Brain natriuretic peptide increases acutely and much more prominently than atrial natriuretic peptide during coronary angioplasty

NT-proANP and NT-proBNP circulating levels as predictors of cardiovascular outcome following coronary stent implantation

BACKGROUND

Natriuretic peptides are diagnostic/prognostic biomarkers in major cardiovascular diseases. We aimed at assessing the predictive role of N-terminal pro-A-type (NT-proANP) and pro-B-type (NT-proBNP) natriuretic peptides levels toward cardiovascular outcome in both stable and unstable coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI) in a non-primary PCI setting.

METHODS

A total of 395 patients undergoing PCI with stent implantation for either stable angina (SA) or non ST-elevation acute coronary syndrome (NSTE-ACS) were enrolled. Pre-procedural NT-proANP and NT-proBNP levels were measured. Occurrence of major adverse cardiac events (MACEs), composite of cardiac death, non-fatal myocardial infarction, and clinically driven target lesion revascularization (c-TLR), was the endpoint of the study. Follow up mean time was 48.53±14.69months.

RESULTS

MACEs occurred in forty-four patients (11%) during follow up. Both NT-proANP levels [3170 (2210-4630) vs 2283 (1314-3913) fmol/mL, p=0.004] and NT-proBNP levels [729 (356-1353) vs 511 (267-1006) fmol/mL, p=0.04] were significantly higher in patients with MACEs compared to patients without MACEs. Similar results were found when considering hard MACEs (myocardial infarction and cardiac death). NT-proANP levels were significantly higher in patients with c-TLR compared with patients without c-TLR [3705 (2766-5184) vs 2343 (1340-3960) fmol/mL, p=0.021]. At multivariate analysis, NT-proANP levels were a significant predictor of MACEs (HR 1.09, 95% CI 1.03-1.18, p=0.04). Kaplan-Meyer curves revealed that patients with elevated NT-proANP levels (>2.100fmol/mL) had a lower MACE free survival (p=0.003).

CONCLUSIONS

Both NT-proANP and NT-proBNP levels were higher in CAD patients experiencing MACEs following PCI in a non-primary setting. Notably, only NT-proANP levels significantly affected prognosis after PCI.

Novel approaches and opportunities for cardioprotective signaling through 3',5'-cyclic guanosine monophosphate manipulation

Limiting the injurious effects of myocardial ischemia-reperfusion is a desirable therapeutic target, which has been investigated extensively over the last three decades. Here we provide an up to date review of the literature documenting the experimental and clinical research demonstrating the effects of manipulating cGMP for the therapeutic targeting of the injurious effects of ischemic heart disease. Augmentation of the cyclic nucleotide cGMP plays a crucial role in many cardioprotective signaling pathways. There is an extensive body of literature which supports pharmacological targeting of cGMP or upstream activators in models of ischemia-reperfusion to limit injury. NO donors have long been utilised to manipulate cGMP, and more recently non-NO synthase derived NOx species have been investigated, resulting in their evaluation in clinical trials for the treatment of ischemic heart disease. Encouraging results demonstrate that natriuretic peptides are worthy candidates in manipulating cGMP and its downstream effectors to afford cytoprotection. Synthetic ligands have been designed which co-activate natriuretic peptide receptors to improve targeting this pathway. Advances have been made in targeting the soluble guanylyl cyclase which catalyzes the production of cGMP independently of the endogenous ligand NO using NO-independent stimulators and activators of sGC. These novel compounds show promise as a new class of drugs that target this signaling cascade specifically under pathological conditions when endogenous NO production may be compromised. Regulating the degradation of cGMP via phosphodiesterase inhibition also shows therapeutic potential. It is clear that production and regulation of cGMP is complex, indeed its spatial production and cellular distribution are only just emerging.

B-type natriuretic peptide blood levels identify patients with non-ST elevation acute coronary syndromes at high risk for complications during intravenous beta-blocker infusion

BACKGROUND

We hypothesized that measurement of B-type natriuretic peptide could identify patients with non-ST elevation acute coronary syndromes at high risk for complications during beta-blocker (esmolol) infusion.

METHODS

We reviewed the records of 340 consecutive patients admitted with a non-ST elevation acute coronary syndrome. Seventy three (47 males, aged 62 ± 14 years) received esmolol up to a maximum dose of 300 μg/ kg/min until the symptoms were relieved or an adverse event occurred.

RESULTS

The median infusion rate at steady state was 175 μg/kg/min (median infusion time 18 h). Infusion was halted in 14 patients. The frequency of drug discontinuation increased across admission BNP quartiles. BNP > 141 pg/ml at admission had a 95% predictive value for subsequent withdrawal of esmolol. The presence of BNP > 141 pg/ml in combination with systolic blood pressure < 130 mmHg and left ventricular ejection fraction < 50% identified a group of patients at high risk for drug interruption (interruption frequency = 83%, 95% CI: 55-95%).

CONCLUSIONS

In conclusion, BNP measurement in combination with systolic blood pressure and 2D echocardiography may identify patients with non-ST elevation acute coronary syndromes at high risk for adverse events during esmolol infusion.

B-Type Natriuretic Peptide (BNP) and Left Ventricular (LV) Function in Patients with ST-Segment Elevation Myocardial Infarction (STEMI)

BACKGROUND

After acute myocardial infarction (AMI), left ventricular (LV) function is a well-established prognostic marker. Recent studies indicate that serum levels of brain natriuretic peptide (BNP) also represent an prognostic marker in this setting but so far without a precise cut-off value.

OBJECTIVE

The aim of this study was to assess the predictive value of BNP serum levels for LV function assessed by echocardiography in STEMI patients undergoing revascularization.

METHODS

We prospectively studied a cohort of 88 consecutive patients (mean age 51.6 years, 88.6% males) hospitalized in our clinic for STEMI in Killip class I (50% anterior infarction), who underwent reperfusion therapy. Serum BNP levels were measured on admission, at 24h and at 30 days after reperfusion. Detailed echocardiography was performed at baseline, at 24 hours after reperfusion, on discharge and at follow-up at 1 month. Left ventricular systolic and diastolic dysfunction were defined by LVEF < 45% and E/A ratio respectively.

