Plasma N-Terminal B-Type Natriuretic Peptide as an Indicator of Long-Term Survival After Acute Myocardial Infarction: Comparison With Plasma Midregional Pro-Atrial Natriuretic Peptide

Quantitative proteomic analysis of human serum using tandem mass tags to predict cardiovascular risks in patients with psoriasis

Although biomarker candidates associated with psoriasis have been suggested, those for predicting the risk of cardiovascular disease (CVD) early in patients with psoriasis are lacking. We aimed to identify candidate biomarkers that can predict the occurrence of CVD in psoriasis patients. We pursued quantitative proteomic analysis of serum samples composed of three groups: psoriasis patients with and those without CVD risk factors, and healthy controls. Age/Sex-matched serum samples were selected and labeled with 16-plex tandem mass tag (TMT) and analyzed using liquid chromatography-mass spectrometry and subsequent verification with ELISA. Of the 184 proteins that showed statistical significance (P-value < 0.05) among the three groups according to TMT-based quantitative analysis, 98 proteins showed significant differences (> 2.0-fold) between the psoriasis groups with and without CVD risk factors. Verification by ELISA revealed that caldesmon (CALD1), myeloid cell nuclear differentiation antigen (MNDA), and zyxin (ZYX) levels were significantly increased in the psoriasis group with CVD risk factors. Further network analysis identified pathways including integrin signaling, which could be related to platelet aggregation, and actin cytoskeleton signaling. Three novel candidates (MNDA, ZYX, and CALD1) could be potential biomarkers for predicting CVD risks in psoriasis patients. We expect these biomarker candidates can be used to predict CVD risk in psoriasis patients in clinical settings although further studies including large validation are needed.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Novel Biomarkers of Heart Failure in Pediatrics

Novel biomarkers of heart failure are the subject of numerous studies. Biomarkers of heart failure can be determined in the blood and in the urine. Seven groups of biomarkers of heart failure based on pathophysiological mechanisms are presented in this review, namely biomarkers of myocardial stretch, myocyte injury, myocardial remodeling, biomarkers of inflammation, renal dysfunction, neurohumoral activation, and oxidative stress. Studies of biomarkers in the pediatric population are scarce, therefore, further investigation is needed for reliable prognostic and therapeutic implications. The future of biomarker use is in multimarker panels that include a combination of biomarkers with different pathophysiological mechanisms in order to improve their diagnostic and prognostic predictive value.

Prognostic Value of N-Terminal Pro-B-Type Natriuretic Peptide and High-Sensitivity C-Reactive Protein in Patients With Previous Myocardial Infarction

Background

Patients with previous myocardial infarction (MI) have a poor prognosis and stratification for recurrent major adverse cardiovascular events (MACE) among these patients is of considerable interest. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hs-CRP) are considered to be potential cardiovascular risk factors, but less is known about their prognostic importance in post-MI patients. This study aimed to evaluate the prognostic value of NT-proBNP and hs-CRP alone or together in patients who reported a prior MI.

Methods

In this prospective study, we consecutively enrolled 3,306 post-MI patients to assess the recurrent MACE. The predictive values of NT-proBNP and hs-CRP alone and together were assessed by multivariable Cox regression using hazard ratios (HR) and 95% confidence intervals (CI).

Results

During the 4-year follow-up period, 335 patients developed recurrent MACE. Multivariate Cox regression analysis showed a significant correlation between NT-proBNP levels and MACE (HR: 2.99, 95%CI: 2.06–4.36, p < 0.001), hard endpoints (HR: 5.44, 95%CI: 2.99–9.90, p < 0.001), cardiac mortality (HR: 5.92, 95%CI: 2.34–14.96, p < 0.001) and all-cause mortality (HR: 5.03, 95%CI: 2.51–10.09, p < 0.001). However, hs-CRP was not an independent predictor after adjusting for NT-proBNP. When patients were divided into six groups by using tertiles values of NT-proBNP and median values of hsCRP, patients with high NT-proBNP/hs-CRP values were 3.27 times more likely to experience MACE than patients with low NT-proBNP/hs-CRP values. The addition of NT-proBNP and hs-CRP to a prognostic model revealed a significant improvement in C-statistic, net reclassification, and integrated discrimination.

Conclusions

Increased NT-proBNP levels were associated with long-term worse outcomes and the combination of NT-proBNP and hs-CRP has an incremental value in the further risk stratification of post-MI patients.

Association of N-terminal pro-brain natriuretic peptide level with adverse outcomes in patients with acute myocardial infarction: A meta-analysis

BACKGROUND

Studies evaluating the association of blood level of N-terminal pro-brain natriuretic peptide (NT-proBNP) with adverse prognosis have yielded conflicting results in patients with acute myocardial infarction (AMI). This meta-analysis sought to evaluate the prognostic value of blood level of NT-proBNP in patients with AMI.

METHODS

Two authors independently searched articles in PubMed and Embase databases up to June 13, 2021. Studies evaluating the association of baseline NT-proBNP level with all-cause mortality or major adverse cardiovascular events (MACEs, including death, new or worsening heart failure, recurrent myocardial infarction, revascularization, stroke, etc.) among AMI patients were selected. Multivariable-adjusted risk ratio (RR) with 95% confidence interval (CI) was pooled by the highest vs. lowest category of NT-proBNP level.

RESULTS

A total of 19 studies enrolling 12,158 AMI patients were identified. When compared highest with the lowest category of NT-proBNP level, the pooled RR was 5.28 (95% CI 2.87-9.73) for in-hospital/30-day death, 2.62 (95% CI 2.04-3.37) for follow-up all-cause mortality, and 2.50 (95% CI 1.91-3.28) for follow-up MACEs, respectively. Subgroup analysis further confirmed the value of NT-proBNP in predicting all-cause mortality and MACEs.

CONCLUSIONS

Elevated NT-proBNP level is independently associated with an increased risk of all-cause mortality and MACEs. Determination of blood NT-proBNP level can improve risk stratification of AMI patients.

Intensive Lifestyle Intervention Increases Plasma Midregional Proatrial Natriuretic Peptide Concentrations in Overweight Children

Background

Overweight adults have low circulating concentrations of ANP (atrial natriuretic peptide) and proANP fragments. We tested the hypothesis that an intensive lifestyle intervention with an intended weight loss would increase plasma concentrations of a proANP fragment in overweight children.

Methods and Results

We measured MR‐proANP (midregional proANP) concentrations in plasma from overweight children who participated in the OOIS (Odense Overweight Intervention Study). OOIS randomized 115 overweight children (11–13 years, 55% girls) to an intensive day‐camp intervention arm with increased physical activity and healthy diet or to a less intensive standard intervention arm for 6 weeks. We used linear mixed‐effects modeling for repeated measures to estimate the difference in the mean change with 95% CIs in fasting plasma MR‐proANP concentrations between the 2 arms, and we used partial least squares regression analysis to identify candidate mediators. Differences in weight, fitness, and metabolic factors were also analyzed. At baseline, fasting plasma MR‐proANP concentrations were (median [interquartile range]) 35.0 pmol/L (26.8–42.0) in the day‐camp intervention arm and 37.2 pmol/L (31.7–44.7) in standard intervention arm participants, respectively. After 6 weeks intervention, children in the day‐camp intervention arm had increased their MR‐proANP (5.4 pmol/L [0.8–10.0], P=0.022) and their fitness (2.33 mL O₂/min per kg [0.52–4.14], P=0.012) and they had deceased their body mass index (−2.12 kg/m² [−2.59 to −1.65], P<0.001) as compared with children in standard intervention arm. In the partial least squares analysis, decreases in fasting insulin and in estimated insulin resistance were associated with the observed increase in MR‐proANP concentrations.

