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

Baseline plasma NT-proBNP and clinical characteristics: results from the irbesartan in heart failure with preserved ejection fraction trial

BACKGROUND

N-terminal B type natriuretic peptide (NT-proBNP) is usually elevated in heart failure (HF) patients with reduced ejection fraction (EF). Less is known about NT-proBNP in HF with preserved EF (HF-PEF). We measured baseline NT-proBNP in 3562 HF-PEF enrolled patients in the Irbesartan in Heart Failure with Preserved Ejection Fraction trial.

METHODS AND RESULTS

Patients with EF >or=45%, age >or=60 years, and either New York Heart Association (NYHA) II-IV symptoms with HF hospitalization (HFH) within 6 months or NYHA III-IV symptoms with corroborative evidence of HF or structural changes associated with HF-PEF. NT-proBNP (pg/mL) measured centrally using the Elecsys proBNP assay (Roche). Mean age 72 +/- 7 years, 60% were women, the investigator indicated HF etiology was hypertension in 64%; the majority were in NYHA III. Medications included diuretics in 82%, angiotensin-converting enzyme inhibitor in 26%, beta-blocker in 59%, and spironolactone in 15%. Median NT-proBNP was 341 pg/mL (interquartile range 135 to 974 pg/mL) and geometric mean was 354 pg/mL. In multivariate analysis, the baseline characteristics most strongly associated with higher NT-proBNP levels were atrial fibrillation (ratio of geometric mean 2.59, P < .001), NYHA IV symptoms (1.52, P < .001), lower estimated glomerular filtration rate (1.44, P < .001), and HFH hospitalization within 6 months (1.37, P < .001).

CONCLUSIONS

Most HF-PEF patients have elevated NT-proBNP levels. The NT-proBNP concentrations were related to baseline characteristics generally associated with worse outcomes for HF patients.

[NT-proBNP in practice: from chemistry to medicine]

Since the introduction of routine assay for natriuretic peptides, there are a growing number of clinical applications for those new tests. Numerous studies have defined analytical characteristics and clinical interest of NT-proBNP assay. Originally limited to acute heart failure diagnosis in the emergency room, NT-proBNP assay has now a wide number of applications. This literature review presents the "state of art" of this marker, detailing NT-proBNP physiological recent knowledge and its recognized or investigated clinical applications.

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.

Brain natriuretic peptides as biomarkers for atherosclerosis

Identification of atherosclerotic risk factors provides targets for development of preventive therapies. Risk factor assessment permits evaluation of an individual's prospective risk of coronary heart disease (CHD). However, it has become apparent that traditional risk factors may not predict CHD in some patients. As a result, many individuals do not receive the benefit of intensive preventive strategies. Accordingly, considerable effort has focused on the identification of novel biomarkers to enhance risk stratification. Given its prognostic utility in heart failure and acute coronary syndrome, brain natriuretic peptide (BNP) and its amino-terminal fragment have received interest as possible biomarkers for CHD.

Detection of acute heart failure in chronic obstructive pulmonary disease patients: role of B-type natriuretic peptide

PURPOSE OF REVIEW

Unrecognized chronic heart failure is present in 21-30% of chronic obstructive pulmonary disease patients. It may be a precipitating factor for acute exacerbation of chronic obstructive pulmonary disease or may hinder weaning from mechanical ventilation. The aim of the review is to emphasize recent studies that validated measurements of plasma B-type natriuretic peptide in the diagnosis of heart dysfunction in chronic obstructive pulmonary disease patients.

RECENT FINDINGS

Measurements of B-type natriuretic peptide or N-terminal pro-B-type natriuretic peptides are accurate in the diagnosis of left heart dysfunction in chronic obstructive pulmonary disease patients either in stable condition or during acute exacerbation of chronic obstructive pulmonary disease. Natriuretic peptide thresholds are elevated in comparison to cut-offs usually reported in patients without pulmonary disease. B-type natriuretic peptide dosage is also able to uncover new onset of left heart failure associated with weaning difficulties from mechanical ventilation in chronic obstructive pulmonary disease patients.

SUMMARY

Recent evidence suggests that natriuretic peptide measurements are accurate in the diagnosis of coexisting left heart failure in chronic obstructive pulmonary disease patients, either in stable condition or during severe cardiopulmonary interactions occurring during acute exacerbation of chronic obstructive pulmonary disease, or evoking weaning difficulties related to left heart dysfunction.

Diagnostic performance and cost effectiveness of measurements of plasma N-terminal pro brain natriuretic peptide in patients presenting with acute dyspnea or peripheral edema

BACKGROUND

The purpose of this study was to determine the diagnostic power of a newly available assay for amino-terminal pro-brain natriuretic peptide (NT-proBNP) to identify patients with acute heart failure. In addition, the influence of initial NT-proBNP measurements on economic consequences, diagnostic procedures and staff involvement was evaluated.

