N-terminal pro-B-type natriuretic peptide and long-term mortality in stable coronary heart disease

Assessing the clinical utility of biomarkers in medicine

Biomarkers in medicine have gained immense scientific and clinical interest in recent years. Biomarkers are potentially useful in the contexts of primary, secondary and tertiary prevention. Some of the characteristics of an ideal biomarker include that they are safe and easy to measure, are associated with acceptable costs (including those of the follow-up tests), and there is scientific evidence to suggest that biomarker use/modification influences disease outcomes. Additionally, variation in biomarker levels with gender and ethnicity should be elucidated, and the biomarker should have 'good performance characteristics' (i.e., sensitivity, specificity, positive- and negative-predictive values and positive- and negative-likelihood ratios). Risk prediction scores can combine information from several different biomarkers in order to estimate an individual's risk of developing an outcome, such as disease or death. Three commonly employed methods to test if a biomarker will add to traditional risk prediction models are model discrimination, model calibration and risk reclassification. 'Multimarker' strategies serve to integrate information from multiple biomarkers into risk prediction but may be limited by the presence of highly correlated biomarkers, economic costs and selection bias of biomarker candidates in a particular study sample. In the future, integration of biomarkers identified using emerging technologies from the 'omics fields (including genomics, proteomics, metabolomics, lipomics, ribomics and pharmacogenomics) may be useful for the 'personalization' of treatment/disease prevention.

Postoperative B-type natriuretic Peptide levels associated with prolonged hospitalization in hypertensive patients after non-cardiac surgery

Background and Objectives

B-type natriuretic peptide (BNP) is an important marker for the diagnosis of heart failure and is useful towards predicting morbidity and mortality after non-cardiac surgery. Nevertheless, information on the relationship between postoperative BNP levels and perioperative prognosis after non-cardiac surgery is scarce. The purpose of the study was to assess whether postoperative BNP levels could be used as a predictor of prolonged hospitalization in elderly hypertensive patients after non-cardiac surgery.

Subjects and Methods

Ninety-seven (97) patients, aged 55 years or older (mean age: 73.12±10.05 years, M : F=24 : 73) were enrolled in a prospective study from May 2005 through August 2010. All patients underwent total knee or hip replacement. Postoperative BNP and other diagnostic data were recorded within 24 hours of surgery. Patients that required a prolonged hospital stay due to operative causes, such as wound infection and re-operation, were excluded.

Results

The length of hospital stay was significantly correlated with postoperative BNP levels (p=0.031). Receiver operating characteristic curves demonstrated postoperative BNP levels as predictors of hospital stay ≥30 days with areas under the curve of 0.774 (95% confidence interval: 0.679-0.87, p<0.0001). A BNP cut-off value above 217.5 pg/mL had a sensitivity of 80.6% and a specificity of 66.7% for predicting postoperative hospital stays of 30 days or more.

Conclusion

Postoperative BNP levels may predict the length of hospital stays after non-cardiac surgery in hypertensive patients. Elevated BNP levels were associated with prolonged hospitalization after elective orthopedic surgery.

Impact of a novel mutation in the 5'-flanking region of natriuretic peptide precursor B gene on the antihypertensive effects of sodium nitroprusside in patients with hypertension

Our aim was to identify the possible mutations of the natriuretic peptide precursor B (NPPB) gene in a family with hereditary hypertension, and determine whether the mutations are associated with the antihypertensive effect of sodium nitroprusside. The subjects included one family with hereditary hypertension, 36 cases of sporadic hypertension and 120 healthy controls. The 5'-flanking sequence of NPPB was amplified with PCR, and the presence of mutations was analyzed by direct sequencing. Patients with hypertension were treated with sodium nitroprusside and blood pressure data and serum B-type natriuretic peptide (BNP) levels were measured. A novel complex mutation in 5'-flanking sequence of the NPPB gene was detected in three patients (II 2, III 2, and III 5) of the hypertension family, which included c.-1195_ -1176 insert 5'-CCTTCTTTCTTTCTTTCTTT-3', c.-1208 T>A, c.-1214 T>C, and c.-1216 T>A. Patients with this mutation were less sensitive to sodium nitroprusside treatment. Sporadic hypertension patients (without NPPB gene mutation) and patients with the c.-1181 T>A point mutation were sensitive to sodium nitroprusside treatment. BNP levels of patients with the complex mutation were significantly lower than that of sporadic hypertension patients and c.-1181 T>A mutation patients before and during the early stage of sodium nitroprusside treatment. The complex mutation of the NPPB gene might be an etiological factor of hereditary malignant hypertension, and it is associated with low sensitivity to the antihypertensive effect of sodium nitroprusside.

Brain natriuretic peptide for prediction of mortality in patients with sepsis: a systematic review and meta-analysis

Introduction

Early identification of septic patients at high risk of dying remains a challenge. The prognostic role of brain natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) in septic patients remains controversial. The purpose of this systematic review and meta-analysis was to investigate the value of elevated BNP or NT-proBNP in predicting mortality in septic patients.

Methods

PubMed, Embase and the Cochrane Central Register of Controlled Trials were searched (up to February 18, 2011). Studies were included if they had prospectively collected data on all-cause mortality in adult septic patients with either plasma BNP or NT-proBNP measurement. Studies that failed to construct a 2 × 2 table of results were excluded. Two authors independently determined the validity of included studies and extracted data.

Results

12 studies with a total of 1,865 patients were included. Elevated natriuretic peptides were significantly associated with increased risk of mortality (odds ratio (OR) 8.65, 95% confidence interval (CI) 4.94 to 15.13, P < 0.00001). The association was consistent for BNP (OR 10.44, 95% CI 4.99 to 21.58, P < 0.00001) and NT-proBNP (OR 6.62, 95% CI 2.68 to 16.34, P < 0.0001). The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 79% (95% CI 75 to 83), 60% (95% CI 57 to 62), 2.27 (95% CI 1.83 to 2.81) and 0.32 (95% CI 0.22 to 0.46), respectively.

Conclusions

Our results suggested that an elevated BNP or NT-proBNP level may prove to be a powerful predictor of mortality in septic patients. Future larger and more adequately powered prospective studies are warranted to clarify the assay standardization, the optimal cut-off, and the prognostic value of BNPs in conjunction with other biomarkers.

