Pathophysiological and clinical relevance of circulating levels of cardiac natriuretic hormones: are they merely markers of cardiac disease?

The Role of Natriuretic Peptides in the Management of Heart Failure with a Focus on the Patient with Diabetes

Natriuretic peptides (NPs) are polypeptide hormones involved in the homeostasis of the cardiovascular system. They are produced by cardiomyocytes and regulate circulating blood volume and sodium concentration. Clinically, measurements of brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) are recommended by international guidelines as evidence is accumulating on their usefulness. They have a high negative predictive value, and in the setting of low NPs, a diagnosis of heart failure (HF) can be safely excluded in both emergency (BNP < 100 pg/mL, NT-proBNP < 300 pg/mL) and outpatient settings (BNP < 35 pg/mL and NT-proBNP < 125 pg/mL). Moreover, the 2023 consensus from the European Society of Cardiology suggests threshold values for inclusion diagnosis. These values are also associated with increased risks of major cardiovascular events, cardiovascular mortality, and all-cause mortality whether measured in inpatient or outpatient settings. Among patients without known HF, but at high risk of developing it (e.g., in the setting of diabetes mellitus, hypertension, or atherosclerotic cardiovascular disease), NPs may be useful in stratifying cardiovascular risk, optimizing therapy, and reducing the risk of developing overt HF. In the diabetes setting, risk stratification with the use of these peptides can guide the physician to a more informed and appropriate therapeutic choice as recommended by guidelines. Notably, NP levels should be carefully interpreted in light of certain conditions that may affect their reliability, such as chronic kidney disease and obesity, as well as demographic variables, including age and sex. In conclusion, NPs are useful in the diagnosis and prognosis of HF, but they also offer advantages in the primary prevention setting.

Association of cardiac biomarkers with long-term cardiovascular events in a community cohort

MATERIALS AND METHODS

The study assessed major adverse cardiac events (MACE) (myocardial infarction, coronary artery bypass graft, percutaneous intervention, stroke, and death. Cox proportional hazards models assessed apolipoprotein AI (ApoA1), apolipoprotein B (ApoB), ceramide score, cystatin C, galectin-3 (Gal3), LDL-C, Non-HDL-C, total cholesterol (TC), N-terminal B-type natriuretic peptide (NT proBNP), high-sensitivity cardiac troponin (HscTnI) and soluble interleukin 1 receptor-like 1. In adjusted models, Ceramide score was defined by from N-palmitoyl-sphingosine [Cer(16:0)], N-stearoyl-sphingosine [Cer(18:0)], N-nervonoyl-sphingosine [Cer(24:1)] and N-lignoceroyl-sphingosine [Cer(24:0)]. Multi-biomarker models were compared with C-statistics and Integrated Discrimination Index (IDI).

RESULTS

A total of 1131 patients were included. Adjusted NT proBNP per 1 SD resulted in a 31% increased risk of MACE/death (HR = 1.31) and a 31% increased risk for stroke/MI (HR = 1.31). Adjusted Ceramide per 1 SD showed a 13% increased risk of MACE/death (HR = 1.13) and a 29% increased risk for stroke/MI (HR = 1.29). These markers added to clinical factors for both MACE/death (p = 0.003) and stroke/MI (p = 0.034). HscTnI was not a predictor of outcomes when added to the models.

DISCUSSION

Ceramide score and NT proBNP improve the prediction of MACE and stroke/MI in a community primary prevention cohort.

Prognostic role of N-terminal prohormone of brain natriuretic peptide for patients in the medical intensive care unit with severe sepsis

BACKGROUND

Sepsis is an important cause of mortality in intensive care units worldwide. The increased levels of N-terminal prohormone of brain natriuretic peptide (NT-pro BNP) are related with dysfunction of the cardiovascular system and systemic inflammation. It is uncertain whether this increase reflects sepsis-related cardiac dysfunction that translates to poorer outcomes.

AIMS AND OBJECTIVES

The primary aim of this study was to evaluate the prognostic role of NT-pro BNP on the outcome and duration of hospital stay of patients admitted with sepsis. The secondary objective was to identify other associated risk factors for mortality in sepsis.

PATIENTS AND METHODS

The patients who presented to emergency room with diagnosis of suspected sepsis were studied. Risk factors associated with outcome were studied by univariate analysis. The variables having statistical significance were further included in multivariate analysis to identify the independent predictors of mortality.

