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

Blood Pressure Drops During Hospitalization for Acute Heart Failure Treated With Serelaxin: A Patient-Level Analysis of 4 Randomized Controlled Trials

BACKGROUND

Hypotensive events and drops in systolic blood pressure (SBP-drop) are frequent in patients hospitalized with acute heart failure. We investigated whether SBP-drops are associated with outcomes in patients treated with serelaxin.

METHODS

Patient-level retrospective analyses of 4 prospective trials investigating serelaxin in acute heart failure. Main inclusion criteria were SBP 125 to 180 mm Hg, pulmonary congestion, and elevated NT-proBNP (N-terminal pro-B-type natriuretic peptide). SBP-drops were prospectively defined as SBP<100 mm Hg, or, if SBP remained >100 mm Hg, a drop from baseline of 40 mm Hg from baseline. Outcomes were a short-term composite outcome (worsening heart failure, hospital readmission for heart failure or all-cause mortality through 14 days) and 180-day mortality.

RESULTS

Overall, 2559/11 226 (23%) patients had an SBP-drop. SBP-drop, versus no SBP-drop, was associated with a worse outcome: cumulative incidence of 180-day mortality (11% versus 9%, hazard ratio [HR]. 1.21 [95% CI, 1.05-1.39]; P=0.009) and the short-term outcome (11% versus 9%, HR, 1.29 [95% CI, 1.13-1.49]; P<0.001). Of the 2 SBP-drop components, an SBP<100 mm Hg was associated with the worst outcome compared with a 40 mm Hg drop: short-term outcome (11% versus 10%) and HRs of 1.32 (95% CI, 1.13-1.55; P=0.0005) and 1.22 (95% CI, 0.97-1.56; P=0.09), for each component respectively, with a P value for interaction of 0.05. SBP-drops were associated with a worse short-term outcome in the placebo group (HR, 1.46 [95% CI, 1.19-1.79]; P=0.0003), but not in the serelaxin-group (HR, 1.18 [95% CI, 0.97-1.42]; P=0.10); P interaction=0.003.

CONCLUSIONS

SBP-drops in patients with acute heart failure and normal to high SBP at admission is associated with worse short- and long-term outcomes especially for SBP <100 mm Hg. However, in patients treated with the intravenous vasodilator serelaxin, SBP-drops seemed less harmful.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02064868, NCT02007720, NCT01870778, NCT00520806.

Quantifying how diagnostic test accuracy depends on threshold in a meta-analysis

Tests for disease often produce a continuous measure, such as the concentration of some biomarker in a blood sample. In clinical practice, a threshold C is selected such that results, say, greater than C are declared positive and those less than C negative. Measures of test accuracy such as sensitivity and specificity depend crucially on C, and the optimal value of this threshold is usually a key question for clinical practice. Standard methods for meta‐analysis of test accuracy (i) do not provide summary estimates of accuracy at each threshold, precluding selection of the optimal threshold, and furthermore, (ii) do not make use of all available data. We describe a multinomial meta‐analysis model that can take any number of pairs of sensitivity and specificity from each study and explicitly quantifies how accuracy depends on C. Our model assumes that some prespecified or Box‐Cox transformation of test results in the diseased and disease‐free populations has a logistic distribution. The Box‐Cox transformation parameter can be estimated from the data, allowing for a flexible range of underlying distributions. We parameterise in terms of the means and scale parameters of the two logistic distributions. In addition to credible intervals for the pooled sensitivity and specificity across all thresholds, we produce prediction intervals, allowing for between‐study heterogeneity in all parameters. We demonstrate the model using two case study meta‐analyses, examining the accuracy of tests for acute heart failure and preeclampsia. We show how the model can be extended to explore reasons for heterogeneity using study‐level covariates.

Role of Biomarkers for the Prevention, Assessment, and Management of Heart Failure: A Scientific Statement From the American Heart Association

BACKGROUND AND PURPOSE

Natriuretic peptides have led the way as a diagnostic and prognostic tool for the diagnosis and management of heart failure (HF). More recent evidence suggests that natriuretic peptides along with the next generation of biomarkers may provide added value to medical management, which could potentially lower risk of mortality and readmissions. The purpose of this scientific statement is to summarize the existing literature and to provide guidance for the utility of currently available biomarkers.

METHODS

The writing group used systematic literature reviews, published translational and clinical studies, clinical practice guidelines, and expert opinion/statements to summarize existing evidence and to identify areas of inadequacy requiring future research. The panel reviewed the most relevant adult medical literature excluding routine laboratory tests using MEDLINE, EMBASE, and Web of Science through December 2016. The document is organized and classified according to the American Heart Association to provide specific suggestions, considerations, or contemporary clinical practice recommendations.

RESULTS

A number of biomarkers associated with HF are well recognized, and measuring their concentrations in circulation can be a convenient and noninvasive approach to provide important information about disease severity and helps in the detection, diagnosis, prognosis, and management of HF. These include natriuretic peptides, soluble suppressor of tumorgenicity 2, highly sensitive troponin, galectin-3, midregional proadrenomedullin, cystatin-C, interleukin-6, procalcitonin, and others. There is a need to further evaluate existing and novel markers for guiding therapy and to summarize their data in a standardized format to improve communication among researchers and practitioners.

