Diagnostic accuracy and prognostic relevance of the measurement of cardiac natriuretic peptides: a review

Development of a high-throughput liquid chromatography-tandem mass spectrometry platform for the determination of intact natriuretic peptides in human plasma

We present an innovative, reliable, and antibody-free analytical method to determine multiple intact natriuretic peptides in human plasma. These biomolecules are routinely used to confirm the diagnosis and monitor the evolution of heart failure, so that their determination is essential to improve diagnosis and monitor the efficacy of treatment. However, common immunoassay kits suffer from main limitations due to high cross-reactivity with structurally similar species. In our method, we pre-treated the sample by combining salting-out with ammonium sulfate with microextraction by packed sorbent technique. Analyses were then carried out by ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry. The use of 3-nitrobenzyl alcohol as a supercharger reagent enhanced the ESI ionization and improved the signal-to-noise ratio. The analytical protocol showed good linearity over one order of magnitude, recovery in the range of 94-105 %, and good intra- and inter-day reproducibility (RSD<20 %), and the presence of a matrix effect. Limits of detection were in the range of pg/mL for all peptides (0.2-20 pg/mL). Stability study in plasma samples demonstrated that proper protease inhibitors need to be included in blood collection tubes to avoid peptide degradation. Preliminary analyses on plasma samples from heart failure patients allow the quantification of ANP 1-28 as the most abundant species and the detection of ANP 5-28, BNP 1-32, and BNP 5-32. The method could be used to investigate how cross-reactivity issues among structurally similar species impact determinations by ELISA kits.

Biomarkers for the Diagnosis of Heart Failure in People with Diabetes: A Consensus Report from Diabetes Technology Society

Diabetes Technology Society assembled a panel of clinician experts in diabetology, cardiology, clinical chemistry, nephrology, and primary care to review the current evidence on biomarker screening of people with diabetes (PWD) for heart failure (HF), who are, by definition, at risk for HF (Stage A HF). This consensus report reviews features of HF in PWD from the perspectives of 1) epidemiology, 2) classification of stages, 3) pathophysiology, 4) biomarkers for diagnosing, 5) biomarker assays, 6) diagnostic accuracy of biomarkers, 7) benefits of biomarker screening, 8) consensus recommendations for biomarker screening, 9) stratification of Stage B HF, 10) echocardiographic screening, 11) management of Stage A and Stage B HF, and 12) future directions. The Diabetes Technology Society panel recommends 1) biomarker screening with one of two circulating natriuretic peptides (B-type natriuretic peptide or N-terminal prohormone of B-type natriuretic peptide), 2) beginning screening five years following diagnosis of type 1 diabetes (T1D) and at the diagnosis of type 2 diabetes (T2D), 3) beginning routine screening no earlier than at age 30 years for T1D (irrespective of age of diagnosis) and at any age for T2D, 4) screening annually, and 5) testing any time of day. The panel also recommends that an abnormal biomarker test defines asymptomatic preclinical HF (Stage B HF). This diagnosis requires follow-up using transthoracic echocardiography for classification into one of four subcategories of Stage B HF, corresponding to risk of progression to symptomatic clinical HF (Stage C HF). These recommendations will allow identification and management of Stage A and Stage B HF in PWD to prevent progression to Stage C HF or advanced HF (Stage D HF).

Prognostic Value of sST2 in Heart Failure

In recent years, there has been growing interest in the risk stratification for heart failure, and the use of multiple biomarkers to identify different pathophysiological processes associated with this condition. One such biomarker is soluble suppression of tumorigenicity-2 (sST2), which has shown some potential for integration into clinical practice. sST2 is produced by both cardiac fibroblasts and cardiomyocytes in response to myocardial stress. Other sources of sST2 are endothelial cells of the aorta and coronary arteries and immune cells such as T cells. Indeed, ST2 is also associated with inflammatory and immune processes. We aimed at reviewing the prognostic value of sST2 in both chronic and acute heart failure. In this setting, we also provide a flowchart about its potential use in clinical practice.

