Plasma brain natriuretic peptide as an indicator of left ventricular systolic function and long-term survival after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide

[Prognostic value of B-type natriuretic peptide in unstable angina and non-ST-elevation myocardial infarction]

BACKGROUND AND OBJECTIVE

The B-type natriuretic peptide (BNP) has recently emerged as a prognostic marker in acute coronary syndromes (ACS). This role is based on results from randomized trials and other high selected population studies. The aim of this study was to determine the prognostic value of BNP in unselected patients with non-ST-elevated-ACS.

PATIENTS AND METHOD

BNP plasma concentrations were measured in 100 consecutive patients admitted in 2007 with non-ST-elevated-ACS, taking as cut-off value 80pg/ml (high BNP levels on 48% of patients).

RESULTS

After one year-of follow-up, 21 major adverse cardiovascular events occurred: 12 ACS, 7 hospitalizations for heart failure and 2 sudden cardiac deaths. No relationship was found between BNP levels and events on follow-up. BNP >80pg/ml was the only independent predictor of heart failure and death. No relationship was found between high levels of BNP and coronary events during the follow-up.

CONCLUSIONS

BNP was an independent predictor of heart failure and mortality in unselected patients with non-ST-elevated-ACS.

Comparison of the cardiac markers B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide

B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide have emerged as powerful biomarkers for heart failure and other cardiovascular conditions. B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide are synthesized on the basis of myocardial stress and hypertrophy and are detectable in serum by several commercially available assays. Although both markers display wide similarities in their predictive values for acute and chronic heart failure, important differences exist regarding cutoff values and influence of noncardiac variables. The similarities and differences between B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide will be reviewed and illustrated in detail regarding preanalytics and analytics, predictive properties for acute and chronic heart failure and prognosis as well as the influence of noncardiac parameters.

Prospective validation of the prognostic usefulness of brain natriuretic peptide in asymptomatic patients with chronic severe mitral regurgitation

OBJECTIVES

The purpose of the study was to determine the independent and additive prognostic value of brain natriuretic peptide (BNP) in patients with severe asymptomatic mitral regurgitation and normal left ventricular function.

BACKGROUND

Early surgery could be advisable in selected patients with chronic severe mitral regurgitation, but there are no criteria to identify candidates who could benefit from this strategy. Assessment of BNP has not been studied in asymptomatic patients with severe mitral regurgitation; hence, its prognostic value remains unclear.

METHODS

We prospectively evaluated 269 consecutive patients with severe asymptomatic organic mitral regurgitation and left ventricular ejection fraction above 60%. The first 167 consecutive patients served as the derivation cohort, and the following 102 patients served as a validation cohort. The combined end point was the occurrence of either symptoms of congestive heart failure, left ventricular dysfunction, or death at follow-up.

RESULTS

The end point was reached in 35 (21%) patients of the derivation set and in 21 (20.6%) patients of the validation cohort. The receiver-operating characteristics curve yielded an optimal cutoff point of 105 pg/ml of BNP that was able to discriminate patients at higher risk in both cohorts (76% vs. 5.4% and 66% vs. 4.0%, respectively). In both sets, BNP was the strongest independent predictor by multivariate analysis.

CONCLUSIONS

Among patients with severe asymptomatic organic mitral regurgitation, BNP > or =105 pg/ml discriminates a subgroup of patients at higher risk. Because of its incremental prognostic value, BNP assessment should be considered in clinical routine workup for risk stratification.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Regional clearance of amino-terminal pro-brain natriuretic peptide from human plasma

AIMS

Mechanisms for clearance of circulating amino-terminal pro-brain natriuretic peptide (NT-proBNP) remain poorly understood and are relevant to the clinical utility of NT-proBNP as a diagnostic and prognostic biomarker in cardiovascular disorders. We sought to determine site(s) of production and clearance of plasma NT-proBNP in the human circulation.

METHODS AND RESULTS

In 120 subjects undergoing clinically indicated cardiac catheterization, blood samples were collected from arterial and multiple venous sites to measure transorgan gradients of plasma NT-proBNP. Clearance of plasma NT-proBNP occurred across kidney, liver, musculoskeletal, and head and neck tissues. Proportions of calculated total body NT-proBNP clearance were 55-65% across the kidney, 20-25% across the liver, 10-15% across musculoskeletal tissue, and 5-10% across the head and neck. Renal fractional extraction of NT-proBNP was unrelated to estimated glomerular filtration rate. Transorgan gradients, reflecting both renal and extra-renal NT-proBNP degradation, were correlated across multiple clearance sites within an individual.

CONCLUSION

Plasma NT-proBNP is cleared by multiple tissues in the human circulation with approximately 55-65% of total clearance occurring in renal tissue. These data provide the first evidence for extra-glomerular clearance of NT-proBNP and suggest a common multisite clearance mechanism subject to generalized regulation. Renal NT-proBNP extraction was sustained in the face of even moderate levels of kidney dysfunction.

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.

