Use of B-type natriuretic peptide in the detection of myocardial ischemia

The association of baseline N-terminal pro-B-type natriuretic peptide with short and long-term prognosis following percutaneous coronary intervention in non-ST segment elevation acute coronary syndrome with multivessel coronary artery disease: a retrospective cohort study

BACKGROUND

Several studies have shown that N-terminal pro-B-type natriuretic peptide (NT-proBNP) is strongly correlated with the complexity of coronary artery disease and the prognosis of patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS), However, it remains unclear about the prognostic value of NT-proBNP in patients with NSTE-ACS and multivessel coronary artery disease (MCAD) undergoing percutaneous coronary intervention (PCI). Therefore, this study aimed to reveal the relationship between NT-proBNP levels and the prognosis for NSTE-ACS patients with MCAD undergoing successful PCI.

METHODS

This study enrolled 1022 consecutive NSTE-ACS patients with MCAD from January 2010 to December 2014. The information of NT-proBNP levels was available from these patients. The primary outcome was in-hospital all-cause death. In addition, the 3-year follow-up all-cause death was also ascertained.

RESULTS

A total of 12 (1.2%) deaths were reported during hospitalization. The 4th quartile group of NT-proBNP (> 1287 pg/ml) showed the highest in-hospital all-cause death rate (4.3%) (P < 0.001). Besides, logistic analyses revealed that the increasing NT-proBNP level was robustly associated with an increased risk of in-hospital all-cause death (adjusted odds ratio (OR): 2.86, 95% confidence interval (CI) = 1.16-7.03, P = 0.022). NT-proBNP was able to predict the in-hospital all-cause death (area under the curve (AUC) = 0.888, 95% CI = 0.834-0.941, P < 0.001; cutoff: 1568 pg/ml). Moreover, as revealed by cumulative event analyses, a higher NT-proBNP level was significantly related to a higher long-term all-cause death rate compared with a lower NT-proBNP level (P < 0.0001).

CONCLUSIONS

The increasing NT-proBNP level is significantly associated with the increased risks of in-hospital and long-term all-cause deaths among NSTE-ACS patients with MCAD undergoing PCI. Typically, NT-proBN P > 1568 pg/ml is related to the all-cause and in-hospital deaths.

Extracellular Vesicles in Diagnosing Chronic Coronary Syndromes the Bumpy Road to Clinical Implementation

Coronary artery disease (CAD), comprising both acute coronary syndromes (ACS) and chronic coronary syndromes (CCS), remains one of the most important killers throughout the entire world. ACS is often quickly diagnosed by either deviation on an electrocardiogram or elevated levels of troponin, but CCS appears to be more complicated. The most used noninvasive strategies to diagnose CCS are coronary computed tomography and perfusion imaging. Although both show reasonable accuracy (80-90%), these modalities are becoming more and more subject of debate due to costs, radiation and increasing inappropriate use in low-risk patients. A reliable, blood-based biomarker is not available for CCS but would be of great clinical importance. Extracellular vesicles (EVs) are lipid-bilayer membrane vesicles containing bioactive contents e.g., proteins, lipids and nucleic acids. EVs are often referred to as the "liquid biopsy" since their contents reflect changes in the condition of the cell they originate from. Although EVs are studied extensively for their role as biomarkers in the cardiovascular field during the last decade, they are still not incorporated into clinical practice in this field. This review provides an overview on EV biomarkers in CCS and discusses the clinical and technological aspects important for successful clinical application of EVs.

Biomarkers of acute myocardial infarction: diagnostic and prognostic value. Part 1 (literature review)

Morbidity and mortality rates from acute myocardial infarction (AMI) have been growing rapidly in recent years, causing significant socio-economic damage. Cardiac biomarkers play an important role in the diagnosis and prediction of AMI. In our review article, we will summarize information about the main existing cardiac biomarkers and focus on their diagnostic and prognostic value for patients with AMI. In the first part of the review, we consider the diagnostic and prognostic value of biomarkers of necrosis and myocardial ischemia (aspartate aminotransferase; creatine phosphokinase; cardiac troponins; myoglobin, ischemia-modified albumin, fatty acid binding protein) and neuroendocrine AMI biomarkers (natriuretic peptides, adrenomedullin, catestatin, components of the renin-angiotensin-aldosterone system). In the second part of the review, we discuss the diagnostic and prognostic value of inflammatory AMI biomarkers (C-reactive protein, interleukin-6, tumor necrosis factor, myeloperoxidase, matrix metalloproteinases, soluble CD40 ligand form (sCD40L), procalcitonin, placental growth factor (PGF), procalcitonin) and recently discovered new biomarkers (microRNA, stimulating growth factor, expressed by genome 2 (ST2), growth differentiation factor 15 (GDF-15), galectin-3).

Plasma extracellular vesicle proteins are associated with stress-induced myocardial ischemia in women presenting with chest pain

Diagnosing stable ischemic heart disease (IHD) is challenging, especially in females. Currently, no blood test is available. Plasma extracellular vesicles (EV) are emerging as potential biomarker source. We therefore aimed to identify stress induced ischemia due to stable IHD with plasma extracellular vesicle protein levels in chest pain patients. We analyzed 450 patients suspected for stable IHD who were referred for ⁸²Rb PET/CT in the outpatient clinic. Blood samples were collected before PET/CT and plasma EVs were isolated in 3 plasma subfractions named: TEX, HDL, LDL. In total 6 proteins were quantified in each of these subfractions using immuno-bead assays. CD14 and CystatinC protein levels were independent significant predictors of stress-induced ischemia in the LDL and the HDL subfraction and SerpinC1 and SerpinG1 protein levels in the HDL fraction. Subgroup-analysis on sex revealed that these associations were completely attributed to the associations in women. None of the significant EV proteins remained significant in men. Plasma EV proteins levels are associated with the presence of stable IHD in females presenting with chest pain. This finding, if confirmed in larger cohort studies could be a crucial step in improving diagnostic assessment of women with suspected IHD.

Efficacy of clopidogrel and ticagrelor under NT-proBNP in hospitalized ST-elevation acute coronary syndrome patients on percutaneous coronary intervention: CCC-ACS Project Analysis

BACKGROUND

Risk stratification with specific biomarkers is proposed for tailored P2Y12 inhibitor therapy in patients with STEMI.

METHODS

This nationwide registry and quality improvement study is from November 1, 2014, to June 30, 2017. In total, 11,512 STEMI patients received aspirin and P2Y12 receptor inhibitor (clopidogrel or ticagrelor) and underwent PCIs in hospitals. Of the patients, 2992 were prescribed ticagrelor and 8520 clopidogrel. The primary effectiveness outcome was major adverse cardiovascular and cerebrovascular events (MACCE: cardiac death, myocardial infarction, stent thrombosis, in-hospital ischemic stroke). The primary safety outcome was in-hospital major bleeding.

RESULTS

MACCE incidence was lower in the ticagrelor group than in the clopidogrel group (0.8% versus 1.2%; P=0.046), but under different NT-proBNP levels, cumulative hazards of MACCE were without statistical significance. Bleeding rates were higher in the ticagrelor group than in the clopidogrel group (all bleeding: 9.9% versus 6.9%, P<0.001; major bleeding: 4.0% versus 2.7%, P<0.001). The higher cumulative hazard of bleeding could be identified in the Kaplan-Meier curves. In the multivariate analysis, ticagrelor increased bleeding events, compared with clopidogrel, at NT-proBNP >1800 ng/L patients (all bleeding: HR 1.46; 95%CI, 1.07-2.01; major bleeding: HR 1.68, 95%CI, 1.03-2.74), but a low effect was found in those with lower NT-proBNP level. Subgroup analyses show that ticagrelor increased major bleeding in patients with left ventricular ejection fraction (LVEF) <0.50 (HR 3.29; 95% CI 1.61-6.74) (interaction p=0.03).