METHODS AND RESULTS

401 patients presenting with acute dyspnea or peripheral edema in the emergency department were enrolled. NT-proBNP was measured after initial clinical evaluation. Clinical routine care and diagnostic assessment were blinded to NT-proBNP results. Two cardiologists independently validated the period of hospitalization, clinical examinations and medical therapies of each patient considering NT-proBNP results. The median NT-proBNP level among patients with acute congestive heart failure (CHF) (n=122) was 3497 pg/ml as compared to 320 pg/ml in patients without (n=279) (p<0.0001). An NT-proBNP cutoff level <300 pg/ml was optimal to rule out acute CHF (negative predictive value 96%; sensitivity 96%). NT-proBNP >or=300 pg/ml could strongly predict acute CHF when compared to patients' history or physical examination (odds ratio 9.5; p<0.0001) and diagnostic technical findings (odds ratio 14.7; p<0.05). In patients with NT-proBNP<300 pg/ml, 14% of the period of hospitalization could be saved, corresponding to savings of US $481 per patient. In addition, 9% of the number and time of staff involvement of clinical examinations and therapies could be saved, 10% of the costs of clinical examinations. Chest X-rays were saved in 34%, echocardiography in 9%.

CONCLUSIONS

Measurement of NT-proBNP leads to multiple saving amounts and optimizes diagnostic pathways and resource allocation.

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.

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.

Diagnostic accuracy of BNP and NT-proBNP in patients presenting to acute care settings with dyspnea: A systematic review

OBJECTIVE

We sought to compare the diagnostic performance of B-type natriuretic peptide (BNP) and N-terminal proBNP measurements in patients presenting to acute care settings with dyspnea, a common presenting symptom of heart failure.

DESIGN AND METHODS

We conducted a systematic review of the literature. For all included studies, we applied the QUADAS 14-question quality assessment tool for systematic reviews of diagnostic accuracy and abstracted the data for every published cut point.

RESULTS

We screened 4338 studies and included nine in the meta-analysis. All 9 studies scored positively on at least 50% of the QUADAS questions. The pooled estimates of sensitivity and specificity were the same for the BNP studies (0.97 (95% CI: 0.96, 0.98) and 0.70 (95% CI: 0.56, 0.85)) as for the NT-proBNP studies (0.95 (95% CI: 0.90, 1.01) and 0.72 (95% CI: 0.53, 0.90)). Tests for heterogeneity were significant in both subgroups: BNP (I(2)=97.9%, p<0.001) and NT-proBNP (I(2)=87.5%, p<0.001). Similar overall results were found for the likelihood and diagnostic odds ratios.

CONCLUSIONS

BNP and NT-proBNP have very similar diagnostic performance characteristics and can be used to rule out heart failure as a cause of dyspnea in the acute clinical setting. However, there is no easily identifiable optimum cut point value for each peptide.

Amino-terminal pro-B-type natriuretic peptide testing for the diagnosis or exclusion of heart failure in patients with acute symptoms

When used for the evaluation of patients with acute symptoms in the emergency department setting, amino-terminal pro-B-type natriuretic peptide (NT-proBNP) testing is highly sensitive and specific for the diagnosis or exclusion of acute destabilized heart failure (HF), with results comparable to those reported for B-type natriuretic peptide (BNP) testing. When used for the diagnostic evaluation of the patient with possible HF, NT-proBNP testing returns information that may be superior to clinical judgment. However, the optimal application of NT-proBNP is in concert with history and physical examination, adjunctive testing, and with the knowledge of the differential diagnosis of an elevated NT-proBNP level. Studies indicate a dual use for NT-proBNP, both to exclude acute HF (where NT-proBNP concentrations <300 ng/L have a 98% negative predictive value), as well as to identify the diagnosis. To identify acute HF in patients with dyspnea, an age-independent NT-proBNP cut point of 900 ng/L has a similar value as that reported for a BNP value of 100 ng/L. However, age stratification of NT-proBNP using cut points of 450, 900, and 1,800 ng/L (for age groups of <50, 50-75, and >75 years) reduces false-negative findings in younger patients, reduces false-positive findings in older patients, and improves the overall positive predictive value of the marker without a change in overall sensitivity or specificity. Clinically validated, cost-effective algorithms for the use of NT-proBNP testing exist. Therefore, the logical use of NT-proBNP for the evaluation of the patient with suspected acute HF is useful, cost-effective, and may reduce adverse outcomes compared with standard clinical evaluation without natriuretic peptide testing.

