Comparative measurement of N-terminal pro-brain natriuretic peptide and brain natriuretic peptide in ambulatory patients with heart failure

Prognostic value of natriuretic peptides in heart failure: systematic review and meta-analysis

Risk models, informing optimal long-term medical management, seldom use natriuretic peptides (NP) in ascertaining the absolute risk of outcomes for HF patients. Individual studies evaluating the prognostic value of NPs in HF patients have reported varying effects, arriving at best estimates requires a systematic review. We systematically summarized the best evidence regarding the prognostic value of brain natriuretic peptide (BNP) and NT-proBNP in predicting mortality and hospitalizations in ambulatory heart failure (HF) patients. We searched bibliographic databases from 2005 to 2018 and included studies evaluating the association of BNP or NT-proBNP with mortality or hospitalization using multivariable Cox proportional hazard models. We pooled hazard ratios using random-effect models, explored heterogeneity using pre-specified subgroup analyses, and evaluated the certainty of evidence using the Grading of Recommendations and Development Evaluation framework. We identified 67 eligible studies reporting on 76,178 ambulatory HF patients with a median BNP of 407 pg/mL (261-574 pg/mL). Moderate to high-quality evidence showed that a 100-pg/mL increase in BNP was associated with a 14% increased hazard of mortality (HR 1.14, 95% CI 1.06-1.22); a 1-log-unit increase was associated with a 51% increased hazard of mortality (HR 1.51, 95% CI 1.41-1.61) and 48% increased hazard of mortality or hospitalization (HR 1.48, 95% CI 1.29-1.69). With moderate to high certainty, we observed a 14% independent relative increase in mortality, translating to a clinically meaningful increase in absolute risk even for low-risk patients. The observed associations may help in developing more accurate risk models that incorporate NPs and accurately prognosticate HF patients.

Determination and stability of N-terminal pro-brain natriuretic peptide in saliva samples for monitoring heart failure

Heart failure (HF) is the main cause of mortality worldwide, particularly in the elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) is the gold standard biomarker for HF diagnosis and therapy monitoring. It is determined in blood samples by the immunochemical methods generally adopted by most laboratories. Saliva analysis is a powerful tool for clinical applications, mainly due to its non-invasive and less risky sampling. This study describes a validated analytical procedure for NT-proBNP determination in saliva samples using a commercial Enzyme-Linked Immuno-Sorbent Assay. Linearity, matrix effect, sensitivity, recovery and assay-precision were evaluated. The analytical approach showed a linear behaviour of the signal throughout the concentrations tested, with a minimum detectable dose of 1 pg/mL, a satisfactory NT-proBNP recovery (95-110%), and acceptable precision (coefficient of variation ≤ 10%). Short-term (3 weeks) and long-term (5 months) stability of NT-proBNP in saliva samples under the storage conditions most frequently used in clinical laboratories (4, - 20, and - 80 °C) was also investigated and showed that the optimal storage conditions were at - 20 °C for up to 2.5 months. Finally, the method was tested for the determination of NT-proBNP in saliva samples collected from ten hospitalized acute HF patients. Preliminary results indicate a decrease in NT-proBNP in saliva from admission to discharge, thus suggesting that this procedure is an effective saliva-based point-of-care device for HF monitoring.

Do N-terminal pro-brain natriuretic peptide levels determine the prognosis of community acquired pneumonia?

OBJECTIVE

Pneumonia is a leading cause of mortality worldwide, especially in the elderly. The use of clinical risk scores to determine prognosis is complex and therefore leads to errors in clinical practice. Pneumonia can cause increases in the levels of cardiac biomarkers such as N-terminal pro-brain natriuretic peptide (NT-proBNP). The prognostic role of the NT-proBNP level in community acquired pneumonia (CAP) remains unclear. The aim of this study was to evaluate the prognostic role of the NT-proBNP level in patients with CAP, as well as its correlation with clinical risk scores.

METHODS

Consecutive inpatients with CAP were enrolled in the study. At hospital admission, venous blood samples were collected for the evaluation of NT-proBNP levels. The Pneumonia Severity Index (PSI) and the Confusion, Urea, Respiratory rate, Blood pressure, and age ≥ 65 years (CURB-65) score were calculated. The primary outcome of interest was all-cause mortality within the first 30 days after hospital admission, and a secondary outcome was ICU admission.

RESULTS

The NT-proBNP level was one of the best predictors of 30-day mortality, with an area under the curve (AUC) of 0.735 (95% CI: 0.642-0.828; p < 0.001), as was the PSI, which had an AUC of 0.739 (95% CI: 0.634-0.843; p < 0.001), whereas the CURB-65 had an AUC of only 0.659 (95% CI: 0.556-0.763; p = 0.006). The NT-proBNP cut-off level found to be the best predictor of ICU admission and 30-day mortality was 1,434.5 pg/mL.

CONCLUSIONS

The NT-proBNP level appears to be a good predictor of ICU admission and 30-day mortality among inpatients with CAP, with a predictive value for mortality comparable to that of the PSI and better than that of the CURB-65 score.

Ultra-Sensitive NT-proBNP Quantification for Early Detection of Risk Factors Leading to Heart Failure

Cardiovascular diseases such as acute myocardial infarction and heart failure accounted for the death of 17.5 million people (31% of all global deaths) in 2015. Monitoring the level of circulating N-terminal proBNP (NT-proBNP) is crucial for the detection of people at risk of heart failure. In this article, we describe a novel ultra-sensitive NT-proBNP test (us-NT-proBNP) that allows the quantification of circulating NT-proBNP in 30 min at 25 °C in the linear detection range of 7.0-600 pg/mL. It is a first report on the application of a fluorescence bead labeled detection antibody, DNA-guided detection method, and glass fiber membrane platform for the quantification of NT-proBNP in clinical samples. Limit of blank, limit of detection, and limit of quantification were 2.0 pg/mL, 3.7 pg/mL, and 7 pg/mL, respectively. The coefficient of variation was found to be less than 10% in the entire detection range of 7-600 pg/mL. The test demonstrated specificity for NT-proBNP without interferences from bilirubin, intra-lipid, biotin, and hemoglobin. The serial dilution test for plasma samples containing various NT-proBNP levels showed the linear decrement in concentration with the regression coefficient of 0.980-0.998. These results indicate that us-NT-proBNP test does not suffer from the interference of the plasma components for the measurement of NT-proBNP in clinical samples.

Missed opportunity for anticoagulation in a patient with AL cardiac amyloidosis and rapidly progressive heart failure

A previously healthy 65-year-old woman presented with progressive symptoms of heart failure. Low-voltage ECG and findings on echocardiography were concerning for infiltrative cardiomyopathy. Cardiac MRI showed biventricular late gadolinium enhancement, and endomyocardial biopsy confirmed monoclonal immunoglobulin light-chain (AL) amyloidosis. Bortezomib-based chemotherapy was initiated, but the patient continued to clinically deteriorate. She required hospital readmission after resuscitated out-of-hospital cardiac arrest attributed to progressive conduction disease, and a permanent pacemaker was implanted. Chest CT angiography showed a small subsegmental pulmonary embolism (PE), but anticoagulation was withheld as her lower extremity Doppler was negative. One month later, another pulseless electrical arrest occurred, due to massive PE. Thereafter, she had refractory class IV congestive heart failure with severe right ventricular dysfunction, and was deemed unsuitable for stem-cell or heart transplantation. This case highlights the predilection for thromboembolism in AL cardiac amyloidosis.