RESULTS

A total of 215 patients with sepsis were included in this study. In univariate analyses, NT-pro BNP, procalcitonin, need of mechanical ventilation (MV), blood culture positivity, chronic kidney disease-chronic liver disease CKD-CLD, and diabetes mellitus were predictors of prolonged hospital stay, and it was same for multivariate analysis excluding procalcitonin. In univariate analysis, NT-pro BNP, MV, and DM were risk factors associated with mortality but in multivariate analysis showed significance only with MV and DM.

CONCLUSION

There was a statistically significant correlation between NT-pro BNP levels and mortality. The other factors associated with increased mortality were diabetes mellitus and need of MV. In addition to the above factors, the presence of CKD and CLD was associated with increased duration of hospital stay. There was concordance between increased NT-pro BNP and elevated trop I, s creatinine, need of MV, and CKD.

B-Type Cardiac Natriuretic Peptides in the Neonatal and Pediatric Intensive Care Units

During the last decade, interest in the brain natriuretic peptide (BNP) and N-terminal probrain natriuretic peptide (NT-proBNP) in the pediatric population has progressively increased. The aim of this article is to provide an up to date review of evidences regarding the use of BNP/NT-proBNP in pediatrics, with a particular focus on neonatal intensive care and congenital heart disease. The potentialities of the BNP have been demonstrated in multiple settings, particularly: the screening of congenital/acquired heart disease (CHD) versus pulmonary disease; the evaluation of CHD severity (grade of heart failure, degree of left-to-right shunts); the management of children undergoing cardiac surgery; and monitoring premature infants with patent arterial duct. BNP/NT-proBNP values may be considered an easy and relatively low cost additional diagnostic and prognostic tool. Interpretation of BNP values in children requires attention to important factors, including: laboratory methods, the type of cardiac defect, its severity, and the presence of extracardiac conditions. Of these, the hemodynamic characteristic of CHD and physiologic variations of BNP values occurring during the first weeks of life play a major role. The current evidences in favor of BNP use are mainly derived from single-center, nonrandomized studies, and cost-effectiveness analysis are still lacking. As such, despite sufficient evidences supporting the diagnostic and prognostic potentialities of BNP, these findings should be reinforced by multicenter, randomized studies specifically designed to evaluate outcomes and cost-effectiveness. In addition, standard consensus documents/guidelines, that are currently lacking, are warranted for a more systematic use of BNP in the pediatric age.

Crosstalk of Various Biomarkers That Might Provide Prompt Identification of Acute or Chronic Cardiorenal Syndromes

INTRODUCTION

Pathophysiological interaction between the heart and kidneys represents the basis for clinical entities called cardiorenal syndromes. The purpose of the study was to assess the relations between acute and chronic cardiorenal syndromes and biomarkers [advanced oxidation protein products, brain natriuretic peptide, malondialdehyde, xanthine oxidoreductase (XOD), xanthine oxidase, xanthine dehydrogenase, interleukin 8, cystatin C, plasminogen activator inhibitor-1, high-sensitive troponin T, C-reactive protein and glomerular filtration rate, measured by the Modification of Diet in Renal Disease (MDRD) formula], to hypothesize biomarkers that might provide a prompt identification of acute or chronic cardiorenal syndromes, and to distinguish acute versus chronic types of these syndromes.

METHODS

A total of 114 participants were enrolled in this study, i.e. 79 patients divided into subgroups of acute and chronic cardiorenal syndromes and 35 volunteers.

RESULTS

Nonadjusted odds ratio (OR) showed that there was a significant risk for acute cardiorenal syndrome with increased XOD activity (p = 0.037), elevated cystatin C concentration (p = 0.038) and MDRD (p = 0.028). Multivariable adjusted OR, on the other hand, revealed that only glomerular filtration rate measured by the MDRD formula had a significance for acute cardiorenal syndrome (p = 0.046). Nonadjusted OR showed a significant risk for chronic cardiorenal syndrome only in elderly (p = 0.002). Multivariable adjusted OR exhibited that age was the only risk factor for chronic cardiorenal syndrome (p = 0.012).

CONCLUSION

Cystatin C, glomerular filtration rate measured by the MDRD equation and XOD were independent risk factors for acute cardiorenal syndrome, while age remained an independent risk factor for chronic cardiorenal syndrome. When comparing ORs of evaluated parameters, the highest significance for acute cardiorenal syndrome was plasma concentration of cystatin C.

BNP in children with congenital cardiac disease: is there now sufficient evidence for its routine use?