Amino-terminal pro-B-type natriuretic peptide testing for inpatient monitoring and treatment guidance of acute destabilized heart failure

Although typically elevated at presentation in the context of destabilized heart failure (HF), amino-terminal pro-B-type natriuretic peptide (NT-proBNP) values typically decrease rapidly among patients who have a favorable response to therapy. Given this, it is natural to examine the relation between NT-proBNP and therapeutic interventions for acute HF. Both presentation and posttreatment NT-proBNP concentrations have some value for prognostication of recurrent HF hospitalization or death. However, the percent change in NT-proBNP after treatment for acute HF may be a more powerful method for risk stratification. Although prospective studies on the effect of NT-proBNP measurement in guiding therapy in acute destabilized HF are lacking, observational data suggest that a 30% decrease in NT-proBNP values during hospitalization is a reasonable goal. If a baseline measure of NT-proBNP is not available, an NT-proBNP level <4,000 ng/L after acute treatment is an alternative goal. Because the criteria for determining restabilization from destabilized HF prominently include clinical and routine laboratory testing rather than NP measures, the frequency of NT-proBNP measurement should not be excessive in patients with acute HF, with measures at baseline/presentation and after perceived recompensation to evaluate for the desired decrease in NT-proBNP concentrations. A remeasurement of NT-proBNP may also be useful for evaluation of new or worsened symptoms. In those patients without a decrease in NT-proBNP despite perceived recompensation from HF, a review of adequacy of treatment, goals of therapy, and consideration of prognosis is recommended.

Usefulness of aminoterminal pro-brain natriuretic peptide testing for the diagnostic and prognostic evaluation of dyspneic patients with diabetes mellitus seen in the emergency department (from the PRIDE Study)

Despite widespread testing, the utility of aminoterminal pro-brain natriuretic peptide (NT-pro-BNP) for diagnosis or risk assessment in patients with diabetes mellitus (DM) in the emergency department (ED) remains unclear. NT-pro-BNP was measured in subjects with dyspnea in the ED. A final diagnosis of acute heart failure (HF) was determined by blinded study physicians using all available hospital records. Vital status was assessed at 1 year; independent predictors of death were identified using Cox analysis. Of 599 subjects, 157 (26.2%) had DM, which was an independent predictor of a final diagnosis of acute HF. In patients diagnosed with acute HF, median concentrations of NT-pro-BNP were similar in patients with and without DM (4,784 vs 3,382 pg/ml, respectively, p = 0.93). In dyspneic subjects without acute HF, median concentrations of NT-pro-BNP were significantly higher in patients with DM (242 vs 115 pg/ml, p = 0.01), but this difference was no longer significant after adjusting for relevant covariates. The area under the curve for NT-pro-BNP to diagnose acute HF in subjects with DM was 0.94 (p <0.001). Using age-adjusted cutpoints, NT-pro-BNP was 92% sensitive and 90% specific for the diagnosis of HF in diabetic subjects. In diabetic patients, a NT-pro-BNP level > or =986 pg/ml was independently associated with an increased risk of death at 1 year (hazard ratio 3.42, 95% confidence interval 1.09 to 10.7, p <0.001). In conclusion, NT-pro-BNP testing offers valuable diagnostic and prognostic information in the evaluation of dyspneic patients with DM in the ED, using identical cutpoints as the population as whole.

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.

Serial NT-proBNP monitoring and outcomes in outpatients with decompensation of heart failure

BACKGROUND

NT-proBNP is useful for heart failure (HF) diagnosis and prognosis. We examined the value of serial NT-proBNP monitoring to predict outcomes in decompensated HF patients attending a structured HF clinic.

METHODS

Patients with decompensation of established optimally treated HF, not requiring emergency hospital admission, were enrolled in the study. Patients received intensive follow-up weekly during 4 weeks and at 3 months in specialist HF clinics. Serial NT-proBNP concentrations were measured at each visit. Primary endpoint was cardiovascular death and hospital admission for HF at 3 months.

RESULTS

Fifty-nine patients were enrolled (60+/-14 years, LVEF 27+/-9%) and 39% had a primary endpoint during follow-up. Baseline NT-proBNP concentration (in ng/L) was 7050+/-6620, and did not differ significantly in patients with and without events (p=0.22). Patients without events showed marked NT-proBNP reduction at week-1 (30% reduction), week-2 (36% reduction), week-3 (34% reduction) and week-4 (37% reduction). By contrast, patients with events showed no significant NT-proBNP reduction during follow-up. Using a general linear model, the relative NT-proBNP reductions (%) at weeks 1-4 were predictors of adverse events (p=0.004, p<0.001, p=0.001 and p=0.03, respectively). In a stepwise multiple Cox regression analysis, NT-proBNP relative reduction (in %) at week 2 was a strong predictor of no events during follow-up (OR 0.79, 95% CI 0.70-0.88, p<0.001).