A phase II trial of lenalidomide, dexamethasone and cyclophosphamide for newly diagnosed patients with systemic immunoglobulin light chain amyloidosis

Immunomodulatory drugs have been shown to be of benefit in relapsed/refractory immunoglobulin light-chain (AL) amyloidosis. We designed a prospective, multicentre phase II trial of lenalidomide, dexamethasone and cyclophosphamide for newly diagnosed patients with AL amyloidosis not eligible for autologous stem-cell transplantation. Twenty-eight patients were included in the study. Cardiac involvement was present in 23 patients; 14 of them had cardiac stage III. The overall haematological response rate was 46%, including complete and very good partial responses in 25% and 18% of patients respectively. Haematological response was mainly associated with absence of cardiac stage III and lower tumour burden. Organ response was observed in 46% of patients. After a median follow-up of 24 months, median progression-free and overall survival have not been reached, both being significantly longer in responders (P < 0·001 and P = 0·001 respectively). Seventeen patients have discontinued treatment, mostly due to amyloid-related death, disease progression or lack of response. Only 14% of the patients discontinued treatment due to therapy-related adverse events. Our results support the efficacy of this regimen, with high quality responses and prolonged survival, as well as its tolerability, in patients with AL amyloidosis not eligible for stem cell transplant and without advanced cardiac involvement (clinicaltrials.gov identifier: NCT01194791).

Safety and efficacy of high-dose melphalan and auto-SCT in patients with AL amyloidosis and cardiac involvement

In Ig light chain (AL) amyloidosis, cardiac involvement is associated with worse prognosis and increased treatment-related complications. In this retrospective cohort study, we assessed survival, hematologic and cardiac responses to high-dose melphalan and auto-SCT (HDM/SCT) in patients with AL amyloidosis and cardiac involvement, stratified by cardiac biomarkers brain natriuretic peptide and Troponin I, analogous to the Mayo cardiac staging. Forty-seven patients underwent HDM/SCT based upon functional measures; six patients had modified cardiac stage I disease, seventeen had modified cardiac stage II disease and twenty-four had modified cardiac stage III disease. Treatment-related mortality was 4% for all patients and 8% for patients with stage III disease. Three-year survival was 88% and EFS was 47%; these did not differ by stage. By intention-to-treat analysis, 27% of patients achieved a hematologic complete response and 32% a very good partial response, of whom 70 and 45%, respectively, have not required additional therapy at 36 months. Cardiac response was achieved in 53% of patients. We conclude that with appropriate patient selection and a risk-adapted treatment approach, HDM/SCT is safe and effective in patients with AL amyloidosis and cardiac involvement.

Predictive cutoff point of admission N-terminal pro-B-type natriuretic peptide testing in the ED for prognosis of patients with acute heart failure

OBJECTIVE

The main objective of this study was to determine a cutoff level of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) that could successfully predict the short- and long-term prognosis of patients with acute heart failure at the time of admission to the emergency department. The results of our study are presented in context with previously published literature. We believe that the present study will be useful and salutary for the progress of literature.

METHODS

N-terminal pro-B-type natriuretic peptide plasma levels were obtained from 100 patients with shortness of breath and left ventricular dysfunction upon admission to the emergency department. All patients underwent follow-up evaluations 30 days and 1 year after admission. The end point was defined as all-cause mortality.

RESULTS

The mean age of the patients in this study was 70.8 ± 11.6 years, and 51% were female. All-cause mortality at the 30-day and 1-year follow-up evaluations was 21.2% and 53.5%, respectively. We determined that the optimal NT-proBNP cutoff point for predicting 30-day mortality at the time of admission was 9152.4 pg/mL, with a 71.4% sensitivity and an 81.3% specificity (95% confidence interval, area under the curve: 0.726; P = .002). The optimal NT-proBNP cutoff point for predicting 1-year mortality at the time of admission was 3630.5 pg/mL, with an 83.0% sensitivity and a 52.2% specificity (95% confidence interval, area under the curve: 0.644; P = .014).

CONCLUSION

Elevated NT-proBNP levels at the time of admission are a strong and independent predictor of all-cause mortality in patients with acute heart failure at 30 days and 1 year after admission. Furthermore, the optimal cutoff level of NT-proBNP used to predict 30-day and 1-year mortality had high sensitivity.

Aminoterminal pro-B-type natriuretic peptide: heart or lung disease in the neonate?

OBJECTIVES

B-type natriuretic peptides have been shown to enable differentiation between heart and lung diseases in adults and children. In neonates, the role of natriuretic peptides for diagnosis of congenital heart defect (CHD) is not yet ascertained. The purpose of this single-center prospective study was to investigate aminoterminal B-type natriuretic peptide concentrations and their time courses during the first 5 days of life in neonates with CHD compared with neonates with respiratory distress.

DESIGN

Single-center prospective study.

SETTING

Tertiary-care neonatal ICU.

PATIENTS

Aminoterminal B-type natriuretic peptide levels of 40 neonates with arterial duct-dependent CHD and of 40 neonates with respiratory distress without CHD were analyzed on the first, second, third, and fifth day of life.

MAIN RESULTS

Mean aminoterminal B-type natriuretic peptide concentrations in the CHD group were significantly higher on the second (14191 vs. 4872 pg/mL), third (17790 vs. 3524 pg/mL), and fifth day (17015 vs. 4044 pg/mL), but not on the first day of life. Repeated measurements analysis of variance revealed a significantly different time course of aminoterminal B-type natriuretic peptide concentrations between the two groups.

CONCLUSIONS

On the first day of life, aminoterminal B-type natriuretic peptide cannot differentiate between CHD and respiratory distress without CHD in the neonate. From the second day onwards, aminoterminal B-type natriuretic peptide in neonates with CHD shows higher values and a different time course and enables differentiation between CHD and respiratory distress due to other than cardiac reasons.

Signal-enhancer molecules encapsulated liposome as a valuable sensing and amplification platform combining the aptasensor for ultrasensitive ECL immunoassay

An innovatory ECL immunoassay strategy was proposed to detect the newly developing heart failure biomarker N-terminal pro-brain natriuretic peptide (NT-proBNP). Firstly, this strategy used small molecules encapsulated liposome as immune label to construct a sandwich immune sensing platform for NT-proBNP. Then the ECL aptasensor was prepared to collect and detect the small molecules released from the liposome. Finally, based on the ECL signal changes caused by the small molecules, the ECL signal indirectly reflected the level of NT-proBNP antigen. In this experiment, the cocaine was chosen as the proper small molecule that can act as signal-enhancer to enhance the ECL of Ru(bpy)(3)(2+). The cocaine-encapsulated liposomes were successfully characterized by TEM. The quantificational calculation proved the ∼5.3×10(3) cocaine molecules per liposome enough to perform the assignment of signal amplification. The cocaine-binding ECL aptasensor further promoted the work aimed at amplifying signal. The performance of NT-proBNP assay by the proposed strategy exhibited high sensitivity and high specificities with a linear relationship over 0.01-500 ng mL(-1) range, and a detection limit down to 0.77 pg mL(-1).

Diagnostic accuracy of plasma brain natriuretic peptide and aminoterminal‐proBNP in mild heart failure depends on assay and introduction of therapy

OBJECTIVE

A reliable biochemical marker of left ventricular dysfunction (LVD) could improve diagnostic accuracy. The aim of this study was to compare the correlation of measurements of brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) with different assays. The diagnostic accuracy of the tests in mild heart failure (HF) was estimated before and after the start of therapy.

MATERIAL AND METHODS

Doppler echocardiography and measurements of plasma BNP and NT-proBNP were performed in 150 patients.