RESULTS

ROC curve analysis showed that BNP measurements on admission and at 24 hours after revascularization have no predictive value neighter for diastolic LV dysfunction in anteior or inferior AMI patients, nor for systolic LV dysfunction in inferior AMI patients. Only BNP levels at 24 hours after revascularization can predict systolic LV dysfunction in anterior AMI patients with a 90.3% sensitivity and a 60% false positive rate at a cutt off value of 90pg/ml.

CONCLUSIONS

Early measurement of BNP levels may allow early prediction of anterior STEMI patients at risk of developing systolic LV dysfunction after revascularization therapy.

Biomarkers of vulnerable plaque: the missing link with ischemia

The initial evaluation of chest pain in the emergency department is based on the patient’s clinical history, changes in the ECG and necrosis biomarkers. Although management of patients with ST-elevation myocardial infarction or non-ST-elevation myocardial infarction with positive markers of myocardial damage is well defined, exclusion of coronary artery disease or myocardial ischemia in the remaining patients is more challenging. This group represents the majority of patients admitted for chest pain syndromes and that have a substantial risk of an adverse outcome. Given that troponin, as a marker of myocardial damage, detects terminal events in the cascade of acute coronary syndrome, there is a need to search for biomarkers that are able to identify patients at high risk, allowing rapid, bedside stratification. Data suggest that clinical events are prone to occur more frequently in patients with coronary artery stenosis associated with myocardial ischemia. Accordingly, identification of systemic biomarkers of ischemia could facilitate identification of high-risk patients with a high burden of coronary atherosclerosis and plaque rupture. We describe six biomarkers that have been linked to myocardial ischemia. Until now, these biomarkers of ischemia are relevant in order to exclude ischemic heart disease (high negative predictive value) but still lack specificity. Future prospective studies should be performed in larger and more diverse sets of patients presenting with ischemia, and in a complementary fashion in order to provide valuable tools for clinical decision making.

Clinical and Laboratory Diagnostics of Cardiovascular Disease: Focus on Natriuretic Peptides and Cardiac Ischemia

Chest pain is the most common clinical presentation of acute ischemic heart disease, but only one third of these patients are ultimately found to have an acute coronary syndrome. Initial assessment of the patient presenting with chest pain includes a careful history, physical examination, an initial electrocardiogram (ECG) and measurement of biochemical markers of myocardial injury. The natriuretic peptide system is activated in a broad spectrum of cardiovascular diseases, including acute coronary syndromes and stable coronary disease. A strong relation between plasma levels of B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) obtained in the subacute phase, and long-term, all-cause mortality, as well as the rate of re-admissions for heart failure after myocardial infarction, has been documented. Persistently elevated NT-proBNP levels during the first 72 hours following admission for an acute coronary syndrome have recently been associated with the presence of refractory ischemia and high risk of short-term recurrent ischemic events. Patients with signs of exercise-induced ischemia by dobutamine stress echocardiography have been reported to have higher baseline BNP values. Moreover, BNP and NT-proBNP levels are increased acutely in proportion to the magnitude of the inducible perfusion defect observed during stress testing, suggesting that BNP and NT-proBNP are markers of acute ischemia. Recently, a relationship between circulating levels of BNP and NT-proBNP and long-term all cause mortality in patients with stable coronary artery disease has been documented.

Diagnostic and prognostic impact of brain natriuretic peptide in cardiac and noncardiac diseases

OBJECTIVE

Cardiac secretion of brain natriuretic peptide (BNP) increases with the progression of congestive heart failure (CHF). The plasma measurement of BNP emerged recently as a useful, cost-effective biomarker for the diagnosis and prognosis of CHF.

METHODS

BNP assay is useful for evaluating patients with acute dyspnea, because a low level can help rule out CHF in primary care settings and reduce the demand for echocardiography. Equally, BNP level can be particularly useful in recognizing heart failure in a patient with acute dyspnea and a history of chronic obstructive pulmonary disease.

RESULTS

However, although the clinical use of BNP as a biomarker in CHF is increasing, the specificity of BNP in CHF is not strong, suggesting that other mechanisms beyond simple ventricular stretch stimulate BNP release. Multiple disorders in the intensive care unit, apart from CHF, cause elevated BNP levels, including cardiovascular disease states such as ischemia, arrhythmias, cardiac hypertrophy, and coronary endothelial dysfunction, as well as disorders of no cardiac origin, such as sepsis, septic shock, and acute respiratory distress syndrome. Moreover, the impact of increased BNP in patients with sepsis is not clear. The relationship between BNP and both left ventricular ejection fraction and left-sided filling pressures is weak, and data on the prognostic impact of high BNP levels in patients with sepsis are conflicting.

CONCLUSION

Nevertheless, this review highlights the potential benefits of BNP in the recognition and management of heart failure, and defines the gray zones of BNP levels; it also identifies conditions influencing BNP levels in relation to a certain heart failure and describes conditions of no cardiac origin with increased BNP.

Brain natriuretic peptide increases in septic patients without severe sepsis or shock

BACKGROUND

B-type natriuretic peptide (BNP) production increases in critically ill septic patients. We assessed the hypothesis that BNP is elevated in patients with community-acquired infections without severe sepsis or septic shock.

METHODS

We studied 54 patients [20 males, median age 39 (interquartile range 23, 71)] without heart disease, persistent arrhythmias, or renal failure. BNP was measured in all patients at hospital admission and at pre-discharge and in a control group of 52 individuals. Myoglobin levels were also measured in septic patients.

RESULTS

The infection was microbial in 40 patients, viral in 11, and of undefined etiology in 3. A systemic inflammatory response was evident in 38 patients on the initial evaluation. BNP on admission was higher in patients than in controls [25 (10, 82) pg/ml vs. 13 (5, 30) pg/ml, p=0.01] and it decreased to 16 (5, 47) pg/ml pre-discharge (p=0.0002). Multiple logistic regression identified the presence of microbial infection as the only independent predictor of an elevated BNP value on admission [adjusted odds ratio 9.8 (1.02-93.8), p=0.04]. In patients with microbial infection, location of infection in the lower respiratory tract and the presence of diabetes mellitus were independent predictors of the magnitude of BNP increase. Myoglobin was also increased on hospital admission 80 (37, 231) ng/ml and decreased pre-discharge to 59 (38, 94) ng/ml, p=0.004. Myoglobin level changes from admission to discharge were more prominent with increasing age and in females.