Interest in brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in the management of children with CHD has increased. There are, however, no current guidelines for their routine use. The aim of this review article is to provide an update on the data regarding the use of BNP/NT-proBNP in the evaluation and surgical treatment of children with CHD. BNP/NT-proBNP levels in children with CHD vary substantially according to age, laboratory assay methods, and the specific haemodynamics associated with the individual congenital heart lesion. The accuracy of BNP/NT-proBNP as supplemental markers in the integrated screening, diagnosis, management, and follow-up of CHD has been established. In particular, the use of BNP/NT-proBNP as a prognostic indicator in paediatric cardiac surgery has been widely demonstrated, as well as its role in the subsequent follow-up of surgical patients. Most of the data, however, are derived from single-centre retrospective studies using multivariable analysis; prospective, randomised clinical trials designed to evaluate the clinical utility and cost-effectiveness of routine BNP/NT-proBNP use in CHD are lacking. The results of well-designed, prospective clinical trials should assist in formulating guidelines and expert consensus recommendations for its use in patients with CHD. Finally, the use of new point-of-care testing methods that use less invasive sampling techniques - capillary blood specimens - may contribute to a more widespread use of the BNP assay, especially in neonates and infants, as well as contribute to the development of screening programmes for CHD using this biomarker.

Comparative effects of recombinant human brain natriuretic peptide and dobutamine on acute decompensated heart failure patients with different blood BNP levels

Background

Recombinant human B-type natriuretic peptide (rhBNP) has been indicated for the treatment of acute decompensated heart failure (ADHF). However, the therapeutic efficacy of intravenous rhBNP is not always satisfactory in patients with extremely high blood BNP levels. In this study, we evaluated the effects of rhBNP on patients with different BNP levels.

Methods

One hundred and five patients with ADHF whose left ventricular ejection fraction (LVEF) was <40%, were assigned to a high BNP group (BNP ≤ 3000 pg/mL) or an extra-high BNP group (BNP > 3000 pg/mL) , depending on their admission plasma BNP levels. Each group was then subdivided into rhBNP or dobutamine subgroups according to intravenous administration with either rhBNP or dobutamine for 24-72h. In the high BNP group, 58 patients were randomized to subgroup rhBNP (n = 28) and subgroup dobutamine (n = 30). In the extra-high BNP group, 47 patients were randomized to subgroup rhBNP (n = 24) and subgroup dobutamine (n = 23). The effects of rhBNP and dobutamine on patients in the high and extra-high BNP groups were compared.

Results

In the high BNP group, rhBNP was more efficient than dobutamine at improving NYHA classification (P < 0.05), decreasing plasma BNP levels (P < 0.05), increasing LVEF (P < 0.05), and reducing hospital length of stay (P < 0.05). However, rhBNP displayed no superior therapeutic efficacy to dobutamine in the extra-high BNP group. Adverse cardiovascular events in patients treated with rhBNP were similar to adverse events in patients treated with dobutamine in both the high and extra-high BNP groups.

Conclusions

rhBNP was more efficient than dobutamine at improving heart function in patients with ADHF when plasma BNP was ≤3000 pg/mL. However, rhBNP treatment showed no advantages over dobutamine when plasma BNP reached extremely high levels (>3000 pg/mL).

Trial registration

ClinicalTrials.gov Identifier: NCT01837849.

Assessment and comparison of acute cardiac toxicity during high-dose cyclophosphamide and high-dose etoposide stem cell mobilization regimens with N-terminal pro-B-type natriuretic peptide

This study was undertaken to prospectively evaluate and compare the acute effect of high-dose (HD), cyclophosphamide (CY) and HD etoposide (ET) on cardiac function assessed by plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients undergoing stem-cell mobilization. NT-proBNP was measured at baseline and 6h after completion of mobilization chemotherapy (MC) in 58 patients. Of 58 patients, 33 received HD CY, and 25 received HD ET. The mean baseline NT-proBNP values were similar between the CY and ET group (119.5 vs 149, respectively, p>0.05). NT-proBNP levels were increased in almost all patients, except 2 from CY group. A significant difference between NT-proBNP concentrations at baseline and 6h after completion of MC was observed in both groups (p<0.001). The value of changes in NT-proBNP was more significant in the ET group. The changes in NT-proBNP according to the MC regimens were analyzed and a cut-off value of 422pg/ml was determined. Based on this cut-off value, only the type of MC was significantly correlated with the chances in NT-proBNP concentrations. Receiving HD ET as a MC was found to be 5.25 times more cardiotoxic compared to the HD CY. Congestive heart failure was seen in 3 (5.2%) patients. Our results suggest that stem cell mobilization with HD CY and HD ET cause acute cardiac toxicity mediated by neurohumoral activation, which was detected by the increases in cardiac biomarker NT-proBNP, and as a matter of fact cardiotoxicity of HD ET seems to be more potent than those exhibited by HD CY.