CONCLUSION

We found that ticagrelor, compared with clopidogrel, increased bleeding complications in hospitalized patients with NT-proBNP>1800 ng/L, especially in patients with EF < 0.50.

Stress-delta B-type Natriuretic Peptide Levels as a Test for Inducible Myocardial Ischemia: A Systematic Review and Meta-Analysis

Background Cardiac ischemia induces myocardial dysfunction and ventricular wall stretch, which causes the release of B-type natriuretic peptide (BNP) into the bloodstream. However, it is unclear whether inducible ischemia produces a significant change in BNP levels ("stress delta-BNP"). The objective of this study was to determine the utility of stress-delta BNP levels and its precursor NT-proBNP for detecting inducible myocardial ischemia during cardiac stress testing. Methods We conducted a systematic review and meta-analysis. We searched PubMed, EMBASE, Web of Science, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Ovid. Studies examining the changes in levels of BNP and its precursor, N-terminal pro-B-type natriuretic peptide (NT-proBNP), after an exercise cardiac stress test were included. Two reviewers independently analyzed titles and abstracts. Abstracts that did not provide enough information regarding eligibility criteria were kept for full-text evaluation. The same two reviewers also performed data extraction for analyses. Any disagreement was resolved by a consensus and, if it persisted, by a third reviewer adjudication. We report the median and mean values in studies in the order of sample size. Results A total of 15 studies met the inclusion criteria. Nine studies reported results in medians and six studies reported results in means. Of the nine studies, five assessed BNP alone, three assessed NT-proBNP, and one assessed both. Due to the non-normal distribution of results in these studies, they could not be meta-analyzed. Of the six studies that reported results in means, three assessed BNP and three assessed NT-proBNP. The standardized difference between normal and ischemic patients' stress-delta BNP values was -0.39 (95% confidence interval (CI): -0.61; -0.17) in a fixed-effects model and -0.73 (95% CI: -1.72; 0.28) in the random-effects model with high heterogeneity (I^2 = 94%, Q test P = 0.001). For NT-proBNP, the meta-analysis model showed no significant difference between the stress-delta test for ischemic and normal patients (standardized mean difference (SMD): -0.02, 95% CI: -0.31; 0.28). Patients without inducible ischemia appeared to have a lower baseline BNP and NT-proBNP compared to patients with inducible ischemia by stress testing. Although some studies report higher stress-delta BNP in the ischemic group, this pattern was not seen consistently across studies. There was high heterogeneity across studies which was not robust to sensitivity analysis. A random-effects model failed to find statistically significant differences in stress-delta BNP or NT-proBNP. Conclusions We failed to find a relationship between stress-delta BNP or NT-proBNP and the presence or absence of ischemia. This may be due to high heterogeneity in the underlying studies.

Diagnostic and prognostic value of biomarkers in acute myocardial infarction

The incidence of acute myocardial infarction (AMI) has been increasing rapidly in recent years, seriously endangering human health. Cardiac biomarkers play critical roles in the diagnosis and prognosis of AMI. Troponin is a highly sensitive and specific biomarker for AMI diagnosis and can independently predict adverse cardiac events. Other biomarkers such as N-terminal B-type natriuretic peptide and C reactive protein are also valuable predictors of cardiovascular prognosis. Recently, several novel biomarkers have been identified for the diagnosis and risk assessment in patients with AMI. A multibiomarker approach can potentially enhance the diagnostic accuracy and provide more information for the early risk stratification of AMI. In this review, we will summarise the biomarkers discovered in recent years and focus on their diagnostic and prognostic value for patients with AMI.

Provocative biomarker stress test: stress-delta N-terminal pro-B type natriuretic peptide

Objective

Stress testing is commonly performed in emergency department (ED) patients with suspected acute coronary syndrome (ACS). We hypothesised that changes in N-terminal pro-B type natriuretic peptide (NT-proBNP) concentrations from baseline to post-stress testing (stress-delta values) differentiate patients with ischaemic stress tests from controls.

Methods

We prospectively enrolled 320 adult patients with suspected ACS in an ED-based observation unit who were undergoing exercise stress echocardiography. We measured plasma NT-proBNP concentrations at baseline and at 2 and 4  hours post-stress and compared stress-delta NT-proBNP between patients with abnormal stress tests versus controls using non-parametric statistics (Wilcoxon test) due to skew. We calculated the diagnostic test characteristics of stress-delta NT-proBNP for myocardial ischaemia on imaging.

Results

Among 320 participants, the median age was 51 (IQR 44-59) years, 147 (45.9%) were men, and 122 (38.1%) were African-American. Twenty-six (8.1%) had myocardial ischaemia. Static and stress-deltas NT-proBNP differed at all time points between groups. The median stress-deltas at 2  hours were 10.4 (IQR 6.0-51.7) ng/L vs 1.7 (IQR -0.4 to 8.7) ng/L, and at 4  hours were 14.8 (IQR 5.0-22.3) ng/L vs 1.0 (-2.0 to 10.3) ng/L for patients with ischaemia versus those without. Areas under the receiver operating curves were 0.716 and 0.719 for 2-hour and 4-hour stress-deltas, respectively. After adjusting for baseline NT-proBNP levels, the 4-hour stress-delta NT-proBNP remained significantly different between the groups (p=0.009).

Conclusion

Among patients with ischaemic stress tests, static and 4-hour stress-delta NT-proBNP values were significantly higher. Further study is needed to determine if stress-delta NT-proBNP is a useful adjunct to stress testing.

Combining high-sensitivity cardiac troponin and B-type natriuretic peptide in the detection of inducible myocardial ischemia

BACKGROUND

Single biomarker approaches provide only moderate accuracy in the non-invasive detection of exercise-induced myocardial ischemia. We therefore assessed the combination of the two most promising single biomarkers: high-sensitivity cardiac troponin I (hs-cTnI) and B-type natriuretic peptide (BNP).

METHODS

Consecutive patients with suspected myocardial ischemia referred to stress myocardial perfusion single-photon emission tomography imaging (MPI) were enrolled. Clinical judgment (CJ) of the treating cardiologist regarding myocardial ischemia, quantified using a visual analogue scale, and blood concentrations of hs-cTnI and BNP were determined before and after stress. The presence of myocardial ischemia was adjudicated by independent cardiologists using MPI, blinded to biomarker measurements. Death and acute myocardial infarction (AMI) during follow-up were the prognostic endpoints.

RESULTS

Among 1142 consecutive patients inducible myocardial ischemia was found in 456 (40%) of all patients. For the detection of inducible myocardial ischemia, CJ before exercise stress testing (CJb) showed an area under the receiver-operating-characteristics curve (AUC) of 0.66 (95%CI 0.63-0.69), hs-cTnI 0.70 (95%CI 0.67-0.73, p=0.07 vs CJb), and BNP 0.66 (95%CI 0.62-0.69, p=0.98). The use of a dual-biomarker strategy combining hs-cTnI and BNP with CJb did not provide a significant advantage over the combination of hs-cTnI alone and CJb (AUC 0.74, 95%CI 0.72-0.77 vs AUC 0.74, 95%CI 0.71-0.77, p=0.16). Hs-cTnI showed good prognostic value for AMI (HR 1.6, 95%CI 1.3-1.9), and BNP for death (HR 1.6, 95%CI 1.3-2.1).