CONCLUSION

BNP levels are elevated in the acute phase of community-acquired microbial infections without severe sepsis or septic shock.

[Increased secretion of Nt-proBNP immediately after percutaneous coronary intervention: about 90 cases]

Nt-proBNP have emerged as useful biomarker for the diagnosis and prognostic of heart failure but also recently in acute coronary syndrome. Myocardial ischemia is probably an important stimulus for Nt-proBNP release. Transient myocardial ischemia is inducing by balloon inflation during percutaneous coronary intervention (PCI). The authors propose to determine the Nt-proBNP secretion after uncomplicated coronary intervention in patients with preserved cardiac function. Ninety patients were enrolled in this study. Plasma Nt-proBNP was increased significantly from 135.5 to 157.8 pg/ml and 202.5 pg/ml at 8 and 24 hours following PCI, respectively. History of myocardial infarction and complex lesions were the most powerful predictors of higher Nt-proBNP peak concentration. Prognostic value must be evaluated in larger studies.

Cardioprotective actions of peptide hormones in myocardial ischemia

The myocardium represents a major source of several families of peptide hormones under normal physiological conditions and the plasma concentrations of many of these "cardiac peptides" (or related pro-peptide fragments) are substantially augmented in many cardiac disease states. In addition to well-characterised endocrine functions of several of the cardiac peptides, pleiotropic functions within the myocardium and the coronary vasculature represent a significant aspect of their actions in health and disease. Here, we focus specifically on the cardioprotective roles of four major peptide families in myocardial ischemia and reperfusion: adrenomedullin, kinins, natriuretic peptides and the urocortins. The patterns of early release of all these peptides are consistent with roles as autacoid cardioprotective mediators. Clinical and experimental research indicates the early release and upregulation of many of these peptides by acute ischemia and there is a convincing body of evidence showing that exogenously administered adrenomedullin, bradykinin, ANP, BNP, CNP and urocortins are all markedly protective against experimental myocardial ischemia-reperfusion injury through a conserved series of cytoprotective signal transduction pathways. Intriguingly, all the peptides examined so far have the potential to salvage against infarction when administered specifically during early reperfusion. Thus, the myocardial secretion of peptide hormones likely represents an early protective response to ischemia. Further work is required to explore the potential therapeutic manipulation of these peptides in acute coronary syndromes and their promise as biomarkers of acute myocardial ischemia.

Effects of lesion complexity on baseline and postprocedural B-type natriuretic peptide levels in patients undergoing percutaneous coronary interventions

The time-related alteration of plasma B-type natriuretic peptide levels after percutaneous coronary interventions has been investigated chiefly in patients with acute coronary syndromes; very few data are available in patients with stable coronary artery disease. Therefore, we aimed to evaluate the alterations of plasma B-type natriuretic peptide levels, and the effects of lesion complexity on these levels, after elective percutaneous coronary interventions in stable coronary artery disease patients. We enrolled 103 of these patients and used modified American College of Cardiology/American Heart Association lesion morphology criteria to qualitatively evaluate the angiograms: type A and B1 lesions were categorized as simple, and type B2 and C lesions were designated as complex. Plasma B-type natriuretic peptide levels were determined before intervention and 1 and 24 hours afterwards. Median baseline B-type natriuretic peptide levels were significantly higher in patients who had complex lesions (n=53) (108 pg/mL) compared with those who had simple lesions (n=50) (33 pg/mL) (P <0.001), and this difference was maintained 1 and 24 hours after intervention (P = 0.003 and P = 0.001, respectively). However, for both lesion types, percutaneous coronary intervention procedures did not significantly alter plasma B-type natriuretic peptide levels (all P >0.05). On binary logistic regression analysis, age and lesion complexity were found to be independently associated with B-type natriuretic peptide levels. We conclude that, in stable coronary artery disease patients, elective percutaneous coronary intervention does not cause any significant alteration in plasma B-type natriuretic peptide levels. However, elevated levels are significantly associated with more complex lesions and with advanced age.

Brain natriuretic peptide as marker of myocardial iron load in beta-thalassemia

Cardiomyopathy due to iron overload represents a frequent life-limiting complication in patients with beta-thalassemia major. We have conducted a study which proved that brain natriuretic peptide plasma levels have high sensitivity and negative predictive value in detecting cardiac hemosiderosis.

The effect of coronary angioplasty on plasma NT-proBNP level in patients with and without arterial hypertension

AIMS

The purpose of the study was to assess the effect of percutaneous transluminal coronary angioplasty (PTCA) on plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level in hypertensive and normotensive subjects with and without systolic left ventricular dysfunction.

METHODS AND RESULTS

Forty patients affected by ischemic heart disease and submitted to PTCA were studied. The patients were divided into four groups: group I - 10 patients with essential arterial hypertension (HT) and normal left ventricular ejection fraction (EF); group II - 10 patients with HT and EF < 55%; group III - 10 patients without HT and with normal EF; group IV - 10 patients without HT and with EF < 55%. Blood samples were collected twice: 24 h before and after PTCA. The plasma NT-proBNP concentrations increased significantly in group I (368+/-103 pg/ml vs 488 +/- 182 pg/ml; p < 0.05), in group III (257 +/- 107 pg/ml vs 447 +/- 198 pg/ml; p < 0.05), and in group IV (419 +/- 99 pg/ml vs 826 +/- 432 pg/ml; p < 0.05) 24 h after PTCA. There were significant differences in the relative change in plasma NT-proBNP concentrations between groups I and II, and between groups III and IV.

CONCLUSIONS

Successful coronary angioplasty results in a rise in plasma NT-proBNP concentration. The increase is less expressive in patients with systolic left ventricular dysfunction. The presence of hypertension does not affect NT-proBNP concentration after PTCA.