Systematic differences between BNP immunoassays: comparison of methods using standard protocols and quality control materials

BACKGROUND

Recent studies suggested that there are marked systematic differences among BNP immunoassays. In this study we compared the BNP data and clinical results obtained with different immunoassays, including a new method (ST-AIA-PACK, TOSOH Corporation).

METHODS

BNP was measured on plasma-EDTA samples of healthy subjects (HS, n=126) and patients with heart failure (HF, n=31 NYHA I, II; n=46 NYHA III, IV) using the ST-AIA-PACK and the Triage Biosite (Beckman Coulter) methods. Control samples distributed in the CardioOrmoCheck external quality assessment were also measured with TOSOH and the most used BNP immunoassays in Italy.

RESULTS

TOSOH method showed a good correlation (R=0.976; n=327) but a mean bias (-46.9%) compared to Triage Biosite. On the base of the results obtained in 10 samples of the CardioOrmoCheck study, TOSOH method showed a strict agreement with ADVIA Centaur, while it underestimated BNP in comparison with Triage (-52.5%) and ARCHITECT methods (-39.4%). The agreement of ST-AIA-PACK and Triage Biosite methods for classification of HF patients was tested using 100 ng/L of BNP; the positive agreement between methods was 65%, overall agreement was 73%.

CONCLUSIONS

Our results confirm that there are marked differences in measured values among commercial methods for BNP assay.

Clinical predictors and hemodynamic consequences of elevated peripheral chemosensitivity in optimally treated men with chronic systolic heart failure

AIMS

Augmented peripheral chemoreflex response is an important mechanism in the pathophysiology of chronic heart failure (CHF). This study characterizes prevalence and clinical predictors of this phenomenon in optimally managed male CHF patients, and seeks to describe the hemodynamic consequences of chemoreceptor hypersensitivity.

METHODS AND RESULTS

Thirty-four optimally managed CHF patients and 16 control subjects were prospectively studied. Hypoxic ventilatory response (HVR)-a measure of peripheral chemosensitivity-was calculated with the use of short nitrogen gas administrations. Systolic blood pressure (SBP) and heart rate (HR) following transient hypoxic challenges were recorded with a Nexfin monitor. Hemodynamic responses to hypoxia were expressed by the linear slopes between oxygen saturation (%) and SBP (mm Hg) or HR (beats/min). Elevated HVR was present in 15 (44%) of the CHF patients. Patients with elevated HVR exhibited higher levels of N-terminal pro-B-type natriuretic peptide, lower left ventricular ejection fraction, and higher prevalence of atrial fibrillation. CHF patients with elevated HVR had significantly greater SBP and HR responses to hypoxia than CHF patients with normal HVR.

CONCLUSIONS

Despite comprehensive pharmacotherapy, elevated HVR is prevalent in CHF patients, related to severity of the disease and associated with augmented hemodynamic responses to hypoxia. CHF patients with elevated HVR may be prone to unfavorable hemodynamic changes.

Multi-marker network in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: when and what to measure

BACKGROUND

Data on the correlations between biomarkers to suggest cost-effective multi-marker (MM) panels predictive for ST-elevation myocardial infarction (STEMI) patients are lacking. We sought to explore the relationship between cardiac troponin I (cTnI), C-reactive protein (CRP), B-type natriuretic peptide (BNP), and chromogranin A (CgA) accounting for biomarkers' profiles detected within 48h from successful primary percutaneous coronary intervention (PPCI).

METHODS

In 73 STEMI patients cTnI, CRP, BNP, and CgA were measured before PPCI and 6, 24, and 48h later. STATIS methods generalizing Principal Component Analysis on three-way data sets were employed to extract information about: 1) similarities between patients, 2) contribution of each time of sampling and 3) correlations between biomarkers' profiles.

RESULTS

STEMI patients who underwent successful PPCI emerged to have a homogeneous profile tailored on biomarkers' evaluation within 48h. Their measurements at 24h contributed the most variability and information both to patients' and to biomarkers' profiles. BNP and cTnI were highly correlated and explained the 40.1% of the total variance, whereas CgA resulted independent and explained the 26.3% of the total variance.

CONCLUSIONS

Markers' measurements at 24h after PPCI contributed most information to the definition of patients' profile. BNP and cTnI resulted interchangeable in a MM panel for reporting about the extent of necrosis.