CONCLUSIONS

Serial NT-proBNP monitoring in decompensated HF patients seen in a structured in-hospital HF clinic predicts cardiovascular events during follow-up. NT-proBNP may be useful in an outpatient basis to identify patients at high risk needing more aggressive therapy.

Left atrial enlargement and NT-proBNP as predictors of sudden cardiac death in patients with heart failure

AIMS

The identification of valuable markers of sudden cardiac death (SCD) in patients with established HF remains a challenge. We sought to assess the value of clinical, echocardiographic and biochemical variables to predict SCD in a consecutive cohort of patients with heart failure (HF) due to systolic dysfunction.

METHODS

A cohort of 494 patients with established HF had baseline echocardiographic and NT-proBNP measurements and were followed for 942+/-323 days.

RESULTS

Fifty patients suffered SCD. Independent predictors of SCD were indexed LA size>26 mm/m2 (HR 2.8; 95% CI 1.5-5.0; p=0.0007), NT-proBNP>908 ng/L (HR 3.1; 95% CI 1.5-6.7; p=0.003), history of myocardial infarction (HR 2.3; 95% CI 1.3-4.1; p=0.007), peripheral oedema (HR 2.1; 95% CI 1.1-3.9; p=0.02), and diabetes mellitus (HR 1.9; 95% CI 1.1-3.3; p=0.03). NYHA functional class, left ventricular ejection fraction and glomerular filtration rate were not independent predictors of SCD in this cohort. Notably, the combination of both LA size>26 mm/m2 and NT-proBNP>908 ng/L increased the risk of SCD (HR 4.3; 95% CI 2.5-7.6; p<0.0001). At 36 months, risk of SCD in patients with indexed LA size<or=26 mm/m2 and NT-proBNP<or=908 ng/L was 3%, while in patients with indexed LA size>26 mm/m2 and NT-proBNP>908 ng/L reached 25% (p<0.0001).

CONCLUSIONS

Among HF patients, indexed LA size and NT-proBNP levels are more useful to stratify risk of SCD than other clinical, echocardiographic or biochemical variables. The combination of these two parameters should be considered for predicting SCD in patients with HF.

N-Terminal Pro–B-Type Natriuretic Peptide Testing Improves the Management of Patients With Suspected Acute Heart Failure

BACKGROUND

The diagnostic utility of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in heart failure has been documented. However, most of the data were derived from countries with high healthcare resource use, and randomized evidence for utility of NT-proBNP was lacking.

METHODS AND RESULTS

We tested the hypothesis that NT-proBNP testing improves the management of patients presenting with dyspnea to emergency departments in Canada by prospectively comparing the clinical and economic impact of a randomized management strategy either guided by NT-proBNP results or without knowledge of NT-proBNP concentrations. Five hundred patients presenting with dyspnea to 7 emergency departments were studied. The median NT-proBNP level among the 230 subjects with a final diagnosis of heart failure was 3697 compared with 212 pg/mL in those without heart failure (P<0.00001). Knowledge of NT-proBNP results reduced the duration of ED visit by 21% (6.3 to 5.6 hours; P=0.031), the number of patients rehospitalized over 60 days by 35% (51 to 33; P=0.046), and direct medical costs of all ED visits, hospitalizations, and subsequent outpatient services (US $6129 to US $5180 per patient; P=0.023) over 60 days from enrollment. Adding NT-proBNP to clinical judgment enhanced the accuracy of a diagnosis; the area under the receiver-operating characteristic curve increased from 0.83 to 0.90 (P<0.00001).

CONCLUSIONS

In a universal health coverage system mandating judicious use of healthcare resources, inclusion of NT-proBNP testing improves the management of patients presenting to emergency departments with dyspnea through improved diagnosis, cost savings, and improvement in selected outcomes.

Left ventricular systolic dysfunction is an independent predictor of homocysteine in angiographically documented patients with or without coronary artery lesions

BACKGROUND

Elevated plasma homocysteine is a risk factor for coronary artery disease (CAD) and thromboembolic disorders that seems also to be associated with chronic heart failure.

OBJECTIVE

To evaluate the association between homocysteine and left ventricular dysfunction and to assess whether it is independent of CAD.

PATIENTS AND METHODS

A prospective study evaluated this relationship in 709 patients referred for diagnostic coronary angiography, including 515 CAD and 194 patients without evidence of coronary artery lesions.