RESULTS

Systolic dysfunction (LV ejection fraction 0.45) was present in 22 patients, and 58 had only abnormalities in LV filling. P-NT-proBNP based on two different assays demonstrated a moderate correlation (r = 0.57, p<0.0001) and a concentration-dependent systematic difference. Excellent correlation (r = 0.95, p<0.0001) was found between BNP and NT-proBNP based on two-site antibody assays, but was moderate between BNP and a one-site antibody NT-proBNP assay (r = 0.58, p<0.0001). Areas under the receiver operating characteristic (ROC) curves (AUCs) were 0.93 (95 % CI, 0.90-0.98) for BNP, 0.95 (0.91-0.99) for NT-proBNP (two-site antibody assay) and 0.77 (0.70-0.85) for the one-site antibody NT-proBNP assay (p = 0.0001). At re-evaluation of LVD at 6 and 12 months, AUCs of BNP were 0.81 (0.74-0.99) and 0.83 (0.76-0.89), respectively, and AUCs of NT-proBNP (two-site) were 0.84 (0.77-0.91) and 0.87 (0.81-0.93), respectively. Using the baseline threshold reduced the sensitivity and specificity of BNP and NT-proBNP measurements.

CONCLUSIONS

BNP and NT-proBNP measurements demonstrated assay-dependent correlations. Measurement of p-BNP or p-NT-proBNP by a two-site antibody assay demonstrated potential as an indicator of mild, incident HF, but the applicability of the index tests was limited over time and was likely influenced by therapeutic interventions.

Clinical significance of N-terminal-probrain natriuretic peptide in hypertrophic cardiomyopathy

N-Terminal-probrain natriuretic peptide (NT-proBNP) plasma levels are elevated in patients with congestive heart failure. Published data concerning the utility of NT-proBNP in hypertrophic cardiomyopathy (HCM) are lacking. Our aim was to evaluate the clinical significance of NT-proBNP in patients with HCM. A blood sample was collected for plasma NT-proBNP measurement from 43 consecutive patients with documented HCM. NT-proBNP was measured using a chemiluminescent immunoassay kit (Roche Diagnostics) on an Elecsys 2010 analyzer. Median value of NT-proBNP was 219 pg/ml (range 8-3 045 pg/ml) in NYHA class I patients, 698 pg/ml (125-2 463 pg/ml) in NYHA class II patients, and 2 683 pg/ml (131-11 542 pg/ml) in NYHA class III and IV patients. NT-proBNP plasma levels were significantly higher across the severity of functional limitation (i.e., NYHA class classification) (P = 0.002). NT-proBNP levels were significantly higher in female than male (P = 0.034), in referral vs nonreferral patients (P = 0.004), in symptomatic vs asymptomatic patients (P = 0.020), in patients with basal subaortic gradient >or=30 mmHg (P = 0.001) and in the patients who were on cardioactive medication (P = 0.010). In univariate analysis NT-proBNP was significantly correlated with age (P < 0.001), left ventricular maximum wall thickness (P = 0.001), left atrial size (P = 0.019), and subaortic gradient >or=30 mmHg (P < 0.001). In multivariate regression analysis, age (P < 0.001), maximum wall thickness (P = 0.007), and gradient >or=30 mmHg (P = 0.027) were independently associated with NT-proBNP levels. Our data support the idea that measurement of plasma NT-proBNP levels in HCM patients is useful to assess their clinical status, especially the severity of hypertrophy and the presence of obstruction, although age must be taken into account.

Comparison of N-terminal pro-B-type natriuretic peptide levels in critically ill children with sepsis versus acute left ventricular dysfunction

OBJECTIVE

N-terminal pro-B-type natriuretic peptide has been shown to be a marker for cardiac dysfunction. The peptide level is also elevated in patients with sepsis. The purpose of this study was to assess whether N-terminal pro-B-type natriuretic peptide levels can differentiate pediatric patients with sepsis from patients with acute left ventricular dysfunction.

PATIENTS AND METHODS

Pediatric patients admitted to an ICU with sepsis or acute left ventricular dysfunction were evaluated clinically, and the grade of systemic inflammatory-response syndrome was determined. Echocardiography was performed, and their levels of N-terminal pro-B-type natriuretic peptide were measured. The N-terminal pro-B-type natriuretic peptide level was also measured in patients with simple febrile illness.

RESULTS

There were 10 patients with sepsis and 10 with acute left ventricular dysfunction. The age of the patients was similar, and systemic inflammatory-response syndrome grading was not different (sepsis: 2.8 +/- 0.4; acute left ventricular dysfunction: 2.6 +/- 0.7). N-terminal pro-B-type natriuretic peptide levels were elevated in patients with sepsis (median: 6064 pg/mL; range: 495-60,417 pg/mL) but were significantly higher in patients with acute left ventricular dysfunction (median: 65,630 pg/mL; range: 15,125-288,000). The area under the receiver operating characteristics curve for the diagnosis of acute left ventricular dysfunction was 0.9. N-terminal pro-B-type natriuretic peptide levels of patients with sepsis and impaired systolic function were not different from those of patients with sepsis and normal systolic function. The N-terminal pro-B-type natriuretic peptide levels of 20 patients with simple febrile illness were significantly lower.

CONCLUSIONS

N-terminal pro-B-type natriuretic peptide levels are elevated in pediatric patients with sepsis but are higher in some, but not all, patients with acute left ventricular dysfunction. The overlap between N-terminal pro-B-type natriuretic peptide levels in sepsis and acute left ventricular dysfunction precludes the use of the peptide's level as a sole means to differentiate between these conditions. Excessive elevation in N-terminal pro-B-type natriuretic peptide levels, however, suggests cardiac etiology for acute hemodynamic deterioration in infants and children.

N-terminal Pro B-type Natriuretic Peptide Levels: Correlation with Echocardiographically Determined Left Ventricular Diastolic Function in an Ambulatory Cohort

OBJECTIVES

To investigate the correlations of plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) levels with echocardiographic measurements of left ventricular (LV) systolic and/or diastolic function.

BACKGROUND

Plasma levels of NT-proBNP are increased in heart failure. The extent to which NT-proBNP levels increase in LV diastolic dysfunction has not been well characterized.

METHODS

Plasma NT-proBNP levels were measured in 191 consecutive, clinically stable, ambulatory patients. Echocardiography was used to determine LV systolic (LV ejection fraction [LVEF]) and diastolic function by mitral E wave to Doppler tissue early diastolic lateral annulus velocity ratio (E/Em). Patients with a history, physical findings, and/or echocardiographic evidence of cardiovascular disease (n = 148) were grouped as: (1) normal LV systolic function (LVEF > or = 55%, n = 81); and (2) LV systolic dysfunction (LVEF < 55%, n = 67). They were compared to a group of healthy control subjects (n = 43). Multivariate regression analyses were used to determine significant correlations with plasma NT-proBNP levels.

RESULTS

NT-proBNP levels correlated negatively with LVEF (P < .001) and positively with E/Em (P = .001). Multivariate regression analysis demonstrated a significant correlation of NT-proBNP levels with LVEF (P < .001) and E/Em (P = .03).

CONCLUSIONS

In this clinically stable, ambulatory cohort of patients with cardiovascular disease and healthy control subjects, plasma NT-proBNP levels were significantly higher in those with LV systolic dysfunction and/or elevated filling pressures, independent of the effects of LV mass, renal function, and age. These results suggest that NT-proBNP levels may be a useful adjunct in the characterization of patients presenting with history and/or symptoms compatible with LV systolic and/or diastolic dysfunction.

N-terminal pro-B-type natriuretic peptide levels in acute versus chronic left ventricular dysfunction

OBJECTIVES

To determine whether acute left ventricular dysfunction (LVD) causes significantly higher elevation of N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels than comparable chronic LVD.