Natriuretic peptide response to dynamic exercise in patients with atrial fibrillation

BACKGROUND

In patients with atrial fibrillation (AF) information regarding exercise release of atrial natriuretic peptide (ANP) is sparse and data on plasma brain natriuretic peptide (BNP) response to exercise is lacking. The aim of this study was to investigate plasma ANP and BNP response to exercise in patients with permanent AF and to assess if the response was different from the response in healthy age- and sex-matched control subjects.

METHODS

Plasma venous concentrations of ANP and BNP were determined at rest, at peak exercise and 30 min from the end of exercise in 38 patients with permanent AF and in 43 age- and sex-matched healthy control subjects.

RESULTS

Plasma concentrations of ANP and BNP were significantly higher in AF patients compared with the healthy control group at rest, peak exercise and after 30 min of recovery (p<0.0001). ANP and BNP increased significantly during exercise in both patients with AF and in the healthy control subjects (p<0.05). The increase in plasma concentration of ANP and BNP during exercise was significantly higher in AF patients compared with healthy controls (p=0.0002 for ANP; p<0.0001 for BNP). In the recovery period plasma BNP decreased significantly (p<0.0001) where as the decrease in plasma ANP was insignificant (p=0.4).

CONCLUSIONS

Patients with permanent AF have elevated levels of ANP and BNP at rest and exhibit much higher exercise release compared to healthy control subjects. This enhanced secretion of potent vasodilating and natriuretic agents may represent an important compensatory mechanism to improve exercise capacity in patients with AF.

Brain natriuretic peptide and optimal management of heart failure

Aside from the important role of brain natriuretic peptide (BNP) in diagnosis, and differential diagnosis of heart failure, this biological peptide has proved to be an independent surrogate marker of rehospitalization and death of the fatal disease. Several randomized clinical trials demonstrated that drugs such as beta blocker, angiotensin converting enzyme inhibitor, spironolactone and amiodarone have beneficial effects in decreasing circulating BNP level during the management of chronic heart failure. The optimization of clinical decision-making appeals for a representative surrogate marker for heart failure prognosis. The serial point-of-care assessments of BNP concentration provide a therapeutic goal of clinical multi-therapy and an objective guidance for optimal treatment of heart failure. Nevertheless new questions and problems in this area remain to be clarified. On the basis of current research advances, this article gives an overview of BNP peptide and its property and role in the management of heart failure.

Markers of Cardiac Ischemia and Inflammation

Because biomarkers of myocardial necrosis only become positive in the setting of myocardial necrosis and disruption of cellular integrity, the diagnosis of myocardial infarction can only be made in retrospect. Ideally, one would like to identify patients at risk for complications before myocardial necrosis occurs. Insights into the pathophysiology of atherothrombosis have allowed development of novel markers to detect not only early ischemia without myocyte death but also early indicators of coronary inflammation inpatients who have preclinical atherosclerosis.

Can Exercise-Induced Changes in B-Type Natriuretic Peptides Be Used to Detect Cardiac Ischemia?

BACKGROUND

We reviewed the current medical literature that pertained to the question of whether myocardial ischemia triggers the release of B-type natriuretic peptides (BNPs) and, in particular, whether transient exercise-induced ischemia can be detected by the measurement of changes in these biomarkers. BNPs are well-established as markers of left ventricular dysfunction, particularly heart failure. There is accumulating evidence that various conditions with the common denominator of myocardial ischemia are also associated with increased circulating levels of these peptides.

METHODS AND RESULTS

Recently published methods and results, which includes our published and unpublished data, were reviewed.

CONCLUSION

The results show that exercise-induced ischemia or its associated regional wall-motion abnormalities trigger the release of BNPs and that the measurement of plasma levels of N-terminal pro brain natriuretic peptide and BNP before and immediately after symptom-limited exercise can distinguish patients with and without ischemia with a high degree of accuracy.

B-type natriuretic peptide and extent of lesion on coronary angiography in stable coronary artery disease

OBJECTIVE

Although it is well established that plasma B-type natriuretic peptide (BNP) levels are higher in patients with acute coronary syndromes, the relationship between plasma BNP level and stable coronary artery disease is not clear. The aim of this study was to examine the relationship between plasma BNP levels and the extent of obstructive lesions on coronary angiography in stable coronary artery patients.

METHODS

Plasma BNP concentrations were measured in 62 patients with a diagnosis of stable angina pectoris who had a left ventricular ejection fraction (LVEF) >or=45% on echocardiographic evaluation. Coronary angiography was performed for all patients, who were than divided into two groups according to the results of the angiography. Group I consisted of the patients who had a lesion leading to an obstruction of the lumen in any coronary artery by less than 50% or those who had normal coronary arteries. All other patients constituted group II.

RESULTS

In group I (n=26), the mean plasma BNP level was 64.8+/-29.5 pg/ml. In group II (n=36), it was 99.7+/-55.4 pg/ml. BNP was significantly higher in group II (P=0.007) than group I. The BNP concentration of the patients with one-vessel disease (n=12), two-vessel disease (n=16), and three-vessel disease (n=8) were 77.9+/-34.9 pg/ml, 109.3+/-67.9 pg/ml, 113.3+/-48.1 pg/ml consecutively. In this respect, the plasma BNP was significantly higher in the groups with more extended vessel disease (P=0.02). When we compared the patients according to involvement of left anterior descending artery (LAD), BNP levels were significantly higher in this group, (116.1+/-55.8 pg/ml versus 64.1+/-30.2 pg/ml; P=0.001).

CONCLUSION

Plasma levels of BNP were higher in patients who have stable coronary artery disease with preserved left ventricular systolic function. The level of increase in plasma BNP concentration was positively correlated with the extent of lesion and LAD involvement on coronary angiography.

Early brain natriuretic peptide increase reflects acute myocardial ischemia in patients with ongoing chest pain

BACKGROUND

Plasma brain natriuretic peptide levels increase during acute ischemic events. In this study we tested the diagnostic performance of brain natriuretic peptide measurements in the detection of acute myocardial ischemia.