CONCLUSION

A dual-biomarker strategy combing BNP and hs-cTnI does not further increase diagnostic accuracy on top of clinical judgment and hs-cTnI alone.

SUMMARY AND HIGHLIGHTS

We included 1142 consecutive patients with suspected inducible ischemia, and evaluated the added value of the biomarkers high-sensitivity cardiac troponin (hs-cTn) and B-type natriuretic peptide (BNP), alone and in combination, on top of clinical judgment.

CLINICAL TRIAL REGISTRATION

Biochemical and Electrocardiographic Signatures in the Detection of Exercise-induced Myocardial Ischemia (BASEL VIII), NCT01838148, https://clinicaltrials.gov/ct2/show/NCT01838148.

Fragmented QRS complex is a prognostic marker of microvascular reperfusion and changes in LV function occur in patients with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention

The present study aimed to investigate the in-hospital and long-term prognostic value of fragmented QRS complex (fQRS) for microvascular reperfusion and changes in left ventricular (LV) function in patients with ST elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). A total of 216 patients with STEMI undergoing primary PCI were included in the current study. Patients were divided into two groups based on the presence (n=126) or absence (n=90) of fQRS following electrocardiograms (ECGs) on admission. Following primary PCI and follow up, patients were divided into four groups based on new onset, resolution, persistence and absence of fQRS. Major adverse cardiac events were defined to include cardiovascular death, arrhythmia, heart failure, reinfarction and target vessel revascularization. The percentage of patients with heart failure and microvascular reperfusion differed significantly between the fQRS(+) and fQRS(−) groups. Levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), Peak creatine kinase-MB (CK-MB) and Troponin I levels were observed to be significantly higher in the fQRS(+) group compared with the fQRS(−) group. In univariate logistic regression analysis, left ventricular ejection fraction (LVEF), NT-proBNP, Troponin I, Peak CK-MB and microvascular reperfusion were found to be associated with fQRS. Multivariate analysis identified that LVEF, NT-proBNP, Troponin I and microvascular reperfusion may be independent predictors of fQRS. The presence of fQRS was demonstrated to be associated with left ventricular dysfunction at follow up assessments. The presence of fQRS was not only significantly associated with myocardial microvascular reperfusion and left ventricular function, but was also a prognostic marker in STEMI.

Low NT-proBNP levels: An early sign for the diagnosis of ischemic heart failure

BACKGROUND

N-terminal pro-brain natriuretic peptide (NT-proBNP) is seen to be mostly elevated in patients with acute heart failure (AHF). However, cases of AHF presenting with low NT-proBNP levels have been reported. In this study designed to investigate the factors associated with low NT-proBNP levels in AHF patients, we discovered that etiology and related factors have an influence on NT-proBNP levels.

METHODS

In this study, 154 AHF patients met the study criteria (117 men, median age 74years; left ventricular ejection fraction [LVEF] 46±13%; New York Heart Association [NYHA] classes II-IV). We analyzed the different clinical variables of patients based on plasma NT-proBNP levels. In addition, we identified the differences in NT-proBNP levels between ischemic and non-ischemic etiologies, as well as the relationships between time from symptom onset to ED visit and NT-proBNP levels.

RESULTS

The group with low NT-proBNP levels showed an ischemic association, higher LVEF, lower NYHA class and shorter time from symptom onset to ED visit. Plasma NT-proBNP levels were lower in the ischemic group than in the non-ischemic group (P<0.01). Meanwhile, NT-proBNP levels were relatively low in patients during early phases of AHF hospitalization and increased with time from symptom onset to ED visit (P<0.01).

CONCLUSION

We inferred that low NT-proBNP levels may infer the ischemic etiology especially in patients with normal LVEF in the early phases of AHF hospitalization.

Relationship of non-cardiac biomarkers with periprocedural myocardial injury in patients undergoing percutaneous coronary intervention

percutaneous coronary intervention (PCI) is one of the dominant methods for revascularization in patient with coronary artery disease (CAD), which accompanied with high incidence of periprocedural myocardial injury (PMI) evaluated by postprocedural cardiac biomarker elevation. For the convenience of risk stratification of PMI following PCI, the aim of present review provides a unique opportunity to summarize the relationship of non-cardiac biomarkers with PMI by extensively searching in the MEDLINE to identify all the relevant studies. In conclusion, we found that PCI related PMI might be correlated positively to those non-cardiac biomarkers such as low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol, total cholesterol, triglyceride, the ratios of LDL-C to high-density lipoprotein cholesterol (HDL-C), the ratios of HDL-C to apolipoprotein A-I, the ratio of eicosapentaenoic acid to arachidonic acid, lectin-like oxidized low-density lipoprotein receptor-1, C-reactive protein, high on-treatment platelet reactivity, platelet-monocyte aggregates, N-term pro-B-type natriuretic peptide, hemoglobin and albuminuria. Inversely, no relationships of PMI with those non-cardiac biomarkers such as mean platelet volume, platelet distribution width, platelet-larger cell ratio, uric acid, eosinophils count and the genetic variant of methylenetetrahydrofolate reductase (MTHFR) 677 C>T polymorphism. Moreover, there were controversial associations between PMI and those non-cardiac biomarkers such as high-density lipoprotein cholesterol, glycosylated hemoglobin, homocysteine and the polymorphism Leu33Pro of platelet glycoprotein IIbIIIa. However, almost all studies failed to provide definite mechanism of its findings, and further reaches are needed to focus on the potential mechanisms of association between non-cardiac biomarkers and PMI related to PCI.

Clinical benefit of high-sensitivity cardiac troponin I in the detection of exercise-induced myocardial ischemia

BACKGROUND

A pilot study using a novel high-sensitivity cardiac troponin I (hs-cTnI) assay suggested that cTnI might be released into blood during exercise-induced myocardial ischemia. We investigated the potential clinical value of this signal.

METHODS

We included 819 patients with suspected exercise-induced myocardial ischemia referred for rest/bicycle myocardial perfusion single-photon emission computed tomography. The treating cardiologist used all available clinical information to quantify clinical judgment regarding the presence of myocardial ischemia using a visual analog scale twice: prior and after stress testing. High-sensitivity cTnI measurements were obtained before, immediately after peak stress, and 2 hours after stress testing in a blinded manner. Myocardial ischemia was adjudicated using perfusion single-photon emission computed tomography and coronary angiography findings.

RESULTS

Exercise-induced myocardial ischemia was detected in 278 (34%) patients. High-sensitivity cTnI levels were significantly higher at all time points in patients with myocardial ischemia as compared with those without (P < .001 for all). Combining clinical judgment prior exercise testing with baseline hs-cTnI levels increased diagnostic accuracy as quantified by the area under the receiver operating characteristics curve (AUC) from 0.672 to 0.757 (P < .001). Combining clinical judgment after exercise testing (AUC 0.704) with baseline or poststress hs-cTnI levels also increased the diagnostic accuracy (AUC 0.761-0.771, P < .001 for all). In contrast, exercise-induced changes in hs-cTnI during exercise did not seem useful, as they were small and similar in patients with or without myocardial ischemia.

CONCLUSIONS

High-sensitivity cTnI concentrations at rest and after exercise, but not its exercise-induced changes, provide substantial incremental value to clinical judgment including exercise electrocardiography regarding the presence of myocardial ischemia.