STUDY DESIGN

Plasma levels of NT-proBNP were measured in 10 pediatric patients diagnosed with acute LVD, in 7 pediatric patients with stable chronic dilated cardiomyopathy (DCM) and comparable levels of echocardiographic dysfunction, and during 5 episodes of acute exacerbation in patients with heart failure. Levels were compared using Mann-Whitney and analysis of variance for rank tests.

RESULTS

Plasma levels of NT-proBNP were excessively elevated in patients with acute LVD in the first 24 to 48 hours of hospitalization (median level, 65,600 pg/mL), and were significantly higher than those in patients with chronic DCM (median level, 1125 pg/mL; P < .0001). NT-proBNP levels decreased in the subsequent days in 83% of patients with serial measurements. The NT-proBNP levels were lower In 5 episodes of acute exacerbation than in acute LVD (median level, 7185 pg/mL; P < .003).

CONCLUSIONS

Acute LVD is associated with elevated NT-proBNP level in children.

Natriuretic peptides in patients with atrial fibrillation and advanced chronic heart failure: determinants and prognostic value of (NT-)ANP and (NT-pro)BNP

AIMS

To study the determinants of natriuretic peptides in advanced chronic heart failure (CHF) patients with and without atrial fibrillation (AF) and to evaluate the prognostic value of natriuretic peptides in AF compared with sinus rhythm patients with advanced CHF.

METHODS AND RESULTS

The study group comprised 354 advanced CHF patients [all New York Heart Association (NYHA) III/IV], including 76 AF patients. AF patients were older (70+/-7 vs. 67+/-8; P=0.01), and non-ischaemic CHF was more common (42 vs. 19%; P=0.002) than in sinus rhythm patients, but left-ventricular ejection fraction was comparable (0.23+/-0.08 vs. 0.24+/-0.07; P=ns). At baseline, (NT-)ANP and NT-proBNP levels were significantly higher in AF patients, compared with those in sinus rhythm. By multivariate regression analysis, AF was identified as independent determinant of (NT-)ANP, but not of (NT-pro)BNP levels. After a mean follow-up of 3.2+/-0.9 (range 0.4-5.4) years, cardiovascular mortality was comparable (55 vs. 47%; P=ns). In both groups, AF and sinus rhythm, NT-proBNP [AF: adjusted HR 5.8 (1.3-25.4), P=0.02; sinus rhythm: adjusted HR 3.1 (1.7-5.7), P<0.001] was an independent risk indicator of cardiovascular mortality.

CONCLUSION

In advanced CHF patients, AF affects (NT-)ANP levels, but not (NT-pro)BNP levels. NT-proBNP is an independent determinant of prognosis in advanced CHF, irrespective of the rhythm, AF, or sinus rhythm.

Head to head comparison of N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide in patients with/without left ventricular systolic dysfunction

BACKGROUND

Human pro-B-type natriuretic peptide is cleaved into the active B-type natriuretic peptide (BNP) and the inactive fragment NT-proBNP. It is unclear if, similar to BNP, NT-proBNP can be used as a marker of impaired left ventricular (LV) ejection fraction (EF). This study evaluated the analytical performance of both assays to detect LV systolic dysfunction.

METHODS

In 72 patients with various degrees of left ventricular systolic dysfunction (LVSD), blood analysis for BNP and NT-proBNP was performed prior to cardiac catheterization, using a point-of-care analyzer (Biosite) and a fully automated laboratory analyzer (Roche-Elecsys), respectively. The within-run and between-run imprecision for BNP and NT-proBNP was calculated.

RESULTS

Both markers were able to detect impaired LV EF with the largest area under the receiver-operating-characteristic curve for NT-proBNP (NT-proBNP: 0.851 (0.747-0.924); BNP: 0.803 (0.692-0.887) 95% confidence interval; P = 0.07). A significant correlation was observed between BNP and NT-proBNP (r = 0.9; P < 0.0001). Estimating the within-run imprecision, the coefficient of variance for BNP was 3.14% (n = 20, mean 316 ng/L) to 3.32% (n = 20, mean 820 ng/L) and for NT-proBNP 0.9% (n = 20, mean 4390.8 ng/L) to 1.4% (n = 20, mean 225 ng/L). The between-run imprecision for NT-proBNP ranged between 2.1% (n = 20, mean 224.6 ng/L) and 2% (n = 20, mean 4391 ng/L). Optimal discriminator values for BNP and NT-proBNP were 139 ng/L and 358 ng/L, respectively. However, adjusting the BNP cut-off value to 54 ng/L improved the negative predictive value and sensitivity of the assay.

CONCLUSION

Similar to BNP, NT-proBNP is a promising marker in identifying LVSD. Although both assays are reliable and have good analytical performance, their diagnostic cut-off value is dynamic and population-dependent. The slightly wider detection range and the more stable structure of NT-proBNP compared to the BNP assay suggest that NT-proBNP could play an additional role in the evaluation of patients with LV systolic dysfunction.

N-terminal pro-brain natriuretic peptide levels are elevated in patients with acute ischemic stroke

Brain natriuretic peptide (BNP) is a counterregulatory hormone released by the ventricles of the heart. Its main actions are natriuresis and vasodilation. The authors studied N-terminal pro-brain natriuretic peptide (NT-proBNP) levels soon after an acute ischemic stroke. They compared plasma NT-proBNP concentrations in 30 patients with an acute ischemic stroke with those of 30 controls. The 2 groups were adjusted for age and gender, and there were no significant differences in vascular risk factors and left ventricular systolic and diastolic function. Venous samples were collected within the first 11.8 +/-1.2 hours after the onset of symptoms and again on day 6. Brain computed tomography/magnetic resonance imaging (CT/MRI) was performed on the same days (day 0 and day 6) in order to assess the site (carotid or vertebrobasilar), cause (atherothrombotic, cardioembolic, or lacunar), and size (large, medium, or small) of the brain infarct. NT-proBNP levels were elevated in patients with acute stroke (129.9 +/-9.9 fmol/mL) compared with the controls (90.8 +/-6.3 fmol/mL, p <0.05). These levels remained elevated at day 6 (113.5 +/-13.0 fmol/mL). NT-proBNP at admission was significantly higher in cardioembolic compared with atherothrombotic infarctions. There was no correlation between circulating NT-proBNP and stroke topography, infarct size, or severity as assessed by the National Institutes of Health Stroke Scale (NIHSS) at any of the 2 time points (admission and day 6). NT-proBNP levels were raised in patients with acute ischemic stroke; this effect persisted until day 6. The authors suggest that neurohumoral activation occurs in patients with acute ischemic stroke, either reflecting a counterbalancing vasodilating response to the cerebral ischemia or direct myocardial dysfunction.

NT-proBNP as a marker for persistent cardiac disease in children with history of dilated cardiomyopathy and myocarditis

Children with myocarditis and dilated cardiomyopathy may recover clinically and echocardiographically. Plasma levels of the N-terminal segment of B-type natriuretic peptide prohormone (NT-proBNP), a sensitive marker for cardiac dysfunction, may reflect residual cardiac damage in these patients. The purpose of this study was to evaluate NT-proBNP status in pediatric patients with a history of myocarditis and dilated cardiomyopathy. Cardiac evaluation was performed and the levels of NT-proBNP were measured in 23 children who had a history of myocarditis or dilated cardiomyopathy. NT-proBNP levels were also measured in 56 age-matched control children. Nine of the 23 patients had evidence of left ventricular dysfunction (DCM group), whereas 14 had none (recovery). NT-proBNP levels were higher in the DCM group (3154 +/- 2858 pg/ml) than in the recovery group (122 +/- 75 pg/ml, p < 0.001) and the control group (113 +/- 96 pg/ml, p < 0.001). There was no difference between the recovery and the control groups (p = 0.45), and none of the recovered patients had a NT-proBNP level higher than the upper limit of normal. The area under the receiver operating characteristics curve for the diagnosis of persistent left ventricular dysfunction was 0.984. NT-proBNP levels correlated with echocardiographically derived shortening fraction and with clinical score. NT-proBNP is a good marker for persistent left ventricular dysfunction in children who have had myocarditis or cardiomyopathy. In this group of patients, NT-proBNP levels are normal in children who recover echocardiographically, suggesting no residual hemodynamic abnormalities.