Cardiac biomarkers are associated with an increased risk of stroke and death in patients with atrial fibrillation: a Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) substudy

BACKGROUND

Cardiac biomarkers are strong predictors of adverse outcomes in several patient populations. We evaluated the prevalence of elevated troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP) and their association to cardiovascular events in atrial fibrillation (AF) patients in the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial.

METHODS AND RESULTS

Biomarkers at randomization were analyzed in 6189 patients. Outcomes were evaluated by Cox proportional hazards models adjusting for established cardiovascular risk factors and the CHADS(2) and CHA(2)DS(2)-VASc risk scores. Patients were stratified based on troponin I concentrations: <0.010 μg/L, n=2663; 0.010 to 0.019 μg/L, n=2006; 0.020 to 0.039 μg/L, n=1023; ≥0.040 μg/L, n=497; and on NT-proBNP concentration quartiles: <387; 387 to 800; 801 to 1402; >1402 ng/L. Rates of stroke were independently related to levels of troponin I with 2.09%/year in the highest and 0.84%/year in the lowest troponin I group (hazard ratio [HR], 1.99 [95% CI, 1.17-3.39]; P=0.0040), and to NT-proBNP with 2.30%/year versus 0.92% in the highest versus lowest NT-proBNP quartile groups, (HR, 2.40 [95% CI, 1.41-4.07]; P=0.0014). Vascular mortality was also independently related to biomarker levels with 6.56%/year in the highest and 1.04%/year the lowest troponin I group (HR, 4.38 [95% CI, 3.05-6.29]; P<0.0001), and 5.00%/year in the highest and 0.61%/year in the lowest NT-proBNP quartile groups (HR, 6.73 [3.95-11.49]; P<0.0001). Biomarkers increased the C-statistic from 0.68 to 0.72, P<0.0001, for a composite of thromboembolic events.

CONCLUSIONS

Elevations of troponin I and NT-proBNP are common in patients with AF and independently related to increased risks of stroke and mortality. Cardiac biomarkers seem useful for improving risk prediction in AF beyond currently used clinical variables.

Changes in cardiac biomarkers during doxorubicin treatment of pediatric patients with high-risk acute lymphoblastic leukemia: associations with long-term echocardiographic outcomes

PURPOSE

Doxorubicin causes cardiac injury and cardiomyopathy in children with acute lymphoblastic leukemia (ALL). Measuring biomarkers during therapy might help individualize treatment by immediately identifying cardiac injury and cardiomyopathy.

PATIENTS AND METHODS

Children with high-risk ALL were randomly assigned to receive doxorubicin alone (n = 100; 75 analyzed) or doxorubicin with dexrazoxane (n = 105; 81 analyzed). Echocardiograms and serial serum measurements of cardiac troponin T (cTnT; cardiac injury biomarker), N-terminal pro-brain natriuretic peptide (NT-proBNP; cardiomyopathy biomarker), and high-sensitivity C-reactive protein (hsCRP; inflammatory biomarker) were obtained before, during, and after treatment.

RESULTS

cTnT levels were increased in 12% of children in the doxorubicin group and in 13% of the doxorubicin-dexrazoxane group before treatment but in 47% and 13%, respectively, after treatment (P = .005). NT-proBNP levels were increased in 89% of children in the doxorubicin group and in 92% of children in the doxorubicin-dexrazoxane group before treatment but in only 48% and 20%, respectively, after treatment (P = .07). The percentage of children with increased hsCRP levels did not differ between groups at any time. In the first 90 days of treatment, detectable increases in cTnT were associated with abnormally reduced left ventricular (LV) mass and LV end-diastolic posterior wall thickness 4 years later (P < .01); increases in NT-proBNP were related to an abnormal LV thickness-to-dimension ratio, suggesting LV remodeling, 4 years later (P = .01). Increases in hsCRP were not associated with any echocardiographic variables.

CONCLUSION

cTnT and NT-proBNP may hold promise as biomarkers of cardiotoxicity in children with high-risk ALL. Definitive validation studies are required to fully establish their range of clinical utility.

Nocturia, sleep-disordered breathing, and cardiovascular morbidity in a community-based cohort

Background

Nocturia has been independently associated with cardiovascular morbidity and all-cause mortality, but such studies did not adjust for sleep-disordered breathing (SDB), which may have mediated such a relationship. Our aims were to determine whether an association between nocturia and cardiovascular morbidity exists that is independent of SDB. We also determined whether nocturia is independently associated with SDB.

Methodology/Principal Findings

In order to accomplish these aims we performed a cross-sectional analysis of the Sleep Heart Health Study that contained information regarding SDB, nocturia, and cardiovascular morbidity in a middle-age to elderly community-based population. In 6342 participants (age 63±11 [SD] years, 53% women), after adjusting for known confounders such as age, body mass index, diuretic use, diabetes mellitus, alpha-blocker use, nocturia was independently associated with SDB (measured as Apnea Hypopnea index >15 per hour; OR 1.3; 95%CI, 1.2–1.5). After adjusting for SDB and other known confounders, nocturia was independently associated with prevalent hypertension (OR 1.23; 95%CI 1.08–1.40; P = 0.002), cardiovascular disease (OR 1.26; 95%CI 1.05–1.52; P = 0.02) and stroke (OR 1.62; 95%CI 1.14–2.30; P = 0.007). Moreover, nocturia was also associated with adverse objective alterations of sleep as measured by polysomnography and self-reported excessive daytime sleepiness (P<0.05).

Conclusions/Significance

Nocturia is independently associated with sleep-disordered breathing. After adjusting for SDB, there remained an association between nocturia and cardiovascular morbidity. Such results support screening for SDB in patients with nocturia, but the mechanisms underlying the relationship between nocturia and cardiovascular morbidity requires further study. MeSH terms: Nocturia, sleep-disordered breathing, obstructive sleep apnea, sleep apnea, polysomnography, hypertension.