N-terminal pro-B-type natriuretic peptide complements the GRACE risk score in predicting early and late mortality following acute coronary syndrome

The GRACE (Global Registry of Acute Coronary Events) risk score has been shown to offer predictive power with regard to death and AMI (acute myocardial infarction) in patients with ACS (acute coronary syndromes). NT-proBNP (N-terminal pro-B-type natriuretic peptide) has also been found to be useful in predicting mortality following ACS. In the present study, we sought to investigate the use of the GRACE score and NT-proBNP levels at predicting risk of early and late deaths following ACS. We studied 1033 patients (740 men, mean age 66.5±12.7 years) with AMI. Blood was drawn once within 24 h following the onset of chest pain. The plasma concentration of NT-proBNP was determined using an in-house non-competitive immunoassay. Patients were GRACE risk scored. The 30-day mortality was 3.7% and the 6-month mortality was 7.8%, and all were related to higher GRACE risk scores (P=0.001 for trend). Higher NT-proBNP levels were also related to increased mortality (P<0.0001). In a Cox proportional hazards model, independent predictors of 30-day and 6-month mortality included NT-proBNP levels and the GRACE risk score. The receiver-operating curve for the GRACE risk score was complemented by NT-proBNP levels for prediction of 30-day mortality [AUC (area under the curve), 0.85] and 6-month mortality (AUC, 0.81). NT-proBNP gives complementary information to the GRACE risk score for predicting early and late mortality. The inclusion of the NT-proBNP blood test is useful in risk-stratifying patients after ACS.

Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. The prevalence of AF increases dramatically with age and is seen in as high as 9% of individuals by the age of 80 years. In high-risk patients, the thromboembolic stroke risk can be as high as 9% per year and is associated with a 2-fold increase in mortality. Although the pathophysiological mechanism underlying the genesis of AF has been the focus of many studies, it remains only partially understood. Conventional theories focused on the presence of multiple re-entrant circuits originating in the atria that are asynchronous and conducted at various velocities through tissues with various refractory periods. Recently, rapidly firing atrial activity in the muscular sleeves at the pulmonary veins ostia or inside the pulmonary veins have been described as potential mechanism,. AF results from a complex interaction between various initiating triggers and development of abnormal atrial tissue substrate. The development of AF leads to structural and electrical changes in the atria, a process known as remodeling. To have effective surgical or catheter ablation of AF good understanding of the possible mechanism(s) is crucial.Once initiated, AF alters atrial electrical and structural properties that promote its maintenance and recurrence. The role of atrial remodeling (AR) in the development and maintenance of AF has been the subject of many animal and human studies over the past 10-15 years. This review will discuss the mechanisms of AR, the structural, electrophysiologic, and neurohormonal changes associated with AR and it is role in initiating and maintaining AF. We will also discuss briefly the role of inflammation in AR and AF initiation and maintenance, as well as, the possible therapeutic interventions to prevent AR, and hence AF, based on the current understanding of the interaction between AF and AR.

Characterization of NT-proBNP in Human Urine

Background: Urine amino-terminal probrain natriuretic peptide (NT-proBNP) concentrations may exclude the presence of heart failure and provide insight into renal clearance mechanisms for human NT-proBNP. We characterized the molecular forms of urine NT-proBNP detected by immunoassay.

Methods: Urine from patients with heart failure was subjected to HPLC and analyzed using immunoassays specific toward different epitopes of NT-proBNP. We assessed urine NT-proBNP immunoreactivity in healthy subjects and patients with heart failure.

Results: Size-exclusion chromatography of heart failure urine identified no NT-proBNP immunoreactivity coeluting with NT-proBNP(1–76); multiple immunoreactive NT-proBNP fragments were present. The absence of intact urinary NT-proBNP was supported by reversed-phase HPLC. Urine NT-proBNP immunoreactivity was higher in patients with acute [median 192 (interquartile range 108–1445) pg/mg creatinine] and chronic [52 (15–118) pg/mg creatinine] heart failure than in healthy subjects [4.2 (2.6–5.8) pg/mg creatinine] (P &lt; 0.001). In 40 patients with heart failure, urine NT-proBNP immunoreactivity correlated with plasma NT-proBNP (r = 0.72, P &lt; 0.001) and inversely with left ventricular ejection fraction (r = −0.33, P = 0.04).

Conclusions: Our findings clarify previous reported relationships of urine NT-proBNP–like immunoreactivity with plasma NT-proBNP concentrations and the diagnosis of heart failure. As urine NT-proBNP immunoreactivity is not intact NT-proBNP(1–76), but rather reflects assorted metabolites, the diagnostic performance of NT-proBNP assays in urine may be assay specific, necessitating validation of biomarker performance on an assay-by-assay basis. .

Prognostic value of N-terminal pro-brain natriuretic peptide in elderly people with acute myocardial infarction: prospective observational study

OBJECTIVE

To examine the influence of age on the predictive value of N-terminal pro-brain natriuretic (NT-proBNP) peptide assay in acute myocardial infarction.

DESIGN

Prospective observational study.

SETTING

All intensive care units in one French region.

PARTICIPANTS

3291 consecutive patients admitted for an acute myocardial infarction, from the RICO survey (a French regional survey for acute myocardial infarction).

MAIN OUTCOME MEASURE

Cardiovascular death at 1 year.