CONCLUSIONS

HF is a complex syndrome involving diverse pathways and pathological processes that can manifest in circulation as biomarkers. A number of such biomarkers are now clinically available, and monitoring their concentrations in blood not only can provide the clinician information about the diagnosis and severity of HF but also can improve prognostication and treatment strategies.

N-terminal pro b-type natriuretic peptide (NT-pro-BNP) -based score can predict in-hospital mortality in patients with heart failure

Serum N-terminal pro b-type natriuretic peptide (NT-pro-BNP) testing is recommended in the patients with heart failure (HF). We hypothesized that NT-pro-BNP, in combination with other clinical factors in terms of a novel NT-pro BNP-based score, may provide even better predictive power for in-hospital mortality among patients with HF. A retrospective study enrolled adult patients with hospitalization-requiring HF who fulfilled the predefined criteria during the period from January 2011 to December 2013. We proposed a novel scoring system consisting of several independent predictors including NT-pro-BNP for predicting in-hospital mortality, and then compared the prognosis-predictive power of the novel NT-pro BNP-based score with other prognosis-predictive scores. A total of 269 patients were enrolled in the current study. Factors such as "serum NT-pro-BNP level above 8100 mg/dl," "age above 79 years," "without taking angiotensin converting enzyme inhibitors/angiotensin receptor blocker," "without taking beta-blocker," "without taking loop diuretics," "with mechanical ventilator support," "with non-invasive ventilator support," "with vasopressors use," and "experience of cardio-pulmonary resuscitation" were found as independent predictors. A novel NT-pro BNP-based score composed of these risk factors was proposed with excellent predictability for in-hospital mortality. The proposed novel NT-pro BNP-based score was extremely effective in predicting in-hospital mortality in HF patients.

Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis

BACKGROUND

Acute heart failure (AHF) is one of the most common diagnoses assigned to emergency department (ED) patients who are hospitalized. Despite its high prevalence in the emergency setting, the diagnosis of AHF in ED patients with undifferentiated dyspnea can be challenging.

OBJECTIVES

The primary objective of this study was to perform a systematic review and meta-analysis of the operating characteristics of diagnostic elements available to the emergency physician for diagnosing AHF. Secondary objectives were to develop a test-treatment threshold model and to calculate interval likelihood ratios (LRs) for natriuretic peptides (NPs) by pooling patient-level results.

METHODS

PubMed, EMBASE, and selected bibliographies were searched from January 1965 to March 2015 using MeSH terms to address the ability of the following index tests to predict AHF as a cause of dyspnea in adult patients in the ED: history and physical examination, electrocardiogram, chest radiograph (CXR), B-type natriuretic peptide (BNP), N-terminal proB-type natriuretic peptide (NT-proBNP), lung ultrasound (US), bedside echocardiography, and bioimpedance. A diagnosis of AHF based on clinical data combined with objective test results served as the criterion standard diagnosis. Data were analyzed using Meta-DiSc software. Authors of all NP studies were contacted to obtain patient-level data. The Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) for systematic reviews was utilized to evaluate the quality and applicability of the studies included.

RESULTS

Based on the included studies, the prevalence of AHF ranged from 29% to 79%. Index tests with pooled positive LRs ≥ 4 were the auscultation of S3 on physical examination (4.0, 95% confidence interval [CI] = 2.7 to 5.9), pulmonary edema on both CXR (4.8, 95% CI = 3.6 to 6.4) and lung US (7.4, 95% CI = 4.2 to 12.8), and reduced ejection fraction observed on bedside echocardiogram (4.1, 95% CI = 2.4 to 7.2). Tests with low negative LRs were BNP < 100 pg/mL (0.11, 95% CI = 0.07 to 0.16), NT-proBNP < 300 pg/mL (0.09, 95% CI = 0.03 to 0.34), and B-line pattern on lung US LR (0.16, 95% CI = 0.05 to 0.51). Interval LRs of BNP concentrations at the low end of "positive" results as defined by a cutoff of 100 pg/mL were substantially lower (100 to 200 pg/mL; 0.29, 95% CI = 0.23 to 0.38) than those associated with higher BNP concentrations (1000 to 1500 pg/mL; 7.12, 95% CI = 4.53 to 11.18). The interval LR of NT-proBNP concentrations even at very high values (30,000 to 200,000 pg/mL) was 3.30 (95% CI = 2.05 to 5.31).

CONCLUSIONS

Bedside lung US and echocardiography appear to the most useful tests for affirming the presence of AHF while NPs are valuable in excluding the diagnosis.

The diagnostic accuracy of the natriuretic peptides in heart failure: systematic review and diagnostic meta-analysis in the acute care setting

OBJECTIVES

To determine and compare the diagnostic accuracy of serum natriuretic peptide levels (B type natriuretic peptide, N terminal probrain natriuretic peptide (NTproBNP), and mid-regional proatrial natriuretic peptide (MRproANP)) in people presenting with acute heart failure to acute care settings using thresholds recommended in the 2012 European Society of Cardiology guidelines for heart failure.

