Diagnostic and prognostic evaluation of left ventricular systolic heart failure by plasma N-terminal pro-brain natriuretic peptide concentrations in a large sample of the general population

Natriuretic peptide vs. clinical information for diagnosis of left ventricular systolic dysfunction in primary care

BACKGROUND

Screening of primary care patients at risk for left ventricular systolic dysfunction by a simple blood-test might reduce referral rates for echocardiography. Whether or not natriuretic peptide testing is a useful and cost-effective diagnostic instrument in primary care settings, however, is still a matter of debate.

METHODS

N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, clinical information, and echocardiographic data of left ventricular systolic function were collected in 542 family practice patients with at least one cardiovascular risk factor. We determined the diagnostic power of the NT-proBNP assessment in ruling out left ventricular systolic dysfunction and compared it to a risk score derived from a logistic regression model of easily acquired clinical information.

RESULTS

23 of 542 patients showed left ventricular systolic dysfunction. Both NT-proBNP and the clinical risk score consisting of dyspnea at exertion and ankle swelling, coronary artery disease and diuretic treatment showed excellent diagnostic power for ruling out left ventricular systolic dysfunction. AUC of NT-proBNP was 0.83 (95% CI, 0.75 to 0.92) with a sensitivity of 0.91 (95% CI, 0.71 to 0.98) and a specificity of 0.46 (95% CI, 0.41 to 0.50). AUC of the clinical risk score was 0.85 (95% CI, 0.79 to 0.91) with a sensitivity of 0.91 (95% CI, 0.71 to 0.98) and a specificity of 0.64 (95% CI, 0.59 to 0.67). 148 misclassifications using NT-proBNP and 55 using the clinical risk score revealed a significant difference (McNemar test; p < 0.001) that was based on the higher specificity of the clinical risk score.

CONCLUSION

The evaluation of clinical information is at least as effective as NT-proBNP testing in ruling out left ventricular systolic dysfunction in family practice patients at risk. If these results are confirmed in larger cohorts and in different samples, family physicians should be encouraged to rely on the diagnostic power of the clinical information from their patients.

Cardiorenal syndrome: refining the definition of a complex symbiosis gone wrong

BACKGROUND

The term "cardiorenal syndrome" has generally been reserved for declining renal function in the setting of advanced congestive heart failure. Considering the complex and bi-directional relationship between the heart and the kidneys, we postulate refining the definition to recognize the symbiotic nature of these organs.

DISCUSSION

We divide the cardiorenal syndrome into five subtypes: type I, acute cardiorenal syndrome; type II, chronic cardiorenal syndrome; type III, acute renocardiac syndrome; type IV, chronic renocardiac syndrome; and type V, secondary cardiorenal syndrome.

CONCLUSIONS

As early recognition of dysfunction in one organ may prove important in mitigating the spiral of co-dysfunction in both, the need for early and treatment-guiding biomarkers, along with their characteristics, are also discussed.

Amino-terminal pro-B-type natriuretic peptides: testing in general populations

Screening of general populations with amino-terminal pro-B-type natriuretic peptides (NT-proBNP) holds promise for the detection of significant underlying cardiac structural and functional abnormalities, as well as for the early detection of the propensity to develop future cardiovascular events. In comparative studies to date, NT-proBNP performs at least as well as BNP in the detection of heart disease and prognostication in the general population. In some studies and subgroups, NT-proBNP appears to outperform BNP in population screening. More needs to be learned about noncardiac sources of NT-proBNP variation in "apparently well" populations. Better understanding of these factors may allow optimization of thresholds for screening of apparently well patients and concomitant delineation of patient populations in whom NT-proBNP screening is less appropriate.

Evidence for the use of B-type natriuretic peptides for screening asymptomatic populations and for diagnosis in primary care

OBJECTIVES

To determine the screening and diagnostic properties of BNP and NT-proBNP for heart failure in primary care.

DESIGN AND METHODS

We conducted a systematic review of randomized control trials and observational (cohort or case-control) studies of heart failure detection using B-type natriuretic peptides published in English from January 1989 to February 2005. We extracted or calculated sensitivity, specificity, positive and negative likelihood ratios, area under the receiver-operator characteristic curve and diagnostic odds ratio (DOR).

RESULTS

We included 17 studies (7 screening, 9 diagnosis in primary care or specialised clinic, 1 both). There was considerable heterogeneity within the study populations, reference standard for diagnosis, and B-type natriuretic peptide decision point. Sensitivity ranged from 26% to 98%; and specificity from 44% to 88%. For screening, the Diagnostic Odds Ratio (DOR) ranged from 2.7 to 29, and for diagnosis from 2.8 to 137.

CONCLUSIONS

The performance characteristics of B-type natriuretic peptides measurement are not suitable for screening asymptomatic patients. For diagnosis in primary care, low B-type natriuretic peptide values may be used to rule-out heart failure but, due to poor specificity, high values cannot be used to rule-in the condition.

Independent value of echocardiography and N-terminal pro-natriuretic Peptide for the prediction of major outcomes in patients with suspected heart failure

N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and echocardiography have been shown to have diagnostic and prognostic value for the assessment of heart failure (HF) in the community. This study evaluated whether echocardiography and serum NT-pro-BNP estimation have independent value for the prediction of major outcome in patients with suspected HF from the community. Accordingly, 137 patients with suspected HF referred from the community were followed up after undergoing clinical assessment, electrocardiography, NT-pro-BNP estimation, and echocardiography. Abnormal echocardiogram was defined as visual left ventricular ejection fraction </=45% or left atrial volume index >26 ml/m(2) or presence of left ventricular hypertrophy or significant valvular heart disease. Data were obtained in 132 patients (96%) over a mean follow-up period of 26 +/- 7 months during which 19 (14%) developed major cardiac events (14 deaths and 5 HF admissions). Univariate predictors for major cardiac event were age (p = 0.05), male gender (p = 0.007), presence of clinical signs of HF (p = 0.02), NT-pro-BNP level >/=50 pmol/L (p <0.001), abnormal electrocardiogram (p = 0.02), and abnormal echocardiogram (p = 0.004). However, the only independent predictors were male gender (odds ratio 3.09, 95% confidence interval 1.01 to 9.46, p = 0.05), NT-pro-BNP level >/=50 pmol/L (odds ratio 5.78, 95% confidence interval 1.63 to 20.5, p = 0.007), and abnormal echocardiogram (odds ratio 11.1, 95% confidence interval 1.43 to 85.6, p = 0.02). In conclusion, NT-pro-BNP and abnormal echocardiogram provided independent information for predicting adverse outcome in patients with suspected HF referred from the community.