Neutrophil to Lymphocyte Ratio Predicts Left Ventricular Remodeling in Patients with ST Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention

BACKGROUND AND OBJECTIVES

It has been demonstrated that the neutrophil/lymphocyte ratio (NLR) might be a useful marker to predict cardiovascular risk and events. We aimed to investigate the role of the NLR to predict ventricular remodeling (VR) in patients with anterior ST-elevation myocardial infarction (STEMI) who were treated with primary percutaneous coronary intervention.

SUBJECTS AND METHODS

We prospectively included 274 consecutive anterior STEMI patients. Echocardiography was performed during admission and at six months after myocardial infarction. VR was defined as at least 20% increase from baseline in left ventricular end-diastolic volume. Patients were divided into two groups according to their VR status: VR (n=67) and non-VR (n=207). Total and differential leukocyte count, N-terminal pro-brain natriuretic peptide (NT-proBNP) and other biochemical markers were measured at admission and 24 hours later.

RESULTS

Compared with the non-VR group, peak creatine kinase MB (CK-MB), NT-proBNP (24 h), neutrophil/lymphocyte ratio, presence of diabetes, no-reflow frequency and wall motion score index were significantly higher in patients with VR (p<0.05 for all). On multivariate logistic regression analysis, NLR (β=2.000, 95% confidence interval=1.577-2.537, p<0.001) as well as peak CK-MB, NT-proBNP (24 h), WMSI and diabetes incidence were associated with VR. The cutoff value of the neutrophil/lymphocyte ratio obtained by receiver operator characteristic curve analysis was 4.25 for the prediction of VR (sensitivity: 79 %, specificity: 74%).

CONCLUSION

In patients with anterior STEMI, initial NLR and NT-proBNP measured 24 hours after admission may be useful for predicting adverse cardiovascular events including left VR.

Preprocedural N-terminal pro-B-type natriuretic peptide as a useful marker for predicting periprocedural myocardial injury following percutaneous coronary intervention in diabetic patients without cardiac dysfunction

BACKGROUND

Elevated preprocedural N-term pro-B-type natriuretic peptide (NT-pro-BNP) and postprocedural cardiac troponin I (cTnI) are related to a poor cardiac outcome in the non-diabetic population. We hypothesized that preprocedural NT-pro-BNP might be a useful marker in predicting periprocedural myocardial injury (PMI) following elective percutaneous coronary intervention (PCI) in type 2 diabetes (T2D).

METHODS

We prospectively enrolled 1194 consecutive diabetic patients with normal cardiac function and preprocedural cTnI who were successfully undergoing elective PCI. Preprocedural NT-pro-BNP levels were assessed at admission, and PMI was evaluated by analysis of cTnI within 24 hours. The relationship between preprocedural NT-pro-BNP levels and the peak values of cTnI after PCI was examined.

RESULTS

Patients with high baseline NT-pro-BNP levels had higher postprocedural cTnI levels (β = 0.123, p < 0.001). In the multivariable model, NT-pro-BNP was associated with higher risk of postprocedural cTnI elevation above 1 × upper limit of normal (ULN, OR, 3.13; 95% CI, 1.51-6.50; p = 0.002), 3 × ULN (OR, 2.44; 95% CI, 1.17-5.08; p = 0.018), 5 × ULN (OR, 3.18; 95% CI, 1.44-7.0; p = 0.004), respectively. Moreover, the incidence of cTnI elevation was higher in patients with the upper tertile of NT-pro-BNP levels than that in ones with the lower tertile of NT-pro-BNP levels (> 1 × ULN: 63.1% vs. 50.0%, p < 0.001; > 3 × ULN: 39.2% vs. 31.9%, p = 0.032; > 5 × ULN: 30.4% vs. 21.9%, p < 0.006; respectively).

CONCLUSIONS

Our data, for the first time, demonstrated that increased preprocedural NT-pro-BNP levels were strongly and independently associated with a higher risk of PMI, suggesting that baseline NT-pro-BNP level might be a useful marker for predicting PMI following PCI in diabetic patients without cardiac dysfunction.

B-type natriuretic peptide expression and cardioprotection is regulated by Akt dependent signaling at early reperfusion

Exogenously administered B-type natriuretic peptide (BNP) has been shown to offer cardioprotection through activation of particulate guanylyl cyclase (pGC), protein kinase G (PKG) and KATP channel opening. The current study explores if cardioprotection afforded by short intermittent BNP administration involves PI3K/Akt/p70s6k dependent signaling, and whether this signaling pathway may participate in regulation of BNP mRNA expression at early reperfusion. Isolated Langendorff perfused rat hearts were subjected to 30min of regional ischemia and 120min of reperfusion (IR). Applying intermittent 3×30s infusion of BNP peptide in a postconditioning like manner (BNPPost) reduced infarct size by >50% compared to controls (BNPPost 17±2% vs. control 42±4%, p<0.001). Co-treatment with inhibitors of the PI3K/Akt/p70s6k pathway (wortmannin, SH-6 and rapamycin) completely abolished the infarct-limiting effect of BNP postconditioning (BNPPost+Wi 36±5%, BNPPost+SH-6 41±4%, BNPPost+Rap 37±6% vs. BNPPost 17±2%, p<0.001). Inhibition of natriuretic peptide receptors (NPR) by isatin also abrogated BNPPost cardioprotection (BNPPost+isatin 46±2% vs. BNPPost 17±2%, p<0.001). BNPPost also significantly phosphorylated Akt and p70s6k at early reperfusion, and Akt phosphorylation was inhibited by SH-6 and isatin. Myocardial BNP mRNA levels in the area at risk (AA) were significantly elevated at early reperfusion as compared to the non-ischemic area (ANA) (Ctr(AA) 2.7±0.5 vs. Ctr(ANA) 1.2±0.2, p<0.05) and the ischemic control tissue (Ctr(AA) 2.7±0.5 vs. ischemia 1.0±0.1, p<0.05). Additional experiments also revealed a significant higher BNP mRNA level in ischemic postconditioned (IPost) hearts as compared to ischemic controls (IPost 6.7±1.3 vs. ischemia 1.0±0.2, p<0.05), but showed no difference from controls run in parallel (Ctr 5.4±0.8). Akt inhibition by SH-6 completely abrogated this elevation (IPost 6.7±1.3 vs. IPost+SH-6 1.8±0.7, p<0.05) (Ctr 5.4±0.8 vs. SH-6 1.5±0.9, p<0.05). In conclusion, Akt dependent signaling is involved in mediating the cardioprotection afforded by intermittent BNP infusion at early reperfusion, and may also participate in regulation of reperfusion induced BNP expression.

High BNP level as risk factor for acute kidney injury and predictor of all-cause mortality in STEMI patients

OBJECTIVES

The aim of this study was to evaluate the predictive value of brain natriuretic peptide (BNP) in the development of acute kidney injury (AKI) and 6-month all-cause mortality after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) in a modest-risk population.

BACKGROUND

The prognostic value of BNP has been well documented in patients with acute coronary syndrome. However, its value in development of AKI and 6-month all-cause mortality in patients with STEMI undergoing primary PCI remains unclear.

METHODS

We prospectively enrolled 424 consecutive STEMI patients (mean age 53.6 ± 12.1 years) undergoing primary PCI. The population was divided into two groups: a high (n = 110) and a low (n = 314) admission BNP group according to the cut-off value (> 88.7 pg/ml) determined by ROC analysis to have the best predictive accuracy for 6-month all-cause mortality. The clinical characteristics as well as the in-hospital and 6-month outcomes of patients undergoing primary PCI were analyzed.

RESULTS

Cox multivariate analysis showed that a high-admission BNP value (> 88.7 pg/ml) was an independent predictor of AKI development (odds ratio, 1.002; 95 % confidence interval, 1.000–1.003; p = 0.02) and 6-month all-cause mortality (odds ratio, 1.003; 95 % confidence interval; 1.001–1.004; p = 0.004).