Conclusions

An intensive lifestyle intervention increases plasma MR‐proANP among overweight children.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01574352.

Prognostic value of right atrial dilation in patients with pulmonary embolism

Aims

Right atrial (RA) dilation and stretch provide prognostic information in patients with cardiovascular diseases. We investigated the prevalence, confounding factors and prognostic relevance of RA dilation in patients with pulmonary embolism (PE).

Methods

Overall, 609 PE patients were consecutively included in a prospective single-centre registry between September 2008 and August 2017. Volumetric measurements of heart chambers were performed on routine non-electrocardiographic-gated computed tomography and plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) measured on admission. An in-hospital adverse outcome was defined as PE-related death, cardiopulmonary resuscitation, mechanical ventilation or catecholamine administration.

Results

Patients with an adverse outcome (11.2%) had larger RA volumes (median 120 (interquartile range 84-152) versus 102 (78-134) mL; p=0.013), RA/left atrial (LA) volume ratios (1.7 (1.2-2.4) versus 1.3 (1.1-1.7); p<0.001) and MR-proANP levels (282 (157-481) versus 129 (64-238) pmol·L^-1; p<0.001) compared to patients with a favourable outcome. Overall, 499 patients (81.9%) had a RA/LA volume ratio ≥1.0 and a calculated cut-off value of 1.8 (area under the curve 0.64, 95% CI 0.56-0.71) predicted an adverse outcome, both in unselected (OR 3.1, 95% CI 1.9-5.2) and normotensive patients (OR 2.7, 95% CI 1.3-5.6). MR-proANP ≥120 pmol·L^-1 was identified as an independent predictor of an adverse outcome, both in unselected (OR 4.6, 95% CI 2.3-9.3) and normotensive patients (OR 5.1, 95% CI 1.5-17.6).

Conclusions

RA dilation is a frequent finding in patients with PE. However, the prognostic performance of RA dilation appears inferior compared to established risk stratification markers. MR-proANP predicted an in-hospital adverse outcome, both in unselected and normotensive PE patients, integrating different prognostic relevant information from comorbidities.

Cardiac biomarkers for risk stratification of arrhythmic death in patients with heart failure and reduced ejection fraction

Objectives. Patients with heart failure and reduced left ventricular ejection fraction (HFrEF) are prone to ventricular tachyarrhythmias. We tested whether biomarkers C-terminal Endothelin 1 (CT-ET1), midregional pro atrial natriuretic peptide (MR-proANP) and midregional pro adrenomedullin (MR-proADM) might improve risk stratification for arrhythmic death.Methods: This prospective observational study included 160 heart failure patients with ischaemic cardiomyopathy (ICM) or non-ischaemic, dilated cardiomyopathy (DCM) and 30 control patients without heart disease. Primary endpoint was arrhythmic death (ArD) or resuscitated cardiac arrest (resCA).Results: A total of 61 patients died during the median follow-up of 7.0 [5.2-8.4] years. An ArD or resCA was observed in 48 patients. Plasma levels of CT-ET1 (p = 0.002), MR-proANP (p < 0.001) and MR-proADM (p = 0.013) were significantly higher in ICM or DCM patients compared to controls. MR-proANP levels in ICM patients were associated with a significantly increased risk for ArD or resCA (hazard ratio (HR) = 1.42, [95%CI: 1.08-1.85], p = 0.011) in a multivariable Cox regression model. Plasma levels of CT-ET1 (HR = 1.07 [0.98-1.17], p = 0.113) and MR-proADM (HR = 1.80 [0.92-3.55], p = 0.087) were not associated with ArD or resCA in ICM patients. No significant association with ArD or resCA was found in DCM patients. Multivariable Cox regression showed that CT-ET1 (HR = 1.14 [1.07-1.22], p < 0.001), MR-proANP (HR = 1.64 [1.29-2.08], p < 0.001) and MR-pro ADM (HR = 2.06 [1.12-3.77], p = 0.020) were associated with a higher risk for overall mortality.Conclusion: Patients with HFrEF had elevated levels of CT-ET1, MR-proANP and MR-proADM. Plasma levels of MR-proANP are useful as predictor for arrhythmic death in patients with ICM.

Early expressed circulating long noncoding RNA CHAST is associated with cardiac contractile function in patients with acute myocardial infarction

BACKGROUND

The mortality rate during the acute myocardial infarction (AMI) phase has substantially decreased, but post-AMI cardiac remodeling remains an important factor affecting patient prognosis. Several circulating long noncoding RNAs (lncRNAs) are reportedly involved in the chronic pathological process of cardiac function and remodeling in cardiovascular diseases. However, the potential roles of these circulating lncRNAs as biomarkers of cardiac function and remodeling during early-stage AMI remain unclear.

METHODS

Fifty-three patients with AMI and 90 controls without AMI were consecutively enrolled in this study. Clinical parameters and blood samples at different time points (i.e., 24 h and 3 days) were collected.

RESULTS

Compared with the controls, the circulating levels of cardiac hypertrophy-associated transcript (CHAST) significantly increased in AMI patients, and the CHAST levels obviously decreased at 3 days. In AMI patients, the expression levels of CHAST at 24 h were positively associated with cardiac contractile function and measured as left ventricular ejection fraction and left ventricular short-axis shortening rate (all P < 0.050). Multivariate regression analysis indicated that the expression level of CHAST at 24 h was an independent predictor of cardiac contractile function (standardized β = 0.319, P =0.034). When grouped according to the quartile values of the CHAST in the AMI population, patients with the highest quartiles of CHAST expression level showed better cardiac contractile function than all the other quartiles (all P < 0.050).

CONCLUSION

CHAST was an independent predictor of cardiac contractile function at early-stage AMI and may serve as a candidate biomarker for cardiac remodeling.

Blood Biomarkers for Stroke Diagnosis and Management

Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment and predict outcomes. Many blood biomarkers already guide decision-making in clinical practice. In stroke, the number of candidate biomarkers is constantly increasing. These biomarkers include proteins, ribonucleic acids, lipids or metabolites. Although biomarkers have the potential to improve the diagnosis and the management of patients with stroke, there is currently no marker that has demonstrated sufficient sensitivity, specificity, rapidity, precision, and cost-effectiveness to be used in the routine management of stroke, thus highlighting the need for additional work. A better standardization of clinical, laboratory and statistical procedures between centers is indispensable to optimize biomarker performance. This review focuses on blood biomarkers that have shown promise for translation into clinical practice and describes some newly reported markers that could add to routine stroke care. Avenues for the discovery of new stroke biomarkers and future research are discussed. The description of the biomarkers is organized according to their expected application in clinical practice: diagnosis, treatment decision, and outcome prediction.