Circulating forms of the b-type natriuretic peptide prohormone: pathophysiologic and clinical considerations

Recent studies reported that many different biochemical forms of B-type-related peptides circulate in human blood. In particular, a significant amount of the prohormone peptide (i.e., proBNP108) can be detected in plasma of patients with heart failure. These data indicate that the posttranslational maturation processing of the B-type natriuretic peptide (BNP) precursor may not be efficient in heart failure. The aim of this chapter is to describe the biochemical pathways of proBNP108 maturation and to discuss the pathophysiological relevance of alteration of the posttranslational maturation mechanisms in heart failure. An impaired cardiac endocrine function was proposed to explain the altered electrolyte and fluid homeostasis occurring in chronic heart failure. Recent studies demonstrated that a great part of BNPs assayed by immunoassay methods in healthy subjects and in patients with cardiovascular disease is devoid of biological activity. These findings suggest that an alteration in posttranslational maturation of BNP precursor may promote the resistance to biological action of BNP in patients with heart failure at a prereceptor level. These studies also open a new and more complex scenario regarding the circulating BNPs. The active hormone (i.e., BNP1-32) may be produced even in vivo from the circulating precursor proBNP108 by plasma enzyme degradation, such as the soluble form of corin, possibly able to process the circulating intact precursor of natriuretic hormones. As a future perspective, the simultaneous measurement of the proBNP1-108 and the active peptide BNP1-32 with more specific methods could allow a more accurate estimation of both production/secretion of B-type-related peptides from cardiomyocytes and the true activity of the cardiac endocrine function.

Atrial natriuretic peptides in Han Wistar, Sprague-Dawley and spontaneously hypertensive rats

The atrial natriuretic peptide (ANP) and its precursor (N-terminal fragment of atrial natriuretic peptide, NT-proANP) are natriuretic peptides released into the circulation as a consequence of an acute atrial stretch. As for the brain natriuretic peptide and its N-terminal fragment, the biological significance of ANP and NT-proANP has been widely studied in humans, but the literature is lacking information about the determination of these biomarkers in veterinary medicine and, in particular, in the toxicological species used in preclinical pharmaceutical drug development. This paper describes the evaluation of ANP and NT-proANP levels in a healthy population of Han Wistar and Sprague-Dawley rats, as well as in a rodent model of hypertension (Spontaneously Hypertensive rats). Both biomarkers were measured by mean of two commercially available enzyme immunoassays and serum levels were correlated with heart weight and histopathological findings in the heart, with the aim of building an integrated assessment of the significance of these biomarkers. Results obtained demonstrated that NT-proANP and ANP can be accurately measured in the different rat strains, with NT-proANP concentrations higher than those of ANP, as expected because of its longer half-life. In addition, both correlated well with cardiac hypertrophy evaluated by means of heart weight and histopathological examination. NT-proANP and ANP represent reliable markers of cardiac hypertrophy in the rat.

Atrial natriuretic peptide serum concentration decreases in donors undergoing discontinuous plasmapheresis involving a large extracorporeal blood volume

BACKGROUND

In donor plasmapheresis, circulatory reactions occur at a similar frequency as in whole-blood donation although the large extracorporeal blood volume (ECV) occurring during discontinuous plasmapheresis might predispose donors to hypovolemic reactions. The regulatory mechanisms compensating for this intradonation blood volume (BV) deficit are not well understood. It was the aim of this study to delineate whether atrial natriuretic peptide (ANP) is involved in the BV regulation of plasmapheresis donors. Because ANP regulates volume overload, it might decrease during BV decrease in plasmapheresis.

STUDY DESIGN AND METHODS

ANP serum concentrations were determined in 60 donors undergoing discontinuous plasmapheresis. Samples were taken before the start of the procedure and when maximum ECV (ECV(max)) was reached at the end of the last withdrawal. Donors were randomly selected after stratification for sex and BV. In a control investigation, the same donors were kept in a reclined position for the duration of a plasmapheresis session without plasma withdrawal. ANP plasma concentration changes were correlated with changes of hemodynamic variables, which were recorded noninvasively with bioelectrical impedance cardiography.

RESULTS

Median ANP concentration decreased from 13.0 to 8.4 pg per mL during donation and from 11.6 to 10.5 pg per mL during the control session. The mean control-adjusted ANP change due to plasma withdrawal was -2.62 pg per mL (p = 0.006). This decrease was not attributable to a dilution effect. ANP change did not correlate with changes of recorded hemodynamic variables.

CONCLUSION

The decrease of the ANP serum concentration during plasmapheresis demonstrates that the ECV(max) constitutes a hypovolemic challenge of the donors, which elicits a neurohormonal regulatory mechanism aimed at maintaining cardiovascular homeostasis.