The Use of Brain Natriuretic Peptide in the Evaluation of Heart Failure in Geriatric Patients

Heart failure is one of the main morbidity and mortality factors in the general population and especially in elderly patients. Thus, at the European level, the prevalence of heart failure is 1% in people under 55 years of age but increases to over 10% in people over 70 years of age. The particularities of the elderly patient, which make the management of heart failure difficult, are the presence of comorbidities, frailty, cognitive impairment and polypharmacy. However, elderly patients are under-represented in clinical trials on the diagnosis and treatment of heart failure. The need for complementary methods (biomarkers) for differential and early diagnosis of heart failure is becoming more and more evident, even in its subclinical stages. These methods need to have increased specificity and sensitivity and be widely available. Natriuretic peptides, in particular B-type natriuretic peptide (BNP) and its fraction NTproBNP, have gained an increasingly important role in the screening, diagnosis and treatment of heart failure in recent years.

Biomarkers of HFpEF: Natriuretic Peptides, High-Sensitivity Troponins and Beyond

Heart failure (HF) is a significant cause of morbidity and mortality worldwide. HF with preserved ejection fraction (HFpEF) is a complex syndrome, often participated by several cardiac and extracardiac conditions, including chronic kidney disease, pulmonary disease, anaemia and advanced age. Circulating biomarkers reflecting pathophysiological pathways involved in HFpEF development and progression may assist clinicians in early diagnosis and management of this condition. Natriuretic peptides (NPs) are cardioprotective hormones released by cardiomyocytes in response to pressure or volume overload and in response to activation of neuro-endocrine-immune system. The relevance of B-type NP (BNP) and N-terminal pro-B-type NP (NT-proBNP) for diagnosis and risk stratification has been extensively demonstrated, and these biomarkers are emerging tools for population screening and as guides to the start of treatment in subclinical HF. On the contrary, conflicting evidence exists on the value of NPs to guide HF therapy. Among the other biomarkers, high-sensitivity troponins and soluble suppression of tumorigenesis-2 are the most promising biomarkers for risk stratification, predicting outcome independently from NPs. In this review, some novel biomarkers are being tested in such clinical scenario, more tightly linked to specific pathophysiological processes of cardiac damage.

Application of integrated management bundle incorporating with multidisciplinary measures improved in-hospital outcomes and early survival in geriatric hip fracture patients with perioperative heart failure: a retrospective cohort study

Background

In elderly, hip fracture is often complicated by perioperative heart failure, related to worse prognosis. We aimed to analyze the effects of integrated management bundle incorporating with multidisciplinary measures on in-hospital outcomes and early survival in elderly hip fracture patients with perioperative heart failure.

Methods

In this retrospective cohort study, a total of 421 hip fracture patients aged 65 and over who developed perioperative heart failure were included. According to different perioperative management modes applied, patients were retrospectively divided into multidisciplinary management group (Group A), including 277 patients, and integrated management bundle group (Group B), including 144 patients. The B-type natriuretic peptide (BNP) and C-reactive protein (CRP) levels, complications, length of stay, and hospitalization costs were observed and compared between two groups. Overall survival was compared by Kaplan–Meier methods. Cox regression analysis was used to identify prognostic factors associated with overall survival.

Results

A total of 421 patients were enrolled for analysis, including 277 in Group A and 144 in Group B. BNP and CRP levels were significantly decreased compared with admission (P < 0.05). Furthermore, BNP and CRP in Group B decreased much more than those in Group A (P < 0.05). The reductions were observed in length of stay, hospitalization costs and incidence of pulmonary infection, hypoproteinemia, and acute cerebral infarction in Group B (all P < 0.05). The Kaplan–Meier plots showed significantly superior overall survival in Group B. Integrated management bundle was independent favorable prognostic factors.

Conclusions

The integrated management bundle incorporating with multidisciplinary measures significantly improved the therapeutic effect of perioperative heart failure, reduced inflammatory response, and yielded better hospital outcomes. It brought better survival benefits for geriatric hip fracture patients with perioperative heart failure. The results of this study can play an important role in clinical work and provide a valuable theoretical basis for selection of management model in elderly hip fracture patients with perioperative heart failure.