Reference intervals and decision limits for B-type natriuretic peptide (BNP) and its precursor (Nt-proBNP) in the elderly

BACKGROUND

Elderly patients have the highest prevalence of heart failure (HF). The aims of the study were to establish a reference interval for B-type natriuretic peptide (BNP) and (Nt-proBNP) in elderly people, and to identify clinically relevant decision limits based on long-term outcome.

METHODS

Plasma concentrations of BNP and Nt-proBNP were measured from two elderly populations: 218 healthy subjects (mean age 73 years, population I), and 474 patients (mean age 73 years, population II) with symptoms associated with HF. Study population II was followed for 6 years with registration of all cardiovascular mortality.

RESULTS

An association between both BNP and Nt-proBNP concentrations and age was found. The upper limit for the reference intervals in the healthy elderly (population I) was: BNP< or =28 pmol/L (< or =97 ng/L), and Nt-proBNP< or =64 pmol/L (< or =540 ng/L). Based on cardiovascular mortality, decision limits for BNP (approximately 50 pmol/L, approximately 170 ng/L) and Nt-proBNP ( approximately 200 pmol/L, approximately 1700 ng/L) (population II) were determined.

CONCLUSIONS

Besides establishing reference intervals for BNP and Nt-proBNP in an elderly population, a higher clinically relevant decision limit for BNP and Nt-proBNP was identified, indicating additive prognostic information of the peptides on top of measurements by echocardiography. Therefore, both reference intervals and decision limits should be included in clinical practice.

Comparison of the clinical utility of atrial and B type natriuretic peptide measurement for the diagnosis of systolic dysfunction in a low-risk population

BACKGROUND

Measurement of B type natriuretic peptide and its N terminal prohormone (NTproBNP) can now be performed routinely by automated high-throughput immunoassays. The study compared measurement of NTproBNP with measurement of N terminal pro-atrial natriuretic peptide (NTproANP) for detection of ventricular systolic dysfunction in primary care.

METHODS

734 subjects aged >45 years (349 men and 385 women, median age 58 years, range 45-89, interquartile range 51-67 years) from seven representative general practices attended for echocardiography with determination of ejection fraction and completed a questionnaire. Blood samples were collected into gel serum separation tubes (Becton-Dickinson, Franklin Lakes, New Jersey, USA), the serum separated and aliquots stored frozen at -70 degrees C until analyses. Samples were analysed for NTproBNP (Roche Diagnostics, Lewes, UK; coefficient of variation (CV) 3.2-2.4%) and for NTproANP (Biomedica, Vienna, Austria; CV 5.6-10.1%). Echocardiography was used as the diagnostic "gold standard", with ventricular systolic dysfunction defined as abnormal when there was an ejection fraction of <or=40%. Patients were dichotomised by ejection fraction from 50% to 30%, and receiver operating characteristic curves constructed and the area under the curve (AUC) compared.

RESULTS

At 40% ejection fraction, NTproANP and NTproBNP showed AUCs of, respectively, 0.738 (0.601-0.875) and 0.973 (0.958-0.989), p<0.004.

CONCLUSION

NTproBNP is superior to NTproANP for detection of systolic dysfunction.

Cost effectiveness of the B type natriuretic peptide, electrocardiography, and portable echocardiography for the assessment of patients from the community with suspected heart failure

To analyze the cost efficiency of guidelines proposed by the European Society of Cardiology for investigation of patients in the community with suspected heart failure (HF). The guidelines recommend electrocardiography (ECG) and/or measurement of N-terminal pro B type natriuretic peptide (NTproBNP) prior to referral for echocardiography. Portable echocardiography is a new but validated technique for the evaluation of HF. Accordingly, 137 suspected HF patients (mean age 71+/-13 years) from the community underwent ECG and NTproBNP estimation prior to portable echocardiography. Cost effective analysis for ECG, NTproBNP, portable echocardiography and a combination of these; to define valvular heart disease, right ventricular dysfunction and left ventricular systolic and diastolic dysfunction were compared. The cost of abnormal NTproBNP followed by portable echocardiography, abnormal ECG followed by portable echocardiography and portable echocardiography alone for the detection per case of left ventricular systolic dysfunction were 313 euro, 310 euro, and 296 euro respectively and that for detection per case of any of the aforementioned cardiac abnormalities were 198 euro, 223 euro, and 170 euro respectively. Portable echocardiography alone for the assessment of suspected HF patients resulted in a cost reduction of up to 1083 euro for the detection per case of cardiac abnormality. While a strategy where initial NTproBNP estimation is cost effective in detecting any causes of heart failure, portable echocardiography remains the most costeffective strategy to assess patients from the community with suspected heart failure.

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.

Higher serum tenascin-C levels reflect the severity of heart failure, left ventricular dysfunction and remodeling in patients with dilated cardiomyopathy

BACKGROUND

Tenascin-C (TN-C), an extracellular matrix glycoprotein, is specifically expressed at high levels during embryonic development, but not in the adult heart. TN-C reappears at sites of inflammatory tissue remodeling or wound healing under various pathologic conditions, such as acute myocardial infarction, acute myocarditis, and some cases of cardiomyopathy. Therefore, the expression of TN-C might be useful for detecting the clinical characteristics of, and ventricular remodeling in, dilated cardiomyopathy (DCM).

METHODS AND RESULTS

Circulating serum TN-C levels in 107 patients with DCM were measured using an ELISA kit. Clinical data were also assessed by Pearson's or Spearman's correlation analysis to estimate correlations between variables. Serum TN-C levels in DCM patients were higher than those in normal controls (p<0.001). TNC levels showed a significantly positive correlation with New York Heart Association functional class (p<0.001), B-type natriuretic peptide level (p<0.001), cardiothoracic ratio on chest X-ray (p<0.01), left ventricular end-diastolic diameter (p<0.05) and left ventricular end-systolic diameter (p<0.01), and a significantly negative correlation with left ventricular ejection fraction (p<0.01).

CONCLUSIONS

The findings suggest that increased serum TN-C levels indicate the severity of heart failure, left ventricular dysfunction and remodeling in patients with DCM.

Effect of atrial fibrillation on plasma NT-proBNP in chronic heart failure

BACKGROUND

Brain natriuretic peptides are elevated in patients with systolic heart failure (HF) as well as in patients with atrial fibrillation (AF) and normal left ventricular ejection fraction (LVEF) and are strong predictors of death in HF patients. The aim of our study was to examine the levels of N-terminal pro brain natriuretic peptide (NT-proBNP) in patients with HF and AF versus HF and sinus rhythm (SR) and if NT-proBNP has prognostic influence in patients with AF.

METHODS

We included 245 patients (72% men, 70 years) with HF referred to a HF clinic. NT-proBNP was measured at referral (baseline).