CONCLUSION

These results suggest that a high-admission BNP level is associated with an increased risk of AKI development and 6-month all-cause mortality in patients with STEMI undergoing primary PCI.

N-Terminal Pro-Brain Natriuretic Peptide Level is Associated With Severity and Complexity of Coronary Atherosclerosis in Patients With Acute Coronary Syndrome

N-terminal pro-brain natriuretic peptide (NT-proBNP) levels are associated with short- and long-term mortality in acute coronary syndrome (ACS). We investigated whether baseline NT-proBNP levels are associated with burden of coronary atherosclerosis assessed by SYNTAX score (SXScore). We enrolled 509 patients with ACS who underwent coronary angiography. The patients were divided into tertiles according to the SXScore: low SXScore (≤ 22), intermediate SXScore (23-32), and high SXScore (≥ 33). The NT-proBNP levels demonstrated an increase from low SXScore tertile to high SXScore tertile. The NT-proBNP levels according to the SXScore tertiles are as follows: low and intermediate (median 635 vs 1635, P = .014), low and high (median 635 vs 4568, P < .001), and intermediate and high (median 1635 vs 4568, P < .001). In multivariate analysis, NT-proBNP remained an independent predictor of high SXScore (odds ratio: 2.688, 95% confidence interval: 1.315-5.494, P = .007) together with age (P = .002), neutrophil-lymphocyte ratio (P = .017), and presence of non-ST-segment elevation ACS (P = .002). The NT-proBNP was independently associated with burden of coronary atherosclerosis in patients with ACS.

B-type natriuretic peptide and clinical judgment in the detection of exercise-induced myocardial ischemia

BACKGROUND

Myocardial ischemia has been shown to be associated with increased levels of B-type natriuretic peptide (BNP). However, it remains unclear whether and how BNP levels could be used clinically in patients with suspected exercise-induced myocardial ischemia.

METHODS

We enrolled 274 consecutive patients with suspected exercise-induced myocardial ischemia referred for evaluation by rest/bicycle myocardial perfusion single-photon emission computed tomography (SPECT). All clinical information available to the treating cardiologist was used to quantify the clinical judgment regarding the presence of myocardial ischemia using a visual analogue scale twice: once before and once after bicycle exercise stress testing. BNP measurements were obtained before, immediately after, and 2 hours after stress testing in a blinded manner. The presence of myocardial ischemia was adjudicated on the basis of perfusion SPECT combined with coronary angiography findings.

RESULTS

Exercise-induced myocardial ischemia was adjudicated to be present in 103 patients (38%). BNP levels were significantly higher at all time points in patients with myocardial ischemia compared with those without (P < .01 for all). The accuracy of BNP levels as quantified by the area under the receiver operating characteristic curve (AUC) was similar among the time points evaluated (AUC, 0.677-0.697). Combining clinical judgment before exercise testing with BNP levels at rest increased diagnostic accuracy from AUC 0.708 to 0.754 (P = .018). When combining clinical judgment after exercise testing with BNP levels, AUC increased from 0.741 to 0.771 (P = .055).

CONCLUSIONS

Combining clinical judgment with BNP levels increased the diagnostic accuracy regarding the presence of myocardial ischemia.

B-type natriuretic peptide predicts an ischemic etiology of acute heart failure in patients with stage 4-5 chronic kidney disease

OBJECTIVES

The non-invasive differentiation of ischemic and non-ischemic acute heart failure (AHF) not resulting from acute myocardial infarction is difficult and has therapeutic and prognostic implications. The aim of this study was to assess whether plasma B-type natriuretic peptide (BNP) can identify ischemic etiology in patients with stage 4-5 chronic kidney disease (CKD) presenting with AHF.

DESIGN AND METHODS

We prospectively analyzed 61 patients. The diagnosis of ischemic AHF was confirmed by coronary angiography or stress myocardial perfusion imaging. Plasma levels of BNP were measured at admission (BNP1) and 48 h after admission (BNP2).

RESULTS

The mean age of the study patients was 67 years. In these patients, 70.5% had diabetes and 47.5% had dialysis-dependent CKD; 28 of these patients (45.9%) had an ischemic etiology with significantly higher concentrations of BNP1 and BNP2 than did patients without ischemia. The area under the receiver operating characteristic curve was 0.755 (P=0.001) for BNP1 and 0.868 (P<0.001) for BNP2 to detect ischemic etiology of AHF. Plasma BNP1 >2907 ng/L (odds ratio [OR], 10.9; 95% confidence interval [CI] 2.5-48.4; P=0.002) and BNP2 >2322 ng/L (OR 93.1, 95% CI 7.0-1238.7; P=0.001) were independently associated with an ischemic etiology of AHF.

CONCLUSIONS

Plasma BNP may represent a clinically useful non-invasive tool for identification of ischemic etiology of AHF in patients with stage 4-5 CKD.

B-type natriuretic peptide levels predict extent and severity of coronary artery disease in non-ST elevation acute coronary syndrome and normal left ventricular function

BACKGROUND

B-type natriuretic peptide has been used as a biological marker for prognosis in patients with acute coronary syndrome (ACS). However, a relation between the quantity of BNP levels and the severity of coronary artery disease has not been systematically evaluated.

METHODS

197 patients with ACS without ST elevation with normal LV systolic function were enrolled. BNP was measured in all recruited patients within 12 h of hospitalization. All patients underwent coronary angiography. We correlated BNP levels in patients with unstable angina (USAP) and non ST-elevation myocardial infarction (NSTEMI) with angiographic disease severity including Gensini Score.

RESULTS

BNP levels were significantly higher in the NSTEMI group in comparison to the USAP Group (161 ± 149.3 vs 79.6 ± 94.2 pg/mL; p < 0.001). BNP levels rose significantly with increasing number of vessels involved (1-vessel = 51.4 ± 31.6; 2-vessels = 114.0 ± 67.8; 3 vessels = 265.4 ± 188.8 pg/mL, p < 0.001). Most importantly, BNP> 80 pg/ml was found to strongly predict the presence of Triple vessel disease (odds ratio 18.87; 95% confidence intervals 5.36-66.36), and Double vessel disease (odds ratio 3.62; 95% confidence intervals 1.75-7.47). In single vessel group, BNP was significantly higher when LAD was involved vessel (64.78 vs 49.76 pg/mL, p < 0.05). Gensini Score showed a strong correlation with BNP levels (r = 0.675, p < 0.01), and Gensini Score was significantly higher in those with BNP> 80 pg/ml (40.9 ± 29.7 vs 13.4 ± 16.5 p < 0.001).

CONCLUSION

Circulating BNP levels appear elevated in Non ST Elevation ACS, even in the absence of LV systolic dysfunction. High BNP levels are associated with multi-vessel disease and diffuse coronary atherosclerosis.

Prevalence, extent, and independent predictors of silent myocardial infarction

BACKGROUND

The phenomenon of silent myocardial infarction is poorly understood.

METHODS

We aimed to evaluate the prevalence, extent, and independent predictors of silent myocardial infarction in 2 large independent cohorts of consecutive patients without a history of myocardial infarction referred for rest/stress myocardial perfusion single photon emission computed tomography. There were 1621 patients enrolled in the derivation cohort and 338 patients in the validation cohort. Silent myocardial infarction was diagnosed in patients with a myocardial scar ≥5% of the left ventricle.