DESIGN

Systematic review and diagnostic meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane central register of controlled trials, Cochrane database of systematic reviews, database of abstracts of reviews of effects, NHS economic evaluation database, and Health Technology Assessment up to 28 January 2014, using combinations of subject headings and terms relating to heart failure and natriuretic peptides.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Eligible studies evaluated one or more natriuretic peptides (B type natriuretic peptide, NTproBNP, or MRproANP) in the diagnosis of acute heart failure against an acceptable reference standard in consecutive or randomly selected adults in an acute care setting. Studies were excluded if they did not present sufficient data to extract or calculate true positives, false positives, false negatives, and true negatives, or report age independent natriuretic peptide thresholds. Studies not available in English were also excluded.

RESULTS

37 unique study cohorts described in 42 study reports were included, with a total of 48 test evaluations reporting 15 263 test results. At the lower recommended thresholds of 100 ng/L for B type natriuretic peptide and 300 ng/L for NTproBNP, the natriuretic peptides have sensitivities of 0.95 (95% confidence interval 0.93 to 0.96) and 0.99 (0.97 to 1.00) and negative predictive values of 0.94 (0.90 to 0.96) and 0.98 (0.89 to 1.0), respectively, for a diagnosis of acute heart failure. At the lower recommended threshold of 120 pmol/L, MRproANP has a sensitivity ranging from 0.95 (range 0.90-0.98) to 0.97 (0.95-0.98) and a negative predictive value ranging from 0.90 (0.80-0.96) to 0.97 (0.96-0.98). At higher thresholds the sensitivity declined progressively and specificity remained variable across the range of values. There was no statistically significant difference in diagnostic accuracy between plasma B type natriuretic peptide and NTproBNP.

CONCLUSIONS

At the rule-out thresholds recommended in the 2012 European Society of Cardiology guidelines for heart failure, plasma B type natriuretic peptide, NTproBNP, and MRproANP have excellent ability to exclude acute heart failure. Specificity is variable, and so imaging to confirm a diagnosis of heart failure is required. There is no statistical difference between the diagnostic accuracy of plasma B type natriuretic peptide and NTproBNP. Introduction of natriuretic peptide measurement in the investigation of patients with suspected acute heart failure has the potential to allow rapid and accurate exclusion of the diagnosis.

Equal performance of novel N-terminal proBNP (Cardiac proBNP®) and established BNP (Triage BNP®) point-of-care tests

Background: Recently, a novel point-of-care test (POCT) for N-terminal proBNP (NTproBNP) has been introduced (Cardiac proBNP®, Roche). Aim: The aim was to compare the novel POCT for NTproBNP with the established POCT for BNP. Methods: NTproBNP and BNP were assessed in 222 individuals with chronic heart failure (n = 151) or controls (n = 71) with both POCTs. Results: NTproBNP and BNP were closely correlated upon regression analysis (r = 0.93; p < 0.01). NTproBNP and BNP were both correlated with ejection fraction and New York Heart Association stage. Receiver operating characteristic analysis yielded satisfying and equivalent predictive values for the detection of left ventricular dysfunction (ejection fraction <40%; NTproBNP: area under the curve 0.97; BNP: area under the curve 0.96; p > 0.05) and presence of New York Heart Association stage >2 (area under the curve 0.92 vs 0.91 for NT-proBNP and BNP, respectively; p > 0.05). Conclusion: The NTproBNP POCT allows biochemical detection of heart failure with satisfactory predictive values, is equivalent to the BNP POCT and will improve near-patient testing.

The diagnostic value of physical examination and additional testing in primary care patients with suspected heart failure

BACKGROUND

Early diagnosis of nonacute heart failure is crucial because prompt initiation of evidence-based treatment can prevent or slow down further progression. To diagnose new-onset heart failure in primary care is challenging.

METHODS AND RESULTS

This is a cross-sectional diagnostic accuracy study with external validation. Seven hundred twenty-one consecutive patients suspected of new-onset heart failure underwent standardized diagnostic work-up including chest x-ray, spirometry, ECG, N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement, and echocardiography in specially equipped outpatient diagnostic heart failure clinics. The presence of heart failure was determined by an outcome panel using the initial clinical data and 6-month follow-up data, blinded to biomarker data. Of the 721 patients, 207 (28.7%) had heart failure. The combination of 3 items from history (age, coronary artery disease, and loop diuretic use) plus 6 from physical examination (pulse rate and regularity, displaced apex beat, rales, heart murmur, and increased jugular vein pressure) showed independent diagnostic value (c-statistic 0.83). NT-proBNP was the most powerful supplementary diagnostic test, increasing the c-statistic to 0.86 and resulting in net reclassification improvement of 69% (P<0.0001). A simplified diagnostic rule was applied to 2 external validation datasets, resulting in c- statistics of 0.95 and 0.88, confirming the results.