METHODS

Blood brain natriuretic peptide was measured in 101 patients with ongoing chest pain but no heart failure or an ST-segment elevation myocardial infarction on arrival at the emergency department (baseline) and at 2 and 6 h later. After diagnostic testing and 1-month follow-up for ischemia, patients were classified as either ischemic or non-ischemic.

RESULTS

In the ischemic group median (25th, 75th percentiles) brain natriuretic peptide values (pg/ml) were 122 (20, 349) at baseline, 116 (36, 347) at 2 h, increasing to 148 (52, 428) at 6 h (p<0.001 vs. baseline). Non-ischemic patients had 12 (5, 32) at baseline, 9 (6, 30) at 2 h, and 13 (5, 29) at 6 h (p<0.001 vs. corresponding values of the ischemic group). Receiver operator characteristic curves were constructed for brain natriuretic peptide values at baseline 2 and 6 h and for the increase of peptide levels from baseline to 6 h. All areas under curve indicated a significant diagnostic ability for the detection of ischemia. The 6-h measurement had better diagnostic performance than baseline and 2-h measurements. The subgroup of ischemic patients without myocardial necrosis also had higher brain natriuretic peptide values and could thus be discriminated from non-ischemic subjects.

CONCLUSIONS

Brain natriuretic peptide values may detect acute myocardial ischemia in patients with ongoing chest pain but without ST-segment elevation, and distinguish ischemic patients from those with pain of non-ischemic origin.

B-type natriuretic peptide and long-term survival in patients with stable coronary artery disease

Circulating B-type natriuretic peptide (BNP) is a strong predictor of survival in patients with acute coronary syndromes and in patients with congestive heart failure. Whether circulating BNP levels are predictive of long-term survival in patients with angiographically documented, clinically stable coronary artery disease is unknown. We studied 186 patients with stable angina pectoris and angiographic evidence of significant coronary artery disease. Patients with a recent myocardial infarction, electrocardiographic evidence of ongoing ischemia, anginal pain at rest, or symptomatic congestive heart failure were excluded from the study. During a follow-up of 7.4 years, 23 patients died. By Cox proportional-hazards regression, patient age (p = 0.031), pathologic Q waves on the electrocardiogram (p = 0.037), left ventricular ejection fraction (p = 0.016), and plasma BNP (p = 0.008) were significantly associated with long-term survival. In a stepwise forward multivariate model, BNP (p = 0.005) provided prognostic information above and beyond conventional risk markers. In patients with clinically stable, angiographically documented coronary artery disease, plasma BNP levels are independently related to long-term survival.

Risk assessment in patients with unstable angina/non-ST-elevation myocardial infarction and normal N-terminal pro-brain natriuretic peptide levels by N-terminal pro-atrial natriuretic peptide

AIMS

To compare the accuracy of the N-terminal fragment of its pro-hormone (Nt-proBNP) and N-terminal pro-atrial natriuretic peptide (Nt-proANP) in the prediction of the 2 year mortality and to investigate whether additional measurement of Nt-proANP to troponin I (TnI) could improve risk assessment in the subgroups of patients with unstable coronary artery disease (UCAD) and normal Nt-proBNP.

METHODS AND RESULTS

Plasma levels of the TnI, Nt-proANP, and Nt-proBNP were determined in 120 consecutive patients with UCAD without ST-segment elevations and normal left ventricular function. In multivariable logistic regression analysis, TnI and Nt-proBNP were independent predictors of mortality (P=0.01 and P=0.02, respectively). However, in the group of patients with normal Nt-proBNP levels, only Nt-proANP and TnI were independently associated with mortality (P=0.007 and P=0.03, respectively). Accordingly, patients with elevated Nt-proANP levels in this group of patients had significantly higher mortality rate than patients with normal Nt-proANP levels (P=0.003).

CONCLUSION

Our results suggest that determination of Nt-proANP might improve risk assessment in patients with UCAD, especially when Nt-proBNP is in the normal range.

N-terminal B-type natriuretic peptide predicts extent of coronary artery disease and ischemia in patients with stable angina pectoris

BACKGROUND

B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) are elevated in patients with acute coronary syndromes and are closely linked to prognosis. Because there is only a small amount of data available concerning NT-proBNP in patients with stable angina pectoris, we aimed to determine whether NT-proBNP is of additional diagnostic value in these patients.

METHODS AND RESULTS

Ninety-four patients with stable angina pectoris were prospectively included. All patients underwent exercise testing and coronary angiography, and 91 patients received thallium-201 single-photon emission computed tomography myocardial scintigraphy. NT-proBNP was analyzed at rest and after exercise testing. NT-proBNP was elevated in patients with inducible myocardial ischemia shown by single-photon emission computed tomography (396 +/- 80 pg/mL vs 160 +/- 101 pg/mL; P <.01) closely linked to the extent of coronary artery disease (CAD) (no CAD, 148 +/- 29 pg/mL; 1- or 2-vessel disease, 269 +/- 50 pg/mL; 3-vessel disease 624 +/- 186 pg/mL; P <.01). In a multivariate analysis, NT-proBNP was an independent predictor for CAD. The area under the curve of the receiver operating characteristic curve was 0.72 for NT-proBNP to predict CAD. Using an optimized cut off level of 214 pg/mL, CAD can be predicted with high accuracy. The total test efficiency of exercise testing can be improved from 1.46 to 1.52 when combined with NT-proBNP measurement.

CONCLUSION

NT-proBNP is elevated in patients with stable angina pectoris and has a close correlation to disease severity. Combining the measurement of NT-proBNP with exercise testing, the test accuracy for predicting severe CAD can be improved. Our data show an incremental value of NT-proBNP in the diagnostic process of stable angina pectoris.

The utility of BNP in clinical practice

Brain natriuretic peptide (BNP) is a cardiac neurohormone of increasing interest over recent years, with research applications expanding at a rapid rate and new data published on a monthly basis. Initially developed as a diagnostic aid for those with acute shortness of breath, clinical applications are now increasing, and this article reviews these clinical applications of BNP and the evidence for effectiveness of the synthetic BNP analogue nesiritide.