RESULTS

At baseline, 26% had AF and at follow-up 35% of the surviving patients. Patients with AF were older than patients with SR (p=0.009), but LVEF and NYHA distribution were similar. Median NT-proBNP levels were higher: 2528 vs. 899 pg/ml (p<0.001). NT-proBNP was significantly correlated with AF at baseline (p<0.001), age (p=0.001), P-creatinine (p<0.001) and reduced LVEF (p=0.002). NT-proBNP was an independent predictor of death in patients with AF, adjusted HR 4.0 (95% CI 1.6-10.2) (p=0.003).

CONCLUSION

NT-proBNP levels are higher in HF patients with AF than in HF patients with SR and has prognostic value despite the presence of AF.

N-terminal pro-B-type natriuretic peptide as a diagnostic test for ventricular dysfunction in patients with coronary disease: data from the heart and soul study

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP) testing is useful for diagnosing acute decompensated heart failure. Whether NT-proBNP can be used to detect ventricular dysfunction in patients with stable coronary heart disease (CHD) and no history of heart failure is unknown.

METHODS

We measured NT-proBNP levels and performed transthoracic echocardiography in 815 participants from the Heart and Soul Study, who had stable CHD and no history of heart failure. We hypothesized that NT-proBNP concentrations lower than 100 pg/mL would rule out ventricular dysfunction and concentrations higher than 500 pg/mL would identify ventricular dysfunction. We calculated sensitivities, specificities, likelihood ratios, and areas under the receiver operating characteristic curves for NT-proBNP as a case-finding instrument for systolic and diastolic dysfunction.

RESULTS

Of the 815 participants with no history of heart failure, 68 (8%) had systolic dysfunction defined as a left ventricular ejection fraction of 50% or lower. Of the 730 participants for whom the presence or absence of diastolic dysfunction could be determined, 78 (11%) had diastolic dysfunction defined as a pseudonormal or restrictive filling pattern. The overall area under the receiver operating characteristic curve for detecting systolic or diastolic dysfunction was 0.78 (95% confidence interval, 0.74-0.82). Likelihood ratios were 0.28 for NT-proBNP concentrations lower than 100 pg/mL, 0.95 for concentrations between 100 and 500 pg/mL, and 4.1 for concentrations higher than 500 pg/mL. A test result lower than 100 pg/mL reduced the probability of ventricular dysfunction from a pretest probability of 18% to a posttest probability of 6%. A test result higher than 500 pg/mL increased the probability of ventricular dysfunction from a pretest probability of 18% to a posttest probability of 47%. A test result between 100 and 500 pg/mL did not change the probability of ventricular dysfunction.

CONCLUSION

In patients with stable CHD and no history of heart failure, NT-proBNP levels lower than 100 pg/mL effectively rule out ventricular dysfunction, with a negative likelihood ratio of 0.28.

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.

N-terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP), cardiovascular events, and mortality in patients with stable coronary heart disease

CONTEXT

Identification of individuals at high risk for cardiovascular events is important for the optimal use of primary and secondary prevention measures.

OBJECTIVE

To determine whether plasma levels of amino terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP) predict cardiovascular events or death independent of other available prognostic tests.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study (2000-2002) of 987 individuals in California with stable coronary heart disease in the Heart and Soul Study, who were followed up for a mean of 3.7 (range, 0.1-5.3) years.

MAIN OUTCOME MEASURES

The association of baseline NT-proBNP levels with death or cardiovascular events (myocardial infarction, stroke, or heart failure). Traditional clinical risk factors, echocardiographic measures, ischemia, other biomarkers, and New York Heart Association classification were adjusted for to determine whether NT-proBNP levels were independent of other prognostic factors. Receiver operating characteristic (ROC) curves were used to assess the incremental prognostic value of adding NT-proBNP level to these other measures.

RESULTS

A total of 256 participants (26.2%) had a cardiovascular event or died. Each increasing quartile of NT-proBNP level (range of quartile 1, 8.06-73.95 pg/mL; quartile 2, 74-174.5 pg/mL; quartile 3, 175.1-459 pg/mL; quartile 4, > or =460 pg/mL) was associated with a greater risk of cardiovascular events or death, ranging from 23 of 247 (annual event rate, 2.6%) in the lowest quartile to 134 of 246 (annual event rate, 19.6%) in the highest quartile (unadjusted hazard ratio [HR] for quartile 4 vs quartile 1, 7.8; 95% confidence interval [CI], 5.0-12.1; P<.001). Each SD increase in log NT-proBNP level (1.3 pg/mL) was associated with a 2.3-fold increased rate of adverse cardiovascular outcomes (unadjusted HR, 2.3; 95% CI, 2.0-2.6; P<.001), and this association persisted after adjustment for all of the other prognostic measures (adjusted HR, 1.7; 95% CI, 1.3-2.2; P<.001). The addition of NT-proBNP level to standard clinical assessment and complete echocardiographic parameters significantly improved the area under the ROC curves for predicting subsequent adverse cardiovascular outcomes (0.80 for clinical risk factors and echocardiographic parameters plus log NT-proBNP vs 0.76 for clinical risk factors and echocardiographic parameters only; P = .006).

CONCLUSIONS

Elevated levels of NT-proBNP predict cardiovascular morbidity and mortality, independent of other prognostic markers, and identify at-risk individuals even in the absence of systolic or diastolic dysfunction by echocardiography. Level of NT-proBNP may help guide risk stratification of high-risk individuals, such as those with coronary heart disease.

Biomarkers of cardiovascular damage

Acute coronary syndromes (ACS) are due to the rupture or erosion of atheromatous plaques. This produces, depending on plaque size, vascular anatomy and degree of collateral circulation, progressive tissue ischaemia which may progress to cardiomyocyte necrosis. This may then result in cardiac remodelling. Serum biomarkers are available which can be used for diagnosis of all of these stages. Markers to detect myocardial ischaemia at the pre-infarction stage are potentially the most interesting but also the most challenging. An ischaemia marker offers the opportunity to intervene to prevent progression to infarction. The problems with potential ischaemia markers are specificity and the reference diagnostic standard against which they can be judged. To date, only one, ischaemia-modified albumin(R), has reached the point where clinical studies can be performed. The measurement of the cardiac troponins, cardiac troponin T and cardiac troponin I, have become recognised as the diagnostic reference standard for myocardial necrosis. The sensitive nature of these tests has also revealed that myocardial necrosis is also found in a range of other clinical situations, highlighting the need to use all clinical information for diagnosis of acute myocardial infarction. The measurement of B-type natriuretic peptides can be shown to be diagnostic and prognostic in both ACS and detecting the sequelae of post-infarction myocardial insufficiency. The role of the B-type natriuretic peptides in detection of cardiac failure, both acute and chronic, is well defined but remains the subject of further studies, in ACS.

N-Terminal ProBNP Levels Can Predict Cardiac Failure After Cardiac Surgery

BACKGROUND

The aim of this study was to evaluate the relationship between the preoperative N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and the need for the inotropic support in the early postoperative period of patients undergoing coronary artery bypass graft surgery.

