart (20-30%; primary breast cancer). C-terminal ANP was determined by radioimmunoassay (RIA) using a commercial kit.

RESULTS

In this study ANP plasma levels of 121 patients (Hodgkin's disease, 73 patients; breast cancer, 48 patients) and 67 controls were examined. ANP plasma levels of both Hodgkin patients (28.8+/-2.2, P=0.003) and breast cancer patients (20.4+/-2.8 ng/l, P=0.01) were significantly elevated when compared to age-matched controls (13.5+/-1.2 ng/l). Both for the Hodgkin (R=0.42, P=0.05) and breast cancer group (R=0.50, P=0.09) a positive relation between ANP plasma values and age was found. However, no clear relation between ANP plasma levels and time post treatment could be demonstrated. Patients with clinical symptoms of cardiovascular disease (n=25) had significantly higher ANP plasma levels (P<0.001) compared to patients in the same treatment group without evidence of cardiac disease (50.2+/-7.5 vs. 23.3+/-1.3 ng/l, P<0.001, and 38.2+/-12.4 vs. 16.3+/-1.6 ng/l, P<0.001, for Hodgkin's disease and breast cancer, respectively). Eight patients suffered from essential hypertension (n=8), whereas the remaining group of 17 patients showed a variety of cardiac disorders (i.e. myocardial infarction, decreasing ventricular function, and atrial fibrillations). In 11 patients cardiac problems were manifest either before or within a few years after mediastinal therapy. In two patients treated for Hodgkin's disease, and in four patients treated for breast cancer cardiac problems became manifest a long time (>10 years) after radiotherapy. Probably in this group of patients cardiac problems are related to the therapy.

CONCLUSIONS

The present study indicates that ANP plasma levels could be used to identify patients with radiation induced cardiac dysfunction.

Nesiritide for the treatment of decompensated heart failure

Nesiritide (human recombinant B-type natriuretic peptide) binds to receptors in the vasculature, kidney, and other organs to mimic the actions of endogenous natriuretic peptides. Intravenous infusion of nesiritide has been studied in more than 1,700 patients with acute decompensated heart failure (HF). Nesiritide causes potent, dose-related vasodilation that is rapid in onset and sustained for the duration of drug infusion. There is balanced arterial and venous dilation as reflected by decreases in systemic vascular resistance, systemic arterial pressure, pulmonary capillary wedge pressure, right atrial pressure, and mean pulmonary arterial pressure. Vasodilation occurs without a change in heart rate and is associated with increases in stroke volume and cardiac output. Nesiritide may promote diuresis because of a direct natriuretic action, increased cardiac output, and/or decreased aldosterone levels. In patients hospitalized for decompensated HF, nesiritide improves symptoms and is well tolerated. The major adverse effect is dose-related hypotension. Nesiritide is thus an attractive new vasodilator that should be valuable in the treatment of patients hospitalized for acute decompensated HF.

Serum N-terminal atrial natriuretic peptide in adult patients late after surgical repair of atrial septal defect

BACKGROUND

The purpose of surgical closure of atrial septal defect (ASD) is to relieve the cardiovascular system from a haemodynamic burden. Excessive amounts of atrial peptides are released in congestive heart failure, valvular diseases and congenital heart diseases.

AIMS

To examine whether patients after surgical repair of ASD have higher concentrations of N-terminal atrial natriuretic peptide (ANP-N) than age-, sex- and body mass index (BMI)-matched control subjects.

METHODS

Medical history, physical examination, standard 12-lead electrocardiogram, and ANP-N concentrations were obtained in 65 adult patients operated for ASD at the age of 21+/-13 years (mean+/-standard deviation), 21+/-6 years after surgical closure of ASD. Sixty-seven healthy subjects matched for age, sex and BMI served as controls.

RESULTS

In the patients serum ANP-N was higher than in the control subjects 0.41+/-0.32 nmol/l, median 0.31 nmol/l, interquartile range (IQR) 0.21-0.49 nmol/l vs. 0.24+/-0.12 nmol/l, median 0.23 nmol/l, IQR 0.17-0.29 nmol/l, (P=0.0003). Patients with concomitant diseases had higher ANP-N concentrations (0.51+/-0.39 nmol/l, median 0.34, IQR 0.26-0.73 nmol/l) than ASD patients without any history or signs of disease (0.28+/-0.16 nmol/l, median 0.27, IQR 0.17-0.40 nmol/l, P=0.01). The 'healthy' ASD patients had higher hormone concentrations than age-, sex- and BMI-matched control subjects (0.28+/-0.16 median 0.27 nmol/l, IQR 0. 17-0.40 nmol/l and 0.21+/-0.07 nmol/l, median 0.20 nmol/l, IQR 0. 15-0.27 nmol/l, P=0.01). Multiple stepwise linear regression analysis showed that age at operation was strongly associated with the post-operative ANP-N concentration (r(2)=0.25, P=0.0002).

CONCLUSION

ASD patients have higher ANP-N concentrations late after surgical repair. Hormone levels correlate with age at operation. Our finding supports the clinical praxis of operating on these patients in their childhood and adolescence.