RESULTS

Among the 3291 participants, mean age was 68 (SD 14) years and 2356 (72%) were men. In the study population, the median NT-proBNP concentration was 1053 (interquartile range 300-3472) pg/ml. Median values for age quarters 1 to 4 were 367 (119-1050), 696 (201-1950), 1536 (534-4146), and 3774 (1168-9724) pg/ml (P<0.001). A multiple linear regression analysis was done to determine the factors associated with the pro-peptide concentrations in the overall population. NT-proBNP was mainly associated with age, left ventricular ejection fraction, creatinine clearance, female sex, hypertension, diabetes, and anterior wall infarction. At one year's follow-up, 384 (12%) patients had died from all causes and 372 (11%) from cardiovascular causes. In multivariate analysis, NT-proBNP remained strongly associated with the outcome, beyond traditional risk factors including creatinine clearance and left ventricular ejection fraction, in each age group except in the youngest one (<54 years) (P=0.29). The addition of NT-proBNP significantly improved the performance of the statistical model in the overall study population (-2log likelihood 3179.58 v 3099.74, P<0.001) and in each age quarter including the upper one (1523.52 v 1495.01, P<0.001).The independent discriminative value of NT-proBNP compared with the GRACE score was tested by a diagonal stratification using the median value of the GRACE score and NT-proBNP in older patients (upper quarter). Such stratification strikingly identified a high risk group-patients from the higher NT-proBNP group and with a high risk score-characterised by a risk of death of almost 50% at one year.

CONCLUSIONS

In this large contemporary non-selected cohort of patients with myocardial infarction, NT-proBNP concentration had incremental prognostic value even in the oldest patients, above and beyond the GRACE risk score and traditional biomarkers after acute myocardial infarction. These data further support the potential interest of clinical trials specifically assessing NT-proBNP measurement as a guide to current treatment strategies, as well as novel strategies, in older patients with acute myocardial infarction.

Relation of B-type natriuretic peptide (BNP) and infarct size as assessed by contrast-enhanced MRI

BACKGROUND

Plasma B-type natriuretic peptide (BNP) measured in acute coronary syndromes independently predicts mortality, myocardial infarction and congestive heart failure.

OBJECTIVES

To investigate the relationship between the extent of delayed enhancement (DE) and microvascular obstruction (MO) in contrast-enhanced MRI and the plasma level of BNP in patients with acute myocardial infarction.

METHODS

The study group consisted of 41 consecutive patients (26 males, mean age 57±11 years) with a first STEMI and complete reperfusion by primary PCI. EDTA-plasma samples were obtained 40±15 h after admission and analyzed for NT-pro-BNP. Cardiac MRI (CMR) was performed 50±29 h after coronary intervention on a 1.5 Tesla scanner. Cine images were acquired in contiguous short-axis views using a segmented steady-state free precession (SSFP) sequence (TR, 3 ms; TE, 1.5 ms; FA, 60°). Additionally, contrast-enhanced imaging was performed using a single shot steady-state free precession (IR-SSFP) sequence with an inversion recovery prepulse (TR, 2.4 ms; TE, 1.1 ms; FA, 50°; TI, 180 to 260 ms).

RESULTS

Strong correlations between NT-pro-BNT plasma levels and delayed enhancement extent (r=0.74, p<0.001) as well as MO (r=0.7, p<0.001) were observed. The correlation between LVEF and plasma levels of BNP, however, was only moderate (r=-0.44, p=0.002). In a multiple linear regression model, DE remains the only parameter with an independent linear association with BNP.

CONCLUSION

NT-pro-BNP, a surrogate biomarker for prognosis after STEMI, is closely associated with myocardial damage as assessed by contrast-enhanced CMR.

Oxidative stress and hyperuricaemia: pathophysiology, clinical relevance, and therapeutic implications in chronic heart failure

Heart failure (HF) is a state of chronic deterioration of oxidative mechanisms due to enhanced oxidative stress and consequent subcellular alterations. In this condition, oxidant-producing enzymes, in particular xanthine oxidase (XO), the major cardiovascular source of reactive oxygen species (ROS), are up-regulated. Growing evidence shows that this impaired oxidative metabolism due to enhanced ROS release is implicated in the development of cardiac hypertrophy, myocardial fibrosis, left ventricular remodelling, and contractility impairment responsible for worsening of cardiac function in CHF. Uric acid (UA) has long been linked with cardiovascular diseases, and hyperuricaemia is a common finding in patients with CHF. Hyperuricaemia is associated with impairment of peripheral blood flow and reduced vasodilator capacity, which relate closely to clinical status and reduced exercise capacity. Recent studies also suggest an association between UA levels and parameters of diastolic function; more importantly, UA has emerged as a strong independent prognostic factor in patients with CHF. In this review, we describe the up-to-date experimental and clinical studies that have begun to test whether the inhibition of XO translates into meaningful beneficial pathophysiological changes. This treatment gives evidence that myocardial energy, endothelial dysfunction, and vasodilator reactivity to exercise are improved by reducing markers of oxidative stress responsible for vascular dysfunction, so it represents an interesting therapeutic alternative for better outcome in CHF patients.

Biomarkers on admission for the prediction of cardiovascular events after primary stenting in patients with ST-elevation myocardial infarction

BACKGROUND

Several cardiac biomarkers have been shown to have predictive values for the development of cardiovascular disease and clinical outcome after events, and are now broadly used by clinicians. Little is known about the utility of these biomarker values on admission in ST-elevation myocardial infarction (STEMI) cases of primary drug-eluting stent (DES) implantation and intense medical therapy.

HYPOTHESIS

Because little is known about the utility of these biomarkers on admission in ST-elevation myocardial infarction (STEMI) in cases primary drug-eluting stent (DES) implantation and intense medical therapy, we evaluated clinical outcomes.