RESULTS

In the derivation cohort, the prevalence of silent myocardial infarction was 23.3% (n = 377). The median infarct size was 10% (interquartile range [IQR] 5%-15%) of the left ventricle. The prevalence of silent myocardial infarction was 28.5% in diabetics and 21.5% in nondiabetics (P = .004). Diabetes mellitus was an independent predictor for the presence of silent myocardial infarction (odds ratio 1.5; 95% confidence interval, 1.1-1.9; P = .004). These findings were confirmed in the independent validation cohort. In the validation cohort, the prevalence of silent myocardial infarction was 26.3% (n = 89), while the prevalence was higher in diabetics (35.8%) than in nondiabetics (24%; P = .049). The median infarct size was 11.8% (IQR 5.9%-17.6%) of the left ventricle. Again, in logistic regression analysis, diabetes mellitus was a significant predictor of the presence of silent myocardial infarction.

CONCLUSION

Silent myocardial infarctions are more common than previously thought. One of 4 patients with suspected coronary artery disease had experienced a silent myocardial infarction; the extent in average is 10% of the left ventricle, and it is more common in diabetics.

Increased plasma levels of intermedin and brain natriuretic peptide associated with severity of coronary stenosis in acute coronary syndrome

Intermedin (IMD) is a newly discovered peptide with increased levels in plasma and cardiac tissue in mice with ischemia/reperfusion. Continuous administration of low dose IMD markedly elevated the mRNA abundance of myocardial BNP in rats. Plasma BNP levels may reflect the severity of degree of coronary stenosis in patients with acute coronary syndrome (ACS). However, the role of circulating IMD in coronary heart disease remains unclear. We aimed to examine the plasma content of IMD and brain natriuretic peptide (BNP) and its clinical significance in patients with ACS. We collected plasma samples from 41 patients with ACS and 31 controls and measured IMD and BNP levels by radioimmunoassay. The severity of coronary artery stenosis for patients with ACS was measured by coronary angiography. Plasma IMD and BNP levels were markedly higher in ACS patients than that in controls (P<0.05). The increased plasma IMD and BNP were positively correlated with degree of coronary stenosis in ACS patients (r=0.263 and r=0.238, respectively, both P<0.05). In addition, plasma levels of IMD were positively correlated with BNP levels.

Early diagnosis of rats with acute myocardial infarction by measurement of brain natriuretic peptide

The aim of this study was to detect early changes (within 1–4 h) in the brain natriuretic peptide (BNP) levels of rats with acute myocardial infarction (AMI). A total of 35 Wistar rats were established as models of AMI and 30 sham-operated rats were used as the control group. The myocardia of the two groups were observed using a transmission electron microscope (TEM) prior to and following surgery. A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect the serum BNP and cardiac troponin I (cTnI) concentrations before and 1–4 h after surgery. Following the successful establishment of the AMI models, serum BNP concentrations were significantly increased within 1–4 h compared with the values prior to surgery and with those of the control group (all P<0.01). The serum BNP concentration reached its highest level 2 h after AMI (532.25±15.16 ng/l). No significant changes were observed in the cTnI serum levels of the AMI group within 1–4 h compared with the values before AMI and those in the control group (all P>0.05). In the 1–4 h following the establishment of the AMI model, significant positive correlations were identified between the serum BNP concentrations and the size of the AMI and the most marked correlation occurred 2 h after AMI (r=0.72, P<0.05). No significant differences were noted in the serum concentrations of BNP and cTnI in the control group prior to and following the sham surgery (all P>0.05). BNP may be used as a blood marker for the early diagnosis of AMI, particularly 1–4 h after the onset of AMI, and to predict the size of the infarct area.

The diagnostic utility of brain natriuretic peptide in heart failure patients presenting with acute dyspnea: a meta-analysis

Heart failure with normal ejection fraction (HFNEF) accounts for approximately 50% of heart failure (HF) cases. To establish the utility of brain natriuretic peptide (BNP) in differentiating HF-related severe dyspnea from non-HF-related acute dyspnea, we used an estimation formula (eF) that was obtained from a series of three meta-regressions. We selected 60 out of 2721 case-control and follow-up studies that were published from 1998 to 2010. The heart failure levels (HFLs) were assessed using the New York Heart Association (NYHA) criteria. Random-effects meta-regression analyses of the natural logarithm (ln) of the BNP odds ratio (OR) were performed on the HFLs. The ln of the median BNP values (lnmBNP) was meta-regressed over the laboratory method (LM). A third meta-regression was performed on the HFLs to account for only the lnmBNP in the homogeneous LM subgroups. To determine the eF, the data from the diseased and control subjects were combined. The Bland-Altman method was used to detect eF bias. The overall BNP(OR) in the subgroup with severe HF was 35. The lnmBNP analysis showed that LM was a significant heterogeneity factor in the meta-regression (slope −0.38; CI −0.59 to −0.16). The meta-regression of lnmBNP on the HFL resulted in the following calculation for eF: estimated HFL (eHFL)=(lnmBNP–3.157)/0.886. The Bland-Altman test revealed no significant difference (0.0997; 95% CI −2.84 to 3.06) between HFL and eHFL. The severe eHFL showed a 78% accuracy. Based on the eF obtained from this meta-analysis, the BNP outcomes were shown to reliably diagnose severe dyspnea in HF and differentiate this condition from non-HF acute dyspnea.

Midregional pro-A-type natriuretic peptide for diagnosis and prognosis in patients with suspected acute myocardial infarction

We hypothesized that midregional pro-A-type natriuretic peptide (MR-proANP), the stable midregional epitope of proANP, might be useful in the early diagnosis and risk stratification of patients with suspected acute myocardial infarction (AMI). In this multicenter study we measured MR-proANP, cardiac troponin T (cTnT), and high-sensitive cTnT (hs-cTnT) at presentation in 675 consecutive patients presenting to the emergency department with suspected AMI. The final diagnosis was adjudicated by 2 independent cardiologists. Patients were followed 360 days for mortality and AMI. AMI was the final diagnosis in 119 patients (18%). Median MR-proANP levels at presentation were significantly higher in patients with AMI (189 pmol/L, interquartile range 97 to 341) versus patients with another final diagnosis (83 pmol/L, 49 to 144, p <0.001). However, neither the combination of MR-proANP with cTnT nor its combination with hs-cTnT significantly improved diagnostic accuracy as quantified by area under the receiver operating characteristic curve (0.91 vs 0.89 for cTnT alone, p = 0.086; 0.95 vs 0.96 for hs-cTnT, respectively, p = 0.02). Cumulative 360-day mortality/AMI rates were 2.4% in the first, 3.6% in the second, 9.5% in the third, and 18.8% in the fourth quartiles of MR-proANP (p <0.001). MR-proANP (area under the curve 0.76) predicted mortality/AMI independently of and more accurately than cTnT (area under the curve 0.62), hs-cTnT (area under the curve 0.71), and Thrombolysis In Myocardial Infarction risk score (area under the curve 0.72). Net reclassification improvements offered by the additional use of MR-proANP were 0.388 (p <0.001), 0.425 (p <0.001), and 0.217 (p = 0.007), respectively. In conclusion, MR-proANP improves risk prediction for 360-day mortality/AMI but does not seem to help in the early diagnosis of AMI.

Prognostic value of N-terminal pro-B-type natriuretic peptide in patients with acute coronary syndromes undergoing left main percutaneous coronary intervention

BACKGROUND

Patients undergoing acute left main (LM) coronary artery revascularization have a high mortality and natriuretic peptides such as N-terminal pro-B-type (NT-proBNP) have been shown to have prognostic value in patients with acute coronary syndromes. The present study looked at the prognostic value of NT-proBNP in these patients.