Prognostic role of B-type natriuretic peptide in patients with diabetes and acute decompensated heart failure

BACKGROUND

Several studies have reported the prognostic value of natriuretic peptides, but their predictive value in patients with diabetes mellitus is unknown. The aim of the study was to test the hypothesis that measurement of brain natriuretic peptide (BNP) levels in ambulatory patients with congestive heart failure (CHF) and diabetes can predict the occurrence of cardiovascular events at 6-month follow-up.

METHODS

We enrolled 145 consecutive patient with diabetes [age 72 +/- 9 years, hypertension (21%), ischaemic heart disease (52%), atrial fibrillation (22%), preserved left ventricular function (29%)] seen in the outpatient heart failure clinic after an acute episode of cardiac failure.

RESULTS

The median (25th/75th interquartile range) BNP concentrations at discharge were 186 (75-348) pg/ml. At 6-month clinical follow-up 10/145 (7%) subjects had died and 31/145 (21%) had been readmitted because of cardiac decompensation. BNP values of 200 and 500 pg/ml were found to have the best compromise between sensitivity (88 and 46%, respectively) and specificity (71 and 89%, respectively) for predicting events at 6 months. Multivariate Cox regression analysis identified only two parameters as predictors of events: serum creatinine [hazard ratio (HR) = 3.3; P = 0.02], and BNP plasma level BNP cut-off values (HR = 3.8; P = 0.03 for 201-499 pg/ml and HR = 7.7; P = 0.001 for > or = 500 pg/ml).

CONCLUSION

These results suggest that BNP and serum creatinine are strong predictors of clinical events in patients with diabetes and CHF. In these patients, clinical outcome might be stratified by plasma BNP levels.

Cardiac function, inflammatory mediators and mortality in critical limb ischemia

Patients with critical limb ischemia (CLI) have a high frequency of concomitant coronary heart disease and congestive heart failure. The aim of the study was to evaluate cardiac function in relation to inflammatory markers and 1-year mortality rate among patients with CLI. The authors investigated 232 consecutive patients with CLI by means of electrocardiogram (ECG), and measurements of endothelin (ET)-1, tumor necrosis factor alpha (TNF)alpha, interleukin (IL)-6, neopterin, CD40 ligand, and 8-epi-prostaglandin (PG)F2alpha in plasma. Echocardiography (echo) was performed in 88 (38%) patients. One-year mortality rate was assessed after prospective follow-up. One hundred and eighty-six (80%) patients had sinus rhythm (SR), 36 (16%) had atrial fibrillation or flutter (AF), and 10 (4%) pacemaker rhythm. Ischemic ECG changes occurred in 143 (62%) patients. Patients with AF showed higher IL-6 (p = 0.0296) and neopterin (p = 0.0494) concentrations. Patients with ischemic ECG changes showed higher ET-1 (p = 0.0303), 8-epi-PGF2alpha (p = 0.0027), neopterin (p = 0.0004) concentrations and 1-year mortality rate (p = 0.0105). The difference in ET-1 remained in logistic regression (p = 0.0152). Internal diameter of the left ventricle on echo correlated with IL-6 (r = 0.345, p = 0.0017), TNFalpha (r = 0.240, p = 0.0273), and neopterin (r = 0.327, p = 0.0028). Internal diameter of the left atrium correlated with TNFalpha (r = 0.384, p = 0.0092) and neopterin (r = 0.526, p = 0.0004), and ejection fraction (EF) correlated inversely with IL-6 (r = -0.380, p = 0.0015) and neopterin (r = -0.346, p = 0.0038). Patients with EF <40% showed higher (p = 0.0462) 1-year mortality rate than patients with EF >40%. In conclusion, in critical limb ischemia, cardiac rhythm disturbances and ischemic ECG changes were related to inflammatory mediators and predicted 1-year mortality rate. The inflammatory mediators correlated with echocardiographic signs of congestive heart failure.

Tei index and neurohormonal activation in patients with incident heart failure: serial changes and prognostic value

BACKGROUND

Natriuretic peptides and Tei index are useful indices for risk stratification in advanced left ventricular dysfunction (LVD). Their role in early stages is less clear.

AIMS

In relation to first diagnosis of LVD to assess the relation of plasma B-type-natriuretic peptide (NT-proBNP) with Tei index, assess serial changes in indices, and to assess the value of indices to predict functional status.

METHODS

Doppler echocardiography and neurohormonal analysis were performed (n=150). NYHA class was registered.