B-type natriuretic peptide (BNP) in HCV-positive Egyptian patients: the impact of HCV eradication on plasma BNP levels

Background

Chronic hepatitis C virus (HCV) infection represents a major health-related burden in Egypt. HCV is considered as a major cardiovascular risk factor. BNP (B-type natriuretic peptide) has been determined as a credible diagnostic and prognostic cardiac biomarker. We aimed to assess plasma BNP in HCV-positive Egyptian patients prior and after HCV eradication by direct-acting antiviral agents (DAAs) therapy. Eighty-nine chronic HCV-positive patients were enrolled in our prospective research. They were provided with DAAs therapy in the form of sofosbuvir and daclatasvir without or with ribavirin for 12 weeks. History, clinical evaluation, and laboratory assessment: CBC, liver and kidney function tests, viral markers (HCVAb, HBVsAg, and HIVAb) by ELISA, HCV RNA by real-time PCR, and BNP by ELISA were assessed. FIB-4 and aspartate aminotransferase-to-platelet ratio index (APRI) scores were ranked.

Results

Plasma BNP displayed a non-significant (p = 0.124) increase of its serum mean values in post eradication of HCV than its baseline values. Baseline BNP exhibited a significant positive correlation with FIB4 (r = 0.411, P < 0.001) and APRI score (r = 0.418, p < 0.001) with a considerably negative correlation with platelets (r = − 0.274, p = 0.009), in addition to higher pretreatment BNP values in cirrhotic than in non-cirrhotic patients (p < 0.001), while non-significant relations were found regarding sex, BMI, and drug regimen (with or without ribavirin) (p = 0.950, 0.845, and 0.738, respectively). Additionally, plasma BNP values considerably decreased post-treatment in patients presented with higher baseline BNP values and more advanced liver disease (higher FIB4, APRI, and the presence of liver cirrhosis).

Conclusion

Our findings propose on the one side, the necessity of cardiac monitoring during chronic HCV infection and, on the other, the valuable impacts of HCV eradication on HCV-associated cardiac morbidities.

B-Type Natriuretic Peptide as a Significant Brain Biomarker for Stroke Triaging Using a Bedside Point-of-Care Monitoring Biosensor

Stroke is a widespread condition that causes 7 million deaths globally. Survivors suffer from a range of disabilities that affect their everyday life. It is a complex condition and there is a need to monitor the different signals that are associated with it. Stroke patients need to be rapidly diagnosed in the emergency department in order to allow the admission of the time-limited treatment of tissue plasminogen activator (tPA). Stroke diagnostics show the use of sophisticated technologies; however, they still contain limitations. The hidden information and technological advancements behind the utilization of biomarkers for stroke triaging are significant. Stroke biomarkers can revolutionize the way stroke patients are diagnosed, monitored, and how they recover. Different biomarkers indicate different cascades and exhibit unique expression patterns which are connected to certain pathologies in the human body. Over the past decades, B-type natriuretic peptide (BNP) and its derivative N-terminal fragment (NT-proBNP) have been increasingly investigated and highlighted as significant cardiovascular biomarkers. This work reviews the recent studies that have reported on the usefulness of BNP and NT-proBNP for stroke triaging. Their classification association is also presented, with increased mortality in stroke, correlation with cardioembolic stroke, and an indication of a second stroke recurrence. Moreover, recent scientific efforts conducted for the technological advancement of a bedside point-of-care (POC) device for BNP and NT-proBNP measurements are discussed. The conclusions presented in this review may hopefully assist in the major efforts that are currently being conducted in order to improve the care of stroke patients.

N-terminal pro-B-type natriuretic peptide levels in children: comparison in cardiac and non-cardiac diseases

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP), a well-known marker of cardiac disease, may be elevated in acute infections and other non-cardiac diseases. The aim of this study was to evaluate NT-proBNP levels in cardiac and non-cardiac diseases and found out the patient's clinical status that affects the NT-proBNP levels.

METHODS

NT-proBNP levels were measured in three groups of children: a cardiac disease group, an infectious disease group, and a non-cardiac, non-infectious disease group.

RESULT

In total, 348 children were enrolled, including 134 patients (38.5%) with cardiac disease, 170 patients (48.9%) with infectious disease, and 44 patients (12.6%) with non-cardiac, non-infectious disease. The NT-proBNP level of the cardiac disease group (median: 548 pg/mL; range: 5-35,000 pg/mL) was significantly higher than that of the infectious disease group (median: 193 pg/mL; range: 10-35,000 pg/mL) and the non-cardiac, non-infectious disease group (median: 280 pg/mL; range: 6-35,000 pg/mL). Regarding clinical status, the NT-proBNP levels were significantly higher in patients who needed mechanical ventilation support, oxygen therapy, or inotropic medication or had a change in mental status than in other patients. However, the systemic inflammatory response syndrome and mortality were not related to the NT-proBNP level.