CONCLUSIONS

In this study, we estimated the quantitative diagnostic contribution of elements of the history and physical examination in the diagnosis of heart failure in primary care outpatients, which may help to improve clinical decision making. The largest additional quantitative diagnostic contribution to those elements was provided by measurement of NT-proBNP. For daily practice, a diagnostic rule was derived that may be useful to quantify the probability of heart failure in patients with new symptoms suggestive of heart failure.

In-hospital brain natriuretic peptide and N-terminal prohormone brain natriuretic peptide variations are predictors of short-term and long-term outcome in acute decompensated heart failure

Acute decompensated heart failure is one of the most important causes of hospitalisation worldwide. Natriuretic peptides have shown their usefulness in the diagnosis and management of heart failure. Their variations during hospitalisation also appear useful to predict outcomes. In particular, data from the literature demonstrate that reduction from admission to discharge of brain natriuretic peptide and N-terminal prohormone brain natriuretic peptide in these patients is a predictor of future cardiovascular events.

Comparison of the utility of preoperative versus postoperative B-type natriuretic peptide for predicting hospital length of stay and mortality after primary coronary artery bypass grafting

BACKGROUND

Preoperative B-type natriuretic peptide (BNP) is known to predict adverse outcomes after cardiac surgery. The value of postoperative BNP for predicting adverse outcomes is less well delineated. The authors hypothesized that peak postoperative plasma BNP (measured postoperative days 1-5) predicts hospital length of stay (HLOS) and mortality in patients undergoing primary coronary artery bypass grafting, even after adjusting for preoperative BNP and perioperative clinical risk factors.

METHODS

This study is a prospective longitudinal study of 1,183 patients undergoing primary coronary artery bypass grafting surgery. Mortality was defined as all-cause death within 5 yr after surgery. Cox proportional hazards analyses were conducted to separately evaluate the associations between peak postoperative BNP and HLOS and mortality. Multivariable adjustments were made for patient demographics, preoperative BNP concentration, and clinical risk factors. BNP measurements were log10 transformed before analysis.

RESULTS

One hundred fifteen deaths (9.7%) occurred in the cohort (mean follow-up = 4.3 yr, range = 2.38-5.0 yr). After multivariable adjustment for preoperative BNP and clinical covariates, peak postoperative BNP predicted HLOS (hazard ratio [HR] = 1.28, 95% CI = 1.002-1.64, P = 0.049) but not mortality (HR = 1.62, CI = 0.71-3.68, P = 0.25), whereas preoperative BNP independently predicted HLOS (HR = 1.09, CI = 1.01-1.18, P = 0.03) and approached being an independent predictor of mortality (HR = 1.36, CI = 0.96-1.94, P = 0.08). When preoperative and peak postoperative BNP were separately adjusted for within the clinical multivariable models, each independently predicted HLOS (preoperative BNP HR = 1.13, CI = 1.05-1.21, P = 0.0007; peak postoperative BNP HR = 1.44, CI = 1.15-1.81, P = 0.001) and mortality (preoperative BNP HR = 1.50, CI = 1.09-2.07, P = 0.01; peak postoperative BNP HR = 2.29, CI = 1.11-4.73, P = 0.02).

CONCLUSIONS

Preoperative BNP may be better than peak postoperative BNP for predicting HLOS and longer term mortality after primary coronary artery bypass grafting surgery.

Assessment of serum N-terminal pro-B-type natriuretic peptide concentration for differentiation of congestive heart failure from primary respiratory tract disease as the cause of respiratory signs in dogs

OBJECTIVE

To determine whether serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration is useful in discriminating between cardiac and noncardiac (ie, primary respiratory tract disease) causes of respiratory signs (ie, coughing, stertor, stridor, excessive panting, increased respiratory effort, tachypnea, or overt respiratory distress) in dogs.

DESIGN

Multicenter cross-sectional study.

ANIMALS

P 115 dogs with respiratory signs.

PROCEDURES

Dogs with respiratory signs were solicited for study. Physical examination, thoracic radiography, and echocardiography were used to determine whether respiratory signs were the result of cardiac (ie, congestive heart failure) or noncardiac (ie, primary respiratory tract disease) causes. Serum samples for NT-proBNP assay were obtained at time of admission for each dog. Receiver-operating characteristic curves were constructed to determine the ability of serum NT-proBNP concentration to discriminate between cardiac and noncardiac causes of respiratory signs.

RESULTS

Serum NT-proBNP concentration was significantly higher in dogs with cardiac versus noncardiac causes of respiratory signs. In dogs with primary respiratory tract disease, serum NT-proBNP concentration was significantly higher in those with concurrent pulmonary hypertension than in those without. A serum NT-proBNP cutoff concentration > 1,158 pmol/L discriminated between dogs with congestive heart failure and dogs with primary respiratory tract disease with a sensitivity of 85.5% and a specificity of 81.3%.

CONCLUSIONS AND CLINICAL RELEVANCE

Measuring serum NT-proBNP concentration in dogs with respiratory signs helps to differentiate between congestive heart failure and primary respiratory tract disease as an underlying cause.