Antidiuretic Hormone and Serum Osmolarity Physiology and Related Outcomes: What Is Old, What Is New, and What Is Unknown?

CONTEXT

Although the physiology of sodium, water, and arginine vasopressin (AVP), also known as antidiuretic hormone, has long been known, accumulating data suggest that this system operates as a more complex network than previously thought.

EVIDENCE ACQUISITION

English-language basic science and clinical studies of AVP and osmolarity on the development of kidney and cardiovascular disease and overall outcomes.

EVIDENCE SYNTHESIS

Apart from osmoreceptors and hypovolemia, AVP secretion is modified by novel factors such as tongue acid-sensing taste receptor cells and brain median preoptic nucleus neurons. Moreover, pharyngeal, esophageal, and/or gastric sensors and gut microbiota modulate AVP secretion. Evidence is accumulating that increased osmolarity, AVP, copeptin, and dehydration are all associated with worse outcomes in chronic disease states such as chronic kidney disease (CKD), diabetes, and heart failure. On the basis of these pathophysiological relationships, an AVP receptor 2 blocker is now licensed for CKD related to polycystic kidney disease.

CONCLUSION

From a therapeutic perspective, fluid intake may be associated with increased AVP secretion if it is driven by loss of urine concentration capacity or with suppressed AVP if it is driven by voluntary fluid intake. In the current review, we summarize the literature on the relationship between elevated osmolarity, AVP, copeptin, and dehydration with renal and cardiovascular outcomes and underlying classical and novel pathophysiologic pathways. We also review recent unexpected and contrasting findings regarding AVP physiology in an attempt to explain and understand some of these relationships.

Biological markers and cardiac remodelling following the myocardial infarction

AIM

To assess growth stimulating factor ST2 and N-terminal pro b-type natriuretic peptide (NT-proBNP) levels in the sera of myocardial infraction (MI) patients, and their correlation with the adaptive and maladaptive variants of cardiac remodelling.

METHODS

87 patients (65 male, 22 females; 67±8.36 years) with ST-elevated MI were included in this study, and 67 patients had an adaptive, physiological, while 20 patients had a maladaptive, pathological variant of myocardium remodelling.

RESULTS

On day 1, ST2 and NT-proBNP levels were shown to increase 2.4 and 4.5 folds, respectively, compared with those in the control. ST2 levels in patients with maladaptive remodelling were 1.5-fold higher than those in the adaptive remodelling group. On day 12, a decrease in ST2 levels was observed in both groups. NT-proBNP levels increased 1.8 folds in both groups on day 1, compared with those in the controls. Increased ST2 levels on day 1 after MI were shown to increase the risk of maladaptive remodelling 4.5 folds, while high NT-proBNP levels increased this risk 2.3 times.

CONCLUSIONS

ST2 level determination allows us to predict the risk of maladaptive remodelling with a higher sensitivity and specificity than using NT-proBNP levels.

ST-segment elevation myocardial infarction

ST-segment elevation myocardial infarction (STEMI) is the most acute manifestation of coronary artery disease and is associated with great morbidity and mortality. A complete thrombotic occlusion developing from an atherosclerotic plaque in an epicardial coronary vessel is the cause of STEMI in the majority of cases. Early diagnosis and immediate reperfusion are the most effective ways to limit myocardial ischaemia and infarct size and thereby reduce the risk of post-STEMI complications and heart failure. Primary percutaneous coronary intervention (PCI) has become the preferred reperfusion strategy in patients with STEMI; if PCI cannot be performed within 120 minutes of STEMI diagnosis, fibrinolysis therapy should be administered to dissolve the occluding thrombus. The initiation of networks to provide around-the-clock cardiac catheterization availability and the generation of standard operating procedures within hospital systems have helped to reduce the time to reperfusion therapy. Together with new advances in antithrombotic therapy and preventive measures, these developments have resulted in a decrease in mortality from STEMI. However, a substantial amount of patients still experience recurrent cardiovascular events after STEMI. New insights have been gained regarding the pathophysiology of STEMI and feed into the development of new treatment strategies.

Midregional pro-atrial natriuretic peptide, an important member of the natriuretic peptide family: potential role in diagnosis and prognosis of cardiovascular disease

Midregional pro-atrial natriuretic peptide (MR-proANP), first isolated in 1981, is a novel peptide with multiple biological functions, especially within the cardiovascular system. This peptide plays an important role in many processes, including natriuresis, diuresis, and other physiological and pathophysiological pathways in the human body. Several electronic databases (PubMed, EBSCO, Scopus, and ScienceDirect) were analyzed in the present literature review. The aim of this study was to elucidate the wide roles of MR-proANP, which can be analyzed because of the development of a new sandwich immunoassay, and to determine the possible diagnostic and prognostic implications of MR-proANP on cardiovascular disease and other disorders. The studies discussed in this literature review provide valuable data on the role of ANP in the pathogenesis, diagnostic process, prognosis, and potential therapeutic strategies for disease. Although ANP is mainly associated with cardiovascular disease, it may be used as a biomarker in diabetology, neurology, and metabolic disorders.

Natriuretic Peptides in Heart Failure: Atrial and B-type Natriuretic Peptides

The natriuretic peptides play a vital role in normal physiology and as counter-regulatory hormones in heart failure (HF). Clinical assessment of their levels (for B-type natriuretic peptide [BNP], N-terminal proBNP, and the midregion of N-terminal pro-atrial natriuretic peptide) have become valuable tools in diagnosing patients with HF as well as risk stratifying and guiding therapy. Their roles have further expanded beyond HF to other cardiovascular conditions and for risk stratification in asymptomatic individuals. Understanding the clinical use of these hormones is vital to achieving their full potential.

The natriuretic peptide MR-proANP predicts all-cause mortality and adverse outcome in community patients: a 10-year follow-up study

BACKGROUND

The precursor peptide of atrial natriuretic peptide (MR-proANP) has a physiological role in fluid homeostasis and is associated with mortality and adverse clinical outcomes in heart failure patients. Little is known about the prognostic potential of this peptide for long-term mortality prediction in community-dwelling patients. We evaluated associations of MR-proANP levels with 10-year all-cause mortality in patients visiting their general practitioner for a respiratory tract infection.

METHODS

In this post-hoc analysis including 359 patients (78.5%) of the original trial, we calculated cox regression models and area under the receiver operating characteristic curve (AUC) to assess associations of MR-proANP blood levels with mortality and adverse outcome including death, pulmonary embolism, and major adverse cardiac or cerebrovascular events.

RESULTS

After a median follow-up of 10.0 years, 9.8% of included patients died. Median admission MR-proANP levels were significantly elevated in non-survivors compared to survivors (80.5 pmol/L, IQR 58.6-126.0; vs. 45.6 pmol/L, IQR 34.2-68.3; p<0.001) and associated with 10-year all-cause mortality (age-adjusted HR 2.0 [95% CI 1.3-3.1, p=0.002]; AUC 0.79). Results were similar for day 7 blood levels and also for the prediction of other adverse outcomes.