METHODS AND RESULTS

The patients were divided into 2 groups: NT-proBNP level<220 pg/ml (group A, n=26) or >220 pg/ml (group B, n=26). The normal value for NT-proBNP level was accepted as <220 pg/ml. The cardiac output was measured on arrival in intensive care and at the 16th hour. The groups were compared with respect to early postoperative hemodynamic measurements, urinary output, use of inotropic agents and requirement for additional cardiac-assist devices. Left ventricular ejection fraction, cardiac output and cardiac index were lower in group B and inotropic agents were used for a longer period of time and at higher doses in this group (p<0.05).

CONCLUSION

Measurement of the NT-proBNP level in the period before cardiac surgery can indicate the postoperative prognosis of the patient and may be a predictor of the need for postoperative inotropic treatment.

Biomarkers of Cardiovascular Damage and Dysfunction—An Overview

Acute coronary syndromes (ACS) are due to the rupture or erosion of atheromatous plaques. This produces, depending on plaque size, vascular anatomy and degree of collateral circulation, progressive tissue ischaemia which may progress to cardiomyocyte necrosis and subsequent cardiac remodelling. Cardiac biomarkers can be used for diagnosis and assessment of all of these stages. Markers to detect myocardial ischaemia at the pre-infarction stage are potentially the most interesting but also the most challenging. An ischaemia marker offers the opportunity to intervene to prevent progression to infarction. The challenges with potential ischaemia markers are specificity and the diagnostic reference standard for assessment. To date, only one, ischaemia modified albumin, has reached the point where clinical studies can be performed. The measurement of the cardiac troponins, cardiac troponin T and cardiac troponin I, has become the diagnostic standard as the biomarker of myocardial necrosis. The sensitive nature of troponin measurement has also revealed that myocardial necrosis is also found in a range of other clinical situations. This illustrates the need to use all clinical information for diagnosis of acute myocardial infarction. The measurement of B type natriuretic peptides can be shown to be diagnostic and prognostic for both acute ACS and detecting the sequelae of post infarction myocardial insufficiency. The role of the B type natriuretic peptides in detection of cardiac failure, acute and chronic, is well defined. Their role in ACS remains the subject of further studies.

Increased plasma concentrations of N-terminal pro-B-type natriuretic peptide in patients with mild primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) is associated with heart disease. The aims of the present study were to evaluate how cardiac function and secretion of N-terminal pro-B-type natriuretic peptide (NT-proBNP) correlate in patients with mild PHPT, and how the plasma level of NT-proBNP is influenced by cure of the parathyroid disease.

DESIGN AND PATIENTS

Forty-two patients with PHPT without symptoms of heart disease were examined before and 1 year after curative parathyroidectomy.

MEASUREMENTS

Plasma or serum concentrations of NT-proBNP, calcium, PTH, creatinine, oestradiol, testosterone and SHBG were measured. Cardiac function was evaluated by equilibrium radionuclide angiography (ERNA).

RESULTS

At baseline, NT-proBNP levels correlated negatively with systolic function [left ventricular ejection fraction (LVEF), P < 0.001]. Twelve per cent of the patients had NT-proBNP levels above normal reference values preoperatively. One year postoperatively, the corresponding proportion was 21%. The mean plasma concentration of NT-proBNP increased after parathyroidectomy (P < 0.01) in parallel with a dip in diastolic function (peak filling rate, P < 0.05) and a falling trend in systolic function (LVEF, P = 0.08). The postoperative percentage changes in circulating NT-proBNP and total oestradiol correlated positively (P < 0.05).

CONCLUSIONS

Patients with mild PHPT and normal renal function may have high levels of circulating NT-proBNP despite the absence of symptomatic heart disease. Cure of the parathyroid disease is followed by a further increase in NT-proBNP secretion in parallel with ERNA measures, indicating subclinical changes in heart function. These results are in line with data indicating an association between PHPT and increased risk of premature death.

Utility of N terminal pro brain natriuretic peptide in elderly patients

OBJECTIVE

To evaluate the utility of N terminal pro brain natriuretic peptide (NT-proBNP) as a diagnostic marker for diastolic dysfunction or failure, systolic dysfunction, and significant valve disorders in patients over 75 years.

DESIGN

Cohort study.

SETTING

Outpatient echocardiography service in a district general hospital.

PARTICIPANTS

100 consecutive patients.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive predictive values, negative predictive values, and area under receiver operating characteristic curve for NT-proBNP assay in the diagnosis of left ventricular diastolic dysfunction or failure, systolic dysfunction, and significant valve disorders.

RESULTS

For diagnosis of systolic dysfunction NT-proBNP level of 424 pg/ml had a sensitivity of 96%, specificity of 45%, positive predictive value of 36%, and negative predictive value of 96%. The area under the curve was 0.71 (95% confidence intervals: 0.69 to 0.89). In valve heart disease, level of 227 pg/ml had sensitivity of 91%, specificity of 43%, positive predictive value of 40%, and negative predictive value of 92%. Patients with diastolic dysfunction/failure had lower plasma concentrations.

CONCLUSIONS

This study showed that NT-proBNP had excellent negative predictive value for systolic dysfunction and significant valve disorders in very elderly patients. It increased significantly in systolic dysfunction, valve heart disease, and atrial fibrillation. NT-proBNP is not useful in the diagnosis of diastolic dysfunction or diastolic heart failure using standard echocardiography criteria.

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.

NT-proBNP levels, echocardiographic findings, and outcomes in breathless patients: results from the ProBNP Investigation of Dyspnoea in the Emergency Department (PRIDE) echocardiographic substudy

AIMS

The objective of this study was to determine the integrative utility of measuring plasma NT-proBNP levels with echocardiography in the evaluation of dyspnoeic patients.

METHODS AND RESULTS

Of 599 emergency department patients enrolled in a clinical study of NT-proBNP at a tertiary-care hospital, 134 (22%) had echocardiographic results available for analysis. Echocardiographic parameters correlating with NT-proBNP levels were determined using multivariable linear-regression analysis. Independent predictors of 1-year mortality were determined using Cox-proportional hazard analysis. Independent relationships were found between NT-proBNP levels and ejection fraction (P = 0.012), tissue Doppler early and late mitral annular diastolic velocities (P = 0.007 and 0.018), right ventricular (RV) hypokinesis (P = 0.006), and tricuspid regurgitation severity (P < 0.001) and velocity (P = 0.007). An NT-proBNP level <300 pg/mL had a negative predictive value of 91% for significant left ventricular systolic and diastolic dysfunction. Overall 1-year mortality was 20.1% and was independently predicted by NT-proBNP level [HR 8.65, 95% confidence interval (CI) 2.7-27.8, P = 0.0003], ejection fraction (HR 0.95, 95% CI 0.91-0.99, P = 0.009), RV dilation (HR 2.98, 95% CI 1.05-12.8, P = 0.04), and systolic blood pressure (HR 0.97, 95% CI 0.96-0.99, P = 0.01).