N-terminal pro-brain natriuretic peptide in cases with metabolic syndrome and its relationship with components of metabolic syndrome and left ventricular mass index

OBJECTIVE

In this study we investigated N-terminal pro-brain natriuretic peptide (Nt-proBNP) levels in patients with metabolic syndrome (MetS) and its relationship between MetS components.

METHODS

Thirty nine recently diagnosed MetS cases and 59 control cases were included in the present study. Left ventricular mass index (LVMI) was calculated and Nt-proBNP was determined.

RESULTS

Both groups were similar in terms of age and sex. Body mass index were significantly higher in MetS than non-MetS. LVMI measurements were not different between MetS and control groups (p=0.168). Nt-proBNP levels were similar in both groups (p=0.954). There was a significant correlation between Nt-proBNP and LVMI, age, serum LDL- and HDL-cholesterol levels. Nt-proBNP was independently related with age (beta=0.357, p=0.015) and LDL-cholesterol (beta=-0.255, p=0.049) in the multivariate analysis.

CONCLUSIONS

Nt-proBNP levels don't have a significant increase in MetS. But there was a significant relationship between Nt-proBNP levels and age and LDL-cholesterol.

A pilot survey of the use and implementation of cardiac markers in acute coronary syndrome and heart failure across Europe. The CARdiac MArker Guideline Uptake in Europe (CARMAGUE) study

BACKGROUND

Guidelines on preferred cardiac marker strategies for investigation of patients with acute coronary syndromes (ACS) are available from the laboratory medicine and cardiology communities. Therefore, implementation of these guidelines into daily clinical practice should be a joint effort of laboratory specialists and clinicians. This was investigated in this survey.

METHODS

A pilot study was performed sponsored by the European Federation of Clinical Chemistry and Laboratory Medicine. A link to an online questionnaire was e-mailed to 990 laboratories from eight European countries in May 2006. The requested information included tests performed, clinical protocol development, and reference limits.

RESULTS

We obtained a total of 220 responses. Out of these, 208 responses (95%) were from hospitals that provide 24-h admission of patients. The suggested turn-around-time (<60 min) was apparently met by >88% for cardiac troponin T/I and for CK-MB mass. The majority of the laboratories derive their decision limits from kit inserts provided by the manufacturers. The results revealed a worrying fact that external quality assessments are not used in all testing.

CONCLUSIONS

Our survey demonstrated that cardiac troponin is the preferred biomarker for the diagnosis of ACS. Half of the participants had written protocols, mostly as a result of collaboration between laboratorians and clinicians.

Usefulness of serial assessment of natriuretic peptides in the emergency department for patients with acute decompensated heart failure

The value of natriuretic peptides, both B-type natriuretic peptide (BNP) and N-terminal prohormone brain natriuretic peptide (NTproBNP), for determining diagnosis, severity, and prognosis of emergency department (ED) patients with acute decompensated heart failure (ADHF) has been well documented. Emerging data support the hypothesis that repeated natriuretic peptide determinations in the acute phase of ADHF may assist in confirming the diagnosis, monitoring drug therapy, and evaluating the adequacy of patient stabilization. Data from the authors' group demonstrate that in patients admitted to the ED for acute dyspnea, serial NTproBNP measurement at admission and 4, 12, and 24 hours later was useful in confirming the diagnosis of ADHF compared with patients with chronic obstructive pulmonary disease. Moreover, in the same patients receiving intensive intravenous diuretic therapy, there was a progressive reduction of NTproBNP blood levels from hospitalization to discharge (P<.001), accompanied by clinical improvement and stabilization of heart failure. More recently, the authors also demonstrated that in ADHF patients improving with diuretics, a progressive reduction in BNP levels was observed, starting 24 hours after ED admission and continuing until discharge. Comparing BNP and NTproBNP, there was a significant correlation between NTproBNP and BNP levels but not between NTproBNP's and BNP's percent variation compared with baseline. In ADHF, serial ED measurements of BNP are useful for monitoring the effects of treatment. A reduction in BNP from admission to discharge is indicative of clinical improvement.

Differential diagnosis of acute dyspnea: the value of B natriuretic peptides in the emergency department

Congestive heart failure (CHF) is the main cause of acute dyspnea in patients presenting to an emergency department (ED) and is associated with high morbidity and mortality. B-type natriuretic peptide (BNP) is a polypeptide, released by ventricular myocytes in direct proportion to wall tension, which lowers renin-angiotensin-aldosterone activation. For the diagnosis of CHF, both BNP and the biologically inactive NT-proBNP have similar accuracy. Threshold values are higher in an elderly population, and in patients with renal dysfunction. They might also have a prognostic value. Studies have demonstrated that the use of BNP or NT-proBNP in dyspneic patients early following admission to the ED, reduced the time to discharge and total treatment cost. BNP and NT-proBNP should be available in every ED 24 h a day, because the literature strongly suggests the beneficial impact of an early appropriate diagnosis and treatment in dyspneic patients. The purpose of this review is to indicate recent developments in biomarkers of heart failure and to evaluate their impact on clinical use in the emergency setting.