RESULTS

The homocysteine level was significantly higher in the 187 patients with a left ventricular ejection fraction (LVEF) dysfunction < 40% (P < 0.0001) than in those without ventricular dysfunction. LVEF, NYHA functional class II or III and CAD, stable angina and hypertension were clinical characteristics that influenced total homocysteine level in univariate analysis. Homocysteine was significantly associated with LVEF and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in univariate regression (r = -0.267, 95% CI -0.33 to -0.19, P < 0.0001, and r = 0.381, 95% CI 0.28-0.47, P < 0.0001, respectively) and in multiple regression (P = 0.0022 and P = 0.0001, respectively). Other determinants were creatinine and vitamin B(12), but not folate. LVEF was a predictor of homocysteine > 15 micromol L(-1) in the whole population (P for trend < or = 0.0001) and in patients without documented CAD (P for trend = 0.0058).

CONCLUSION

Our results showed an association of homocysteine with left ventricular systolic dysfunction and NT-pro-BNP that existed independently of documented CAD. Whether this association reflects a causative factor or a consequence of CHF and influences the prognosis of the disease remains an open question.

Hemoglobin and N-terminal pro-brain natriuretic peptide: Independent and synergistic predictors of mortality in patients with acute heart failure

BACKGROUND

Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent predictors of mortality in patients with chronic HF. Their combined predictive power for mortality in the setting of acute HF is uncertain.

METHODS

In an international prospective cohort design, we evaluated the relationships between hemoglobin, NT-proBNP, and 60-day mortality in 690 patients with acute HF.

RESULTS

The median hemoglobin for the entire cohort was 13.0 g/dL (interquartile range 11.6-14.3). The WHO criterion for anemia was met by 44% (n=305). The 60-day mortality rate for anemic patients was 16.4% vs. 8.8% in non-anemic patients (p<0.001). Anemia was an independent predictor of short-term mortality (OR=1.72, 95% CI=1.05-2.80, p=0.03), as was a NT-proBNP concentration >5180 pg/mL (OR=2.32, 95% CI=1.36-3.94 p=0.002). Consideration of four risk groups: not anemic/low NT-proBNP (reference group, n=220), anemic/low NT-proBNP (n=152), not anemic/high NT-proBNP (n=165), and anemic/high NT-proBNP (n=153) revealed respective 60-day mortality rates of 5.0% (referent), 9.2% (OR=1.93, 95% CI=0.85-4.36; p=0.12), 13.9% (OR=3.07, 95% CI=1.45-6.50, p=0.003), and 23.5% (OR=5.84, 95% CI=2.87-11.89, p<0.001).

CONCLUSIONS

Anemia was common in this cohort of subjects with acute HF and was related to adverse short-term outcome. Integrated use of hemoglobin and NT-proBNP measurements provides powerful additive information and is superior to the use of either in isolation.

Canadian Cardiovascular Society Consensus Conference recommendations on heart failure update 2007: Prevention, management during intercurrent illness or acute decompensation, and use of biomarkers

Heart failure is common, yet it is difficult to treat. It presents in many different guises and circumstances in which therapy needs to be individualized. The Canadian Cardiovascular Society published a comprehensive set of recommendations in January 2006 on the diagnosis and management of heart failure, and the present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. Specific recommendations and practical tips were written for the prevention of heart failure, the management of heart failure during intercurrent illness, the treatment of acute heart failure, and the current and future roles of biomarkers in heart failure care. Specific clinical questions that are addressed include: which patients should be identified as being at high risk of developing heart failure and which interventions should be used? What complications can occur in heart failure patients during an intercurrent illness, how should these patients be monitored and which medications may require a dose adjustment or discontinuation? What are the best therapeutic, both drug and nondrug, strategies for patients with acute heart failure? How can new biomarkers help in the treatment of heart failure, and when and how should BNP be measured in heart failure patients? The goals of the present update are to translate best evidence into practice, to apply clinical wisdom where evidence for specific strategies is weaker, and to aid physicians and other health care providers to optimally treat heart failure patients to result in a measurable impact on patient health and clinical outcomes in Canada.

Clinical trials update from the American Heart Association 2006: OAT, SALT 1 and 2, MAGIC, ABCD, PABA-CHF, IMPROVE-CHF, and percutaneous mitral annuloplasty