BNP--Considering a heartfelt message

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

Assessment of BNP and NT-proBNP in emergency department patients presenting with suspected acute coronary syndromes

OBJECTIVES

The relationship between BNP and NT-proBNP among physiologically and clinically relevant demographic subgroups has never been clarified in the context of the emergency department (ED).

DESIGN AND METHODS

A blood sample taken from patients presenting to the E.D. with suspected acute coronary syndromes (ACS) was analyzed for BNP and NT-proBNP, and correlation between them was examined as an entire group then as subgroups according to gender, ethnicity, age, and comorbidity variables.

RESULTS

BNP and NT-proBNP correlate well (0.89, P < 0.0001) in a population of 420 patients and in patient subgroups with a history of various etiologies, including vascular disorders.

CONCLUSIONS

In general, BNP and NT-proBNP correlate very well in patients with suspected ACS and may aid in the risk stratification process in emergency departments.

Plasma amino-terminal pro-B-type natriuretic peptide quantification in hypertrophic cardiomyopathy

BACKGROUND

Plasma B-type natriuretic peptide (BNP) is a sensitive functional marker in heart disease including hypertrophic cardiomyopathy (HCM). The utility of plasma amino-terminal pro-BNP (NT-proBNP) quantification in heart disease has been investigated, but there are no published data regarding this test in HCM.

METHODS

Plasma NT-proBNP was assessed in 71 patients with HCM and in 40 healthy subjects. Symptomatic status was assessed according to the New York Heart Association classification. M-mode and Doppler echocardiographic data were obtained in all patients and healthy subjects to study their correlations and comparisons (Spearman and Mann-Whitney tests).

RESULTS

Median NT-proBNP was 848 pg/mL in patients and 28 pg/mL in the control group (P < .0001). Patients in New York Heart Association functional class I/II had a median NT-proBNP of 669 pg/mL as compared with 3357 pg/mL for patients in class III/IV (P < .0001). Amino-terminal pro-BNP levels correlated positively with left atrial diameter (r = 0.40, P = .0005), septal thickness (r = 0.35, P = .002), and mitral flow velocity/mitral annulus velocity (E/Ea) ratio (r = 0.42, P < .0001). There was a weak correlation with obstruction (r = 0.23, P = .05), and a significant difference in the medians was observed between obstructive (1651 pg/mL) and nonobstructive (669 pg/mL) HCM groups (P = .01). Patients with Doppler E/Ea ratios > or = 10 had higher NT-proBNP levels than patients with E/Ea < 10 (P < .0001). Multivariate analysis showed that NT-proBNP correlated independently with left atrial diameter (P < .01), hypertrophy (P < .01), and E/Ea (P < .01).

CONCLUSIONS

In HCM, plasma NT-proBNP levels are elevated and correlate positively with symptoms of heart failure, hypertrophy severity, and Doppler echocardiographic signs of left ventricular diastolic dysfunction. Further studies are necessary to assess the usefulness of the test in clinical practice and its role as a prognostic marker.

Lower rather than higher levels of B-type natriuretic peptides (NT-pro-BNP and BNP) predict short-term mortality in end-stage heart failure patients treated with nesiritide

Elevated plasma natriuretic peptides in heart failure (HF) usually indicate a poor outcome and low levels a compensated state. In advanced chronic HF, however, low levels may reflect an impaired neurohormonal response. To assess this hypothesis, this study analyzed whether N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) and B-type natriuretic peptide (BNP) levels were related to mortality in 40 patients treated for decompensated chronic HF. Cardiovascular mortality during follow-up (10 +/- 1 months) was 40%. BNP levels were lower in patients who died (487 +/- 60 vs 836 +/- 99 pg/ml, p <0.02), as were NT-pro-BNP levels (9,507 +/- 1,178 vs 17,611 +/- 4,338 pg/ml, p <0.05). These data support the hypothesis that patients with end-stage HF and poor short-term survival have lower natriuretic peptide levels than those who survive. These findings suggest that the natriuretic peptide system can no longer contribute adequately to neurohormonal compensation and that paradoxically low peptide levels are an adverse prognostic marker in advanced HF.

Preoperative plasma N-terminal pro-brain natriuretic peptide as a marker of cardiac risk in patients undergoing elective non-cardiac surgery

Background

Plasma N-terminal pro-brain natriuretic peptide (NTproBNP) is a sensitive marker for heart failure. This study tested whether the preoperative plasma level of NTproBNP could predict cardiac complications in patients undergoing non-cardiac surgery.

Methods

A total of 190 consecutive patients who underwent elective non-cardiac surgery that required general anaesthesia were studied. In addition to routine preoperative evaluation, a blood sample was taken for estimation of plasma NTproBNP concentration. Postoperative cardiac complications were defined as cardiac death, acute coronary syndrome, heart failure and haemodynamic compromise from cardiac arrhythmias.

Results

Fifteen of the 190 patients had a cardiac complication: four had acute coronary syndrome and 13 had congestive heart failure. NTproBNP concentration was significantly higher in patients with a cardiac complication; a level greater than 450 ng/l was predictive of cardiac complications with a sensitivity of 100 per cent and a specificity of 82·9 per cent. Other factors associated with cardiac complications were a higher American Society of Anesthesiologists grade, age and clinical cardiac impairment, but in a multivariate analysis NTproBNP level was the only independent factor.

Conclusion

Preoperative plasma NTproBNP concentration may be an independent predictor of cardiac complications in patients undergoing non-cardiac surgery.

Elecsys NT-ProBNP and BNP Assays: Are There Analytically and Clinically Relevant Differences?

BACKGROUND

B-type natriuretic peptide (BNP; 77-108 amino acids) and its N-terminal (1-76 amino acids) counterpart, NT-proBNP, are cardiac biomarkers that have been established for the assessment of left ventricular dysfunction and congestive heart failure and provide prognostic and risk stratification information for patients with acute coronary syndrome. Various automated immunoassays currently are available for the measurement of these natriuretic peptides, but there are significant analytical differences, especially between BNP and NT-proBNP.

METHODS AND RESULTS

Recently published methods and results were reviewed.

CONCLUSION

Although there are significant pre-analytical and analytical differences between the Triage BNP and Elecsys NT-proBNP and other BNP methods, they do not translate to clinically significant differences in their diagnostic and prognostic application in the assessment of systolic heart failure and risk stratification of patients with acute coronary syndrome. However, there appears to be some evidence that suggests that NT-proBNP may have an advantage in the detection of patients with mild or asymptomatic heart disease.

Tissue Doppler velocities of mitral annulus and NT-proBNP in patients with heart failure

BACKGROUND

It has been shown that pulsed wave tissue Doppler velocities of mitral annulus correlate well with left ventricular (LV) diastolic and systolic functions. It is not yet clear whether these velocities can be used to estimate left ventricular dysfunction in an unselected population of patients with clinical signs and symptoms of heart failure (HF).