N-terminal pro-brain natriuretic peptide testing in the emergency department: beneficial effects on hospitalization, costs, and outcome

BACKGROUND

N-terminal pro-brain natriuretic peptide (NT-proBNP) is an established biomarker for heart failure. Assessment of this biomarker in patients with acute dyspnea presenting to the emergency department (ED) may aid diagnostic decision-making, resulting in improved patient care and reduced costs.

METHODS

In a prospective clinical trial, patients presenting with acute dyspnea to the ED of the Erasmus Medical College, Rotterdam, the Netherlands, were randomized for either rapid measurement or no measurement of NT-proBNP. For ruling out heart failure, cutoff values of 93 pg/mL in male and 144 pg/mL in female patients were used, and for ruling in heart failure, a cutoff value of 1,017 pg/mL was used. Time to discharge from the hospital and costs related to hospital admission were primary end points. Bootstrap analysis was used for comparison of costs and 30-day mortality between the NT-proBNP and control group.

RESULTS

A total of 477 patients (54% male) was enrolled. The mean age was 59 years, with 44% of patients having a history of cardiac disease. Median time to discharge from the hospital was 1.9 days (interquartile range [IQR], 0.12-8.4 days) in the NT-proBNP group (n = 241) compared with 3.9 days (IQR, 0.16-11.0 days) in the control group (n = 236) (P = .04). Introduction of NT-proBNP testing resulted in a trend toward reduction in costs related to hospital admission and diagnostic investigations of $1,364 per patient (95% CI $-246 to $3,215), whereas 30-day mortality was similar (15 patients in the NT-proBNP and 18 patients in the control group).

CONCLUSIONS

Introduction of NT-proBNP testing for heart failure in the ED setting reduces the time to discharge and is associated with a trend toward cost reduction.

BNP or NTproBNP? A clinician's perspective

Existing literature on two natriuretic peptides--B-type natriuretic peptide (BNP) and amino terminal pro-brain natriuretic peptide (NTproBNP)--is overwhelming. Both peptides are acknowledged markers for cardiac dysfunction. Most of the sources present data on either BNP or NTproBNP making the comparison difficult. This paper focuses on reviewing studies directly comparing two peptides in the setting of chronic and acute heart failure (HF) and coronary artery disease. Many concomitant diseases influence these two peptides to varying extent. These characteristics should be taken into consideration when interpreting results. For most practical purposes, BNP and NTproBNP are interchangeable, and can be used based on local preferences and availability. NTproBNP seems to be more advantageous for diagnosing mild HF or asymptomatic left ventricular dysfunction.

Useulness of B Natriuretic Peptides and Procalcitonin in Emergency Medicine

Congestive heart failure (CHF) is the main cause of acute dyspnea in patients presented to an emergency department (ED), and it is associated with high morbidity and mortality. B-type natriuretic peptide (BNP) is a polypeptide, released by ventricular myocytes directly proportional to wall tension, for lowering renin-angiotensin-aldosterone activation. For diagnosing CHF, both BNP and the biologically inactive NT-proBNP have similar accuracy. Threshold values are higher in elderly population, and in patients with renal dysfunction. They might have also a prognostic value. Studies demonstrated that the use of BNP or NT-proBNP in dyspneic patients early in the ED reduced the time to discharge, total treatment cost. BNP and NT-proBNP should be available in every ED 24 hours a day, because literature strongly suggests the beneficial impact of an early appropriate diagnosis and treatment in dyspneic patients.

Etiologic diagnosis of febrile patients who present to an ED is complex and sometimes difficult. However, new evidence showed that there are interventions (including early appropriate antibiotics), which could reduce mortality rate in patients with sepsis. For diagnosing sepsis, procalcitonin (PCT) is more accurate than C-reactive protein. Thus, because of its excellent specificity and positive predictive value, an elevated PCT concentration (higher than 0.5 ng/mL) indicates ongoing and potentially severe systemic infection, which needs early antibiotics (e.g. meningitis). In lower respiratory tract infections, CAP or COPD exacerbation, PCT guidance reduced total antibiotic exposure and/or antibiotic treatment duration.

Analytical and clinical performance of three natriuretic peptide tests in the emergency room

BACKGROUND

The aim of the present study was to investigate the analytical and diagnostic utility of B-type natriuretic peptide (BNP) and the N-terminus of this prohormone, N-terminal pro-BNP (NT-pro-BNP) testing in the emergency department to identify acute congestive heart failure (CHF).

METHODS

A blood sample taken from patients presenting to the emergency department with acute dyspnoea (n=80) was analyzed for natriuretic peptides using three different assays [Triage BNP (Biosite), Centaur BNP (Bayer) and Elecsys NT-pro-BNP (Roche)]. A cardiologist and a pulmonologist, blinded to the actual natriuretic peptide levels, reviewed all test results (including echocardiography, etc.) retrospectively and made a diagnosis of dyspnoea due to CHF or not.