CONCLUSION

NT-proBNP levels correlate with, and provide important prognostic information beyond, echocardiographic parameters of cardiac structure and function. Routine NT-proBNP testing may thus be useful to triage patients to more timely or deferred echocardiographic evaluation.

Is N-terminal pro B-type natriuretic peptide (NT-proBNP) a useful screening test for angiographic findings in patients with stable coronary disease?

BACKGROUND

Whether N-terminal pro B-type natriuretic peptide (NT-proBNP) is a useful screening tool for angiographic coronary artery disease in patients with angina is not known. Therefore, the purpose of this study was to assess the diagnostic test performance of NT-proBNP in detecting coronary atherosclerotic lesions, as assessed by coronary angiography.

METHODS

We examined 1034 patients referred for diagnostic angiography because of symptoms or signs of coronary artery disease. The diagnostic value of NT-proBNP in predicting clinically significant coronary disease was assessed.

RESULTS

In a multiple logistic regression model, NT-proBNP above the upper normal limit (125 pg/mL) predicted clinically significant coronary disease at angiography independently of traditional cardiovascular risk factors and invasive measurements of left ventricular function (odds ratio 2.1, 95% CI 1.3-3.2, P = .001). The ability of NT-proBNP in detecting clinically significant coronary disease at angiography was modest, however, with sensitivity of 0.61, specificity 0.60, accuracy 61 (95% CI 58-64), positive likelihood ratio 1.5 (95% CI 1.3-1.8), negative likelihood ratio 0.7 (95% CI 0.6-0.8), and area under the ROC curve 0.61 (95% CI 0.58-0.64).

CONCLUSIONS

NT-proBNP is associated with clinically significant coronary disease at angiography, independently of left ventricular dysfunction. However, NT-proBNP is not a useful screening test for diagnosing significant angiographic lesions in patients with stable coronary disease.

NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1256 patients: the International Collaborative of NT-proBNP Study

AIMS

Experience with amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing for evaluation of dyspnoeic patients with suspected acute heart failure (HF) is limited to single-centre studies. We wished to establish broader standards for NT-proBNP testing in a study involving four sites in three continents.

METHODS AND RESULTS

Differences in NT-proBNP levels among 1256 patients with and without acute HF and the relationship between NT-proBNP levels and HF symptoms were examined. Optimal cut-points for diagnosis and prognosis were identified and verified using bootstrapping and multi-variable logistic regression techniques. Seven hundred and twenty subjects (57.3%) had acute HF, whose median NT-proBNP was considerably higher than those without (4639 vs. 108 pg/mL, P<0.001), and levels of NT-proBNP correlated with HF symptom severity (P=0.008). An optimal strategy to identify acute HF was to use age-related cut-points of 450, 900, and 1800 pg/mL for ages <50, 50-75, and >75, which yielded 90% sensitivity and 84% specificity for acute HF. An age-independent cut-point of 300 pg/mL had 98% negative predictive value to exclude acute HF. Among those with acute HF, a presenting NT-proBNP concentration >5180 pg/mL was strongly predictive of death by 76 days [odds ratio=5.2, 95% confidence interval (CI)=2.2-8.1, P<0.001].

CONCLUSION

In this multi-centre, international study, NT-proBNP testing was valuable for diagnostic evaluation and short-term prognosis estimation in dyspnoeic subjects with suspected or confirmed acute HF and should establish broader standards for use of the NT-proBNP in dyspnoeic patients.

The prognostic value of N-terminal proB-type natriuretic peptide

The heart is not only a pump, but also it is an endocrine organ. Cardiac stretch and overload stimulate the secretion of natriuretic peptides, which have a variety of beneficial actions, such as vasodilation and natriuresis. Cardiac-derived natriuretic peptides, especially B-type natriuretic peptide (BNP), have emerged as useful biomarkers for the diagnosis, and potentially the treatment, of heart failure patients. The inactive amino-terminal fragment of the BNP prohormone (NT-proBNP), which is more stable than mature BNP, has also been recognized as an aid in the diagnosis of left-ventricular systolic dysfunction. Furthermore, elevated NT-proBNP concentrations have been shown to be predictive of poor prognosis in a variety of cardiovascular diseases, suggesting that it could be useful for risk stratification of patients. This review summarizes current literature that has addressed the issue of NT-proBNP as a prognostic tool in heart failure, acute coronary syndromes and other conditions.

Amino-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide in the general community: determinants and detection of left ventricular dysfunction

OBJECTIVES

This study sought to characterize factors influencing amino-terminal pro-B-type natriuretic peptide (NT-proBNP) and to evaluate the ability of NT-proBNP to detect left ventricular (LV) dysfunction in a large community sample.

BACKGROUND

Secretion of BNP increases in cardiac disease, making BNP an attractive biomarker. Amino-terminal proBNP, a fragment of the BNP prohormone, is a new biomarker. We evaluated factors influencing NT-proBNP in normal patients and compared the ability of NT-proBNP and BNP to detect LV dysfunction in a large community sample.

METHODS

Amino-terminal pro-BNP was determined in plasma samples of a previously reported and clinically and echocardiographically characterized random sample (n = 1,869, age > or =45 years) of Olmsted County, Minnesota.

RESULTS

In normal patients (n = 746), female gender and older age were the strongest independent predictors of higher NT-proBNP. Test characteristics for detecting an LV ejection fraction < or =40% or < or =50% were determined in the total sample with receiver operating characteristic curves. Amino-terminal pro-BNP had significantly higher areas under the curve for detecting an LV ejection fraction < or =40% or < or =50% than BNP in the total population and in several male and age subgroups, whereas areas were equivalent in female subgroups. Age- and gender-adjusted cutpoints improved test characteristics of NT-proBNP. Both assays detected patients with systolic and/or moderate to severe diastolic dysfunction to a similar degree, which was less robust than the detection of LV systolic dysfunction alone.

CONCLUSIONS

Amino-terminal pro-BNP in normal patients is affected primarily by gender and age, which should be considered when interpreting values. Importantly, in the entire population sample NT-proBNP performed at least equivalently to BNP in detecting LV dysfunction and was superior in some subgroups in detecting LV systolic dysfunction.

Increased plasma N-terminal pro-B-type natriuretic peptide and markers of inflammation related to atherosclerosis in patients with primary hyperparathyroidism

OBJECTIVE

Increased risk of cardiovascular disease has been reported in patients with primary hyperparathyroidism (PHPT). The aim of this study was to evaluate novel plasma risk markers of cardiovascular disease in patients with PHPT.