CONCLUSIONS

Increased MR-proANP levels were associated with 10-year all-cause mortality and adverse clinical outcome in a sample of community-dwelling patients. If diagnosis-specific cut-offs are confirmed in future studies, this marker may help to direct preventive measures in primary care.

Serial Assessment of Natriuretic Peptides in Patients Undergoing Interventional Closure of the Left Atrial Appendage

BACKGROUND

Closure of the left atrial appendage (LAA) to prevent cardioembolic events is an alternative therapy to oral anticoagulation in patients with non-valvular atrial fibrillation. The LAA is an important source of natriuretic peptides and its exclusion from the circulation may alter the blood level of these hormones, thereby influencing their diagnostic value and clinical effects.

METHODS

We aimed to prospectively assess potential changes in mid-regional pro A-type natriuretic peptide (MR-proANP) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels 6 weeks and 6 months after interventional LAA closure using the WATCHMAN device.

RESULTS

In 29 consecutive patients with successful LAA closure baseline MR-proANP level was 274±208pmol/l and decreased by -24.5±68 (p=0.07) and -15.0±44pmol/l (p=0.10) after 6 weeks and 6 months, respectively. The drop in the MR-proANP level after 6 weeks and 6 months was significant in patients with elevated (≥214pmol/l) baseline MR-proANP level (n=15: -54.3±78.0, p<0.01 and -31.8±45.4pmol/l, p=0.03, respectively) and those with reduced left ventricular ejection fraction (LVEF<45%, n=7: -87.4±97.3, p=0.02 and -60.3±42.6pmol/l, p=0.01, respectively). Baseline NT-proBNP level (median 1054pg/ml; IQR 621-1977pg/ml), sodium, potassium, mean systolic or diastolic blood pressure did not change significantly in the mentioned patient groups.

CONCLUSIONS

After LAA closure, MR-proANP level decreased significantly in patients with elevated baseline MR-proANP level or reduced LVEF, whereas NT-proBNP level remained unchanged, thereby altering the correlation coefficient between the two biomarkers. Our findings should be considered when using these biomarkers for diagnostic or prognostic evaluation in patients with interventional LAA closure.

Combined baseline and one-month changes in big endothelin-1 and brain natriuretic peptide plasma concentrations predict clinical outcomes in patients with left ventricular dysfunction after acute myocardial infarction: Insights from the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) study

OBJECTIVE

Increased levels of neuro-hormonal biomarkers predict poor prognosis in patients with acute myocardial infarction (AMI) complicated by left ventricular systolic dysfunction (LVSD). The predictive value of repeated (one-month interval) brain natriuretic peptides (BNP) and big-endothelin 1 (BigET-1) measurements were investigated in patients with LVSD after AMI.

METHODS

In a sub-study of the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS trial), BNP and BigET-1 were measured at baseline and at 1month in 476 patients.

RESULTS

When included in the same Cox regression model, baseline BNP (p=0.0003) and BigET-1 (p=0.026) as well as the relative changes (after 1month) from baseline in BNP (p=0.049) and BigET-1 (p=0.045) were predictive of the composite of cardiovascular death or hospitalization for worsening heart failure. Adding baseline and changes in BigET-1 to baseline and changes in BNP led to a significant increase in prognostic reclassification as assessed by integrated discrimination improvement index (5.0%, p=0.01 for the primary endpoint).

CONCLUSIONS

Both increased baseline and changes after one month in BigET-1 concentrations were shown to be associated with adverse clinical outcomes, independently from BNP baseline levels and one month changes, in patients after recent AMI complicated with LVSD. This novel result may be of clinical interest since such combined biomarker assessment could improve risk stratification and open new avenues for biomarker-guided targeted therapies.

KEY MESSAGES

In the present study, we report for the first time in a population of patients with reduced LVEF after AMI and signs or symptoms of congestive HF, that increased baseline values of BNP and BigET-1 as well as a further rise of these markers over the first month after AMI, were independently predictive of future cardiovascular events. This approach may therefore be of clinical interest with the potential of improving risk stratification after AMI with reduced LVEF while further opening new avenues for biomarker-guided targeted therapies.

Biomarkers in cardiovascular disease: Statistical assessment and section on key novel heart failure biomarkers

Cardiovascular disease (CVD) is a leading cause of death worldwide and continues to increase in prevalence compared to previous decades, in part because of the aging of the world population. Atherosclerotic CVD starts at a very young age and progresses over time allowing sufficient time for screening and early detection of the condition. Advances in biomarker research and developments related to CVD over the past 30 years have led to more sensitive screening methods, a greater emphasis on its early detection and diagnosis, and improved treatments resulting in more favorable clinical outcomes in the community. However, the use of biomarkers for different purposes in CVD remains an important area of research that has been explored by scientists over the years and many new developments are still underway. Therefore, a detailed description of all CVD biomarkers that are currently been used or investigated for future use in the field of cardiovascular medicine is out of scope for any review article. In the present review, we do not intend to replicate the information from previous exhaustive review on biomarkers, but highlight key statistical and clinical issues with an emphasis on methods to evaluate the incremental yield of biomarkers, including their clinical utility, a prerequisite before any putative novel biomarker is utilized in clinical practice. In addition, we will summarize information regarding recent novel heart failure biomarkers in current practice, which are undergoing scrutiny before they can be available for clinical use, and their impact on clinical outcomes.

The influence of confounders in the analysis of mid-regional pro-atrial natriuretic peptide in patients with chronic heart failure

BACKGROUND

Natriuretic peptides play an important role in the diagnosis and risk stratification of patients with acute and chronic heart failure. Multiple studies have shown that these peptides are liable to the influence of individual factors. For N-terminal-pro-B-type natriuretic peptide (NT-proBNP) some of these confounding factors have been evaluated over the years such as age, gender, New York Heart Association (NYHA) class and body mass index (BMI). The aim of this study was to establish confounding factors of mid-regional pro-atrial natriuretic peptide (MR-proANP) assessment.

METHODS AND RESULTS

We studied 684 patients (94% male, age 61.2±11.2, left ventricular ejection fraction [LVEF]<35%-45%, NYHA class (I/II/III/IV: 8.4/45.8/39.5/6.3%), ischaemic aetiology 71%, body mass index [BMI] 26.5±4.3kg/m(2), mean MR-proANP 296.0±281.0pmol/L, mean NT-proBNP 2792.0±5328.6pg/mL, mean creatinine level 110.2±38.0μmol/L and mean haemoglobin 13.9±1.5g/dL) with clinically stable chronic heart failure. MR-proANP levels increased with increasing NYHA class (p<0.0001) and an increasing BMI category was associated with decreasing values of MR-proANP (p<0.0001). We found MR-proANP to be independently associated with BMI, creatinine, ischaemic aetiology, LVEF and NYHA class. Meanwhile, NT-proBNP was independently associated with BMI, creatinine, haemoglobin, LVEF and NYHA class.

CONCLUSION

MR-proANP is subject to the almost identical influencing factors like NT-proBNP. The effects of anaemia warrant further study.