RESULTS

Analytical testing showed good correlation and coefficients of variation of less than 10% for all three assays. Cardiac-related dyspnoea was found in 40 patients (50%). NT-proBNP and BNP values were significantly elevated in these patients. For identifying patients with CHF, BNP and NT-proBNP scored equally well (area under the receiver operating characteristic curve of 0.78, 0.77 and 0.78 for the Biosite, Roche and Bayer assays, respectively).

CONCLUSIONS

In general, the different assays tested for BNP and NT-pro-BNP correlate very well in patients with suspected CHF and may aid in the risk stratification process in emergency departments. However, the value must always be interpreted in conjunction with other clinical information. It should also be considered that renal impairment can affect the results.

The utility of B-type natriuretic peptide in the diagnosis of heart failure in the emergency department: a systematic review

BACKGROUND

Dyspnea is a common chief complaint in the emergency department (ED); differentiating heart failure (HF) from other causes can be challenging. Brain Natriuretic Peptide (BNP) is a new diagnostic test for HF for use in dyspneic patients in the ED. The purpose of this study is to systematically review the accuracy of BNP in the emergency diagnosis of HF.

METHODS

We searched MEDLINE (1975-2005) supplemented by reference tracking. We included studies that reported the sensitivity and specificity of BNP for diagnosing HF in ED patients with acute dyspnea. Two reviewers independently assessed study quality. We pooled sensitivities and specificities within five ranges of BNP cutoffs.

RESULTS

Ten studies including 3,344 participants met inclusion criteria. Quality was variable; possible verification or selection bias was common. No studies eliminated patients with obvious medical causes of dyspnea. Most studies used the Triage BNP assay; all utilized a clinical reference standard. Pooled sensitivity and specificity at a BNP cutoff of 100-105 pg/ml were 90% and 74% with negative likelihood ratio (LR) of 0.14; pooled sensitivity was 81% with specificity of 90% at cutoffs between 300 and 400 pg/ml with positive LR of 7.6.

CONCLUSION

Our analysis suggests that BNP has moderate accuracy in detecting HF in the ED. Our results suggest utilizing a BNP of less than 100 pg/ml to rule out HF and a BNP of greater than 400 pg/ml to diagnose HF. Many studies were of marginal quality, and all included patients with varying degrees of diagnostic uncertainty. Further studies focusing on patients with diagnostic uncertainty will clarify the real-world utility of BNP in the emergency management of dyspnea.

Comparison of brain natriuretic peptide (BNP) and amino-terminal ProBNP for early diagnosis of heart failure

BACKGROUND

We compared the diagnostic accuracy of brain natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) for diagnosis of preclinical and mild heart failure (HF).

METHODS

We assayed plasma NT-proBNP and BNP in 182 healthy controls and in a prospective cohort of 820 HF patients divided according to the American Heart Association/American College of Cardiology classification. These included 86 patients in stage A [mean (SE) ejection fraction 61% (1%); mean (SE) age 47 (2) years], 255 in stage B [65% (2%); 62 (1) years], 420 patients in stage C [35% (1%); 68 (1) years] and 59 in stage D [25% (1%); 74 (1) years]. Diagnostic accuracies of BNP and NT-proBNP were evaluated by ROC analysis, and a multivariate linear regression model was applied to predict HF staging.

RESULTS

Median BNP and NT-proBNP concentrations increased from stage A to D 57-fold and 107-fold, respectively. Both assays were accurate (P <0.001) in separating stage B from controls or stage A, and stage C from controls or stage A or B. NT-proBNP was more accurate (P <0.001) than BNP in differentiating stage C from stages A and B patients and controls and was a better predictor of HF classification in a model including age, sex, and renal function (P <0.001).

CONCLUSIONS

Monitoring BNP or NT-proBNP enabled identification of asymptomatic patients at risk for the development of HF. NT-proBNP showed better accuracy than BNP for identifying mild HF.

Comparison of the Diagnostic Accuracy of Brain Natriuretic Peptide (BNP) and the N-Terminal Part of the Propeptide of BNP Immunoassays in Chronic and Acute Heart Failure: A Systematic Review

Background: We used evidence-based laboratory medicine principles to compare the diagnostic accuracy of brain natriuretic peptide (BNP) and the N-terminal part of the propeptide of BNP (NT-proBNP) assays for the diagnosis of heart failure.

Methods: In May 2006, we performed a computerized literature search of the online National Library of Medicine to select studies specifically designed to compare the diagnostic accuracy of BNP and NT-proBNP assays. The comparison took into account the area under the curve and diagnostic odds ratio (DOR) derived from ROC analysis of original studies.

Results: Both BNP and NT-proBNP assays were found to be clinically useful for the diagnosis of heart failure. Metaanalysis of these data was difficult because of the heterogeneity of data regarding patient population, diagnostic criteria, end-points, and immunoassay methods for both BNP and NT-proBNP. Separate metaanalyses were performed for acute and chronic heart failure. In chronic heart failure, the diagnostic DOR for BNP (8.44, 95% CI 4.66–15.30) was not significantly different from that of NT-proBNP (23.36, 95% CI 9.38–58.19). In patients with acute heart failure, the mean DOR for BNP (16.46, 95% CI 10.65–25.43) was not significantly different from that of NT-proBNP (18.61, 95% CI 12.99–26.65).