METHODS

We enrolled 207 consecutive STEMI patients treated with primary stenting (mean age, 57.3 +/- 12.0 y). We evaluated the association between B-type natriuretic peptide (BNP), cardiac troponin I (cTnI), high-sensitivity C-reactive protein (hs-CRP) on admission, and death, reinfarction, and new or worsening congestive heart failure (CHF) through 1 y.

RESULTS

In backward-elimination models including all biomarkers, only the cTnI level was retained as a predictor of 1-y CHF (odds ratio [OR]: 1.017, 95% confidence interval [CI]: 1.001-1.034, p = 0.039). There were no predictors in terms of 1-y death, reinfarction, and composite endpoint. When we applied a simple score system, in which patients were categorized on the basis of the number of elevated biomarkers, the 1-y risks of death (p = 0.600), reinfarction (p = 0.185), and composite endpoint (p = 0.620) did not increase in proportion to the number of elevated biomarkers on admission. One-y CHF only tended to increase according to the number of elevated biomarkers (p = 0.067).

CONCLUSIONS

The use of cardiac biomarkers on admission, in each or in combination, had only a minimal impact for the prediction of long-term cardiovascular events after primary stenting in STEMI patients.

Clinical significance of brain natriuretic peptide in patients with postmyocardial infarction

BACKGROUND

Risk stratification after acute myocardial infarction (AMI) includes the evaluation of left ventricular (LV) function. Natriuretic peptides, and particularly brain natriuretic peptide (BNP), emerged as a potential marker of ventricular function and prognosis after AMI.

HYPOTHESIS

Brain natriuretic peptide levels are related to ventricular function, either systolic or isolated diastolic, and can give prognostic information in patients surviving AMI.

METHODS

In all, 101 patients were enrolled. An echocardiographic (M-mode, two-dimensional, and pulsed Doppler) evaluation was performed and blood samples for BNP measurement were obtained. Clinical events were recorded during 12 months of follow-up.

RESULTS

A negative correlation between BNP and LV ejection fraction was observed (r = -0.38; p < 0.001). The BNP levels were higher among patients with LV systolic dysfunction than in patients with isolated diastolic dysfunction (339.1 +/- 249.9 vs. 168.0 +/- 110.5 pg/ml, p = 0.001). The latter had higher levels of BNP than those with normal LV function (68.3 +/- 72.6 pg/ml, p < 0.001). The BNP accuracy to detect LV systolic dysfunction was good (area under the ROC curve [AUC] = 0.83) and increased when isolated diastolic dysfunction was also considered (AUC = 0.87). Brain natriuretic peptide had a very good accuracy in the prediction of death (AUC = 0.95) and the development of heart failure (AUC = 0.90).

CONCLUSION

These results extend previous evidence relating BNP to systolic function after AMI. Furthermore, a relationship between BNP levels and diastolic function was found. Brain natriuretic peptide had a very good performance in detecting the occurrence of an adverse event. We conclude that BNP can detect high-risk patients and help select patients for more aggressive approaches.

Cystatin C and cardiovascular mortality in patients with coronary artery disease and normal or mildly reduced kidney function: results from the AtheroGene study

AIMS

Chronic kidney disease is associated with increased risk of cardiovascular disease. Cystatin C is a promising marker to reliably mirror renal function. The role of cystatin C in patients with coronary artery disease (CAD) and normal or mildly reduced kidney function is the subject of current investigation.

METHODS AND RESULTS

In 2162 patients, over the whole spectrum of CAD, baseline cystatin C concentrations were measured. Patients with an estimated glomerular filtration rate of < or =60 mL/min per 1.73 m(2) (n = 295) were excluded. In patients with complete follow-up information (n = 1827), 66 cardiovascular deaths were registered during a median follow-up of 3.65 years. Logarithmically transformed, standardized cystatin C was associated with cardiovascular death [hazard ratio: 1.94, 95% confidence interval (CI): 1.59-2.37, P < 0.001]. A potential threshold effect was observed; patients in the upper quartile had a 3.87-fold (95% CI: 2.33-6.42; P < 0.001) risk of mortality compared with the pooled lower quartiles. This risk association remained robust after adjustment for potential confounders including classical risk factors and N-terminal pro B-type natriuretic peptide. Serum creatinine was not associated with the outcome in this group of patients with normal renal function.

CONCLUSION

Results of this prospective study show that cystatin C is a potent predictor of cardiovascular mortality beyond classical risk factors in patients with CAD and normal or mildly reduced kidney function.

Elevated plasma brain natriuretic peptide levels independent of heart disease in acute ischemic stroke: correlation with stroke severity

We tested the hypothesis that plasma brain natriuretic peptide (BNP) levels are elevated in patients with acute cerebrovascular diseases (CVD) independent of heart disease, and reflect CVD severity. After careful evaluations for heart disease, the study included 79 consecutive patients with CVD without any evidence of heart disease admitted within 48 h after onset (71+/-10 years), and 26 control subjects without CVD (CT, 67+/-12 years). Ischemic stroke subtypes were defined by the TOAST classification. Large-artery atherosclerosis (LAA, n=27), small-artery occlusion (SAO, n=27), and intracerebral hemorrhage (ICH, n=25) were included. The plasma BNP levels were measured at admission and 1 month later. Stroke severity and brain infarct volume were evaluated. There were no significant differences in the clinical profiles including echocardiographic parameters among the groups. The plasma BNP level (pg/mL) upon admission was higher in LAA (70.6+/-53.9) than in SAO (38.2+/-28.4) and CT (28.5+/-19.9) (both p<0.05). The level in ICH (47.3+/-28.6) was not significantly different from that in CT. The BNP level in ischemic stroke was positively correlated with the NIH Stroke Scale (NIHSS) (rho=0.42, p<0.05) and infarct volume (r=0.34, p<0.05). Brain infarct volume and NIHSS were independent contributors to the plasma BNP level in ischemic stroke. One month later, the BNP level was significantly decreased and was similar in all CVD groups. The plasma BNP level transiently increased in patients with LAA independently of heart disease, and reflected infarct volume and the severity of acute ischemic stroke.