DESIGN

PHPT patients were evaluated with a control group. Patients who underwent parathyroidectomy were re-evaluated after 7 and 18 months.

PATIENTS

Forty-five PHPT patients and 40 matched controls participated. Seventeen patients underwent parathyroidectomy.

MEASUREMENTS

Plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha), lipids and blood pressure were measured. In 27 patients a bicycle exercise test and radionuclide angiography were performed, and repeated in those who underwent parathyroidectomy.

RESULTS

Plasma NT-proBNP, CRP and TNF-alpha, but not IL-6, were higher in patients with PHPT than in controls (P < 0.01 and P = 0.17, respectively). In patients with PHPT, NT-proBNP correlated with systolic blood pressure, left ventricular end-diastolic volume, and peak oxygen uptake (all P < 0.01). Log CRP correlated with systolic and diastolic blood pressure (both P < 0.05) and log IL-6 (P < 0.01). No significant correlations were observed between PTH or calcium and risk markers of cardiovascular disease. No decrease in NT-proBNP, markers of inflammation or blood pressure was observed after parathyroidectomy.

CONCLUSIONS

Our data suggest that hypertension or other factors, rather than plasma calcium or PTH, could explain the increased levels of the inflammatory markers and NT-proBNP in PHPT. We therefore suggest that aggressive treatment of hypertension should be initiated in patients with PHPT to try to reduce the increased cardiovascular mortality described in PHPT. Further prospective studies are needed to validate the suggestion that increased levels of NT-proBNP and inflammatory markers also represent strong prognostic markers of cardiovascular disease in patients with PHPT.

Role of N-terminal pro-B-type natriuretic peptide in risk stratification in patients presenting in the emergency room

BACKGROUND

Natriuretic peptides are promising markers in diagnosing acute and chronic heart failure and assessing prognosis in these patients. Increasing routine use to unselected patients is challenged by false-positive results. The aims of this study were to assess (a) the distributions of N-terminal B-type natriuretic peptide (NT-proBNP) values in various diagnostic groups, (b) factors that influence NT-proBNP, and (c) the value of NT-proBNP in risk stratification in unselected emergency room (ER) patients.

METHODS

NT-proBNP was measured in 876 unselected consecutive patients [mean (SD) age, 58 (18) years; 53% male] attending the ERs of 2 university hospitals and 1 community hospital. Diagnoses, age, sex, hemoglobin, creatinine (CREA), C-reactive protein (CRP), troponin T, and intensity of care were documented. In a subset consisting of all 417 patients at 1 center, in-hospital follow-up was completed with respect to a complicated clinical course, including intensive care treatment and death.

RESULTS

NT-proBNP was significantly increased in patients with cardiac diagnoses or histories compared with patients with only pulmonary or other diagnoses. In patients with other diagnoses, NT-proBNP values increased significantly with the number of atherosclerotic risk factors (P=0.044). Age, renal function, CRP, and to a much lesser extent, hemoglobin significantly influenced NT-proBNP values. The amount of care was positively correlated with NT-proBNP (P<0.001). Classification and regression tree analysis showed a superior impact of NT-proBNP for identification of high-risk patients.

CONCLUSIONS

NT-proBNP is a promising marker for identification of patients with structural heart disease in the ER and a suitable tool for risk stratification. Its use in the ER should be limited to clearly clinically defined patient groups at present to avoid a potential excess of additional diagnostic procedures in positive but asymptomatic patients.

Plasma N-terminal pro-brain natriuretic peptide concentration predicts coronary events in men at work: a report from the BELSTRESS study

AIMS

Increased levels of neurohormonal markers, including the N-terminal fragment of pro-brain natriuretic peptide (NT-pro-BNP), have been shown to be of prognostic significance in patients with heart failure or coronary heart disease (CHD). The aim of this study was to study the predictive value of NT-pro-BNP for coronary events in a middle-aged population of men at work.

METHODS AND RESULTS

A nested case-control study was performed in a large cohort of over 10 000 men at work (aged 35-59) after a median follow-up of 2.66 years. In total, 66 individuals who developed coronary events were matched on a 3-to-1 basis to 198 controls free of coronary events during follow-up. Besides clinical characteristics and conventional cardiac risk factors, NT-pro-BNP (electrochemiluminiscence assay, Roche diagnostics) and serum creatinine levels were determined. In univariable analysis, cases were more frequently current smokers and diabetics, had more frequently a history of CHD, and had higher levels of total cholesterol and systolic blood pressure (SBP), and lower levels of HDL cholesterol. A highly significant difference (P < 0.0001) was noted for NT-pro-BNP levels between cases (median 48.5 pg/mL, interquartile range 26.4-116.6 pg/mL) and controls (30.0 pg/mL, 19.5-47.6 pg/mL). In multivariable conditional logistic regression analysis, NT-pro-BNP remained strongly associated with risk for coronary events [third vs. first tertile, odds ratio (95% CI) 3.24 (1.18-8.85)], independent of body mass index, smoking, diabetes, SBP, total and HDL cholesterol, creatinine, and previous CHD.

CONCLUSION

NT-pro-BNP is a strong predictor of coronary events in men at work after a relatively short period, even after adjustment for conventional risk factors.

Risk of cardiovascular death in elderly patients with possible heart failure. B-type natriuretic peptide (BNP) and the aminoterminal fragment of ProBNP (N-terminal proBNP) as prognostic indicators in a 6-year follow-up of a primary care population

Heart failure is common in the elderly population and carries a serious prognosis. We evaluated EDTA-plasma B-type natriuretic peptide (brain natriuretic peptide, BNP) and the aminoterminal fragment of proBNP (N-terminal proBNP) as prognostic markers in elderly primary care patients with symptoms of heart failure.

METHODS

From 474 patients attending primary care for symptoms of dyspnea, fatigue and/or peripheral edema, blood was sampled in plastic tubes containing EDTA to measure BNP by non-extraction immunoradiometric assay and N-terminal proBNP by non-extraction radioimmunoassay. Patients were evaluated with respect to history and function by NYHA classification and Doppler echocardiography. Follow-up time was 6 years. Cox regression analysis was performed to identify the weight of risk variables.

CONCLUSION

Total 6-year mortality was 20% (102 patients out of 510), and cardiovascular (CV) mortality was 14% (71 patients, 70% of total mortality). BNP and N-terminal proBNP were essentially equally useful as prognostic markers. In patients with the highest quartiles of plasma concentration of BNP and N-terminal proBNP, respectively, the risk of cardiovascular mortality was 10 and 4.8 times, respectively, higher than that in those in the lowest quartile. Peptide concentrations varied widely within all functional groups including those with normal echocardiographic findings. Plasma concentrations of BNP and N-terminal proBNP give important prognostic information concerning risk of cardiovascular mortality. Cost-effective "clinical pathways" should be outlined for patients with elevated peptide concentrations.