Postoperative pro-adrenomedullin levels predict mortality in thoracic surgery patients: comparison with Acute Physiology and Chronic Health Evaluation IV Score*

OBJECTIVES

Risk assessment in ICU patients using commonly used prognostic models may be influenced using different data definitions and by errors in data collection. We investigated whether a set of biomarkers (procalcitonin, MR-pro-adrenomedullin, CT-pro-endothelin-1, CT-pro-arginine vasopressin, and MR-pro-atrial natriuretic peptide), alone or as a panel, could be useful in postoperative risk assessment for hospital mortality in comparison with the Acute Physiology and Chronic Health Evaluation IV score.

DESIGN

In a prospective observational cohort study, we analyzed 800 consecutive patients undergoing elective cardiac surgery. We assessed biomarker levels on admission to the ICU and every 6 hours thereafter for 24 hours. For every postoperative time point and for every biomarker, we determined the predictive value for hospital mortality and made a comparison with the Acute Physiology and Chronic Health Evaluation IV score.

SETTING

Intensive care of an academic referral hospital.

PATIENTS

A total of 800 consecutive patients undergoing elective cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

MR-pro-adrenomedullin is a good predictor of mortality (c-statistic at time point 6 hr after admission to the ICU, 0.940; 95% CI, 0.918-0.956) and performed better than the Acute Physiology and Chronic Health Evaluation IV score (c-statistic, 0.842; 95% CI, 0.811-0.868). The c-statistic did not change significantly on the time points 6, 12, and 18 hours after admission. Using a cutoff value for proadrenomedullin taken 6 hours after admission on ICU (time point 2) of 3.2 nmol/L sensitivity was 81.8% and specificity 93.9%, the positive likelihood ratio was 13.3, positive predictive value was 31.0%, and negative predictive value was 99.4%. Patients with a MR-pro-adrenomedullin above this cutoff level had an odds ratio of 68.9 (95% CI, 22.2-213.1) for not surviving their hospital stay. The other biomarkers had less predictive power.

CONCLUSIONS

In elective cardiac surgery, MR-pro-adrenomedullin measured between 6 and 18 hours after admission to the ICU is a better predictor of hospital mortality in comparison with the Acute Physiology and Chronic Health Evaluation IV score.

Predicting mortality and morbidity after elective cardiac surgery using vasoactive and inflammatory biomarkers with and without the EuroSCORE model

BACKGROUND

In cardiac surgery, preoperative mortality risk assessment tools like the EuroSCORE help to guide physicians in optimizing perioperative care of patients. We investigated the value of preoperative levels of inflammatory (procalcitonin [PCT]) and vasoactive (C-terminal pro-arginine vasopressin [CT-proAVP], midregional pro-atrial natriuretic peptide [MR-proANP], midregional proadrenomedullin [MR-proADM], and C-terminal pro-endothelin-1 [CT-proET-1]) biomarkers for risk assessment of mortality and morbidity and compared it with the EuroSCORE.

METHODS

We performed a prospective observational cohort study in a single-center academic medical hospital and analyzed 746 consecutive patients undergoing elective cardiac surgery. In a directly preoperative blood sample, we assessed PCT, CT-proAVP, MR-proANP, MR-proADM, and CT-proET-1 levels.

RESULTS

In single-variable logistic regression models, all biomarkers predicted 30-day mortality. The biomarkers CT-proET-1 (C statistic, 0.785; 95% CI, 0.687-0.883) and MR-proADM (C statistic, 0.780; 95% CI, 0.671-0.889) predicted 30-day mortality. For the EuroSCORE, the C statistic was 0.689 (95% CI, 0.594-0.784). There was a significant improvement in the prediction of 30-day mortality when the EuroSCORE was combined with MR-proADM (C statistic, 0.792; 95% CI, 0.699-0.884) or CT-proET-1 (C statistic, 0.798; 95% CI, 0.715-0.880). The model with EuroSCORE, MR-proADM, and CT-proET1 had the highest C statistic of 0.803 (95% CI, 0.717-0.890) and was significantly better than the EuroSCORE alone.

CONCLUSIONS

In elective cardiac surgery, preoperative levels of MR-proADM and CT-proET-1 are predictors of 30-day mortality and could improve the predictive accuracy of the EuroSCORE. Further research should confirm the place of these new biomarkers in the prediction of mortality and identification of patients at risk.

The in vitro stability of novel cardiovascular and sepsis biomarkers at ambient temperature

BACKGROUND

The in vitro stability of a biomarker can determine whether it should be used in clinical practice where long delays between sampling and assay are common. We measured the in vitro stability of five novel biomarkers that are being evaluated for their diagnostic and/or prognostic utility in patients with heart failure: mid-regional pro-atrial natriuretic peptide (MR-proANP), mid-regional pro-adreno-medullin (MR-proADM), C-terminal pro-endothelin-1 (CT-proET-1), C-terminal pro-arginine vasopressin (copeptin) and ultrasensitive procalcitonin (PCT).

METHODS

Peripheral venous blood samples were obtained from 19 patients with chronic heart failure into four EDTA tubes. The first tubes were centrifuged immediately at 4°C with the other tubes stored at 20°C for 4, 24 or 72 hours (h) before centrifuging. Supernatant plasma was frozen and stored at -80°C until assay. The levels of analyte in samples processed with and without delay were compared using correlation analysis, paired t-tests and Bland-Altman plots.

RESULTS

Copeptin and PCT were stable up to 72 h at 20°C in whole blood and MR-proANP and MR-proADM up to 24 h. However, CT-proET-1 showed some signs of degradation after only 4 h with 94% of analyte recovered after 24 h, dropping to 80% after 72 h.

CONCLUSIONS

MR-proANP, MR-proADM, copeptin and PCT are stable biomarkers and therefore suitable for introduction into routine clinical practice in a primary or secondary care setting where delays in sample preparation and assay are likely. Ideally, samples for measurement of CT-proET-1 should be centrifuged soon after venepuncture but the analyte is stable enough for most routine clinical purposes.

Effect of right ventricular pacing lead site on left ventricular function in patients with high-grade atrioventricular block: results of the Protect-Pace study

AIM

Chronic right ventricle (RV) apical (RVA) pacing is standard treatment for an atrioventricular (AV) block but may be deleterious to left ventricle (LV) systolic function. Previous clinical studies of non-apical pacing have produced conflicting results. The aim of this randomized, prospective, international, multicentre trial was to compare change in LV ejection fraction (LVEF) between right ventricular apical and high septal (RVHS) pacing over a 2-year study period.

METHODS AND RESULTS

We randomized 240 patients (age 74 ± 11 years, 67% male) with a high-grade AV block requiring >90% ventricular pacing and preserved baseline LVEF >50%, to receive pacing at the RVA (n = 120) or RVHS (n = 120). At 2 years, LVEF decreased in both the RVA (57 ± 9 to 55 ± 9%, P = 0.047) and the RVHS groups (56 ± 10 to 54 ± 10%, P = 0.0003). However, there was no significant difference in intra-patient change in LVEF between confirmed RVA (n = 85) and RVHS (n = 83) lead position (P = 0.43). There were no significant differences in heart failure hospitalization, mortality, the burden of atrial fibrillation, or plasma brain natriutetic peptide levels between the two groups. A significantly greater time was required to place the lead in the RVHS position (70 ± 25 vs. 56 ± 24 min, P < 0.0001) with longer fluoroscopy times (11 ± 7 vs. 5 ± 4 min, P < 0.0001).