N-terminal pro-brain natriuretic peptide in the elderly with myocardial infarction

BACKGROUND

The myocardial infarction (MI) results in the change of the levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) in blood. In addition, attention is paid to the dependence of NT-proBNP levels on the patients' age. However, the behavior of natriuretic peptide levels has not been recognized well enough in the elderly with MI treated with invasive methods.

HYPOTHESIS

The aim of the study was to estimate the effect of age on NT-proBNP levels in patients with first MI, and treated with primary percutaneous coronary intervention (PCI) with complete coronary revascularization.

METHODS

One hundred and sixty-one consecutive patients with first ST-elevation MI, and treated with primary PCI with stent implantation (occlusion in infarct-related artery was the patient's only lession) were included. Determination of NT-proBNP level and echocardiography were performed on the 4th-5th day of MI.

RESULTS

Thirty-seven patients (23%) aged>or=65 y were considered as a study group. The NT-proBNP levels were nearly 4-fold higher in older patients than in younger patients. Only systolic and diastolic dysfunction, mitral regurgitation, troponin T levels, and glomerular filtration rate (GFR) were independent risk factors of the occurrence of elevated NT-proBNP concentration above median.

CONCLUSIONS

The patients' age was not a factor independently affecting the increase of NT-proBNP level above the median in patients with first MI and treated successfully with primary PCI. Independently associated elevated levels of NT-proBNP were as follows: presence of diastolic dysfunction, mitral regurgitation, left ventricular systolic dysfunction, troponin T concentration, and GFR.

Brain natriuretic peptides as biomarkers for atherosclerosis

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

Plasma tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9: novel indicators of left ventricular remodelling and prognosis after acute myocardial infarction

AIMS

Matrix metalloproteinase (MMP) activity is central to the development of left ventricular (LV) remodelling and dysfunction after acute myocardial infarction (AMI). We assessed the relationships with LV structure and function and outcome, of tissue inhibitors of metalloproteinase-1 (TIMP-1) and MMP-9, and compared with N-terminal pro-B-type natriuretic peptide (NTproBNP).

METHODS AND RESULTS

We studied 404 patients with AMI. Primary outcome measures were the associations of TIMP-1, MMP-9, and NTproBNP with death or heart failure, and with LV dimensions, function and remodelling (ΔLVEDV, change in LV end-diastolic volume between discharge and follow-up). Cut-off concentrations for prediction of death or heart failure were identified from receiver operator characteristic (ROC) curves. In multivariable analysis, TIMP-1 and NTproBNP had predictive value for LV ejection fraction pre-discharge (TIMP-1 P = 0.023; N-BNP P = 0.007) and at follow-up (TIMP-1 P = 0.001; N-BNP P = 0.003). MMP-9, TIMP-1, and NTproBNP correlated directly with LV volumes. MMP-9 (P = 0.005) and TIMP-1 (P = 0.036), but not NTproBNP, correlated with ΔLVEDV. For the combined endpoint of death or heart failure the area under the ROC curve was 0.640 for MMP-9, 0.799 for NTproBNP and 0.811 for TIMP-1. Patients with TIMP-1 > 135 ng/mL (P < 0.001) or NTproBNP >1472 fmol/mL (P < 0.001) had increased risk of endpoint. Consideration of both NTproBNP and TIMP-1 further improved risk stratification.

CONCLUSION

TIMP-1 and MMP-9 correlate with echocardiographic parameters of LV dysfunction and remodelling after AMI and may identify patients at risk of subsequent LV remodelling and adverse prognosis.

Midregional pro-atrial natriuretic peptide is a useful indicator for the detection of impaired left ventricular function in patients with coronary artery disease

AIMS

We compared the diagnostic performance of N-terminal pro-brain natriuretic peptide (NT-proBNP) with a newly developed assay for the midregional part of pro-atrial natriuretic peptide (MR-proANP) concerning the detection of impaired left ventricular ejection function (LVEF) among patients with coronary artery disease (CAD).

METHODS AND RESULTS

Plasma levels of MR-proANP and NT-proBNP were determined in 102 consecutive patients with a history of ST-elevation myocardial infarction. Plasma levels of both markers were measured during a mean follow-up period of 687 days after acute myocardial infarction. Univariate analyses revealed inverse correlations between MR-proANP levels and LVEF (r=-0.39; p<0.001), NT-proBNP levels and LVEF (r=-0.39; p<0.001) and a positive correlation between MR-proANP and NT-proBNP (r=0.75; p<0.001). After adjustment for traditional risk factors, MR-proANP was the strongest predictor for LVEF (p=0.001) in multivariate analysis, being even superior to NT-proBNP. The area under the ROC curve (AUC) indicated moderate performance (AUC=0.73; p<0.01) of MR-proANP regarding the detection of a reduced LVEF<50%. The AUC of NT-proBNP for detection of impaired LVEF<50% was 0.68 (p=0.019). The negative predictive values of both markers were 86% for MR-proANP at a cut-off >135 pmol/L and NT-proBNP at a cut-off >560 pmol/L. At these cut-offs, the specificity of MR-proANP was 90%, and the specificity of NT-proBNP was 84%.