RESULTS

Tei index correlated with p-NT-proBNP (r=0.75, p<0.0001), and changes in indices correlated (r=0.36, p=0.001) in LVD (n=80). No functional improvement (n=47) was related to a median increase in Tei index (-0.2, -0.16; 0.09); an improvement (n=31) to a reduction (0.06; -0.19; 0.35), p=0.02. In the group with functional improvement, more patients had >/=30% reduction in p-NT-proBNP (75% vs. 45%, p<0.01). Addition of NT-proBNP or Tei index to a clinical model, of no functional improvement, improved log-likelihood chi(2) from 9.32 to 20.18 (p=0.001) and 20.67 (p=0.001).

CONCLUSION

Tei index and p-NT-proBNP demonstrated a fair correlation. Unimproved NYHA class was related to progressive LVD and might be identified by monitoring Tei index or p-NT-proBNP. Advanced LVD and high pre-treatment p-NT-proBNP levels indicated a potential of improvement in functional status.

Cardiac endocrine function is an essential component of the homeostatic regulation network: physiological and clinical implications

The discovery of cardiac natriuretic hormones required a profound revision of the concept of heart function. The heart should no longer be considered only as a pump but rather as a multifunctional and interactive organ that is part of a complex network and active component of the integrated systems of the body. In this review, we first consider the cross-talk between endocrine and contractile function of the heart. Then, based on the existing literature, we propose the hypothesis that cardiac endocrine function is an essential component of the integrated systems of the body and thus plays a pivotal role in fluid, electrolyte, and hemodynamic homeostasis. We highlight those studies indicating how alterations in cardiac endocrine function can better explain the pathophysiology of cardiovascular diseases and, in particular of heart failure, in which several target organs develop a resistance to the biological action of cardiac natriuretic peptides. Finally, we emphasize the concept that a complete knowledge of the cardiac endocrine function and of its relation with other neurohormonal regulatory systems of the body is crucial to correctly interpret changes in circulating natriuretic hormones, especially the brain natriuretic peptide.

N-Terminal Pro-B-Type Natriuretic Peptide after High-Dose Chemotherapy: A Marker Predictive of Cardiac Dysfunction?

Background: Chronic cardiac dysfunction may develop after administration of aggressive chemotherapy, sometimes leading to development of congestive heart failure (CHF). Recently, N-terminal pro-B-type natriuretic peptide (NT-proBNP) was implicated as a marker of CHF. In this study we evaluated the predictive role of NT-proBNP in patients treated with high-dose chemotherapy (HDC).

Methods: NT-proBNP was measured after 62 chemotherapy treatments in 52 patients affected by aggressive malignancies. Blood samples were drawn before the start of HDC, at the end of HDC administration, and 12, 24, 36, and 72 h thereafter. In these patients, echocardiograms were performed regularly during a 1-year follow-up.

Results: Seventeen patients (33%) had persistently increased NT-proBNP, 19 patients (36%) had only transient increases (concentrations went back to baseline at 72 h), and 16 (31%) had no increases [mean (SD) values at 72 h, 1163 (936) ng/L vs 185 (101) ng/L vs 39 (19) ng/L, respectively; P &lt;0.0001]. Only patients with persistently increased NT-proBNP had a significant worsening of the left ventricular diastolic indexes from baseline to 12 months [ratio of peak early to peak late flow velocities from 1.42 (0.33) to 0.78 (0.11); P &lt;0.0001; isovolumetric relaxation time from 90 (15) to 141 (26) ms; P &lt;0.0001; E-wave deceleration time from 162 (17) to 224 (32) ms; P = 0.0004] and of the left ventricular ejection fraction [from 62.8 (3.4)% to 45.6 (11.5)%; P &lt;0.0001].

Conclusions: Persistently increased NT-proBNP early after administration of HDC is strongly associated with development of cardiac dysfunction. This finding has important implications for identifying patients at risk of developing chemotherapy-induced cardiotoxicity.

The role and assessment of ventricular peptides in heart failure

Although heart failure may be diagnosed readily in its advanced stages, it may be difficult to diagnose clinically in its early stages.Thus, there is a critical need for an inexpensive, simple, rapid,and objective test for heart failure. This article discusses the role and assessment of ventricular natriuretic peptides and related pep-tides in heart failure.