Association of Elevated B-Type Natriuretic Peptide Levels With Angiographic Findings Among Patients With Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction

OBJECTIVES

We hypothesized that elevated B-type natriuretic peptide (BNP) levels would be associated with a greater severity of angiographic disease and a greater extent of myocardium at risk.

BACKGROUND

Elevations of BNP have been associated with increased risk of adverse outcomes in patients with unstable angina and non-ST-segment elevation myocardial infarction (UA/NSTEMI).

METHODS

Of the 2,220 patients with UA/NSTEMI enrolled in the Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis In Myocardial Infarction-18 (TACTICS-TIMI-18) trial, 276 randomized to the invasive arm had both baseline BNP levels and angiographic core laboratory data. Patients were categorized according to their baseline BNP levels as < or =80 or >80 pg/ml.

RESULTS

A total of 233 patients (84%) had BNP levels >80 pg/ml, and 43 (16%) had admission BNP levels >80 pg/ml. Patients with BNP >80 pg/ml had tighter culprit vessel stenosis on quantitative coronary angiography (median stenosis 76% vs. 67%, p = 0.004) and a higher (slower) corrected TIMI frame count (median CTFC 43 vs. 30, p = 0.018) in the culprit vessel. The median BNP level was higher in patients with a left anterior descending coronary artery (LAD) versus non-LAD culprit lesion location (median BNP level 40 vs. 24 pg/ml, p = 0.005), and the culprit artery was more often the LAD in patients with BNP >80 pg/ml compared with < or =80 pg/ml (44% vs. 30%, p = 0.06).

CONCLUSIONS

Among patients with UA/NSTEMI, elevated BNP levels are associated with tighter culprit stenosis, higher CTFC, and LAD involvement. These findings suggest that elevated BNP may be associated with a greater severity and extent of myocardial ischemic territory during the index event and may partly explain the association between elevated BNP and adverse outcomes.

Pathophysiology, prognostic significance and clinical utility of B-type natriuretic peptide in acute coronary syndromes

The natriuretic hormones are a family of vasoactive peptides that can be measured circulating in the blood. Because they serve as markers of hemodynamic stress, the major focus of the use of natriuretic peptide levels [predominantly B-type natriuretic peptide (BNP) and N-terminal (NT)-pro-BNP] has been as an aid to the clinical diagnosis and management of congestive heart failure (CHF). Recently, however, the measurement of natriuretic peptides in the acute coronary syndromes (ACS) has been shown to provide information complementary to traditional biomarkers (of necrosis) such as cardiac troponins and creatine kinase (CK). Studies in several types of acute coronary syndromes [ST-segment elevation myocardial infarction (STEMI), non-ST elevation MI (NSTEMI) and unstable angina (UA)] have shown that elevated levels of natriuretic peptides are independently associated with adverse outcomes, particularly mortality. Additional information is obtained from the use natriuretic peptides in combination with other markers of risk including biomarkers of necrosis and inflammation. This review will summarize the scientific rationale and clinical evidence supporting measurement of natriuretic peptides for risk stratification in acute coronary syndromes. Future research is needed to identify therapies of particular benefit for patients with ACS and natriuretic peptide elevation.

Autocrine and paracrine actions of natriuretic peptides in the heart

The natriuretic peptides, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), are a family of polypeptide mediators exerting numerous actions in cardiovascular homeostasis. ANP and BNP are cardiac derived, being secreted and up-regulated in myocardium in response to many pathophysiological stimuli. CNP is an endothelium-derived mediator. The classical endocrine effects of ANP and BNP on fluid homeostasis and blood pressure, especially in conditions characterised by left ventricular dysfunction, are well recognised and extensively researched. However, there is accumulating evidence that, in addition to endocrine actions, ANP and BNP exhibit important autocrine and paracrine functions within the heart and coronary circulation. These include regulation of myocyte growth, inhibition of fibroblast proliferation and extracellular matrix deposition, a cytoprotective anti-ischaemic (preconditioning-like) function, and influences on coronary endothelium and vascular smooth muscle proliferation and contractility. Most if not all of these actions can be ascribed to particulate guanylyl cyclase activation because the ANP/BNP receptor, natriuretic peptide receptor (NPR)-A, has an intracellular guanylyl cyclase domain. Subsequent elevation of the intracellular second messenger cGMP may exert diverse physiological effects through activation of cGMP-dependent protein kinases (cGK), predominantly cGK-I. However, there appear to be other contributory mechanisms in several of these actions, including the augmentation of nitric oxide synthesis. These diverse actions may represent counterregulatory mechanisms in the pathophysiology of many cardiovascular diseases, not just those typified by left ventricular dysfunction. Ultimately, insights from the autocrine/paracrine actions of natriuretic peptides may provide routes to therapeutic application in cardiac diseases of natriuretic peptides and drugs that modify their availability.

N-terminal pro-brain natriuretic peptide on admission has prognostic value across the whole spectrum of acute coronary syndromes

BACKGROUND

The prognostic value of natriuretic peptide elevations in patients with acute coronary syndromes (ACS) is still incompletely defined. We measured N-terminal pro-brain natriuretic peptide (NT-proBNP) on admission in patients with ACS and ECG evidence of myocardial ischemia.

METHODS AND RESULTS

The NT-proBNP was measured at a median time of 3 hours after symptom onset in 1756 patients. The outcome measure was death at 30 days, which occurred in 113 patients (6.4%). The median NT-proBNP level was 353 ng/L (107 to 1357 ng/L). Compared with the lowest quartile, patients in the second, third, and fourth quartiles had a relative risk of subsequent death of 2.94 (95% CI, 1.15 to 7.52), 5.32 (95% CI, 2.19 to 12.91), and 11.5 (95% CI, 4.90 to 26.87), respectively. The NT-proBNP was independently associated with death in a logistic regression model, which included clinical variables, ECG, and troponin T in patients either with (OR of highest versus lowest quartile, 7.0; 95% CI, 1.9 to 25.6) or without (OR of highest versus lowest quartile, 4.1; 95% CI, 1.1 to 14.6) persistent ST-segment elevation. NT-proBNP was also an independent predictor of severe heart failure.