AIM

To determine whether LV mitral annulus velocities measured by tissue Doppler imaging (TDI) correlate with plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with HF.

METHODS AND RESULTS

Early diastolic (E(m)) and systolic (S(m)) TDI velocities of septal and lateral mitral annulus were measured in 50 patients with HF together with other conventional echocardiographic parameters, and compared with plasma NT-proBNP levels. Significant correlations were found between NT-proBNP level and E(m) velocity (r=-0.79), S(m) velocity (r=-0.43), early transmitral to E(m) velocity ratio (r=0.38), LV end diastolic diameter (r=0.29), LV ejection fraction (r=-0.44) and tricuspid regurgitant velocity (r=0.31). In multiple regression model (R(2)=0.733), the E(m) velocity was the most important predictor of NT-proBNP level.

CONCLUSIONS

Early diastolic mitral annulus velocity measured by TDI correlates strongly with plasma NT-proBNP levels, and provides a simple, accurate and reproducible echocardiographic index of heart failure.

Association between C-reactive protein levels and N-terminal pro-B-type natriuretic peptide in pre-dialysis patients

BACKGROUND

The prevalence of inflammation is high among patients with chronic renal failure but the reason of inflammation is unclear. We test the hypothesis that inflammation in chronic renal failure could be the consequence of an increased left-ventricular wall tension related to ventricular dysfunction, hypervolemia or both.

METHODS

For assessing left-ventricular filling pressure, plasma level of N-terminal pro-B-type natriuretic peptide (N-BNP) was used, as B-type natriuretic peptide is secreted from the cardiac ventricles in response to increased wall tension. N-BNP levels and C-reactive protein (CRP) were measured on the same day in 75 pre-dialysis patients. A previous history of cardiomiopathy with systolic dysfunction was present in 27 (36%) of them.

RESULTS

The levels of N-BNP were not normally distributed (mean: 2,589 +/- 4,514 pg/ml; median: 789 pg/ml). The distribution of CRP levels was also not normal (mean: 15 +/- 27 mg/l; median: 5 mg/l). Both parameters correlated significantly (r: 0.41; p < 0.005). N-BNP was higher (p < 0.001) in patients with known ventricular dysfunction. Excluding these patients, the correlation between N-BNP and CRP was stronger (r: 0.88; p < 0.001). Univariate analysis in these patients without known cardiomyopathy showed that N-BNP levels also correlated with systolic and diastolic blood pressure (r: 0.54; p < 0.005) and inversely with creatinine clearance (r: -0.43; p < 0.01), serum albumin (r: 0.6; p < 0.001) and hemoglobin levels (r: 0.37; p < 0.05). CRP levels correlated significantly (p < 0.01) with the same parameters as N-BNP in univariate analysis. However, in multiple stepwise regression analysis in which CRP was the dependent variable, only the association with N-BNP remained significant (r: 0.87; p < 0.001).

CONCLUSIONS

Our results suggest a link between left-ventricular filling pressure and inflammation in patients with advanced renal insufficiency. The importance of strict volume control in these patients, in order to reduce left-ventricular pressure and therefore inflammation, should be considered.

Biomarker Responses during and after Treatment with Nesiritide Infusion in Patients with Decompensated Chronic Heart Failure

Background: Objective methods to assess the adequacy of medication therapy for patients with advanced heart failure are lacking. Serial measurements of biomarkers might be beneficial. Therapy guided by N-terminal pro-B-type natriuretic peptide (NT-proBNP) might be helpful because NT-proBNP should be lowered by therapies that decrease endogenous BNP secretion.

Methods: NT-proBNP and BNP were measured in a nonconsecutive patient cohort receiving clinically indicated intravenous nesiritide. Blood samples were drawn before, at 6 and 24 h during, and at 6 h after infusion. A reduction in NT-proBNP was defined as a decrease from baseline during infusion (“infusion responders”) of &gt;3 SD of the variability of the assay measurement (∼20%). Patients with decreases &gt;20% in both NT-pro BNP and BNP at 6 h post infusion were designated “biochemical responders”.

Results: Forty patients [27 males; mean (SE) age, 68 (2) years; mean (SE) left ventricular ejection fraction, 25 (1.4)%] were studied. All patients improved clinically. Overall, the changes in NT-proBNP were a 18 (4.6)% [mean (SE)] and 19.8% (median) decrease from baseline at 24 h of infusion and a 22 (6.0)% and 17.8% decrease at 6 h post infusion (P &lt;0.001 compared with baseline). In a large number of patients, decreases in NT-proBNP were, however, within the variability of the assay. Subgroup analysis showed that 22 of 40 patients were infusion responders with a &gt;20% decrease from baseline in NT-proBNP during nesiritide infusion, whereas only 12 patients were biochemical responders with &gt;20% decreases from baseline postinfusion for both NT-proBNP and BNP.

Conclusions: In this study, many patients had decreased NT-proBNP and BNP values after therapy with nesiritide, but the majority of patients did not demonstrate biochemically significant decreases in analytes despite a clinical response. Until we know more about the responses of natriuretic peptides to therapies such as nesiritide, a strategy of monitoring NT-proBNP and BNP to guide therapy cannot be universally advocated.

Analytical correlation between plasma N-terminal pro-brain natriuretic peptide and brain natriuretic peptide in patients presenting with dyspnea

OBJECTIVES

We examined the analytical correlation N-terminal pro-brain natriuretic peptide (NT-proBNP) and brain natriuretic peptide (BNP).

DESIGN AND METHODS

Electrochemiluminescence and fluorescence immunoassays were used to measure NT-proBNP and BNP levels, respectively.

RESULTS

The analytical correlation was satisfactory using the equation: NT-proBNP = 8.56 x BNP + 91.7 and a correlation r = 0.85. The correlation was not influenced by age, gender and BMI of patients.

CONCLUSIONS

We conclude that NT-proBNP correlates with BNP.

Prognostic value of cardiac troponin T in patients with both acute and chronic stable congestive heart failure: comparison with atrial natriuretic peptide, brain natriuretic peptide and plasma norepinephrine

BACKGROUND

The prognostic value of cardiac troponin T (cTn-T) in a mixture of patients with both acute and chronic congestive heart failure (CHF), simultaneously assessed and compared with neurohormonal factors, has not yet been thoroughly evaluated. Thus, we focused on the prognostic value of cTn-T in comparison with atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and plasma norepinephrine (PNE) in this population.

METHODS

Prognostic correlates of elevation of cTn-T, ANP, BNP, PNE were analyzed in 63 acute and chronic CHF patients followed up to record worsening CHF and cardiac death.

RESULTS

cTn-T (> or =0.03 microg/L) was found in 17.4% (11 of 63) of patients. cTn-T correlated with ANP, BNP, PNE. Acute CHF patients were more positive for cTn-T and BNP. In our cohort, neither cTn-T (> or =0.03 microg/L) nor PNE were associated with increased mortality and worsening HF in CHF patients. After adjustment, BNP was the only independent predictor of cardiac events (RR, 3.23; p=0.01).

CONCLUSIONS

BNP emerged as the only independent predictor of cardiac events in a mixture of patients with both acute and chronic CHF, suggesting that it is the analyte that best reflects long-term prognosis in a diverse population enrolled to mirror the "real world" situation.