High sensitivity troponin T provides useful prognostic information in non-acute chest pain

OBJECTIVE

To evaluate the prognostic value of high-sensitivity troponin T (hs-cTnT) in patients who present to General Practitioners (GPs) with non-acute chest pain.

DESIGN, SETTING AND PATIENTS

A total of 625 patients who were referred by their GPs to a regional Rapid Access Chest Pain Clinic in Tayside, Scotland were consented and recruited. Diamond-Forrester pretest probability of coronary artery disease (CAD) was used to select patients with intermediate and high-pretest probability. Hs-cTnT and B-type Natriuretic Peptide (BNP) were measured and final diagnosis recorded. Twelve-month follow-up for cardiac events and hospital admission data was collected. Sensitivity, specificity, positive predictive value and negative predictive value (NPV), for both prognosis and diagnosis, were produced using various pre-specified cut-off values for hs-cTnT and BNP.

RESULTS

A total of 579 patients were included in the final analysis. Of these, 477 had intermediate/high-pretest probability of CAD. A total of 431 (90.4%) of patients had a hs-cTnT ≤14 ng/l. In this study, hs-cTnT of 14 ng/l was the best cut-off for ruling out if a patient would have an admission for cardiac chest pain in the following 12 months (specificity 90%, NPV 91.4%). It performed well as a predictor of a subsequent negative diagnosis of cardiac chest pain with a specificity of 92.4% and NPV of 83.5%.

CONCLUSIONS

Hs-cTnT, at the same level currently used in clinical practice as a diagnostic cut-off for myocardial infarction and acute coronary syndromes, is also a clinically-meaningful indicator for further 12-month cardiac chest pain hospital admissions in patients with non-acute chest pain referred to chest pain clinics by GPs.

Midregional Proadrenomedullin for Prediction of Cardiovascular Events in Coronary Artery Disease: Results from the AtheroGene Study

BACKGROUND

Midregional proadrenomedullin (MR-proADM) is a newly identified prognostic marker in heart failure. We evaluated the prognostic impact of MR-proADM in a cohort of patients with symptomatic coronary artery disease according to their clinical presentation.

METHODS

We measured baseline MR-proADM concentrations in 2240 individuals from the prospective AtheroGene study and evaluated the prognostic impact on future fatal and nonfatal cardiovascular events during a follow-up period of 3.6 (1.6) years.

RESULTS

The sample comprised 1355 individuals with stable angina pectoris (SAP) and 885 with acute coronary syndrome (ACS). A cardiovascular event occurred in 192 people. Individuals presenting with SAP had only slightly lower plasma MR-proADM concentrations than those with ACS (0.53 vs 0.55 nmol/L, P = 0.006). MR-proADM showed a moderate association with age, serum N-terminal pro–B-type natriuretic peptide (NT-proBNP), glomerular filtration rate, serum C-reactive protein, hypertension, diabetes, and prevalent multivessel disease (all P &lt; 0.0005). Individuals suffering from a cardiovascular event had higher MR-proADM concentrations at baseline in both groups (SAP 0.63 vs 0.53 nmol/L and ACS 0.65 nmol/L vs 0.55 nmol/L, both P &lt; 0.0005). Cox regression analysis incorporating various variables of cardiovascular risk and NT-proBNP revealed a hazard ratio of 1.4 (95% CI 1.2–1.6; P &lt; 0.0005) per increment of MR-proADM by 1SD. In risk models for secondary prevention, MR-proADM provided information comparable to that of NT-proBNP.

CONCLUSIONS

MR-proADM is an independent predictor for future cardiovascular events in patients with symptomatic coronary artery disease, providing information comparable to NT-proBNP for secondary risk stratification.

Hypertension-Related Gene Polymorphisms of G-Protein-Coupled Receptor Kinase 4 Are Associated with NT-proBNP Concentration in Normotensive Healthy Adults

G protein-coupled receptor kinase 4 (GRK4) with activating polymorphisms desensitize the natriuric renal tubular D1 dopamine receptor, and these GRK4 polymorphisms are strongly associated with salt sensitivity and hypertension. Meanwhile, N-terminal pro-B-type natriuretic peptide (NT-proBNP) may be useful in detecting slight volume expansion. However, relations between hypertension-related gene polymorphisms including GRK4 and cardiovascular indices such as NT-proBNP are not clear, especially in healthy subjects. Therefore, various hypertension-related polymorphisms and cardiovascular indices were analyzed in 97 normotensive, healthy Japanese adults. NT-proBNP levels were significantly higher in subjects with two or more GRK4 polymorphic alleles. Other hypertension-related gene polymorphisms, such as those of renin-angiotensin-aldosterone system genes, did not correlate with NT-proBNP. There was no significant association between any of the hypertension-related gene polymorphisms and central systolic blood pressure, cardioankle vascular index, augmentation index, plasma aldosterone concentration, or an oxidative stress marker, urinary 8-OHdG. Normotensive individuals with GRK4 polymorphisms show increased serum NT-proBNP concentration and may be at a greater risk of developing hypertension and cardiovascular disease.

Role of N-terminal pro-brain natriuretic peptide in ST-segment elevation myocardial infarction: experience from a tertiary centre in India

BACKGROUND

Role of biomarkers in ST-segment elevation myocardial infarction (STEMI) is paramount, as they aid in diagnosis and gauge prognosis of the disease. In this project, we sought to study the short-term outcome and clinical associates of N-terminal pro-brain natriuretic peptide (NT-proBNP) in the setting of STEMI at a tertiary center in India.

METHODS

In all, 173 STEMI patients (mean age: 57 ± 12 years, 38 women) had their NT-proBNP assayed in addition to troponins and high-sensitive C-reactive protein. Subjects were divided according to NT-proBNP levels into 2 groups: group 1 (NT-proBNP ≤100 pg/mL) and group 2 (NT-proBNP >100 pg/mL).