Conclusion: Our results indicate that both BNP and NT-proBNP assays have a high degree of diagnostic accuracy and clinical relevance for both acute and chronic heart failure.

[Determining factors of cardiac biomarkers in hemodialysed diabetic and non-diabetic patients]

INTRODUCTION

Cardiovascular diseases are highly prevalent in chronic renal failure patients, especially in diabetic population. Cardiac biomarkers such as pro-brain natriuretic peptide N-terminal piece (NT-proBNP), cardiac troponin T (cTnT) and high sensitive CRP (hs-CRP) are increasingly used for early detection.

AIMS

The authors analysed, which factors influence cardiac biomarker levels in hemodialysed patients and whether these factors depend on the presence of diabetes.

METHODS

In 28 diabetic and 40 non-diabetic patients on chronic hemodialysis was analysed the association between routine laboratory data, bioimpedance parameters, results of echocardiography and ambulatory blood pressure monitoring on cardiac biomarkers. Multivariate linear regression analysis (ANOVA) was applied for statistical evaluation.

RESULTS

The authors found stronger correlation (p = 0.034 vs. p = 0.001) between NT-proBNP and extracellular volume/total water volume hyperhydration ratio (ecv/twv) evaluated in diabetics than in non-diabetics. In case of cTnT, no relation was found with CaxP, iPTH, Kt/V, beta2-microglobulin, and serum uric acid levels. The hs-CRP was correlated with total cholesterol (p = 0.039) and EPO-dose (p = 0.03) in diabetics, while with serum fibrinogen (p = 0.025) in non-diabetics. The HbA1c didn't influence biomarkers in the diabetic group.

CONCLUSIONS

The factors having an impact on cardiac biomarker levels are similar in diabetic and non-diabetic hemodialysed patients. According to results the presence of end-stage renal disease in a cross-sectional survey probably overcomes the impact of diabetes and quality of glycaemic control on cardiac biomarker levels.

Intérêt du dosage des peptides natriurétiques en urgence

OBJECTIVES

Acute dyspnea is frequent in emergency medicine. The B-type natriuretic peptide is a polypeptide, released by ventricular myocytes directly proportional to wall tension, for lowering renin-angiotensin-aldosterone activation. Conversely, NT-proBNP has no physiological activity. BNP and NT-proBNP concentration closely correlate to various indicators of heart failure.

CURRENT KNOWLEDGE AND KEY POINTS

Numerous studies have demonstrated high usefulness of BNP and NT-proBNP to diagnose heart failure, which is the main cause of acute dyspnea in emergency medicine. The diagnostic accuracy of BNP and NT-proBNP seems similar, and is higher than that of the emergency physician. Bedside dosages are now available, with high sensibility and specificity for the diagnosis of heart failure. For BNP, threshold value is ranging from 100 to 300 pg/ml in patients aged over 65 years; for NT-proBNP the threshold value is 1000 to 2000 pg/ml in elderly patients. Briefly, heart failure is unlikely when BNP is below 100 pg/ml (NT-proBNP<500 pg/ml), and very likely when BNP is higher than 400 pg/ml (or NT-proBNP>2000 pg/ml).

FUTURE PROJECTS

Early rapid measurement of BNP could improved the evaluation and treatment of patients with acute dyspnea and reduce the total cost of treatment.

Influence of renal function on N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients admitted for dyspnoea in the Emergency Department: Comparison with brain natriuretic peptide (BNP)

BACKGROUND

Renal dysfunction influences the optimum brain natriuretic peptide (BNP) threshold for a diagnosis of cardiac-related dyspnoea, but this has not been demonstrated for N-terminal pro-brain natriuretic peptide (NT-proBNP). We studied the influence of renal function on NT proBNP and BNP concentrations in dyspnoeic patients admitted by night to the Emergency Department (ED).

METHODS

NT-proBNP, BNP, and creatinine levels were measured in blood samples collected routinely from 381 patients; estimated glomerular filtration rate (eGFR) was calculated.

RESULTS

Cardiac-related dyspnoea was found in 115 patients (30.2%). NT-proBNP and BNP values were elevated in patients with cardiac-related dyspnoea (6823+/-6569 vs. 2716+/-4838 pg/ml, and 642+/-329 vs. 243+/-267 pg/ml, p<0.0001, respectively). Log-transformed NT-proBNP and BNP values were correlated to eGFR values. Mean NT-proBNP and BNP values stratified by ED diagnosis increased in line with eGFR categories, but in each category both peptide concentrations remained elevated in cardiac-related dyspnoea when compared with non-cardiac-related dyspnoea (p<0.05). NT-proBNP (and BNP) cut-off points rose as a function of eGFR categories: from 1360 (and 290) pg/ml in patients with eGFR 60-89 ml/min/1.73 m2, to 6550 (and 515) pg/ml in patients with eGFR 15-29 ml/min/1.73 m2.

CONCLUSION

Renal function influences the optimal cut-off points of NT-proBNP and BNP for the diagnosis of cardiac-related dyspnoea.