CONCLUSION

In patients with a high-grade AV block and preserved LV function requiring a high percentage of ventricular pacing, RVHS pacing does not provide a protective effect on left ventricular function over RVA pacing in the first 2 years.

PROTECT-PACE

ClinicalTrials.gov number NCT00461734.

MR-proANP improves prediction of mortality and cardiovascular events in patients with STEMI

BACKGROUND

Atrial natriuretic peptide (ANP) is released from the atria (on cleavage of proANP) in response to elevated intra-atrial pressure and wall stretch. Clinical data on proANP are still limited, mainly due to limitations in assaying the protein, which recently have been solved. ProANP is elevated in cardiovascular disease and predicts outcome in heart failure. However, knowledge of the prognostic value in acute myocardial infarction remains limited.

METHODS

We prospectively included 680 patients with STEMI treated with primary-PCI, from September 2006 to December 2008. Blood samples were drawn immediately before PCI. Plasma MR-proANP was measured using an automated processing assay. Endpoints were all-cause mortality (n = 137) and the combined endpoint (n = 170) of major adverse cardiovascular events (MACE) defined as cardiovascular mortality and admission due to recurrent MI, ischaemic stroke or heart failure.

RESULTS

During 5-year follow-up, MR-proANP was associated with increased risk of all-cause mortality and MACE (both p < 0.001). After adjustment for confounding risk factors (age, gender, hypertension, diabetes, hypercholesterolaemia, smoking, previous MI, BMI, eGFR, CRP, peak-TnI, symptom-to-balloon time, multivessel disease, complex lesion, LAD-lesion and use of glycoprotein inhibitor), MR-proANP remained an independent predictor of all-cause mortality and MACE - hazard ratio: 1.68 (95% CI 1.35-2.10; p < 0.001) and 1.68 (95% CI 1.39-2.03; p < 0.001) per standard deviation increase in MR-proANP. MR-proANP significantly increased C-statistics and reclassified 26% of the patients for all-cause mortality and 34% for MACE into higher or lower risk categories, matching actual event rates more accurately.

CONCLUSIONS

Plasma MR-proANP independently predicts all-cause mortality and MACE in patients with STEMI.

Midregional pro-atrial natriuretic peptide in the general population/Insights from the Gutenberg Health Study

BACKGROUND

The use of biomarkers is firmly established for the assessment of cardiovascular disease. Emerging biomarkers such as midregional pro-atrial natriuretic peptide (MR-proANP) challenge established markers regarding risk prediction and stratification ability. The aim of the present study was to describe the distribution of a contemporary MR-proANP assay in a large population-representative sample and to evaluate the association with prevalent cardiac diseases and cardiovascular risk factors.

METHODS

MR-proANP was determined by the use of a contemporary commercially available assay (BRAHMS GmbH, Hennigsdorf, Germany) in a representative sample of 5000 participants from the large population-based Gutenberg Health Study. N-terminal pro B-type natriuretic peptide (NT-proBNP) was used as a comparator.

RESULTS

Mean age was 55.5 ± 10.9 years. Coronary artery disease (CAD) was documented in 4.6%, heart failure (HF) in 1.5% of the study participants. We observed a moderate to strong correlation of the biomarkers with age, diabetes, hypertension, smoking, renal function, prevalence of CAD and HF. Males showed lower MR-proANP concentrations than females. MR-proANP showed no relevant correlation with BMI (ρ=-0.030) and CRP (ρ=0.039). Reference limits for MR-proANP representing the 95th/97.5th/99th percentile were determined for healthy individuals with 116/132/169 pmol/mL.

CONCLUSIONS

The current analysis in a large population-based sample elucidates the correlations and distribution of MR-proANP. Its concentration in healthy individuals depends on prevalent cardiovascular diseases and classical risk factors. The reported population-based reference values might be useful for distinguishing between healthy and diseased individuals, thus improving risk stratification and triaging in various clinical settings.

B-type natriuretic peptide clinical activation in aortic stenosis: impact on long-term survival

OBJECTIVES

This study was conducted to define the association between serum B-type natriuretic peptide (BNP) activation and survival after the diagnosis of aortic stenosis (AS).

BACKGROUND

In AS, the link between BNP levels and clinical outcome is in dispute. Failure to account for the normal shifting of BNP ranges with aging in men and women, not using hard endpoints (survival), and not enrolling large series of patients have contributed to the uncertainty.

METHODS

A program of prospective measurement of BNP levels with Doppler echocardiographic AS assessment during the same episode of care was conducted. BNP ratio (measured BNP/maximal normal BNP value specific to age and sex) >1 defined BNP clinical activation.

RESULTS

In 1,953 consecutive patients with at least moderate AS (aortic valve area 1.03 ± 0.26 cm(2); mean gradient 36 ± 19 mm Hg), median BNP level was 252 pg/ml (interquartile range: 98 to 592 pg/ml); BNP ratio 2.46 (interquartile range 1.03 to 5.66); ejection fraction (EF) 57% ± 15%, and symptoms present in 60% of patients. After adjustment for all survival determinants, BNP clinical activation (BNP ratio >1) independently predicted mortality after diagnosis (p < 0.0001; hazard ratio [HR]: 1.91; 95% CI: 1.55 to 2.35) and provided incremental power to the survival predictive model (p < 0.0001). Eight-year survival was 62 ± 3% with normal BNP levels, 44 ± 3% with BNP ratio of 1 to 2 (adjusted HR: 1.49; 95% CI: 1.17 to 1.90), 25 ± 4% with BNP ratio of 2 to 3 (adjusted HR: 2.12; 95% CI: 1.63 to 2.75), and 15 ± 2% with BNP ratio of ≥3 (adjusted HR: 2.43; 95% CI: 1.94 to 3.05). This strong link to survival was confirmed in asymptomatic patients with normal EF (adjusted HR: 2.35 [95% CI: 1.57 to 3.56] for BNP clinical activation and 2.10 [95% CI: 1.32 to 3.36] for BNP ratio of 1 to 2, 2.25 [95% CI: 1.31 to 3.87] for BNP ratio of 2 to 3, 3.93 [95% CI: 2.40 to 6.43] for BNP ratio of ≥3). Aortic valve replacement was associated with survival improved by a similarly high margin (p = 0.54) with BNP ratio of <2 (HR: 0.68; 95% CI: 0.52 to 0.89; p = 0.003) or BNP ratio of >2 (HR: 0.56; 95% CI: 0.47 to 0.66; p < 0.0001).

CONCLUSIONS

In this large series of patients with AS, BNP clinical activation was associated with excess long-term mortality incrementally and independently of all baseline characteristics. Higher mortality with higher BNP clinical activation, even in asymptomatic patients, emphasizes the importance of appropriate clinical interpretation of BNP levels in managing patients with AS.