RESULTS

NT-proBNP values (pg/mL) were elevated in group 2 (group 1: 61.7 ± 6.2; group 2: 1006.5 ± 990.6, P < 0.0001). Significantly greater number of females had elevated NT-proBNP (P < 0.05) that could be predicted by the duration of chest pain related to STEMI (area under the curve: 0.72), and age at presentation (area under the curve: 0.66). Multiple regression analysis showed a strong inverse association between NT-proBNP and left ventricular ejection fraction and a strong positive association between the peptide and high-sensitive C-reactive protein. A significant positive association was also noted between NT-proBNP and troponin I (all P < 0.05, Global R = 0.47). Diabetes mellitus and/or hypertension, and infarction localization showed no effect on NT-proBNP levels along with death, primary coronary intervention-related bleeding, and arrhythmias, (χ, P = ns).

CONCLUSIONS

The data suggest that women are more likely to have increased NT-proBNP while presenting with STEMI. Duration of chest pain and age at presentation are the best predictors of elevated NT-proBNP, though without much bearing on short-term morbidity and mortality.

Elevated N-terminal pro-brain natriuretic peptide is associated with mortality in tobacco smokers independent of airflow obstruction

Background

Tobacco use is associated with an increased prevalence of cardiovascular disease. N-terminal pro-brain natiuretic peptide (NT-proBNP), a widely available biomarker that is associated with cardiovascular outcomes in other conditions, has not been investigated as a predictor of mortality in tobacco smokers. We hypothesized that NT-proBNP would be an independent prognostic marker in a cohort of well-characterized tobacco smokers without known cardiovascular disease.

Methods

Clinical data from 796 subjects enrolled in two prospective tobacco exposed cohorts was assessed to determine factors associated with elevated NT-proBNP and the relationship of these factors and NT-proBNP with mortality.

Results

Subjects were followed for a median of 562 (IQR 252 – 826) days. Characteristics associated with a NT-proBNP above the median (≥49 pg/mL) were increased age, female gender, and decreased body mass index. By time-to-event analysis, an NT-proBNP above the median (≥49 pg/mL) was a significant predictor of mortality (log rank p = 0.02). By proportional hazard analysis controlling for age, gender, cohort, and severity of airflow obstruction, an elevated NT-proBNP level (≥49 pg/mL) remained an independent predictor of mortality (HR = 2.19, 95% CI 1.07–4.46, p = 0.031).

Conclusions

Elevated NT-proBNP is an independent predictor of mortality in tobacco smokers without known cardiovascular disease, conferring a 2.2 fold increased risk of death. Future studies should assess the ability of this biomarker to guide further diagnostic testing and to direct specific cardiovascular risk reduction inventions that may positively impact quality of life and survival.

Sensitivity and specificity of NT-proBNP to detect heart failure at post mortem examination

NT-proBNP, a marker of cardiac failure, has been shown to be stable in post mortem samples. The aim of this study was to assess the accuracy of NT-proBNP to detect heart failure in the forensic setting. One hundred sixty-eight consecutive autopsies were included in the study. NT-proBNP blood concentrations were measured using a chemiluminescent immunoassay kit. Cardiac failure was assessed by three independent forensic experts using macro- and microscopic findings complemented by information about the circumstances of body discovery and the known medical story. Area under the receiving operator curve was of 65.4% (CI 95%, from 57.1 to 73.7). Using a standard cut-off value of >220 pg/mL for NT-proBNP blood concentration, heart failure was detected with a sensitivity of 50.7% and a specificity of 72.6%. NT-proBNP vitreous humor values were well correlated to the ones measured in blood (r (2) = 0.658). Our results showed that NT-proBNP can corroborate the pathological findings in cases of natural death related to heart failure, thus, keeping its diagnostic properties passing from the ante mortem to the post mortem setting. Therefore, biologically inactive polypeptides like NT-proBNP seem to be stable enough to be used in forensic medicine as markers of cardiac failure, taking into account the sensitivity and specificity of the test.

Sensitive troponin and N-terminal probrain natriuretic peptide in stable angina

BACKGROUND

High-sensitivity cardiac troponin (hs-TnT) and N-terminal probrain natriuretic peptide (NT-proBNP) are powerful predictors of mortality in patients with stable coronary artery disease. Whether their combined use may further improve mortality prediction in these patients is unknown.

MATERIALS AND METHODS

The study included 869 patients with stable coronary artery disease who underwent percutaneous coronary intervention. Hs-TnT and NT-proBNP were measured before angiography. Using median values of hs-TnT (0·008 μg L(-1)) and NT-proBNP (250·0 ng L(-1)) as cut-off points, patients were divided into four groups: low hs-TnT/low NT-proBNP group (293 patients with hs-TnT and NT-proBNP < median); low hs-TnT/high NT-proBNP group (142 patients with hs-TnT < median and NT-proBNP ≥ median); high hs-TnT/low NT-proBNP group (142 patients with hs-TnT ≥ median and NT-proBNP < median) and high hs-TnT/high NT-proBNP group (292 patients with hs-TnT and NT-proBNP ≥ median). The primary end point was all-cause mortality.

RESULTS

The 4-year follow-up was complete in 90·7% of the patients. There were 76 deaths during the follow-up: seven in low hs-TnT/low NT-proBNP, 8 in low hs-TnT/high NT-proBNP, 10 in high hs-TnT/low NT-proBNP and 51 in high hs-TnT/high NT-proBNP groups (mortality estimates, 2·5%, 5·9%, 7·4% and 18·1%, respectively; odds ratio = 8·64, 95% confidence interval 3·85-19·4, P < 0·001 for high hs-TnT/high NT-proBNP vs. low hs-TnT/low NT-proBNP). Inclusion of hs-TnT and NT-proBNP in the multivariable model increased the discriminatory power of the model regarding mortality prediction compared with the model without biomarkers (absolute and relative integrated discrimination improvement 0·039 and 26·0%, P = 0·0015).

CONCLUSIONS

Combined use of hs-TnT and NT-proBNP improves long-term risk prediction of mortality in patients with stable coronary heart disease.

Plasma B-type natriuretic peptide levels in children with heart disease

AIM

To determine plasma B-type natriuretic peptide (BNP) levels in children with heart diseases before medical or surgical treatment for monitoring therapeutic efficacy in an observational prospective clinical trial at tertiary care centre.

METHODS

In 522 paediatric patients at an age of 6.4 ± 5.2 years (mean ± SD; range: 14 days-18 years) with congenital heart disease (CHD), cardiomyopathies (CMP) or pulmonary arterial hypertension (PAH), plasma BNP levels were evaluated before and under treatment.