Analytical performance and diagnostic accuracy of a fully-automated electrochemiluminescent assay for the N-terminal fragment of the pro-peptide of brain natriuretic peptide in patients with cardiomyopathy: comparison with immunoradiometric assay methods for brain natriuretic peptide and atrial natriuretic peptide

We evaluated the analytical performance of a fully-automated electrochemiluminescence “sandwich” immunoassay method for the N-terminal fragment of the pro-peptide of brain natriuretic peptide (BNP). We then compared the diagnostic accuracy of this method in discriminating between normal subjects and patients with cardiomyopathy with that found with two previously described immunoradiometric assay methods for the assay of atrial natriuretic peptide (ANP) and BNP. We studied 193 consecutive patients (mean age 64.4±12.3 years, range 20–89 years, including 56 women and 137 men) with chronic cardiomyopathy and a group of 85 healthy subjects (mean age 52.3±12.0 years, 42 women and 43 men, range 20–79 years). N-terminal fragment of proBNP

N-terminal pro-atrial natriuretic peptide as a biochemical marker of long-term interventional success after radiofrequency catheter ablation of paroxysmal supraventricular tachyarrhythmias

Radiofrequency (RF) catheter ablation has been shown to be highly effective in the treatment of supraventricular tachycardias. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (B-type natriuretic peptide; BNP) are secreted by the heart mainly in response to myocardial stretch induced by volume load. The aim of the present study was to determine the time course of the N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) in patients undergoing radiofrequency (RF) catheter ablation for paroxysmal supraventricular tachycardias.

Serial blood samples were taken from 13 patients with symptomatic paroxysmal supraventricular tachycardias undergoing RF ablation and from 13 age- and gender-matched healthy controls. Blood was taken before ablation (day 0, baseline), and at day one and day 120 after ablation. Levels of NT-proANP were significantly higher before RF ablation (4862 ± 726 pmol/l) as compared to day one (2021 ± 220 pmol/l) and day 120 after RF ablation (2470 ± 349 pmol/l) (with p < 0.01 on day one and p < 0.05 on day 120; n = 13). The size of the left atrium decreased from 41.0 ± 5.5 mm before ablation to 34.9 ± 5.9 mm (n = 13; p < 0.05) on day 120 as measured by M-mode echocardiography. Levels of NT-proBNP showed comparable values before and on day one and day 120 after ablation and were not significantly elevated as compared to healthy controls.

NT-proANP levels are increased in patients presenting with paroxysmal supraventricular tachycardias and decrease one day after radiofrequency catheter ablation, possibly reflecting a transient reduction of ANP secretion from injured myocardial cells. Lower NT-proANP levels in the long-term time course may result from reduction of atrial volume load and reconstitution of atrial architecture after successful treatment of supraventricular tachycardias. NT-proANP may serve as a useful laboratory marker to describe the long-term interventional success after RF ablation.

Biochemical markers of cardiac diseases

This article reviews the current contribution of the determination of biochemical markers to clinical cardiology and discusses some important developments in this field. Biochemical markers play a pivotal role in the diagnosis and management of patients with acute coronary syndrome (ACS), as witnessed by the incorporation of cardiac troponins into new international guidelines for patients with ACS and in the redefinition of myocardial infarction. Despite the success of cardiac troponins, there is still a need for development of early markers that can reliably rule out ACS from the emergency room at presentation and detect myocardial ischemia also in the absence of irreversible myocyte injury. Under investigation are two classes of indicators: markers of early injury/ischemia and markers of coronary plaque instability and disruption. Finally, with the characterization of the cardiac natriuretic peptides, Laboratory Medicine is also assuming part in the assessment of cardiac function.

The increasing impact of laboratory medicine on clinical cardiology

The practice of cardiology continues to evolve along with a better understanding of the pathophysiology of cardiovascular disease and the development of new therapeutic procedures. Consequently, new demands are being made on the in vitro diagnostics industry to improve the performance of existing cardiac markers and to develop novel markers for new cardiac disease indications. Indeed, in the last 20 years there has been a progressive increase in new laboratory tests for markers of cardiac diseases. Several highly sensitive and/or specific assays for the detection of myocardial ischemic damage as well as some immunoassays for cardiac natriuretic hormones, now considered a reliable marker of myocardial function, have become commercially available. In parallel, a growing number of some novel risk factors, which can be assessed and monitored by laboratory methods, have been added to the classical risk factors for cardiovascular disease. Finally, the recent explosion of genetic analysis may soon place at the clinical cardiologist's disposal many laboratory tests for defining the diagnosis at the molecular level, assessing new risk factors, and better targeting the pharmaceutical approaches in patients with cardiovascular disease. In the present article, after a brief description of the analytical tests included in these four groups, each group's impact on clinical cardiology is discussed in detail.