Prediction of Myocardial Infarction by N-Terminal-Pro-B-Type Natriuretic Peptide, C-Reactive Protein, and Renin in Subjects With Cerebrovascular Disease

Background— B-type natriuretic peptide (BNP), C-reactive protein (CRP), and renin are elevated in persons at risk for cardiovascular disease. However, data that directly compare these markers in the prediction of myocardial infarction (MI) are limited.

Methods and Results— N-terminal-proBNP (NT-proBNP), CRP, and renin were measured in baseline blood samples from a nested case-control study of the 6105 participants of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS), a placebo-controlled study of a perindopril-based blood pressure-lowering regimen among individuals with previous stroke or transient ischemic attack. Each of 206 subjects who experienced MI, either fatal or nonfatal, during a mean follow-up of 3.9 years was matched to 1 to 3 control subjects. Most MI cases (67%) occurred in subjects without a history of coronary heart disease. NT-proBNP, CRP, and renin each predicted MI; the odds ratio for subjects in the highest compared with the lowest quarter was 2.2 (95% CI, 1.3 to 3.6) for NT-proBNP, 2.2 (95% CI, 1.3 to 3.6) for CRP, and 1.7 (95% CI, 1.1 to 2.8) for renin. NT-proBNP and renin, but not CRP, remained predictors of MI after adjustment for all other predictors, including LDL and HDL cholesterol levels. Individuals with both NT-proBNP and renin in their highest quarters had 4.5 times the risk of MI compared with subjects with both biological markers in their lowest quarters.

Conclusions— NT-proBNP and renin, but not CRP, are independent predictors of MI risk after stroke or transient ischemic attack, providing information additional to that provided by classic risk factors, and may enable more effective targeting of MI prevention strategies.

Diagnostic and Prognostic Performance of N-Terminal ProBNP in Primary Care Patients With Suspected Heart Failure

BACKGROUND

The value of N-terminal pro-brain natriuretic peptide (NT-proBNP) in terms of diagnosis and prognosis in congestive heart failure (CHF) and left ventricular systolic dysfunction (LVSD) has been demonstrated previously in various populations, but data on primary care patients are sparse. The aim of this study was to evaluate the diagnostic and prognostic performance of NT-proBNP in primary care patients with suspected CHF.

METHODS AND RESULTS

Three hundred sixty-seven consecutive patients (mean age, 68.8 years; range, 39.0-84.0 years) who had been referred by their general practitioner for echocardiographic evaluation because of suspected CHF. In all patients, NT-proBNP was measured at baseline and left ventricular ejection fraction (LVEF) was estimated with echocardiography. LVSD (LVEF < or =0.40) was found in 9% of the patients. NT-proBNP was significantly higher in patients with LVSD (P < .0001). With predefined cut off values for NT-proBNP (125 pg/mL), the sensitivity, specificity, positive predictive value, and negative predictive value for the detection of LVSD were 0.97, 0.46, 0.15 and 0.99, respectively. Area under the receiver operating characteristic curve was 0.87. The application of an age-differentiated cut-off value for NT-proBNP (125 pg/mL for <75 years old and 450 pg/mL for > or =75 years old) did not increase diagnostic performance. Patients were followed for a median of 778 days; 8% of the patients died during the follow-up period. The mortality rate was higher in patients with NT-proBNP of >125 pg/mL than in patients with normal values (P < .002, log rank), and the difference persisted after controlling for age, gender, and LVEF (hazard ratio per unit increase in log NT-proBNP, 2.2; range, 1.2-4.1; P = .015).

CONCLUSION

In primary care patients who were referred for echocardiography because of suspected CHF, NT-proBNP values <125 pg/mL effectively rule out LVSD. Furthermore low NT-proBNP values are associated with a lower risk of death, independently of age, gender, and LVEF.

N-Terminal Pro-Brain Natriuretic Peptide in Arterial Hypertension: A Valuable Prognostic Marker of Cardiovascular Events

BACKGROUND

N-terminal pro-brain natriuretic peptide (NT-proBNP) provides important prognostic information in patients with chronic heart failure and in the general population. The aim of this study was to evaluate NT-proBNP as a prognostic marker of cardiovascular morbidity and death in a sample of subjects with hypertension and preserved left ventricular systolic function from the general population.

METHODS AND RESULTS

The study population was recruited from 4 general practitioners. The study participants (n = 569 subjects; ages, 50-89 years) completed a heart failure questionnaire and were submitted to blood pressure measurement, electrocardiography, echocardiography, and blood sampling. After exclusion of subjects with left ventricular ejection fraction of <50%, 270 subjects fulfilled the following criteria for hypertension: history of hypertension or blood pressure >150/90 mmHg. During 3 years of follow-up, 28 subjects (10.4%) reached the composite end point of death, stroke/transient ischemic attack, or myocardial infarction. After adjustment for cardiovascular risk factors, NT-proBNP (logarithmically transformed) independently predicted the risk of experiencing a composite end point (hazard ratio, 1.94; P < .0001), and death (hazard ratio, 2.28; P < .0001). The risk of having a composite end point (21 vs 7; P = .005) was significantly higher for subjects with NT-proBNP above the study median than for subjects with NT-proBNP below the study median.

CONCLUSION

In this sample of subjects with hypertension and preserved left ventricular systolic function from the general population, plasma NT-proBNP was found to be a valuable cardiovascular risk marker, independently of traditional risk factors and prevalent cardiovascular disease.

Novel markers for heart failure diagnosis and prognosis

PURPOSE OF REVIEW

This paper reviews recent advances in heart failure biomarkers for identification of disease precursors, subclinical disease, and onset or progression of overt disease.

RECENT FINDINGS

Heart failure biomarkers can be categorized empirically as neurohormonal mediators, markers of myocyte injury and remodeling, and indicators of systemic inflammation. Brain natriuretic peptide is the most widely studied, with a potentially important but evolving role for determining prognosis and as a surrogate endpoint in clinical trials. Strong evidence exists for use of brain natriuretic peptide in the diagnosis of acute heart failure and for improved clinical outcomes with a brain natriuretic peptide-guided approach to heart failure care. The use of brain natriuretic peptide as a screening tool for asymptomatic left ventricular systolic dysfunction, or to distinguish systolic from diastolic heart failure, is not supported by current data. Markers of myocyte injury, including troponins, heart-type fatty acid binding protein, and myosin light chain-1, may further improve heart failure prognostication in conjunction with plasma brain natriuretic peptide. Biomarkers of matrix remodeling and inflammation have emerged as potential preclinical indicators to identify individuals at risk of developing clinical heart failure. A role for cellular adhesion molecules may also emerge in identifying those at risk for cardiovascular thrombotic complications, such as stroke.