RESULTS

Most types of heart disease are associated with increased mean plasma BNP levels before treatment, with highest values in children with CMP (BNP 6165 pg/mL in dilated CMP vs. 817 pg/mL in hypertrophic, vs. 1236 pg/mL in restrictive CMP, each p < 0.05). Children with PAH showed a significant decrease in BNP levels under medical treatment (mean BNP 981 pg/mL before vs. 26 pg/mL under treatment, p < 0.05). Children with univentricular CHD undergoing surgical staged palliation showed a significant decrease in BNP levels after bidirectional cavopulmonary anastomosis (BDCP) (BNP 109 pg/mL before vs. 70 pg/mL after BDCP, p < 0.05).

CONCLUSION

Plasma BNP levels are elevated in children with heart disease before treatment and are a useful laboratory parameter under treatment during long-term follow-up.

Gender-specific differences in biomarkers responses to acute coronary syndromes and revascularization procedures

A growing body of gender-related research in coronary artery disease is beginning to gradually elucidate differences between women and men. In patients presenting with acute coronary syndromes (ACS), these sex differences include varying risk factor profiles, accuracy of diagnostic testing, clinical presentations, treatment practices and outcomes. There is also a differential expression of cardiac biomarkers by sex, which remains unexplained. This paper reviews all the available information on the effect of gender on cardiac biomarkers by search of MEDLINE using the terms gender differences, biomarkers, ACS and revascularization procedures. A better understanding of the sex disparities in biomarkers along with all other clinical information is essential to optimal management and patient care in the future.

Importance of suitable reference gene selection for quantitative real-time PCR: special reference to mouse myocardial infarction studies

BACKGROUND

Quantitative real-time PCR (qPCR) is a widely used technique for gene expression analysis. Its reliability is highly dependent upon selection of the appropriate reference genes for accurate gene expression normalization. In this study, we investigated the expression stability of 10 commonly used reference genes in a mouse myocardial infarction model.

METHODS & RESULTS

The expression stability of the 10 reference genes (Actb, B2m, Eef1a1, Gapdh, Hprt, Polr2a, Ppia, Rpl13a, Tbp, Tpt1) was analyzed using the geNorm software. Overall, the combination of Hprt, Rpl13a and Tpt1 was the most stable reference gene set in our experiments. Gapdh, Polr2a and Actb consistently showed the highest gene expression variability and the expression levels of Gapdh, Polr2a, Actb, B2m and Eef1a1 were found to be selectively up- or downregulated after myocardial infarction. We normalized the expression of Nppb and Vcam1, using different reference gene strategies and demonstrated that their induction after myocardial infarction was most clearly revealed with the optimal reference gene combination. However, the use of suboptimal reference gene combinations resulted in detrimental effects on gene expression levels and variability with a gradual loss of the expression differences and a significant reduction in statistical power.

CONCLUSIONS

Hprt, Rpl13a and Tpt1 are a set of stably expressed reference genes for accurate gene expression normalization in myocardial infarction studies in mice. We found that Gapdh, Polr2a and Actb display high expression variability in mouse myocardial infarction tissues and that loss of statistical power and increase in sample size are the evident consequences of choosing suboptimal combinations of reference genes. We furthermore caution against the use of Gapdh, Polr2a, Actb, B2m and Eef1a1 for gene expression normalization in myocardial infarction studies because of selective up- or downregulation after myocardial infarction, which could potentially lead to biased study outcomes.

Association of NT-proBNP and multiple biomarkers with severity of angiographic coronary artery disease in diabetic and pre-diabetic Chinese patients

BACKGROUND

Little is known about the plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), and the relationship between the severity of coronary heart disease (CHD) with NT-proBNP and multiple biomarkers in diabetic and pre-diabetic patients, compared to individuals with normal glucose levels.

METHODS

Four hundred and fifteen consecutive Chinese patients of both sexes were assigned to three groups on the basis of the new hemoglobin (Hb) A1c (HbA1c) cut-off points for diagnosis of diabetes and pre-diabetes. The three groups were divided into tertiles according to NT-proBNP, hs-CRP, cystatin C, and troponin T levels. Gensini scores were compared among the three groups and biomarker tertiles. Receiver operating characteristic (ROC) curves were used to obtain the angiographic CHD cut-off points for each biomarker. Stepwise multivariate linear correlation analysis was applied to examine the association between the severity of CHD and biomarker levels.

RESULTS

Gensini scores increased with increasing biomarker tertile levels and HbA1c. Gensini scores were significantly different in the middle and upper NT-proBNP tertiles of the diabetic, pre-diabetic and control groups. NT-proBNP had the highest positive and negative predictive values and area under the curve for CHD. Only NT-proBNP was identified as an independent variable for Gensini score.

CONCLUSIONS

Plasma NT-proBNP may be an important biomarker to evaluate the severity of CHD and screen for CHD in diabetic or pre-diabetic patients.

Measurement of NT-proBNP with LOCI technology in heart failure patients

OBJECTIVES

The aim of our study was to determine NT-proBNP concentrations in heart failure (HF) patients with a luminescent oxygen channeling immunoassay (LOCI).

DESIGN AND METHODS

Seventy HF patients were enrolled. NT-proBNP levels were measured with LOCI method and compared to a reference NT-proBNP assay.

RESULTS

LOCI NT-proBNP levels were significantly correlated with the reference NT-proBNP assay and were related to HF severity.

CONCLUSIONS

LOCI assay demonstrates performances close to the comparative assay for NT-proBNP testing and allows a significant reduction of the time of analysis.