ProANP plasma measurement predicts all-cause mortality in acutely hospitalised patients: a cohort study

IMPORTANCE

The association of natriuretic peptide measurement with all-cause mortality in a broad selection of acutely admitted patients has not yet been examined.

OBJECTIVE

To test the risk association between pro-atrial natriuretic peptide (ANP) and short-term and long-term mortality and its predictive value in acutely hospitalised patients and compare this to N-terminal B-type natriuretic peptide (NT-proBNP).

DESIGN, SETTING AND PATIENTS

Participants were selected from the Copenhagen Hospital Heart Failure Study (n=3644). Medical history, satisfactory echocardiography and blood samples were available on 2193 participants in 1998-1999 where NT-proBNP was measured. Vital status after discharge was obtained from national central data registers. A total of 1337 participants with eligible blood samples were selected in 2010-2011 for proANP measurement. Among these, 1255 (94%) were acutely hospitalised in 1998-1999.

MAIN OUTCOME MEASURE(S)

1-year and long-term mortality.

RESULTS

Median follow-up period was 11.5 years. At the end of follow-up, 926 patients had died, 239 during the first year. ProANP quartiles to 2-4 (median proANP levels 594 pmol/L, 990 pmol/L and 2052 pmol/L, respectively) associated with a stepwise increase in risk of 1-year and long-term mortality compared to the first quartile (336 pmol/L) in multivariable adjusted Cox proportional regression models (HR 1.53 95% CI 1.30 to 1.81 and HR 1.26 95% CI 1.17 to 1.36, respectively). An addition of NT-proBNP attenuated proANP's association with mortality in the models (HR 1.24 95% CI 1.01 to 1.53 and 1.14 95% CI 1.03 to 1.26, respectively). The increased risk was observed in participants with the highest proANP levels (fourth quartile). Similar results were observed in subgroups of participants with no evidence of cardiovascular disease (CVD). ProANP in quartiles improved discrimination when added to traditional risk factors in prediction models for 1-year (integrated discrimination improvement (IDI) 0.141 95% CI 0.085 to 0.197; C-index 0.753 95% CI 0.724 to 0.783, P for improvement 0.003) and long-term mortality (IDI 0.053 95% CI 0.032 to 0.074; C-index 0.736 95% CI 0.720 to 0.752, P for improvement <0.001) with similar results in subgroups. Discrimination was best in a combined model with proANP as well as NT-proBNP included.

CONCLUSIONS AND RELEVANCE

High plasma proANP concentrations are associated with and predict short-term and long-term all-cause mortality in acutely hospitalised patients irrespective of CVD status at admission.

The midregional fragment of pro-A-type natriuretic peptide, blood pressure, and mortality in a prospective cohort study of patients with type 2 diabetes (ZODIAC-25)

OBJECTIVE

Evidence that midregional fragment of pro-A-type natriuretic peptide (MR-proANP) is a marker of mortality in patients with type 2 diabetes is limited. Therefore, we aimed to investigate the capabilities of MR-proANP in predicting mortality. We also investigated whether MR-proANP influences the relationship between blood pressure and mortality in old age.

RESEARCH DESIGN AND METHODS

In 1998, 1,143 primary care patients with type 2 diabetes participated in the ZODIAC study. Because blood was drawn for 867 patients (76%) and confounders were missing for 19 patients, the final study sample comprised 848 patients. After a follow-up time of 10 years, we used Cox proportional hazard models to evaluate the relationship between MR-proANP and (cardiovascular) mortality. Harrell C statistic was used to compare models with and without MR-proANP. The regression analyses were repeated without MR-proANP for patients aged older than 75 years.

RESULTS

Median MR-proANP in the total study sample was 75 pmol/L (interquartile range, 48-124 pmol/L). During follow-up, 354 (42%) out of 848 patients had died, of whom 152 (43%) deaths were attributable to cardiovascular factors. MR-proANP was independently associated with all-cause and cardiovascular mortality, irrespective of age. During old age, there was a significant inverse relationship between blood pressure and mortality. This relationship did not change after adjustment for MR-proANP.

CONCLUSIONS

MR-proANP is independently associated with mortality in patients with type 2 diabetes. MR-proANP did not influence the inverse relationship between blood pressure and mortality in elderly patients.

High-sensitivity troponin assay improves prediction of cardiovascular risk in patients with cerebral ischaemia

BACKGROUND AND PURPOSE

Clinical scores are recommended for predicting cardiovascular risk in patients with cerebral ischaemia to inform secondary prevention. Blood biomarkers may improve prediction beyond clinical scores.

METHODS

Within the observational Find-AF trial (ISRCTN46104198), 197 patients >18 years of age with cerebral ischaemia and without atrial fibrillation had blood sampled at baseline. The predictive value of five biomarkers for a combined vascular endpoint (acute coronary syndrome, stroke, cardiovascular death) and all-cause mortality was determined, alone and in addition to the Essen Stroke Risk Score (ESRS), Stroke Prognostic Instrument 2 (SPI-2) and National Institutes of Health Stroke Scale (NIH-SS).

RESULTS

There were 23 vascular events (11.7%) and 13 deaths (6.6%) to 1 year follow-up. In multivariate analyses of all markers, only high-sensitivity troponin T (hsTropT) remained independently predictive for vascular events (p=0.045) and all-cause mortality (p=0.004). hsTropT was higher in patients with a vascular event (median 12.7 ng/ml vs 5.1 ng/ml), and patients with hsTropT above the median of 6.15 ng/ml had vascular events more frequently (HR 3.86, p=0.008). For prediction of vascular events as well as all-cause mortality, hsTropT significantly improved multivariate Cox regression models with ESRS, SPI-2 or NIH-SS. The c-statistic increased non-significantly from 0.695 (ESRS) or 0.710 (hsTropT) to 0.747 (ESRS+hsTropT) and from 0.699 (SPI-2) to 0.763 (SPI-2+hsTropT). No patient with a low-risk ESRS and an hsTropT below the median had a vascular event or died.

CONCLUSIONS

hsTropT predicts vascular events and all-cause mortality in patients with acute cerebral ischaemia and improves prediction beyond established clinical scores.

Pathophysiological roles and clinical importance of biomarkers in acute coronary syndrome

Early diagnosis of acute coronary syndrome (ACS) is important to guide appropriate therapy at a time when it is most likely to be of value. Accurate prognostic and risk stratification will facilitate high-risk patients to have early advanced diagnostic investigations and early appropriate interventions in a cost-effective and efficient manner, while those patients at low risk of ACS complications do not need such costly diagnostic tests and unnecessary hospital admission. Recent investigations have demonstrated that elevation of biomarkers upstream from acute-phase biomarkers, biomarkers of plaque destabilization and rupture, biomarkers of myocardial ischemia, necrosis, and dysfunction may provide an earlier assessment of patient risk and identify patients with higher risk of having an adverse event. This review provides an overview of the pathophysiology and clinical characteristics of several well-established biomarkers as well as emerging biomarkers that may have potential clinical utility in patients with ACS. Such emerging biomarkers hold promise and need to be more thoroughly evaluated before utilization in routine clinical practice.