CONCLUSIONS

MR-proANP is a useful indicator for the exclusion of a preserved left ventricular function in patients with coronary artery disease. The study demonstrates that the diagnostic performance of MR-proANP is comparable to the "gold standard" NT-proBNP.

Time course of effects of cardiac resynchronization therapy in chronic heart failure: benefits in patients with preserved exercise capacity

OBJECTIVES

To assess in patients with chronic heart failure the effect of cardiac resynchronization therapy (CRT) over 12 months' follow-up the time course of the changes in functional and neurohormonal indices and to identify responders to CRT.

METHODS

Eighty-nine patients (74.1 +/- 1 years, left ventricular ejection fraction [LVEF] < 35%), QRS complex duration >150 ms, in stable New York Heart Association (NYHA) class III or IV on optimal medical treatment were prospectively randomized either in a control (n = 45) or CRT (n = 44) group and underwent clinical evaluation, cardiopulmonary exercise testing (CPET), 2D-Echo, heart rate variability (HRV), carotid baroreflex (BRS), and BNP assessments before and at 6- and 12-month follow-up.

RESULTS

In the CRT group, improvement of cardiac indices and BNP concentration were evident at medium term (over 6 months) follow-up, and these changes persisted on a longer term (12 months) (all P < 0.05). Instead CPET indices and NYHA class improved after 12 months associated with restoration of HRV and BRS (all P < 0.05). We identified 26 responders to CRT according to changes in LVEF and diameters. Responders presented less depressed hemodynamic (LVEF 25 +/- 1.0 vs 22 +/- 0.1%), functional (peak VO(2) 10.2 +/- 0.2 vs 6.9 +/- 0.3 ml/kg/min), and neurohormonal indices (HRV 203.6 +/- 15.7 vs 147.6 +/- 10.ms, BRS 4.9 +/- 0.2 vs 3.6 +/- 0.3 ms/mmHg) (all P < 0.05). In the multivariate analysis, peak VO(2) was the strongest predictor of responders.

CONCLUSIONS

Improvement in functional status is associated with restoration of neurohormonal reflex control at medium term. Less depressed functional status (peak VO(2)) was the strongest predictor of responders to CRT.

N-terminal pro-B-type natriuretic peptide is associated with adverse short-term clinical outcomes in patients with acute ST-elevation myocardial infarction underwent primary percutaneous coronary intervention

BACKGROUND

Increased level of N-terminal pro-B type natriuretic peptide (NT-proBNP) is known to be associated with adverse outcome in patients with acute coronary syndrome. We evaluated early outcomes of patients with acute ST-elevated myocardial infarction (STEMI) according to the level of NT-proBNP as a substudy of Korean Acute Myocardial Infarction Registry (KAMIR).

METHODS

Study population consisted of 1052 consecutive patients (mean 61.3+/-12.8 years old, male 73.2%) with STEMI of onset <12 h who underwent primary percutaneous coronary intervention (PCI) and who had baseline NT-proBNP level by electrochemiluminescence immnunoassay (ECLIA, NT-proBNP kit, Roche Diagnostics, Mannheim, Germany). The study subjects were divided into two groups according to the level of serum NT-proBNP.

RESULTS

Patients with NT-proBNP level >991 pg/mL (n=329, 57.1% male) had lower left ventricle ejection fraction (LVEF) (47.8+/-11.8% vs. 53.0+/-10.8%, p<0.001), needed longer intensive care (3.7+/-3.6 days vs. 2.8+/-2.4 days, p<0.001) and had higher in-hospital mortality (1.3% vs. 7.4%, p<0.001) than those with NT-proBNP level<or=991 pg/mL (n=723, 80.5% male). Multiple logistic regression analysis revealed that the independent predictors of in-hospital mortality were LVEF<45% (OR 5.43, 95% CI 1.71 to 17.29, p=0.004), elevated NT-proBNP (>991 pg/mL) (OR 3.70, 95% CI 1.14 to 12.03, p=0.030), old age (>or=70 years) (OR 4.71, 95% CI 1.43 to 15.52, p=0.011), advanced Killip class (>1) (OR 4.96, 95% CI 1.58 to 15.53, p=0.006), male gender (OR 5.67, 95% CI 1.45 to 22.21, p=0.013) and TIMI flow 0 before PCI (OR 5.04, 95% CI 1.08 to 23.41, p=0.039).

CONCLUSIONS

This study suggests that baseline NT-proBNP level is associated with short term mortality in patients with STEMI underwent primary PCI.

Advances in congestive heart failure management in the intensive care unit: B-type natriuretic peptides in evaluation of acute heart failure

BACKGROUND

Circulating concentrations of B-type natriuretic peptide (BNP) and the aminoterminal fragment (NT-proBNP) of its prohormone (proBNP) are increased in congestive heart failure in proportion to the severity of symptoms, the degree of left ventricular dysfunction, and cardiac filling pressures. Following the introduction of rapid, automated assays for determination of BNP and NT-proBNP, these peptides are increasingly used for diagnostic and prognostic purposes.