METHODS AND RESULTS

We studied all consecutive patients undergoing acute LM coronary artery percutaneous coronary intervention between January 2005 and December 2008 in whom NT-proBNP was measured (n=71). We analyzed the clinical characteristics and the short- and long-term outcomes in relation to NT-proBNP level at admission. Median NT-proBNP was 1,364 ng/L, ranging from 46 to 70,000 ng/L. NT-proBNP was elevated in 63 (89%) patients and was ≥1,000ng/L in 42 (59%). Log NT-proBNP (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.55-7.97, P=0.003) and left ventricular ejection fraction (HR 0.95, 95%CI 0.91-0.99, P=0.007) were predictors for all-cause mortality. Log NT-proBNP was the only independent significant predictor of cardiovascular mortality. In-hospital mortality was 0% for patients with NT-proBNP <1,000, but 17% for those with NT-proBNP ≥1,000 (P=0.036).

CONCLUSIONS

NT-proBNP is a strong predictor of outcome in patients undergoing acute LM coronary artery stenting. Mortality in such patients is high, but those with NT-proBNP < 1,000ng/L may have a favorable short- and long-term prognosis. Further research, including a larger patient population, is needed to determine the optimal cut-off value for NT-proBNP in patients undergoing acute LM coronary artery intervention.

Serum high-sensitivity C-reactive protein, amyloid associated protein and N-terminal proBNP levels do not predict reversible myocardial ischaemia

AIM

The aim of this study was to detect any relationship between serum high-sensitivity C-reactive protein (hs-CRP), serum amyloid-associated protein (SAA) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, and reversible myocardial ischaemia during cardiovascular exercise tests and to determine whether these biomarkers could predict transient myocardial ischaemia.

METHODS

Ninety-six patients (36 women, 60 men, mean age 57 ± 8.5 years) were included in the study. Venous blood samples were taken from patients before and 15 minutes after exercise testing. SAA and hs-CRP were analysed using immunonephelometric assays (Dade-Behring, BN II, Marburg, Germany). NT-proBNP (pg/ml) was determined using the immulite 1 000 chemiluminescence immunoassay system (Siemens Medical Solution Diagnostics, Deerfiled, USA). Forty-eight patients (18 women, 30 men) with positive exercise tests were allocated to the exercise-positive group and 48 (18 women, 30 men) with negative exercise tests were put in the exercise-negative group. Coronary angiography was performed on all patients in the exercise-positive group.

RESULTS

There was no difference between the levels of hs-CRP, SAA and NT-pro-BNP before and after exercise testing in both of the exercise groups.

CONCLUSION

Serum levels of hs-CRP, SAA and NT-proBNP could not predict the occurrence of reversible myocardial ischaemia during exercise. Large-scale clinical studies are needed to clarify the status of hs-CRP, SAA and NT-proBNP with exercise.

Combined Assessments of Biochemical Markers and ST-Segment Resolution Provide Additional Prognostic Information for Patients With ST-Segment Elevation Myocardial Infarction

Background and Objectives

The prognostic value of biochemical markers and the resolution of ST-segment elevation on electrocardiogram are well established. However, how a combination of these two tools affects the evaluation of risk stratification has not yet been evaluated.

Subjects and Methods

Between January 2006 and June 2008, 178 consecutive patients treated with primary percutaneous coronary interventions after ST-segment elevation myocardial infarctions (STEMI) were analyzed at two coronary care units. Patients were divided into the following three groups according to ST-segment resolution: complete (≥70% depression of the elevated ST-segment, n=63), partial (30% to 70%, n=90), and incomplete (<30%, n=25). Demographic data, including history, electrocardiography, biochemical markers, initial ejection fraction, and angiographic findings were also evaluated.

Results

There were 7 deaths, 3 repeated myocardial infarctions, and 17 readmissions for worsening heart failure during six months of follow-up. In a multivariate analysis to predict clinical outcomes, ejection fraction {hazard ratio (HR): 0.83 (0.76-0.91), p<0.01}, high-sensitivity C-reactive protein {HR: 1.15 (1.05-1.26), p<0.05}, and the degree of ST-segment resolution {HR: 0.96 (0.93-0.09), p<0.05} were independently associated with clinical outcomes. According to the Cox-proportional hazards model, the addition of ST-segment resolution markedly improved the prognostic utility of the model containing biochemical markers and ejection fraction.

Conclusion

Assessment of biomarkers upon admission and ST-segment resolution are strong predictors of clinical outcomes. The combination of these data provides additive information about prognosis at an early point in the disease progression and further improves risk stratification for STEMI.

B-type natriuretic peptide in the early diagnosis and risk stratification of acute chest pain

BACKGROUND

Myocardial ischemia is a strong trigger of B-type natriuretic peptide (BNP) release. As ischemia precedes necrosis in acute myocardial infarction, we hypothesized that BNP might be useful in the early diagnosis and risk stratification of patients with acute chest pain.

METHODS

In a prospective, international multicenter study, BNP was measured in 1075 unselected patients with acute chest pain. The final diagnosis was adjudicated by 2 independent cardiologists. Patients were followed long term regarding mortality.

RESULTS

Acute myocardial infarction was the adjudicated final diagnosis in 168 patients (16%). BNP levels at presentation were significantly higher in acute myocardial infarction as compared with patients with other diagnoses (median 224 pg/mL vs. 56 pg/mL, P <.001). The diagnostic accuracy of BNP for the diagnosis of acute myocardial infarction as quantified by the area under the receiver operating characteristic curve (AUC) (0.74; 95% confidence interval [CI], 0.70-0.78) was lower compared with cardiac troponin T at presentation (AUC 0.88; 95% CI, 0.84-0.92; P <.001). Cumulative 24-month mortality rates were 0.5% in the first, 2.1% in the second, 7.0% in the third, and 22.9% in the fourth quartile of BNP (P <.001). BNP predicted all-cause mortality independently of and more accurately than cardiac troponin T: AUC 0.81 (95% CI, 0.76-0.86) versus AUC 0.70 (95% CI, 0.62-0.77; P <.001). Net reclassification improvement for BNP was 0.10 (P=.04), and integrated discrimination improvement 0.068 (P=.01).

CONCLUSIONS

BNP accurately predicts mortality in unselected patients with acute chest pain independently of and more accurately than cardiac troponin T, but does not seem to help in the early diagnosis of acute myocardial infarction.

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.

Biochemical markers in acute coronary syndrome

Owing to their higher risk for cardiac death or ischemic complications, patients with acute coronary syndrome (ACS) must be identified from other causes of chest pain. Patients with acute coronary syndrome are divided into categories based on their electrocardiogram; those with new ST-segment elevation and those who present with ST-segment depression. The subgroups of patients with ST-segment elevation are candidates for immediate reperfusion, while fibrinolysis appears harmful for those with non-ST elevation myocardial infarction. There is increasing evidence to encourage appropriate risk stratification before deciding on a management strategy (invasive or conservative) for each patient. The TIMI, GRACE or PURSUIT risk models are recommended as useful for decisions regarding therapeutic options. Cardiac biomarkers are useful additions to these clinical tools to correctly risk stratify ACS patients. Cardiac troponin is the biomarker of choice to detect myocardial necrosis and is central to the universal definition of myocardial infarction. The introduction of troponin assays with a lower limit of detection will allow for earlier diagnosis of patients who present with chest pain. Analytical and clinical validations of these new assays are currently in progress. The question is whether the lower detection limit of the troponin assays will be able to indicate myocardial ischemia in the absence of myocardial necrosis. Previous to the development of ultrasensitive cardiac troponin assays free fatty acids unbound to albumin and ischemia modified albumin were proposed as biochemical markers of ischemia. Advances in our knowledge of the pathogenesis of acute coronary thrombosis have stimulated the development of new biomarkers. Markers of left ventricular performance (N-terminal pro-brain natriuretic peptide) and inflammation (e.g. C-reactive protein) are generally recognized as risk indicators. Studies suggest that using a number of biomarkers clinicians can risk stratify patients over a broad range of short and long term cardiac events. Nevertheless, it is still under debate as to which biomarker combination is best preferred for risk prediction. This review will focus on recent practice guidelines for the management of patients with ACS as well as current advances in cardiac biomarkers, their integration into clinical care and their diagnostic, prognostic and therapeutic utility.