This article provides information and a commentary on trials presented at the American Heart Association meeting held in November 2006, relevant to the pathophysiology, prevention and treatment of heart failure. All reports should be considered as preliminary data, as analyses may change in the final publication. The OAT study failed to show a benefit of PCI over optimal medical therapy in patients with persistent total occlusion of the infarct related artery following a myocardial infarction. In SALT 1 and 2, tolvaptan was found to correct hyponatraemia of various aetiologies; however, whether this has an impact on heart failure prognosis requires further evaluation. A placebo controlled study of myocardial implantation of skeletal myoblasts in patients with moderate to severe LVSD (MAGIC) showed equivocal/uncertain effects, long term follow-up data are awaited. The ABCD study which compared the ability of an invasive and a non-invasive test to identify patients at risk of arrhythmic events prior to ICD implantation, suggested that the two strategies were comparable, although the practical value of either test remains uncertain and the study had many major flaws. The PABA-CHF study hinted that pulmonary vein antrum isolation might be more effective than AV node ablation with bi-ventricular pacing for the treatment of patients with heart failure in atrial fibrillation. In IMPROVE-CHF, an NT-pro BNP guided treatment strategy was found to reduce the cost of managing patients with acute breathlessness.

B-type natriuretic peptide in heart failure

PURPOSE OF REVIEW

This review focuses on recent literature pertaining to the role of B-type natriuretic peptide (BNP) in heart failure.

RECENT FINDINGS

Heart failure is a common disorder that is associated with significant mortality and morbidity. The diagnosis of heart failure may at times be difficult when using conventional tools. The cardiac natriuretic peptides, particularly BNP, have evolved to be useful biomarkers in heart failure and other cardiovascular disorders. Recent studies have established a close association between plasma BNP and the amino-terminal fragment of the BNP prohormone (NT-proBNP) with the diagnosis of heart failure and independent prediction of mortality and heart failure events. Furthermore, preliminary data from randomized controlled trials suggest that knowledge of BNP and/or NT-proBNP level may optimize the management of patients with heart failure. Exogenous natriuretic peptide in the form of recombinant human BNP (nesiritide) has been shown to improve hemodynamics and dyspnea and is approved in the USA and several other countries for the management of patients with acute decompensated heart failure. The effect of nesiritide on clinical outcome, however, remains unclear.

SUMMARY

When used in the appropriate clinical settings, BNP or NT-proBNP testing is extremely useful in establishing diagnosis and predicting prognosis in heart failure. Nesiritide holds promise in the management of patients with acute decompensated heart failure. Large-scale randomized controlled trials to evaluate BNP/NT-proBNP-guided therapy are currently in progress and studies of the impact of exogenous BNP on clinical outcomes in heart failure are likely to be forthcoming.

Influence of history of heart failure on diagnostic performance and utility of B-type natriuretic peptide testing for acute dyspnea in the emergency department

BACKGROUND

The aim of this study was to assess the impact of a history of heart failure (HF) on emergency department (ED) B-type natriuretic peptide (BNP) testing and impact of feedback of BNP level to ED physicians.

METHODS

Admission BNP was measured in 143 patients (mean age 79 +/- 10 years) presenting to the ED with dyspnea. Emergency department physicians scored probability of HF as cause of dyspnea and categorized cause of dyspnea. An independent cardiologist determined cause of dyspnea after chart review. In 83 patients, ED physicians rescored and reclassified patients after BNP measurement and evaluated test utility.

RESULTS

The area under the receiver operating characteristic curve for BNP diagnosis of HF cause of dyspnea was significantly worse in patients with history of HF than those without (0.74 vs 0.94, P < .01) and in those with left ventricular ejection fraction <50% (0.64 vs 0.87, P < .05). A BNP cut point of 100 pg/mL had 100% sensitivity but only 41% specificity for diagnosing acute HF, whereas a cut point of 400 pg/mL had 87% sensitivity and 76% specificity. Emergency department physicians rated BNP useful in 64% of patients, and diagnostic uncertainty was reduced from 53% to 25% (P < .001).

CONCLUSION

B-type natriuretic peptide test performance for diagnosis of dyspnea cause is significantly reduced in patients with a history of HF and must be taken into consideration in the evaluation of such patients in the ED.

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.

Estabilidad de NT-proBNP en pacientes con insuficiencia cardiaca sistólica

Natriuretic peptides are extremely useful in the diagnosis and prognosis of patients with heart failure. However, it is not clear whether their values are stable. We carried out a prospective study of 30 consecutive ambulatory patients (mean age, 62.6 [12.2] years) with stable systolic heart failure, as determined by the 6-minute walk test, who were in New York Heart Association class II or III and who had a left ventricular ejection fraction <30% (mean ejection fraction, 24.2% [6.68%]). At baseline, the mean N-terminal pro-brain natriuretic peptide (NT-proBNP) level and the mean distance walked in 6 minutes were 2237.3 pg/mL and 348.26 m, respectively. At 3-month follow-up, the corresponding values were 2096.2 pg/mL and 372.05 m, respectively. No significant difference was observed in NT-proBNP level or in distance walked in 6 minutes between baseline and 3 months (P=.8). Overall, there was a good correlation (r=0.94; P< .001) between the plasma NT-proBNP level at baseline and at 3 months in patients with stable chronic heart failure due to systolic dysfunction in New York Heart Association class II or III.