OBJECTIVE

To review studies evaluating the diagnostic and prognostic value of BNP and NT-proBNP, with special emphasis on their performance as indicators of acute heart failure in the intensive care unit.

RESULTS

In patients presenting with acute dyspnea, both BNP and NT-proBNP are accurate indicators of acute heart failure and provide prognostic information above and beyond conventional risk markers. Increased plasma levels of BNP and NT-proBNP are not specific for heart failure and may be influenced by a variety of cardiac and noncardiac conditions commonly seen in the intensive care unit, including myocardial ischemia, cardiac arrhythmias, sepsis, shock, anemia, renal failure, hypoxia, acute pulmonary embolism, pulmonary hypertension, and acute respiratory distress syndrome.

CONCLUSIONS

The diagnostic performance of BNP and NT-proBNP as indicators of acute heart failure depends on the clinical setting. In the intensive care unit, particular caution should be used in the interpretation of elevated BNP and NT-proBNP levels.

Screening and therapy of pulmonary hypertension in systemic sclerosis

PURPOSE OF REVIEW

Systemic sclerosis is a major risk factor for the development of pulmonary arterial hypertension. Often this disease is far advanced by the time it is detected in the individual patient, severely impacting quality of life and survival.

RECENT FINDINGS

Therapeutic options available for patients with scleroderma-associated pulmonary arterial hypertension have increased significantly over the last few years, fueling our desire to improve early detection of disease.

SUMMARY

During the course of this manuscript I will review the literature examining approaches towards screening for scleroderma-associated pulmonary arterial hypertension. I will then discuss the most recent studies examining therapeutic options for patients with this disease.

Relation of B-type natriuretic peptide to left ventricular wall stress as assessed by cardiac magnetic resonance imaging in patients with dilated cardiomyopathy

Ventricular loading conditions are crucial determinants of cardiac function and prognosis in heart failure. B-type natriuretic peptide (BNP) is mainly stored in the ventricular myocardium and is released in response to an increased ventricular filling pressure. We examined, therefore, the hypothesis that BNP serum concentrations are related to ventricular wall stress. Cardiac magnetic resonance imaging (MRI) was used to assess left ventricular (LV) mass and cardiac function of 29 patients with dilated cardiomyopathy and 5 controls. Left ventricular wall stress was calculated by using a thick-walled sphere model, and BNP was assessed by immunoassay. LV mass (r = 0.73, p < 0.001) and both LV end-diastolic (r = 0.54, p = 0.001) and end-systolic wall stress (r = 0.66, p < 0.001) were positively correlated with end-diastolic volume. LV end-systolic wall stress was negatively related to LV ejection fraction (EF), whereas end-diastolic wall stress was not related to LVEF. BNP concentration correlated positively with LV end-diastolic wall stress (r = 0.50, p = 0.002). Analysis of variance revealed LV end-diastolic wall stress as the only independent hemodynamic parameter influencing BNP (p < 0.001). The present approach using a thick-walled sphere model permits determination of mechanical wall stress in a clinical routine setting using standard cardiac MRI protocols. A correlation of BNP concentration with calculated LV stress was observed in vivo. Measurement of BNP seems to be sufficient to assess cardiac loading conditions. Other relations of BNP with various hemodynamic parameters (e.g., EF) appear to be secondary. Since an increased wall stress is associated with cardiac dilatation, early diagnosis and treatment could potentially prevent worsening of the outcome.

Prognostic value of reduced kidney function and anemia in patients with chronic heart failure

OBJECTIVES

The present study aimed to evaluate the prognostic value of B-type natriuretic peptide (N-proBNP), renal dysfunction and anemia in chronic heart failure (CHF) patients.

METHODS

We analyzed data from a prospective cohort of 153 patients (mean age 64 years) with CHF referred to our hospital center. Clinical, echocardiographic and laboratory data were drawn during hospital recovery in all patients. Kidney dysfunction was defined as a glomerular filtration rate (GFR) < 60 ml/min and anemia as a hematocrit < 35%. After discharge, patients attended the outpatient clinic of our institution.

RESULTS

Kidney dysfunction was diagnosed in 37% of cases, whereas anemia was present in 25% of patients. During follow-up (median time 456 days), 32 patients died. Multivariate Cox proportional hazard model revealed that N-proBNP [hazard ratio (HR) = 1.002; P < 0.001] and GFR (HR = 0.972; P < 0.005) were significant predictors for mortality after adjustment for confounding variables. Kaplan-Maier analysis demonstrated a progressive decrease in survival from lowest to highest tertiles of N-proBNP values (log rank = 28.7; P < 0.001) and from higher to lower GFR values (log rank = 5.63; P < 0.01). Moreover, parametric survival analysis by the Weibull model demonstrated that the estimated probability of survival adjusted for N-proBNP values was higher in patients with GFR > or = 60 ml/min than in those with GFR < 60 ml/min (P < 0.001).

CONCLUSION

Increased N-proBNP and decreased kidney function, but not anemia, are independent risk factors for mortality in patients with CHF.

Effects of cardiac resynchronization therapy on insulin-like growth factor-1 in patients with advanced heart failure

BACKGROUND

Although a more favorable neurohormonal balance may contribute to improving symptoms following cardiac resynchronization therapy (CRT), no information is available regarding the effects of CRT on insulin-like growth factor-1 (IGF-1). This study assessed the effects of CRT on IGF-1 levels and their correlation with changes in quality of life and left ventricular (LV) function.