Mid-regional pro-atrial natriuretic peptide as a prognostic marker for all-cause mortality in patients with symptomatic coronary artery disease

In the present study, we investigated the prognostic value of MR-proANP (mid-regional pro-atrial natriuretic peptide). We consecutively evaluated a catheterization laboratory cohort of 2700 patients with symptomatic CAD (coronary artery disease) [74.1% male; ACS (acute coronary syndrome), n=1316; SAP (stable angina pectoris), n=1384] presenting to the Cardiology Department of a large primary care hospital, all of whom underwent coronary angiography. Serum MR-proANP and other laboratory markers were sampled at the time of presentation or in the catheterization laboratory. Clinical outcome was assessed by hospital chart analysis and telephone interviews. The primary end point was all-cause death at 3 months after enrolment. Follow-up data were complete in 2621 patients (97.1%). Using ROC (receiver operating characteristic) curves, the AUC (area under the curve) of 0.73 [95% CI (confidence interval), 0.67-0.79] for MR-proANP was significantly higher compared with 0.58 (95% CI, 0.55-0.62) for Tn-I (troponin-I; DeLong test, P=0.0024). According to ROC analysis, the optimal cut-off value of MR-proANP was at 236 pmol/l for all-cause death, which helped to find a significantly increased rate of all-cause death (n=76) at 3 months in patients with elevated baseline concentrations (≥236 pmol/l) compared with patients with a lower concentration level in Kaplan-Meier survival analysis (log rank, P<0.001). The predictive performance of MR-proANP was independent of other clinical variables or cardiovascular risk factors, and superior to that of Tn-I or other cardiac biomarkers (all: P<0.0001). MR-proANP may help in the prediction of all-cause death in patients with symptomatic CAD. Further studies should verify its prognostic value and confirm the appropriate cut-off value.

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.

Different treatment interventions affect plasma NT-ProBNP levels and early exercise tolerance in patients with acute ST-segment elevation myocardial infarction

OBJECTIVE

The aim of this study was to investigate the effect of different treatment interventions on plasma N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) levels and early exercise tolerance in patients with acute ST-segment elevation myocardial infarction.

METHODS

146 consecutive patients with ST-segment elevation myocardial infarction who received emergency percutaneous coronary intervention (PCI) (n = 55), elective PCI (n = 47), or drug treatment (n = 44) were included. Plasma NT-proBNP levels and left ventricular ejection fractions (LVEFs) were measured before the treatment intervention and at 1 week and 1 month afterward. An exercise stress test was performed 1 month after the intervention, and the occurrences of major adverse cardiac events (MACE) were recorded at the 1-month follow-up.

RESULTS

Compared with the elective PCI and drug treatment groups, at 1 week and 1 month after the intervention, the emergency PCI group's plasma NT-proBNP levels were significantly lower, and the group's LVEFs were significantly higher (all P < 0.05). There was a significantly negative correlation between plasma NT-proBNP levels and LVEFs in each group (all P < 0.05). The positive exercise stress testing rates were 13.0%, 32.6%, and 38.6% in the emergency PCI, elective PCI, and drug treatment groups, respectively (P < 0.05). The occurrences of MACE in the emergency PCI, elective PCI, and drug treatment groups were 34.5%, 59.5%, and 65.9%, respectively (P < 0.05).

CONCLUSION

Emergency PCI resulted in lower plasma NT-proBNP levels, lower MACE incidence, higher LVEFs, and better early exercise tolerance compared with elective PCI or drug treatment, indicating that lower plasma NT-proBNP levels predicted a better prognosis.

Release of tissue-specific proteins into coronary perfusate as a model for biomarker discovery in myocardial ischemia/reperfusion injury

Diagnosis of acute coronary syndromes is based on protein biomarkers, such as the cardiac troponins (cTnI/cTnT) and creatine kinase (CK-MB) that are released into the circulation. Biomarker discovery is focused on identifying very low abundance tissue-derived analytes from within albumin-rich plasma, in which the wide dynamic range of the native protein complement hinders classical proteomic investigations. We employed an ex vivo rabbit model of myocardial ischemia/reperfusion (I/R) injury using Langendorff buffer perfusion. Nonrecirculating perfusate was collected over a temporal profile of 60 min reperfusion following brief, reversible ischemia (15 min; 15I/60R) for comparison with irreversible I/R (60I/60R). Perfusate proteins were separated using two-dimensional gel electrophoresis (2-DE) and identified by mass spectrometry (MS), revealing 26 tissue-specific proteins released during reperfusion post-15I. Proteins released during irreversible I/R (60I/60R) were profiled using gel-based (2-DE and one-dimensional gel electrophoresis coupled to liquid chromatography and tandem mass spectrometry; geLC-MS) and gel-free (LC-MS/MS) methods. A total of 192 tissue-specific proteins were identified during reperfusion post-60I. Identified proteins included those previously associated with I/R (myoglobin, CK-MB, cTnI, and cTnT), in addition to examples currently under investigation in large cohort studies (heart-type fatty acid binding protein; FABPH). The postischemic release profile of a novel cardiac-specific protein, cysteine and glycine-rich protein 3 (Csrp3; cardiac LIM domain protein) was validated by Western blot analysis. We also identified Csrp3 in serum from 6 of 8 patients postreperfusion following acute myocardial infarction. These studies indicate that animal modeling of biomarker release using ex vivo buffer perfused tissue to limit the presence of obfuscating plasma proteins may identify candidates for further study in humans.

Comparison of Midregional Pro–A-Type Natriuretic Peptide and the N-Terminal Pro–B-Type Natriuretic Peptide for Predicting Mortality and Cardiovascular Events

BACKGROUND

N-terminal pro–B-type natriuretic peptide (NT-proBNP) provides prognostic information on mortality and future cardiovascular events for individuals from the general population. A novel immunoassay was recently developed that measures a midregional fragment of pro–A-type natriuretic peptide (MR-proANP). We compared the capabilities of MR-proANP and NT-proBNP for predicting mortality and cardiovascular events in a population-based study.

METHODS

A total of 7819 patients participated in the population-based Prevention of Renal and Vascular End-stage Disease (PREVEND) study, a prospective observational study. Three clinical end points were studied: all-cause mortality, cardiovascular mortality, and cardiovascular events. After a median follow-up of 10.5 years, we used a Cox proportional hazards model to investigate the relationship between the 2 natriuretic peptides and the clinical end points. The Harrell C statistic and the integrated discrimination improvement (IDI) were used to compare MR-proANP and NT-proBNP.

RESULTS

Increased plasma concentrations of both natriuretic peptides were associated with an increased risk of all-cause mortality and cardiovascular events, after adjustment for age, sex, and other cardiovascular risk factors. According to the Harrell C statistic analysis, the models with MR-proANP and NT-proBNP were comparable in predicting all-cause mortality, cardiovascular mortality, and cardiovascular events. In contrast to NT-proBNP, MR-proANP was not independently related to cardiovascular mortality. In all models, the IDI was higher for NT-proBNP than for MR-proANP.

CONCLUSIONS

MR-proANP was as efficient as NT-proBNP in predicting all-cause mortality, cardiovascular mortality, and cardiovascular events; however, its association with cardiovascular mortality was not independent from other confounders.