Amino-Terminal Pro-Brain Natriuretic Peptide, Renal Function, and Outcomes in Acute Heart Failure

OBJECTIVES

We sought to study the individual and integrative role of amino-terminal pro-brain natriuretic peptide (NT-proBNP) and parameters of renal function for prognosis in heart failure.

BACKGROUND

Amino-terminal pro-BNP and renal impairment both predict death in patients with heart failure. Worsening of renal function in heart failure even defines the "cardiorenal syndrome."

METHODS

Seven hundred twenty subjects presenting with acute heart failure from 4 university-affiliated medical centers were dichotomized according to NT-proBNP concentration and baseline glomerular filtration rate. In addition, patients were divided according to changes in renal function. The primary end point was 60-day mortality.

RESULTS

The combination of a glomerular filtration rate (GFR) <60 ml/min/1.73 m2 with an NT-proBNP >4,647 pg/ml was the best predictor of 60-day mortality (odds ratio 3.46; 95% confidence interval 2.13 to 5.63). Among subjects with an NT-proBNP above the median, those with a GFR <60 ml/min/1.73 m2 or a creatinine rise > or =0.3 mg/dl had the worst prognosis, whereas in subjects with a NT-proBNP below the median, prognosis was not influenced by either impaired renal function at presentation or the development of renal impairment during admission.

CONCLUSIONS

The combination of NT-proBNP with measures of renal function better predicts short-term outcome in acute heart failure than either parameter alone. Among heart failure patients, the objective parameter of NT-proBNP seems more useful to delineate the "cardiorenal syndrome" than the previous criteria of a clinical diagnosis of heart failure.

Usefulness of intermediate amino-terminal pro-brain natriuretic peptide concentrations for diagnosis and prognosis of acute heart failure

Age-stratified cutpoints for aminoterminal pro-brain natriuretic peptide (NT-pro-BNP) concentrations are diagnostic in 83% of all subjects with acute dyspnea. This study analyzed subjects with NT-pro-BNP concentrations between the "rule-out" and "rule-in" cutpoints, the so-called natriuretic peptide gray zone. NT-pro-BNP concentrations, clinical characteristics, and 60-day mortality were studied in 1,256 acutely dyspneic patients from an international multicenter study. Of all subjects, 215 had gray-zone NT-pro-BNP concentrations, 116 of whom (54%) were diagnosed with heart failure (HF). Among these subjects, patients with HF were more likely to be older, to have a history of HF, to be in atrial fibrillation, and to have elevated troponin T concentrations compared with those without HF. In multivariate analysis, the use of loop diuretics on presentation (odds ratio [OR] 3.99, 95% confidence interval [CI] 1.58 to 10.1, p = 0.003), paroxysmal nocturnal dyspnea (OR 4.50, 95% CI 1.31 to 15.4, p = 0.02), jugular venous distention (OR 3.05, 95% CI = 1.06 to 8.79, p = 0.04), and the absence of cough (OR 0.18, 95% CI 0.06 to 0.52, p = 0.001) were associated with a diagnosis of acute HF in gray-zone patients. Subjects with HF and diagnostically elevated NT-pro-BNP concentrations had the highest mortality rates, subjects without HF and NT-pro-BNP concentrations < 300 ng/L had the lowest mortality rates, and subjects with gray-zone NT-pro-BNP had intermediate outcomes, irrespective of their final diagnoses. Adding specific clinical information to NT-pro-BNP improves diagnostic accuracy in subjects with intermediate NT-pro-BNP concentrations. Mortality rates in subjects with intermediate NT-pro-BNP concentrations are lower than in those with NT-pro-BNP concentrations diagnostic for HF but are higher than in subjects with NT-pro-BNP concentrations less than the gray zone.

Diagnosis of heart failure in primary care

Heart failure is becoming an increasing concern to healthcare worldwide. It is the only cardiovascular disorder that continues to increase in both prevalence and incidence, and as the population continues to age, it is expected that the prevalence of this disease will continue to rise. Guidelines on diagnosis and treatment of heart failure are to be met. Most patients with heart failure will present themselves in general practice. Therefore, the community management of heart failure has become increasingly important and the role of General Practitioners even more crucial. Improving the reliability of diagnosis in primary care is essential since determining the aetiology and stage of heart failure leads to different management choices to improve symptoms, quality of life and disease prognosis. Furthermore, early diagnosis is needed, when there may be no symptoms, since treatment can delay or reverse disease progression. Diagnostic methods may therefore need to encompass screening strategies, as well as symptomatic case identification, in the future. General Practitioners must make correct decisions regarding appropriate further investigation, treatment and referral. A correct diagnosis is the cornerstone leading to effective management. The aim of this paper is to review the role of symptoms and signs and diagnostic tests, such as, chest X-ray, ECG, natriuretic peptides and echocardiography, for diagnosing heart failure in the primary care setting. Improving diagnostic skills remains a continuous challenge for clinicians. Simple and reliable diagnostic procedures are crucial to comply with Guidelines and reduce healthcare utilisation and costs.