SUMMARY

The spectrum of heart failure biomarkers and their potential clinical applications continues to grow. Ongoing research on multimarker strategies will likely identify biomarker combinations that are optimal at various stages during the evolution of heart failure, ranging from their use for screening, diagnosis, determining prognosis, and guiding management.

The N-terminal Pro-BNP investigation of dyspnea in the emergency department (PRIDE) study

The utility of aminoterminal pro-brain natriuretic peptide (NT-proBNP) testing in the emergency department to rule out acute congestive heart failure (CHF) and the optimal cutpoints for this use are not established. We conducted a prospective study of 600 patients who presented in the emergency department with dyspnea. The clinical diagnosis of acute CHF was determined by study physicians who were blinded to NT-proBNP results. The primary end point was a comparison of NT-proBNP results with the clinical assessment of the managing physician for identifying acute CHF. The median NT-proBNP level among 209 patients (35%) who had acute CHF was 4,054 versus 131 pg/ml among 390 patients (65%) who did not (p <0.001). NT-proBNP at cutpoints of >450 pg/ml for patients <50 years of age and >900 pg/ml for patients >or=50 years of age were highly sensitive and specific for the diagnosis of acute CHF (p <0.001). An NT-proBNP level <300 pg/ml was optimal for ruling out acute CHF, with a negative predictive value of 99%. Increased NT-proBNP was the strongest independent predictor of a final diagnosis of acute CHF (odds ratio 44, 95% confidence interval 21.0 to 91.0, p <0.0001). NT-proBNP testing alone was superior to clinical judgment alone for diagnosing acute CHF (p = 0.006); NT-proBNP plus clinical judgment was superior to NT-proBNP or clinical judgment alone. NT-proBNP measurement is a valuable addition to standard clinical assessment for the identification and exclusion of acute CHF in the emergency department setting.

How well does B-type natriuretic peptide predict death and cardiac events in patients with heart failure: systematic review

OBJECTIVE

To assess how well B-type natriuretic peptide (BNP) predicts prognosis in patients with heart failure.

DESIGN

Systematic review of studies assessing BNP for prognosis in patients with heart failure or asymptomatic patients.

DATA SOURCES

Electronic searches of Medline and Embase from January 1994 to March 2004 and reference lists of included studies.

STUDY SELECTION AND DATA EXTRACTION

We included all studies that estimated the relation between BNP measurement and the risk of death, cardiac death, sudden death, or cardiovascular event in patients with heart failure or asymptomatic patients, including initial values and changes in values in response to treatment. Multivariable models that included both BNP and left ventricular ejection fraction as predictors were used to compare the prognostic value of each variable. Two reviewers independently selected studies and extracted data.

DATA SYNTHESIS

19 studies used BNP to estimate the relative risk of death or cardiovascular events in heart failure patients and five studies in asymptomatic patients. In heart failure patients, each 100 pg/ml increase was associated with a 35% increase in the relative risk of death. BNP was used in 35 multivariable models of prognosis. In nine of the models, it was the only variable to reach significance-that is, other variables contained no prognostic information beyond that of BNP. Even allowing for the scale of the variables, it seems to be a strong indicator of risk.

CONCLUSION

Although systematic reviews of prognostic studies have inherent difficulties, including the possibility of publication bias, the results of the studies in this review show that BNP is a strong prognostic indicator for both asymptomatic patients and for patients with heart failure at all stages of disease.

Cardiac natriuretic peptides for cardiac health

The cardiac natriuretic peptides, ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide), are secreted by the heart in proportion to cardiac transmural pressures. They possess a wide range of effects in multiple tissues facilitating overall pressure/volume homoeostasis. The close relationship between plasma concentrations of these peptides and 'cardiac load' has led to their use as biomarkers of cardiac health with diagnostic and prognostic applications in a variety of disorders affecting the cardiovascular system. BNP and its N-terminal fragment (NT-BNP) are especially sensitive indicators of cardiac dysfunction and remodelling, and correlate strongly with severity. Given that cardiac ischaemia is also an important trigger for the release of these ventricular peptides, they may likewise play a role in the detection of coronary artery disease. Measurement of BNP/NT-BNP shows particular promise as a 'rule out' test for suspected cases of HF (heart failure) in both emergency care and outpatient settings, and may assist in identifying individuals with asymptomatic ventricular impairment who will benefit from therapy preventing progression to overt HF. The BNP peptides also predict subsequent haemodynamic deterioration and adverse events in cardiovascular disease, and can therefore be used to monitor those at high risk and act as a guide to optimization of treatment. The favourable biological properties of the natriuretic peptides have also led to their use as therapeutic agents.

Prediction of Heart Failure by Amino Terminal-pro–B-Type Natriuretic Peptide and C-Reactive Protein in Subjects With Cerebrovascular Disease

B-type natriuretic peptide (BNP) and C-reactive protein (CRP) are elevated in persons at risk for congestive heart failure (CHF). However, limited data are available directly comparing BNP-related peptides and CRP in persons at risk of CHF. To evaluate amino terminal-pro-BNP (NT-proBNP) and CRP, separately and together, for assessment of risk of CHF, we performed a nested case-control study of the 6105 participants of the Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS), a placebo-controlled study of a perindopril-based blood pressure-lowering regimen among individuals with previous stroke or transient ischemic attack (TIA). Each of 258 subjects who developed CHF resulting in death, hospitalization, or withdrawal of randomized therapy during a mean follow-up of 3.9 years was matched to 1 to 3 control subjects. NT-proBNP and CRP predicted CHF; the odds ratio for subjects in the highest compared with the lowest quarter was 4.5 (95% confidence interval, 2.7 to 7.5) for NT-proBNP and 2.9 (confidence interval, 1.9 to 4.7) for CRP, and each remained a predictor of CHF after adjustment for all other predictors. Screening for both markers provided better prognostic information than screening for either alone. Elevation of NT-proBNP above 50 pmol/L and CRP above 0.84 mg/L predicted CHF with sensitivity of 64% and specificity of 66%. NT-proBNP and CRP predicted CHF in subjects receiving perindopril-based therapy. We conclude that NT-proBNP and CRP are independent predictors of CHF risk after stroke or TIA. Moreover, NT-proBNP and CRP may be markers of mechanisms of CHF pathogenesis distinct from those responsive to angiotensin-converting enzyme inhibitor-based therapy.

Brain natriuretic peptide in the contemporary management of congestive heart failure

Brain natriuretic peptide is a cardiac neurohormone that is secreted by the left ventricle in response to an increase in wall stress. Brain natriuretic peptide has emerged as a neurohormone with multiple roles in heart failure management. This review will discuss the role of brain natriuretic peptide in heart failure diagnosis, prognostic assessment, screening for asymptomatic left-ventricular dysfunction, and in the treatment of heart failure.