Meta-analysis of B-type natriuretic peptide's ability to identify stress induced myocardial ischemia

Studies in victims of sudden cardiac death and those surviving a cardiac arrest have confirmed that extent of coronary artery disease is similar in those with and without angina, suggesting that it is the presence of myocardial ischemia rather than associated symptoms that determine the prognosis. Experimental models show that hypoxic myocardial tissue results in production of extra B-type natriuretic peptide (BNP), suggesting that BNP could potentially serve as a biomarker of myocardial ischemia. We performed a meta-analysis of the studies that link BNP to inducible myocardial ischemia as indicated by noninvasive stress tests. Values of true positive, false positive, true negative, and false negative were calculated from the reported sensitivity, specificity, disease prevalence, and total number of patients studied. Sixteen studies reporting data on 2,784 patients across 14 study populations were included in the final analysis. Mean age of participants was 55 to 69 years and 55% to 90% were men. Pooled sensitivity and specificity of BNP for detection of stress-induced myocardial ischemia were 71% (95% confidence interval [CI] 68 to 74) and 52% (95% CI 52 to 54), respectively. Pooled diagnostic odds ratio was 3.5 (95% CI 2.46 to 5.04) and summary receiver operating characteristic curve revealed an area under the curve of 0.71 ± 0.02 (mean ± SE). In conclusion, this meta-analysis suggests that an increased BNP level can identify inducible ischemia as detected by standard noninvasive stress tests. This raises the possibility of a whole new role for BNP in the diagnosis and management of myocardial ischemia.

Exercise-induced changes of B-type natriuretic peptide uncover the unknown coronary artery disease in patients with chest pain and normal left ventricular systolic function

AIM

The diagnostic and prognostic utility of B-type natriuretic peptide (BNP) has been shown in patients either with heart failure or with known coronary artery disease (CAD). We aimed to investigate the utility of the exercise-induced changes of BNP in patients with chest pain, unknown CAD, and normal left ventricular systolic function.

METHODS

We evaluated 100 consecutive patients (mean age 58.7 ± 9 years) (80% male) with left ventricular ejection fraction of more than 50%. Blood samples were collected and BNP was measured before exercise stress testing, at peak, and 20 min after it. All patients underwent coronary artery angiography. We used univariate and multivariate logistic regression analysis.

RESULTS

An increment in BNP values of 1.3 fold (from before to peak exercise BNP values) have 11 times greater odds of having CAD [odds ratio (OR): 11.45 with 95% confidence interval (CI): 3.48–37.66, P < 0.001]. Receiver operating curve analysis revealed a sensitivity of 81.8% and a specificity of 71.8%. Multivariate analysis revealed that BNP increment from before to peak exercise remained statistically significant regardless of the presence of other risk factors for atherosclerosis (OR: 18.59 with 95% CI: 4.14–83.45, P < 0.001). Interestingly, patients showing 1.79 times increment of before to peak exercise BNP values have 19 times greater odds of having multivessel disease (OR: 19.28 with 95% CI: 4.95–75.17, P < 0.001) with a sensitivity of 81% and specificity of 81.8%.

CONCLUSION

The exercise-induced changes of BNP in patients with chest pain, normal left ventricular systolic function, and unknown CAD may uncover patients with CAD and discriminate those with angiographically severe one.

Additive Value of B-Type Natriuretic Peptide on Rest Tl-Dipyridamole Stress Tc-Sestamibi Gated Myocardial SPECT in Patients with Normal Left Ventricular Systolic Function

We evaluated whether BNP has additive value to SPECT in patients with normal left ventricular (LV) systolic function. Data from 224 consecutive patients who underwent rest (201)Tl-dipyridamole stress (99m)Tc-sestamibi gated SPECT and coronary angiography due to chest pain were analyzed. Patients with true positive SPECT showed significant higher BNP level than those with false positive defect (38.5 (19.0-79.8) versus 19.0 (9.3-35.8), P = .01). Patients with true negative SPECT also showed significantly lower BNP level than those with false negative SPECT (39.0 (23.0-77.0) versus 22.0 (15.0-43.0), P = .002). In multivariate analyses, elevated BNP level (using a cut-off value of 23.0 pg/mL) was the strongest and independent predictor of CAD in overall patients (OR 2.75, 95% CI: 1.50-5.023, P = .001) and patients with positive SPECT (OR 3.34, 95% CI: 1.51-7.37, P = .003). The area under the receiver-operating characteristic curve for CAD in overall patients and patients with positive SPECT was 0.673 (95% CI: 0.603-0.743, P < .001) and 0.694 (95% CI: 0.602-0.786, P < .001), respectively. This study suggests that BNP level has additive diagnostic value to SPECT findings in predicting CAD in patients with normal LV systolic function.

Determinants of absolute and relative exercise-induced changes in B-type natriuretic peptides

BACKGROUND

Exercise is associated with changes in circulating B-type natriuretic peptide (BNP) and N-terminal-proBNP (NT-proBNP). However, the biological relevance of this phenomenon is poorly examined. We sought to assess determinants of absolute (Δ) and relative (Δ%) exercise-induced changes in BNP and NT-proBNP.

METHODS

BNP (n = 418) and NT-proBNP (n = 478) at rest and peak exercise were measured in patients undergoing symptom-limited cycle ergometer tests. Multivariate logistic regression was performed to identify predictors of high ΔBNP/ΔNT-proBNP and high ΔBNP/Δ%NT-proBNP defined as their highest quartiles (Q4).

RESULTS

The median (interquartile range) ΔBNP and ΔNT-proBNP was 12 (0-28) pg/ml and 7 (2-21) pg/ml respectively, and Δ%BNP and Δ%NT-proBNP was 21 (0-46) % and 7 (3-12) % respectively. Higher BNP [odds ratio (OR) 3.92 per ln unit; p < 0.001] or NT-proBNP [OR 4.88 per ln unit; p<0.001] at rest was the strongest predictor of ΔBNP in Q4 (≥ 28 pg/ml) or ΔNT-proBNP in Q4 (≥ 21 pg/ml). In contrast, higher maximal work rate expressed as the percentage of the predicted value (OR 1.015 per %; p = 0.007) was the only independent predictor of Δ%BNP in Q4 (≥ 46%), and lower resting heart rate (OR 0.97 per bpm; p = 0.001) and lower age (OR 0.95 per year; p = 0.001) were the only independent predictors of Δ%NT-proBNP in Q4 (≥ 12%).

CONCLUSIONS

Higher ΔBNP and ΔNT-proBNP primarily reflected higher BNP and NT-proBNP plasma levels at rest. In contrast, higher Δ%BNP and Δ%NT-proBNP were associated with several prognostically favorable features, indicating that higher Δ%BNP and Δ%NT-proBNP may be markers of health rather than disease.