METHODS AND RESULTS

Patients with cardiomyopathy in New York Heart Association class III or IV (n = 18; age 71 +/- 10 years), left ventricular ejection fraction (LVEF) < or = 40% and QRS > or = 130 ms or ventricular dyssynchrony were enrolled in the study and followed up for 6 months. After 3 months, there was an improvement in LVEF (from 29 +/- 7 to 33 +/- 10%, P = 0.0136) and quality of life (from 33 +/- 14 to 13 +/- 12, P = 0.0000) and an increase in IGF-1 levels (from 137 +/- 79 to 175 +/- 111 ng/ml, P = 0.01353). The change in quality of life correlated with changes in IGF-1 levels (P = 0.02) but not with LVEF changes.

CONCLUSIONS

In patients with advanced heart failure, CRT leads to a significant increase in plasma IGF-1 levels within 3 months. This increase is correlated with the improvement in quality of life, whereas the increase in LVEF is not. This finding suggests that IGF-1 may play a role as a mediator in the early phase of symptomatic improvement after CRT.

Can we use B-type natriuretic peptides to monitor patients with heart failure?

The B-type natriuretic peptides (BNPs) now have a well-established role in the diagnosis of heart failure. There is also a wealth of evidence on their ability as prognostic markers in patients with heart failure. The other potential role of BNPs is in the arena of therapy monitoring, although much less is known regarding this putative application. This review summarizes what evidence there is both for and against using BNPs to monitor heart failure patients.

A systematic review of BNP as a predictor of prognosis in persons with coronary artery disease

OBJECTIVE

This systematic review was conducted to examine whether B-type natriuretic peptide (BNP) can predict mortality and other cardiac endpoints in persons diagnosed with coronary artery disease (CAD).

DESIGN AND METHODS

Databases were searched from 1989 to February 2005 for primary studies that measured BNP for the purpose of diagnosis, prognosis, and monitoring treatment.

RESULTS

In 18 studies, concentrations of BNP were found to have consistent positive associations with poorer prognoses for persons with CAD. The overall range of effect (95% confidence interval) was 2.31 to 5.02, measured via a random effects meta-analysis on studies reporting an odds ratio. Prognostic ability was similar for mortality and non-fatal outcomes. Ranges of estimated measures of effect (i.e., odds ratio, relative risk, hazard ratio) were concentrated between 1.33 to 2.94 for mortality and 1.01 to 3.03 for non-fatal outcomes.

CONCLUSIONS

Further research is needed to assess whether prognostic ability differs by comorbidity or concomitant treatment. As well, the importance and selection of cut points remains unresolved. Until greater clarity is given to these matters, it would be prudent for clinicians to employ caution when using concentrations of BNP to predict the prognosis of persons with CAD.

Accuracy of N-Terminal Probrain Natriuretic Peptide to Predict Mortality or Detect Acute Ischemia in Patients with Coronary Artery Disease

OBJECTIVE

The aim of the study was to assess the accuracy of N-terminal probrain natriuretic peptide (NT-proBNP) to predict mortality or detect acute ischemia in patients with coronary artery disease (CAD).

METHODS

This study included 1,552 patients with stable (n = 1,059) or unstable (n = 493) CAD undergoing percutaneous coronary intervention. NT-proBNP was measured before percutaneous coronary intervention. The primary endpoint of the study was mortality. Patients were followed for 3.6 years.

RESULTS

There were 171 deaths (11%) during follow-up. In the entire group of patients, NT-proBNP had the best accuracy to predict mortality (area under receiver operating characteristic curve 0.76, 95% CI 0.72-0.80). In patients without congestive heart failure (n = 760) there were 46 deaths (6%). The area under receiver operating characteristic curve of NT-proBNP was reduced to 0.70 (95% CI 0.63-0.79) which was not better than the area under curve of age (p = 0.981) or C-reactive protein (p = 0.082) regarding mortality. NT-proBNP showed limited power to detect patients with acute ischemia (area under curve 0.63, 95% CI 0.60-0.66) among consecutive patients with stable and unstable CAD.

CONCLUSIONS

NT-proBNP has a moderate accuracy to predict mortality and does not assist in the diagnosis of acute myocardial ischemia in patients with CAD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Analytical validation of commercial immunoassays for the measurement of cardiovascular peptides in the dog

Immunoassays for the measurement of concentrations of the cardiovascular peptides pro-atrial natriuretic peptide (proANP), brain natriuretic peptide (BNPPen and BNPPhoe), endothelin-1 (ET-1Bio, ET-1IBL and ET-1Phoe) and big endothelin-1 (Big-ETBio and Big-ETIBL) were validated in canine serum by determination of intra-assay variability and dilutional parallelism. Commercial kits that showed good results were further validated by determination of intra- and inter-assay variability, dilutional parallelism and spiking recovery. Assays for proANP, BNPPhoe, ET-1IBL and Big-ETIBL showed acceptable results in the preliminary validation and were fully validated. The intra- and inter-assay variability was acceptable for all four assays, linearity was demonstrated and recovery rates were acceptable. The performances of the different immunoassays varied considerably, underscoring the importance of validation. Of the assays studied, proANP, BNP(Phoe), ET-1IBL and Big-ETIBL produced precise, reproducible and accurate results and can be recommended for clinical application.