Plasma N-terminal pro-brain natriuretic peptide and brain natriuretic peptide in assessment of acute dyspnea

We examined the analytical correlation between non-radioimmunometric plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) and B-type natriuretic peptide (BNP) and evaluated whether NT-proBNP or BNP was superior in the emergency diagnosis of heart failure and whether this was influenced by age, gender, body mass index (BMI) and renal function. Data were collected prospectively from patients admitted to the emergency department for acute dyspnea. Plasma BNP (Triage, Biosite) and NT-proBNP (Elecsys, Roche diagnostic(R)) were measured at admission in addition to other standard biological parameters and clinical variables. Reference diagnosis was adjudicated by two independent cardiologists using the European society of cardiology guidelines. We evaluated the influence of creatinine clearance, age, gender and BMI on plasma BNP and NT-proBNP levels. One hundred and sixty consecutive patients were included: 84 females and 76 males, mean age 80.1 + 13.5 (16-98). The analytical correlation between the automated electro-chemiluminescence immunoassay for NT-proBNP and the single use fluorescence immunoassay for BNP was satisfactory using the equation: NT-proBNP = 1.1 BNP + 0.57 and a correlation r = 0.93. This was established over a wide range of concentration (5-6400 pg/ml for BNP). Areas under receiver operating characteristic (ROC) curve for BNP and NT-proBNP as a diagnostic marker for heart failure were 0.82 and 0.84, respectively and a BNP level of 150 pg/ml has similar sensitivity and specificity that NT-proBNP level of 1000 pg/ml. The correlation was not influenced by age, gender and BMI of patients. Renal dysfunction did not affect significantly this correlation (r = 0.93). We conclude that NT-proBNP, as assayed in the present study, correlates closely with BNP. This correlation is only slightly modulated by creatinine clearance values. The NT-proBNP appears as accurate as BNP according to area under ROC curve. Used in conjunction with other clinical information, rapid measurement of BNP or NT-proBNP is useful in establishing or excluding the diagnosis of congestive heart failure in patients with acute dyspnea.

Influence of age on natriuretic peptides in patients with chronic heart failure: a comparison between ANP/NT-ANP and BNP/NT-proBNP

BACKGROUND

Natriuretic peptides are currently used in the diagnosis and follow-up of patients with Chronic Heart Failure (CHF). However, it is unknown whether there are different influences of age on atrial natriuretic peptide (ANP)/N-terminal-ANP (NT-ANP) or B-type natriuretic peptide (BNP)/N-terminal-proBNP (NT-proBNP).

AIMS

To compare the influence of age and gender on plasma levels of ANP/NT-ANP and BNP/NT-proBNP in CHF patients.

METHODS AND RESULTS

Natriuretic peptides were measured in 311 CHF patients (68+/-8 years, 76% males, left ventricular ejection fraction (LVEF) 0.23+/-0.08). All natriuretic peptides were significantly related to age (p<0.05) on multivariate regression analysis, with partial correlation coefficients of 0.18, 0.29, 0.28 and 0.25 for ANP, NT-ANP, BNP and NT-proBNP, respectively. The relative increase of both BNP/NT-proBNP were more pronounced than of ANP/NT-ANP (p<0.01). Furthermore, the relative increase of BNP with age was markedly larger than of NT-proBNP (p<0.01). Levels of all natriuretic peptides were also significantly related to cardiothoracic ratio, renal function and LVEF.

CONCLUSION

In patients with CHF, BNP/NT-proBNP were more related to age than ANP/NT-ANP, and BNP was more related to age than NT-proBNP. However, in these CHF patients the influence of age on the levels of all natriuretic peptides was modest, and comparable to several other factors.

Serum cardiac troponins and N-terminal pro-brain natriuretic peptide: a staging system for primary systemic amyloidosis

PURPOSE

Primary systemic amyloidosis (AL) is a multisystemic disorder resulting from an underlying plasma cell dyscrasia. There is no formal staging system for AL, making comparisons between studies and treatment centers difficult. Our group previously identified elevated serum cardiac troponin T (cTnT) as the most powerful predictor of overall survival. Others have reported that N-terminal pro-brain natriuretic peptide (NT-proBNP) is a valuable prognostic marker. We sought to develop a staging system for patients with AL.

PATIENTS AND METHODS

Two hundred forty-two patients with newly diagnosed AL who were seen at the Mayo Clinic between April 1979 and November 2000, and who had echocardiograms and stored serum samples at presentation were eligible for this retrospective review. NT-proBNP measurements were performed on 242 patients in whom cTnT and cardiac troponin I (cTnI) had been previously run. Two prognostic models were designed using threshold values of NT-proBNP and either cTnT or cTnI (NT-proBNP < 332 ng/L, cTnT < 0.035 microg/L, and cTnI < 0.1 microg/L). Depending on whether NT-proBNP and troponin levels were both low, were high for only one level, or were both high, patients were classified as stage I, II, or III, respectively.

RESULTS

Using the cTnT+NT-proBNP model 33%, 30%, and 37% of patients were stages I, II, and III, respectively, with median survivals of 26.4, 10.5, and 3.5 months, respectively. The alternate cTnI+NT-proBNP model predicted median survivals of 27.2, 11.1, and 4.1 months, respectively.

CONCLUSION

Stratification of AL patients into three stages is possible with two readily available and reproducible tests setting the stage for more consistent and reliable cross comparisons of therapeutic outcomes.

Biochemical indicators of cardiac and renal function in a healthy elderly population

OBJECTIVES

To examine the distributions of NT-proBNP and cystatin C and their relation to age, gender, and other physiological factors in an apparently healthy elderly population.

METHOD

NT-proBNP and cystatin C were analyzed in 407 and 408 healthy individuals, median age: 65 (range 40-76).

RESULTS

Increasing age, female gender and CRP were independently associated to higher NT-proBNP levels. Age, body mass index, and CRP level were independently associated to the cystatin C level. In women and men, < or =65 years, the 97.5th percentile value for NT-proBNP was 268 ng/l and 184 ng/l, in those older, 391 ng/l and 269 ng/l. For those < or =65 years the 97.5th percentile value for cystatin C was 1.12 mg/l, and for those older 1.21 mg/l.

CONCLUSION

In a healthy elderly population, NT-proBNP is influenced by age and gender, whereas cystatin C is influenced by age but not by gender. Both markers seem to be associated to the CRP level.

Multicenter evaluation of the Roche NT-proBNP assay and comparison to the Biosite Triage BNP assay

BACKGROUND

Brain natriuretic peptides (BNPs) are useful in the assessment of heart failure, left ventricular dysfunction, and acute coronary syndromes.

METHODS

We performed a multicenter evaluation of the automated Roche NT-proBNP assay and compared its performance to the Biosite Triage BNP assay.

RESULTS

The N-terminal (1-76) pro brain natriuretic peptide (NT-proBNP) method is precise (CV<or=6.1%), has a wide dynamic measuring range (30-35000 ng/l), is free from common interferences, and does not cross-react with BNP. EDTA or heparinized plasma samples collected in glass or plastic tubes can be used, and samples are stable at room temperature or 4 degrees C for up to 3 days. In contrast, the Biosite BNP assay has >2-fold higher CV, and plasma samples are more labile when stored at room temperature and 4 degrees C. Comparison studies showed a reasonable correlation between NT-proBNP and BNP assays, with a substantially higher slope bias of 6-20 for the NT-proBNP assay.

CONCLUSIONS

The automated Roche NT-proBNP assay has good analytical performance and better precision than the Biosite BNP assay. Unlike BNP, NT-proBNP is stable in EDTA plasma for 3 days at room temperature or longer at 4 degrees C. The Roche NT-proBNP is fully automated and will accommodate the testing of large numbers of clinical samples for assessing cardiac dysfunction.

NT-proBNP in severe chronic heart failure: rationale, design and preliminary results of the COPERNICUS NT-proBNP substudy

BACKGROUND

Neither profiles nor prognostic value of cardiac N-terminal proBNP (NT-proBNP) have been prospectively evaluated in a sufficient number of patients with severe chronic heart failure (CHF) treated with carvedilol or placebo.