NT-pro brain natriuretic peptide levels and the risk of death in the cooperative study of sickle cell disease

Epidemiological studies support a hypothesis that pulmonary hypertension (PH) is a common complication of sickle cell disease (SCD) that is associated with a high risk of death and evolves as a complication of haemolytic anaemia. This fundamental hypothesis has been recently challenged and remains controversial. In order to further test this hypothesis in a large and independent cohort of SCD patients we obtained plasma samples from the Cooperative Study of Sickle Cell Disease (CSSCD) for analysis of a biomarker, N-terminal-pro brain natriuretic peptide (NT-proBNP), which is elevated in the setting of pulmonary arterial and venous hypertension. A NT-pro-BNP value previously identified to predict PH in adults with SCD was used to determine the association between the risk of mortality in 758 CSSCD participants (428 children and 330 adults). An abnormally high NT-proBNP level ≥160ng/l was present in 27·6% of adult SCD patients. High levels were associated with markers of haemolytic anaemia, such as low haemoglobin level (P<0·001), high lactate dehydrogenase (P<0·001), and high total bilirubin levels (P<0·007). A NT-proBNP level ≥160ng/l was an independent predictor of mortality (RR 6·24, 95% CI 2·9-13·3, P<0·0001). These findings provide further support for an association between haemolytic anaemia and cardiovascular complications in this patient population.

N-terminal pro-brain natriuretic Peptide is a more useful predictor of cardiovascular disease risk than C-reactive protein in older men with and without pre-existing cardiovascular disease

OBJECTIVES

We aimed to compare the predictive capabilities of N-terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) for risk of cardiovascular disease (CVD) in older men with and without pre-existing CVD.

BACKGROUND

The clinical utility of NT-proBNP in CVD risk stratification in the general population remains unclear.

METHODS

A prospective study of 3,649 men age 60 to 79 years were followed for a mean of 9 years during which there were 608 major CVD events (major fatal and nonfatal coronary heart disease, stroke, and CVD death).

RESULTS

NT-proBNP was significantly associated with risk of all major CVD outcomes after adjustment for CV risk factors in both men with and without CVD. The adjusted standardized hazard ratios for CVD events in those without pre-existing CVD and those with pre-existing CVD were 1.49 (95% confidence interval [CI]: 1.33 to 1.65) and 1.52 (95% CI: 1.33 to 1.75), respectively. CRP was associated with CVD outcomes only in men without pre-existing CVD (adjusted standardized hazard ratios: 1.22 [95% CI: 1.10 to 1.34] and 1.00 [95% CI: 0.86 to 1.38], respectively). NT-proBNP was more strongly associated with CVD outcome than CRP, particularly among those with pre-existing CVD. Inclusion of NT-proBNP in a Framingham-based model yielded significant improvement in C-statistics in both men with and without CVD and resulted in a net reclassification improvement of 8.8% (p = 0.0009) and 8.2% (p < 0.05), respectively, for major CVD events. Inclusion of CRP in the Framingham-based model did not improve prediction in either group (net reclassification improvement 3.8% and 0.6%, respectively).

CONCLUSIONS

NT-proBNP, but not CRP, improved prediction of major CVD events in older men with and without pre-existing CVD.

Plasma neutrophil gelatinase-associated lipocalin predicts recovery from acute kidney injury following community-acquired pneumonia

Although plasma neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker for early detection of acute kidney injury, its ability to predict recovery is unknown. Using RIFLE criteria to define kidney injury, we tested whether higher plasma NGAL concentrations on the first day of RIFLE-F would predict failure to recover in a post hoc analysis of a multicenter, prospective, cohort study of patients with community-acquired pneumonia. Recovery was defined as alive and not requiring renal replacement therapy during hospitalization or having a persistent RIFLE-F classification at hospital discharge. Median plasma NGAL concentrations were significantly lower among the 93 of 181 patients who recovered. Plasma NGAL alone predicted failure to recover with an area under the receiver operating characteristic curve of 0.74. A clinical model using age, serum creatinine, pneumonia severity, and nonrenal organ failure predicted failure to recover with area under the curve of 0.78. Combining this clinical model with plasma NGAL concentrations did not improve prediction. The reclassification of risk of renal recovery, however, significantly improved by 17% when plasma NGAL was combined with the clinical model. Thus, in this cohort of patients with pneumonia-induced severe acute kidney injury, plasma NGAL appears to be a useful biomarker for predicting renal recovery.

Left atrial distensibility and E/e' for estimating left ventricular filling pressure in patients with stable angina. -A comparative echocardiography and catheterization study-

BACKGROUND

Although E/e' (the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity) is widely used to measure left ventricular filling pressure (LVFP), its accuracy is questionable in coronary artery disease patients.

METHODS AND RESULTS

Echocardiograms and LVFP were obtained from 174 patients with stable angina (Canadian Cardiovascular Society angina grade I-II) who had received interventions for angiography-confirmed coronary stenosis. Compared with single-vessel groups, the multiple-vessel group exhibited lower mitral annular velocities, higher LVFP, and stronger correlations between E/regional e' and LVFP. Additionally, stronger correlations between E/regional e' and LVFP existed in patients with systolic dysfunction or lower variation of myocardial performance index (MPI) among anterior, inferior and lateral borders of mitral annulus. Average e' was not superior to any regional e' for assessing LVFP by the E/e' method. E/e' and left atrial (LA) ejection fraction (EF) correlated linearly with LVFP, but the correlation between LA distensibility and LVFP was logarithmical. Compared with E/e', LA distensibility and LAEF were superior for identifying high LVFP.

CONCLUSIONS

E/e' is not completely satisfactory for assessing LVFP in patients with stable angina, especially those with single-vessel disease, preserved systolic function or high MPI variation. For identifying high LVFP, LA distensibility and LAEF are better than E/e'.

Values of using QTc and N-terminal fragment of B-type natriuretic peptide as markers for early detection of acute antipsychotic drugs-induced cardiotoxicity

We aimed at studying the acute cardiotoxicity of the most commonly used antipsychotics in Egypt using QTc interval and NT-proBNP as markers for the early detection of such cases. Eighty-two admitted patients, at El-Minia PCC (period from 1-7-2005 to 30-6-2010), were classified into 3 groups: I: acute thioridazine overdose (n = 28), II: acute pimozide overdose (n = 23), and III: acute clozapine overdose (n = 31). Patients were investigated for NT-proBNP level and QTc on admission (day 0) and after 24 h (day 1). All the studied drugs had the ability to induce cardiotoxicity in the form of hypotension and dysrhythmias. Thioridazine and pimozide had potentially serious cardiotoxic effects than clozapine. NT-proBNP levels were elevated significantly in all groups on days 0 and 1 when compared with the reference value and a significant decrease in the same parameter on day 1 when compared with that of day 0 within the same group. QTc showed a significant prolongation in all studied groups on days 0 and 1, and there was a significant shortening of QTc on day 1 when compared with that of day 0 within the same group. A significant positive correlation of NT-proBNP level elevation with QTc prolongation was reported in all groups on days 0 and 1. Serious dysrhythmias were associated with QTc prolongation greater than 500 ms. And it was concluded that NT-proBNP, in adjunction with QTc measurement, may be a valuable and sensitive laboratory biomarker to predict cardiotoxicity of antipsychotic overdose. Larger multicenter studies are still needed to verify this possible relationship.