Use of N-terminal prohormone brain natriuretic peptide assay for etiologic diagnosis of acute dyspnea in elderly patients

BACKGROUND

B-type peptide assay (brain natriuretic peptide [BNP] and N-terminal prohormone brain natriuretic peptide [NT-proBNP]) is useful for the diagnosis of heart failure (HF), but few data are available on the use of these markers in elderly subjects. The aim of this study was to evaluate NT-proBNP assay for the diagnosis of acute left HF in patients older than 70 years hospitalized for acute dyspnea.

METHODS

We prospectively enrolled 256 elderly patients with acute dyspnea. They were categorized by 2 cardiologists unaware of NT-proBNP values into a cardiac dyspnea subgroup (left HF) and a noncardiac dyspnea subgroup (all other causes).

RESULTS

Mean age was 81 +/- 7 years, and 52% of the patients were women. The diagnoses made in the emergency setting were incorrect or uncertain in 45% of cases. The median NT-proBNP value was higher (P < .0001) in patients with cardiac dyspnea (n = 142; 7906 pg/mL) than in patients with noncardiac dyspnea (n = 112; 1066 pg/mL). The area under the receiver operating characteristic curve was 0.86 (95% CI 0.81-0.91). At a cutoff of 2000 pg/mL, NT-proBNP had a sensitivity of 86%, a specificity of 71%, and an overall accuracy of 80% for cardiac dyspnea. The use of 2 cutoffs (< 1200 and > 4500 pg/mL) resulted in an 8% error rate and a gray area englobing 32% of values.

CONCLUSION

NT-proBNP appears to be a sensitive and specific means of distinguishing pulmonary from cardiac causes of dyspnea in elderly patients. An optimal diagnostic strategy requires the use of 2 cutoffs and further investigations of patients with values in the gray area.

Amino-terminal pro-brain natriuretic peptide for the diagnosis of acute heart failure in patients with previous obstructive airway disease

STUDY OBJECTIVE

We evaluate results from amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing with or without those of clinical judgment for the evaluation of dyspneic patients with previous chronic obstructive pulmonary disease or asthma.

METHODS

As a secondary analysis of previously collected observational data from a convenience sample of 599 breathless patients, 216 patients with previous chronic obstructive pulmonary disease or asthma who presented to the emergency department were analyzed according to results of NT-proBNP, clinical impression, and their final diagnosis. Test performance of NT-proBNP in these patients with chronic obstructive pulmonary disease or asthma was examined for the group as a whole, as well as in patients with and without previous heart failure. NT-proBNP results were compared to clinician-estimated likelihood for heart failure using receiver operating curves and as a function of NT-proBNP plus clinical evaluation. The final diagnosis was determined by 2 independent cardiologists blinded to NT-proBNP using all available data from the 60-day follow-up period.

RESULTS

Overall, 55 patients (25%) had acute heart failure; the median value of NT-proBNP was higher in these patients compared with those without acute heart failure (2,238 vs 178 pg/mL); use of cut points of 450 pg/mL for patients younger than 50 years and 900 pg/mL for patients 50 years or older yielded a sensitivity of 87% (95% confidence interval [CI] 72% to 93%) and a specificity of 84% (95% CI 76% to 88%). In patients without previous heart failure (n=164), median NT-proBNP levels were also higher in patients with heart failure of new onset compared with those with chronic obstructive pulmonary disease or asthma exacerbation (1561 versus 168 pg/mL). High clinical suspicion for acute heart failure (probability >80%) detected only 23% of patients with new-onset heart failure, whereas 82% of these patients had elevated NT-proBNP levels. In patients who had both previous acute heart failure and chronic obstructive pulmonary disease or asthma (n=52), median NT-proBNP levels were significantly higher in those with acute heart failure (4,435 pg/mL) than patients with chronic obstructive pulmonary disease or asthma exacerbation (536 pg/mL). In patients with acute-on-chronic heart failure, NT-proBNP levels were elevated in 91%, whereas clinical impression considered only 39% of cases as high likelihood for acute heart failure.

CONCLUSION

NT-proBNP may be a useful adjunct to standard clinical evaluation of dyspneic patients with previous obstructive airway disease.