CONCLUSIONS

The measurement of NT-proBNP on admission improves the early risk stratification of patients with ACS, suggesting the need for the development of targeted therapeutic strategies.

Coagulation, inflammation and myocardial dysfunction in unstable coronary artery disease and the influence of glycoprotein IIb/IIIa inhibition and low molecular weight heparin

Patients with unstable coronary artery disease (CAD) have an increased risk of subsequent myocardial infarction and death. This study evaluated the safety and efficacy of treatment with glycoprotein IIb/IIIa inhibition in addition to aspirin, low molecular-weight heparin and its influence on coagulation and inflammation. Also, early and differentiated risk assessment utilising markers of inflammation, myocardial damage and dysfunction were evaluated. The Global Utilisation of Strategies To open Occluded arteries-IV (GUSTO-IV) trial randomised 7800 patients with unstable CAD to 24 or 48 hours infusion of abciximab or placebo in addition to routine treatment with aspirin and heparin or dalteparin. Baseline levels of creatinine, C-reactive protein (CRP), troponin T (TnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were analysed. At selected sites, all patients received subcutaneous dalteparin (n=974), in stead of heparin infusion (n=6826). In a sub-population of dalteparin treated patients (n=404), serial measurements of markers of coagulation, fibrinolysis and inflammation were also performed. Addition of abciximab to dalteparin as the primary treatment of unstable CAD was not associated with any significant reduction in cardiac events but a doubled risk of bleedings. The combination of abciximab with dalteparin seemed as safe when used with heparin. Despite full dose dalteparin and aspirin there was a simultaneous activation of the inflammation, coagulation and fibrinolysis systems without any influence of the abciximab treatment. Elevated levels of CRP, TnT, and NT-proBNP and reduced creatinine clearance were independently related to short and long-term mortality. The best prediction of high and low risk was provided by a combination of NT-proBNP and creatinine clearance. Any detectable elevation of TnT and reduced creatinine clearance, but neither elevation of CRP nor NT-proBNP, were also independently associated to a raised risk of subsequent myocardial infarction.

B-Type Natriuretic Peptide as a Marker of Resuscitation in Patients With Cardiac Arrest Outside the Hospital

BACKGROUND

Although the circulating concentration of B-type natriuretic peptide (BNP) has both a prognostic and diagnostic value in heart disease, no data are available regarding its resuscitative value for out-of-hospital cardiac arrest.

METHODS AND RESULTS

The present study was a prospective study of 401 patients whose BNP was measured on arrival at the emergency room after an out-of-hospital cardiac arrest with a cardiac cause. The primary endpoint was survival to hospital discharge. The unadjusted rate of survival to hospital discharge decreased in a stepwise fashion among patients in increasing quartiles of BNP concentration (p<0.001). After adjusting for independent predictors of resuscitation, the odds ratios for survival to hospital discharge in the second, third and fourth quartiles of BNP were 0.13 (95% confidence interval (CI), 0.04-0.46), 0.10 (95% CI, 0.03-0.41), and 0.004 (95% CI, 0.00-0.16), respectively. The BNP cutoff value of 100 pg/ml for survival had a sensitivity of 83% and a negative predictive value of 96%.

CONCLUSIONS

The measurement of BNP was found to provide valuable predictive information for survival to hospital discharge in patients with out-of-hospital cardiac arrest of cardiac etiology.

N-terminal pro-brain natriuretic peptide and other risk markers for the separate prediction of mortality and subsequent myocardial infarction in patients with unstable coronary artery disease: a Global Utilization of Strategies To Open occluded arteries (GUSTO)-IV substudy

BACKGROUND

Biochemical markers are useful for prediction of cardiac events in patients with non-ST-segment-elevation acute coronary syndrome (ACS). The associations between N-terminal pro-brain natriuretic peptide (NT-proBNP) and other biochemical and clinical risk indicators, as well as their prognostic value concerning the individual end points of death and myocardial infarction (MI), were elucidated in a large cohort of ACS patients.

METHODS AND RESULTS

NT-proBNP, troponin T, and C-reactive protein (CRP) were analyzed in blood samples obtained at a median of 9.5 hours from symptom onset in 6809 of 7800 ACS patients in the Global Utilization of Strategies To Open occluded arteries-IV (GUSTO-IV) trial. Levels of NT-proBNP were correlated independently with age, female gender, low body weight, diabetes, renal dysfunction, history of MI, heart failure, heart rate, ongoing myocardial damage, and time since onset of ischemia. Increasing quartiles of NT-proBNP were related to short- and long-term mortality that reached 1.8%, 3.9%, 7.7%, and 19.2%, (P<0.001), respectively, at 1 year. Levels of troponin T, CRP, heart rate, and creatinine clearance, in addition to ST-segment depression, were also correlated independently with 1-year mortality, but NT-proBNP was the marker with the strongest relation. In contrast, only troponin T, creatinine clearance, and ST-segment depression were independently related to future MI. The combination of NT-proBNP and creatinine clearance provided the best prediction, with a 1-year mortality of 25.7% with both markers in the top quartile vs 0.3% with both markers in the bottom quartile.

CONCLUSIONS

The use of NT-proBNP appears to add critical prognostic insight to the assessment of patients with ACS.

Evaluation of B-type natriuretic peptide for risk assessment in unstable angina/non-ST-elevation myocardial infarction: B-type natriuretic peptide and prognosis in TACTICS-TIMI 18

OBJECTIVES

This study was designed to evaluate B-type natriuretic peptide (BNP) for risk assessment and clinical decision making over a range of cut points, alone and with cardiac troponin I (cTnI), in patients with non-ST-elevation acute coronary syndromes (ACS).

BACKGROUND

B-type natriuretic peptide holds promise for risk stratification. Additional evidence regarding optimal decision limits, use in combination with troponin, and use in targeting therapy is needed before acceptance into clinical use for ACS.

METHODS

We evaluated BNP at baseline in 1,676 patients with non-ST-elevation ACS randomized to early invasive versus conservative management.