B-type natriuretic peptides: looking to the future

Whereas the role of the cardiac natriuretic peptides, ANP and BNP, in some aspects of physiology and pathophysiology is clear, their potential in diagnosis, prognosis, and therapeutics in many clinical disorders remains uncertain. We predict that circulating levels of these peptides will find increasing diagnostic utility in patients presenting with dyspnoea, in guiding the complex pharmacotherapy in heart failure, and may likewise be useful in guiding the management of patients on chronic maintenance renal dialysis. We predict also that levels of these peptides will be of practical use as prognostic indicators in 'at-risk' populations (such as those with diabetes, coronary heart disease, hypertension, thalassaemia, etc.) but probably not in the general population. It appears likely that administration of these peptides will find a place in the therapeutics of acute myocardial infarction, but this is less clear for heart failure. We describe the presence of a segment of the signal peptide for BNP within the circulation and discuss its potential clinical utility.

Prediction of long-term survival in chronic heart failure by multiple biomarker assessment: a 15-year prospective follow-up study

BACKGROUND

In chronic heart failure (CHF), several plasma biomarkers identify subjects at risk of death over the midterm. However, their long-term predictive value in the context of other candidate predictors has never been assessed. This information may prove valuable in the management of a chronic disease with a long natural history, as CHF is today.

HYPOTHESIS

We aimed to assess the very-long-term prognostic power of a set of biomarkers to identify CHF patients at highest risk for all-cause mortality.

METHODS

A group of 106 consecutive outpatients with CHF (85 male and 21 female, median age 56 y) was followed for 15 years. Echocardiographic tracings and blood samples were collected at study entry to evaluate cardiac function, plasma atrial natriuretic peptide (ANP), aldosterone, and erythropoietin, and plasma renin activity. The relationships between biomarkers, clinical and echocardiographic variables, and mortality were assessed.

RESULTS

After 15 years, 86 of the 106 patients (81%) had died. Multivariate analysis showed that ANP was the best independent predictor of survival over several clinical, echocardiographic, and humoral variables (hazard ratio: 5.62, 95% confidence interval: 3.37-9.39, P < 0.001 for plasma levels < median value of 71 pg/mL). Plasma renin activity and erythropoietin provided prognostic information in univariate analysis, but lost their predictive power when adjusted for covariates.

CONCLUSIONS

The present study represents the longest available follow-up of patients with CHF evaluating the prognostic power of multiple biomarkers. It shows that a simple assessment of plasma ANP levels is the strongest long-term predictor of death in all stages of heart failure.

Cardiovascular effects in childhood cancer survivors treated with anthracyclines

Anthracyclines are commonly used to treat childhood leukemias and lymphomas, as well as other malignancies, leading to a growing population of long-term childhood cancer survivors. However, their use is limited by cardiotoxicity, increasing survivors' vulnerability to treatment-related complications that can markedly affect their quality of life. Survivors are more likely to suffer from heart failure, coronary artery disease, and cerebrovascular accidents compared to the general population. The specific mechanisms of anthracycline cardiotoxicity are complex and remain unclear. Hence, determining the factors that may increase susceptibility to cardiotoxicity is of great importance, as is monitoring patients during and after treatment. Additionally, treatment and prevention options, such as limiting cumulative dosage, liposomal anthracyclines, and dexrazoxane, continue to be explored. Here, we review the cardiovascular complications associated with the use of anthracyclines in treating malignancies in children and discuss methods for preventing, screening, and treating such complications in childhood cancer survivors.

Serum N-terminal pro-B-type natriuretic peptide levels at the time of hospital admission predict of microvascular obstructions after primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction

BACKGROUND

Significant microvascular obstruction (MVO) during primary percutaneous coronary intervention (PCI) may suggest severe myocardial damage. The predictive value of N-terminal pro-B-type natriuretic peptide levels (NT-proBNP) for MVO has not been previously evaluated.

HYPOTHESIS

The purpose of the study was to determine whether NT-proBNP levels measured upon hospital admission of ST-segment elevation myocardial infarction (STEMI) patients receiving primary PCI have predictive value for MVO.

METHODS

NT-proBNP levels were obtained upon admission to the emergency department, for 41 acute STEMI patients. Cardiac contrast-enhanced magnetic resonance imaging (CE-MRI) was performed within 4 days after PCI. The optimal cut-off value to predict grade 3 MVO was determined using a receiver operating characteristic (ROC) curve. Multivariate regression analysis was performed to determine predictors for grade 3 MVO.

RESULTS

MVO grade correlated with left ventricular ejection fraction (LVEF; r =-0.383, P = 0.013), peak serum creatine kinase MB iso-enzyme (CK-MB; r = 0.470, P = 0.002), and NT-proBNP levels (r = 0.357, P = 0.022). The optimal cut-off value to predict grade 3 MVO was an NT-proBNP level of ≥80 pg/mL. Multivariate regression analysis, including LVEF, peak CK-MB, and an NT-proBNP ≥80 pg/mL revealed that only an NT-proBNP ≥80 pg/mL was an independent factor related to grade 3 MVO.

CONCLUSION

NT-proBNP levels upon hospital admission have a predictive value for MVOs. Further study is needed to determine if protective treatment strategies are warranted in STEMI patients with high NT-proBNP levels at presentation.

NT-proBNP and circulating inflammation markers in prediction of a normal myocardial scintigraphy in patients with symptoms of coronary artery disease

BACKGROUND

Myocardial perfusion imaging (MPI) can detect myocardial perfusion abnormalities but many examinations are without pathological findings. This study examines whether circulating biomarkers can be used as screening modality prior to MPI.