METHODS

Baseline and follow-up plasma concentrations of NT-proBNP were measured in the European part of the COPERNICUS Trial. This study enrolled patients with an ejection fraction <25% and symptoms of CHF at rest or on minimal exertion, equally randomized to placebo or carvedilol.

RESULTS

NT-proBNP concentrations were increased at baseline (mean+/-S.D.=579+/-822 pmol/l, median=322.5 pmol/l) with a marked decrease during follow-up in the carvedilol, but not in the placebo group. One-year mortality rates were 3.9, 12 and 27.9% in the lower, middle and upper tertiles of NT-proBNP, respectively. When mortality was calculated separately in the placebo and carvedilol group, rates were 0.8, 6.3 and 19.1% in the carvedilol treated but 6.7, 17.9 and 36.9% in the placebo treated patients.

CONCLUSIONS

NT-proBNP was a powerful predictor of subsequent all-cause mortality in patients with severe CHF. This marker should therefore be further evaluated for risk stratification and monitoring of therapy in CHF.

N-terminal probrain natriuretic peptide (NT-proBNP) in the emergency diagnosis and in-hospital monitoring of patients with dyspnoea and ventricular dysfunction

OBJECTIVE

To evaluate the utility of NT-proBNP in the emergency diagnosis and in-hospital monitoring of patients with acute dyspnoea and ventricular dysfunction.

BACKGROUND

Misdiagnosis of heart failure (HF) is common in the urgent care setting using clinical diagnostic tests. Reports show that BNP is useful to diagnose HF in patients with acute dyspnoea.

METHODS

Prospective study of 100 patients attending the Emergency Department (ED) for acute dyspnoea. Final diagnosis was determined on the basis of ED data sheets, echocardiography and pulmonary function tests. NT-proBNP levels were obtained on admission, at 24 h and at day 7.

RESULTS

Patients with ventricular dysfunction were sub-classified into decompensated HF and masked HF, defined as HF with concomitant signs of pulmonary disease. Decompensated and masked HF patients had significantly higher NT-proBNP values than patients with non-cardiac dyspnoea (normal ventricular function) (920+/-140 and 978+/-363 vs. 50+/-15 pmol/L; P<0.001 and P<0.01, respectively). The mean area under the ROC curve for NT-proBNP was 0.957 (95% CI, 0.918 to 0.996, P<0.001). In multiple logistic-regression analysis NT-proBNP>115 pmol/l was the strongest independent predictor of ventricular dysfunction (odds ratio 45.4; 95% CI: 4.5-452.3). At day 7, a significant and similar reduction in NT-proBNP was observed in the two groups of patients with ventricular dysfunction (P<0.001 vs. admission values), but complete clinical resolution was less frequent in masked HF patients (P<0.05 vs. decompensated HF).

CONCLUSIONS

NT-proBNP is a new candidate marker for the detection and exclusion of ventricular dysfunction in patients attending the ED for acute dyspnoea. NT-proBNP may also serve to monitor outcome during hospitalization.

N-terminal pro-B-type natriuretic peptide: reference plasma levels from birth to adolescence. Elevated levels at birth and in infants and children with heart diseases

AIM

Determination of plasma levels of N-terminal pro-B-type natriuretic peptide (N-BNP) in infants and children with and without heart diseases.

METHODS

Plasma N-BNP was measured in 78 infants and children without heart disease and in 55 infants and children with heart disease causing volume and pressure overload. Heart diseases included chronic dilated cardiomyopathy, acute left ventricular dysfunction, and congenital cardiac anomalies resulting in left and right ventricular volume or pressure overload. The Mann-Whitney rank-sum test and the ANOVA for ranks test were used to compare two or more groups, respectively.

RESULTS

N-BNP levels were elevated in the first days of life but were not significantly different in children from 4 mo to 15 y old. The upper limit in children older than 4 mo with no heart disease was 349 pg/ml. In patients with heart disease, N-BNP levels were significantly higher than in control children (p < 0.0001).

CONCLUSION

N-BNP levels are elevated in the first days of life and are stable from age 4 mo to adolescence. Elevated N-BNP levels reflect cardiac dysfunction in infants and children.

Head-to-head comparison of the diagnostic utility of BNP and NT-proBNP in symptomatic and asymptomatic structural heart disease

BACKGROUND

B-type natriuretic peptide (BNP) and the amino-terminal fragment of the BNP prohormone (NT-proBNP) are markers for functional cardiac impairment and are elevated in heart failure (HF). Aim of the present study was to perform a head-to-head comparison of the diagnostic utility of BNP and NT-proBNP in symptomatic and asymptomatic structural heart disease.

METHODS

We prospectively classified 180 consecutive subjects according to ACC/AHA guidelines. Blood concentrations of BNP and NT-proBNP were determined by two fully automated chemiluminescent assays (Bayer and Roche method). Diagnostic utilities were tested by ROC analyses and logistic regression.

RESULTS

ROC curves of BNP and NT-proBNP in patients with symptomatic HF (n=43) and asymptomatic subjects (n=137) did not differ significantly (AUC 0.930 vs. 0.918, p=0.650), but comparison of patients with asymptomatic structural heart disease (n=56) and subjects without structural disorder of the heart (n=81) revealed different AUCs for the respective assays (0.735 vs. 0.839, p=0.009). In the population studied, age, sex and renal function had no impact on the diagnostic performance of both tests when compared by logistic regression models.

CONCLUSIONS

Both assays facilitate diagnosis of symptomatic and asymptomatic structural heart disease. BNP and NT-proBNP may be equally useful as an aid in the differential diagnosis of probable signs or symptoms of HF. In contrast, NT-proBNP might be a more discerning marker of early cardiac dysfunction than BNP.

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

Multicenter analytical performance evaluation of the Elecsys® proBNP assay

The purpose of this multicenter study was to evaluate the technical performance of the automated Elecsys proBNP (brain natriuretic peptide) assay, which is indicated as an aid in the diagnosis of individuals suspected of having congestive heart failure. The Elecsys proBNP assay is an electrochemiluminescent immunoassay employing two polyclonal NT-proBNP-specific antibodies in a sandwich test format. The study was performed on the three Elecsys analyzers (E 1010, E 2010, and E 170) at eight different sites world-wide. Within- and total precision were ≤3%, with total precision slightly higher on the Elecsys E 170 instrument with multiple modules. Reproducibility among sites and platforms was <5%. Precision at particularly low NT-proBNP concentrations was assessed down to approximately 25 pg/ml with CVs of 12.6% at 29.2 pg/ml and 9.6% at 38.5 pg/ml for the Elecsys 1010/2010 and E 170, respectively. Linearity was evaluated up to 25,000 pg/ml with a sample-based non-linear response observed with recoveries of <90% for proBNP concentrations <10 000 pg/ml. Slopes ranged between 0.92 and 1.02 and intercepts from –5.3 to 10.4 pg/ml (r≥0.998) among the three types of analyzers. Slopes were 4.95 and 4.53 in comparison to the Biosite Triage and Shionogi BNP assays. There was no assay interference, and no effect of barrier gels, tube composition, or freeze-thaw. NT-proBNP concentrations in EDTA plasma were up to 10% lower than in serum or heparinized plasma and the analyte was stable at 4°C for up to 72 hours (the maximum time tested). There was no circadian rhythm in normal subjects or congestive heart failure patients and there was no effect of drawing position. In summary, the Elecsys proBNP assay exhibits good technical performance and is suitable for use in routine clinical laboratories to aid in the diagnosis of congestive heart failure.