RESULTS

Patients with elevated BNP (>80 pg/ml; n = 320) were at higher risk of death at seven days (2.5% vs. 0.7%, p = 0.006) and six months (8.4% vs. 1.8%, p < 0.0001). The association between BNP and mortality at six months (adjusted odds ratio [OR] 3.3; 95% confidence interval [CI] 1.7 to 6.3) was independent of important clinical predictors, including cTnI and congestive heart failure (CHF). Patients with elevated BNP had a fivefold higher risk of developing new CHF by 30 days (5.9% vs. 1.0%, p < 0.0001). B-type natriuretic peptide added prognostic information to cTnI, discriminating patients at higher mortality risk among those with negative (OR 6.9; 95% CI 1.9 to 25.8) and positive (OR 4.1; 95% CI 1.9 to 9.0) baseline cTnI results. No difference was observed in the effect of invasive versus conservative management when stratified by baseline levels of BNP (p(interaction) > or = 0.6).

CONCLUSIONS

Elevated BNP (>80 pg/ml) at presentation identifies patients with non-ST-elevation ACS who are at higher risk of death and CHF and adds incremental information to cTnI. Additional work is needed to identify therapies that may reduce the risk associated with increased BNP.

Natriuretic peptides in the diagnosis of heart disease--first amongst equals?

The natriuretic peptides and their role in neurohumoral regulation of the cardiovascular system have become the focus of considerable interest from the scientific and clinical community in recent years. BNP in particular has been shown to be an important diagnostic and prognostic marker of use in a wide range of applications. As measurement techniques develop and are refined, routine evaluation of serum levels of these markers is expected to become more widespread. We have reviewed the biochemistry of the natriuretic peptide family, their role in cardiovascular pathophysiology and the evidence supporting their use in the clinical setting.

BNP and congestive heart failure

Brain natriuretic peptide (BNP), a peptide hormone secreted chiefly by ventricular myocytes, plays a key role in volume homeostasis. The plasma concentration of BNP is raised in various pathological states, especially heart failure. Many studies suggest that measurement of plasma BNP has clinical utility for excluding a diagnosis of heart failure in patients with dyspnea or fluid retention and for providing prognostic information in those with heart failure or other cardiac disease. It may also be of value in identifying patients after myocardial infarction in whom further assessment of cardiac function is likely to be worthwhile. Preliminary evidence suggests that measuring the plasma concentration of BNP may be useful in fine tuning therapy for heart failure. Artificially raising the circulating levels of BNP shows considerable promise as a treatment for heart failure. With simpler assay methods now available, it is likely that many physicians will measure plasma BNP to aid them in the diagnosis, risk stratification, and monitoring of their patients with heart failure or other cardiac dysfunction.

The prognostic value of B-type natriuretic peptide in patients with acute coronary syndromes

BACKGROUND

Brain (B-type) natriuretic peptide is a neurohormone synthesized predominantly in ventricular myocardium. Although the circulating level of this neurohormone has been shown to provide independent prognostic information in patients with transmural myocardial infarction, few data are available for patients with acute coronary syndromes in the absence of ST-segment elevation.

METHODS

We measured B-type natriuretic peptide in plasma specimens obtained a mean (+/-SD) of 40+/-20 hours after the onset of ischemic symptoms in 2525 patients from the Orbofiban in Patients with Unstable Coronary Syndromes-Thrombolysis in Myocardial Infarction 16 study.

RESULTS

The base-line level of B-type natriuretic peptide was correlated with the risk of death, heart failure, and myocardial infarction at 30 days and 10 months. The unadjusted rate of death increased in a stepwise fashion among patients in increasing quartiles of base-line B-type natriuretic peptide levels (P< 0.001). This association remained significant in subgroups of patients who had myocardial infarction with ST-segment elevation (P=0.02), patients who had myocardial infarction without ST-segment elevation (P<0.001), and patients who had unstable angina (P<0.001). After adjustment for independent predictors of the long-term risk of death, the odds ratios for death at 10 months in the second, third, and fourth quartiles of B-type natriuretic peptide were 3.8 (95 percent confidence interval, 1.1 to 13.3), 4.0 (95 percent confidence interval, 1.2 to 13.7), and 5.8 (95 percent confidence interval, 1.7 to 19.7). The level of B-type natriuretic peptide was also associated with the risk of new or recurrent myocardial infarction (P=0.01) and new or worsening heart failure (P<0.001) at 10 months.

CONCLUSIONS

A single measurement of B-type natriuretic peptide, obtained in the first few days after the onset of ischemic symptoms, provides powerful information for use in risk stratification across the spectrum of acute coronary syndromes. This finding suggests that cardiac neurohormonal activation may be a unifying feature among patients at high risk for death after acute coronary syndromes.

ANP, BNP, and CNP enhance bradycardic responses to cardiopulmonary chemoreceptor activation in conscious sheep

We demonstrated previously that atrial natriuretic peptide (ANP) enhances reflex bradycardia to intravenous serotonin [5-hydroxytryptamine (5-HT)] (von Bezold-Jarisch reflex) in rats. To determine whether 1) ANP affects this cardiopulmonary vagal reflex in another species and 2) B-type (BNP) and C-type (CNP) natriuretic peptides share with ANP the ability to modulate this reflex, we used intravenous phenylbiguanide (PBG), a 5-HT(3) agonist, as the stimulus to evoke a von Bezold-Jarisch reflex (dose-related, reproducible bradycardia) in conscious adult sheep (n = 5). Three doses of PBG (13 +/- 3, 20 +/- 3, and 31 +/- 4 microg/kg) injected into the jugular vein caused reflex cardiac slowing of -7 +/- 1, -15 +/- 2, and -36 +/- 3 beats/min, respectively, under control conditions. These doses of PBG were repeated during infusions of ANP, BNP, or CNP (10 pmol. kg(-1). min(-1) iv), or vehicle (normal saline). Each of the natriuretic peptides significantly (P < 0.05) enhanced the sensitivity of bradycardic responses to PBG by 94 +/- 8% (ANP), 142 +/- 55% (BNP), and 61 +/- 16% (CNP). Thus not only did ANP sensitize cardiopulmonary chemoreceptor activation in a species with resting heart rate close to that in humans, but BNP and CNP also enhanced von Bezold-Jarisch reflex activity in conscious sheep.