METHODOLOGY/PRINCIPAL FINDINGS

243 patients with an intermediate risk of CAD or with known CAD with renewed suspicion of ischemia were referred to MPI. Blood samples were analyzed for N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP), YKL-40, IL-6, matrix metalloproteinase 9 (MMP-9) and high sensitive C-reactive protein (hsCRP). Patients with myocardial perfusion defects had elevated levels of NT-proBNP (p<0.0001), YKL-40 (p = 0.03) and IL-6 (p = 0.03) but not of hsCRP (p = 0.58) nor of MMP-9 (p = 0.14). The NT-proBNP increase was observed in both genders (p<0.0001), whereas YKL-40 (p = 0.005) and IL-6 (p = 0.02) were elevated only in men. A NT-proBNP cut off-concentration at 25 ng/l predicted a normal MPI with a negative predictive value >95% regardless of existing CAD.

CONCLUSIONS

20-25% of patients suspected of CAD could have been spared a MPI by using a NT-proBNP cut-off concentration at 25 ng/l with a negative predictive value >95%. NT-proBNP has the potential use of being a screening marker of CAD before referral of the patient to MPI.

Value of N-terminal brain natriuretic peptide as a prognostic marker in patients with CKD: results from the CREATE study

BACKGROUND AND OBJECTIVES

This study assessed plasma N-terminal prohormone brain natriuretic peptide (NT-proBNP) as a prognostic marker of cardiovascular risk in patients with chronic kidney disease stages 3-4 and anaemia treated with epoetin beta to two haemoglobin target ranges.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Of 603 patients enrolled in the Cardiovascular Risk Reduction by Early Anaemia Treatment with Epoetin Beta (CREATE) trial (baseline creatinine clearance 15-35 mL/min; haemoglobin 11.0-12.5 g/dL), 291 were included in this sub-study. Patients received subcutaneous epoetin beta either immediately after randomisation (target 13.0-15.0 g/dL; Group 1), or after their haemoglobin levels had fallen < 10.5 g/dL (target 10.5-11.5 g/dL; Group 2). Chronic heart failure New York Heart Association class III-IV was an exclusion criterion. (ClinicalTrials.gov Identifier: NCT00321919)

RESULTS

Cardiovascular event rates were higher in patients with baseline NT-proBNP > 400 vs. ≤ 400 pg/mL (39 vs. 13 events; p = 0.0002). Dialysis was initiated in 68 vs. 42 patients with NT-proBNP > 400 vs. ≤ 400 pg/mL (p = 0.0003). Amongst patients with NT-proBNP > 400 pg/mL, there was no significant difference between treatment groups in risk of cardiovascular events (HR = 0.57; p = 0.08) or time to dialysis (HR = 0.65; p = 0.08). The overall interpretation of this substudy is, however, limited by its relatively small sample size which, together with low clinical event rates, result in a lack of statistical power for some analyses and should be viewed as being hypothesis-generating in nature.

CONCLUSIONS

In chronic kidney disease patients with mild-to-moderate anaemia, elevated baseline plasma NT-proBNP levels are associated with a higher risk of cardiovascular events and an accelerated progression towards end-stage renal disease.

N-terminal pro-B-type natriuretic peptide is associated with sudden cardiac death risk: the Cardiovascular Health Study

BACKGROUND

Sudden cardiac death (SCD), the cause of 250,000-450,000 deaths per year, is a major public health problem. The majority of those affected do not have a prior cardiovascular diagnosis. Elevated B-type natriuretic peptide levels have been associated with the risk of heart failure and mortality as well as with sudden death in women.

OBJECTIVE

The purpose of this study was to examine the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and SCD in the Cardiovascular Health Study population.

METHODS

The risk of SCD associated with baseline NT-proBNP was examined in 5,447 participants. Covariate-adjusted Cox model regressions were used to estimate the hazard ratios of developing SCD as a function of baseline NT-proBNP.

RESULTS

Over a median follow-up of 12.5 years (maximum 16), there were 289 cases of SCD. Higher NT-proBNP levels were strongly associated with SCD, with an unadjusted hazard ratio of 4.2 (95% confidence interval [2.9, 6.1]; P <.001) in the highest quintile compared with in the lowest. NT-proBNP remained associated with SCD even after adjustment for numerous clinical characteristics and risk factors (age, sex, race, and other associated conditions), with an adjusted hazard ratio for the fifth versus the first quintile of 2.5 (95% confidence interval [1.6, 3.8]; P <.001).

CONCLUSION

NT-proBNP provides information regarding the risk of SCD in a community-based population of older adults, beyond other traditional risk factors. This biomarker may ultimately prove useful in targeting the population at risk with aggressive medical management of comorbid conditions.

Long-term prognostic value of mitral regurgitation in acute coronary syndromes

Objectives

To determine the additional prognostic value of mitral regurgitation (MR) over B-type natriuretic peptide (BNP), left ventricular ejection fraction (LVEF) and clinical characteristics in patients with acute coronary syndromes (ACS).

Design

Long-term follow-up in a prospective ACS cohort with Doppler-assessed MR, echocardiographically-determined LVEF and plasma BNP levels by ELISA.

Setting

Single-centre university hospital.

Patients

725 patients with ACS.

Main outcome measures

Death and readmission for congestive heart failure.

Results

During a median follow-up of 98 months, 235 patients (32%) died. Significant MR (grade >1 of 4) was found in 90 patients (12%). In a multivariate model including MR grade >1, LVEF <0.40 and BNP >373 pg/ml (75th percentile), MR was significantly associated with long-term mortality (HR 2.28, 95% CI 1.67 to 3.12; p<0.0001). When also adjusting for conventional risk factors, MR remained significantly associated with mortality (HR 1.53, 95% CI 1.06 to 2.19; p=0.02), as well as with congestive heart failure (HR 2.08, 95% CI 1.29 to 3.35; p=0.003).

Conclusions

MR is common in patients with ACS, provides independent risk information and should be taken into account in the evaluation of the long-term prognosis.