CONCLUSION

Among heterogeneous group of children, NT-proBNP level can be a useful marker of cardiac disease. Furthermore, the NT-proBNP levels were related to patients' clinical deteriorations, such as shock rather than the inflammatory status of patients.

Analyse biochimique multi-paramétrique révélant une augmentation de l'homocystéinémie et du NT-ProBNP chez les patients hypertendus à Bamako (Mali)

Introduction

L'hypertension artérielle est un problème majeur de santé publique en Afrique subsaharienne par sa fréquence élevée et le risque cardiovasculaire qu'elle entraine. L'objectif de cette étude était d'évaluer la prévalence des facteurs de risques cliniques et biologiques de l'hypertension artérielle à Bamako (Mali).

Méthodes

Il s'agit d'une étude cas-témoin, stratifiée en fonction du sexe, portant sur 72 participants dont 36 hypertendus et 36 contrôles. Vingt-deux paramètres biochimiques plasmatiques ont été mesurés et analysés par des tests univariés et multivariés.

Résultats

Une hyperhomocystéinémie a été retrouvée chez 55,6% des femmes (p = 0,03) et 100% des hommes (p = 0,007) hypertendus. Le N-terminal pro B-type natriuretic peptide (NT-Pro-BNP) était également augmenté chez 16,7% des femmes (VIP > 1 dans le modèle multivarié) et des hommes hypertendus (p = 0,00006). Un bon modèle multivarié prédictif (OPLS-DA) a uniquement été obtenu chez les femmes hypertendues, avec un Q²cum = 0,73, attestant ainsi d'un important dimorphisme sexuel associé à l'hypertension artérielle. Ce modèle impliquait huit paramètres dont la concentration plasmatique était modifiée (homocystéine, NT-Pro-BNP, potassium, urée, glycémie, sodium, chlore et protéines totales).

Conclusion

Nous avons noté une association significative entre l'hyperhomocystéinémie et l'hypertension artérielle. Par conséquent, le dosage de l'homocystéine associé à une bonne prise en charge diminuerait le risque cardiovasculaire tout en améliorant la qualité de vie des patients hypertendus.

The Role of Serial NT-ProBNP Level in Prognosis and Follow-Up Treatment of Acute Heart Failure after Coronary Artery Bypass Graft Surgery

BACKGROUND:

After coronary artery bypass graft (CABG) surgery, heart failure is still major problem. The valuable marker for it is needed.

AIM:

Evaluating the role of serial NT-proBNP level in prognosis and follow-up treatment of acute heart failure after CABG surgery.

METHODS:

The prospective, analytic study evaluated 107 patients undergoing CABG surgery at Ho Chi Minh Heart Institute from October 2012 to June 2014. Collecting data was done at pre- and post-operative days with measuring NT-proBNP levels on the day before operation, 2 hours after surgery, every next 24 h until the 5^th day, and in case of acute heart failure occurred after surgery.

RESULTS:

On the first postoperative day (POD1), the NT-proBNP level demonstrated significant value for AHF with the cut-off point = 817.8 pg/mL and AUC = 0.806. On the second and third postoperative day, the AUC value of NT- was 0.753 and 0.751. It was statistically significant in acute heart failure group almost at POD 1 and POD 2 when analyzed by the doses of dobutamine, noradrenaline, and adrenaline (both low doses and normal doses).

CONCLUSION:

Serial measurement of NT-proBNP level provides useful prognostic and follow-up treatment information in acute heart failure after CABG surgery.

Inflammatory and cardiovascular diseases biomarkers in chronic hepatitis C virus infection: A review

Hepatitis C virus (HCV) infects 180 million people worldwide and over 4 million people in the United States. HCV infection is a major cause of chronic liver disease and is recognized as a risk factor for clinical cardiovascular disease (CVD). Many studies have shown increased prevalence of cardiac and inflammatory biomarkers in patients with chronic HCV infection (CHC), and though these markers may be used to risk stratify people for cardiac disease in the general population their role in the HCV population is unknown. Patients with CHC have elevated cardiac and inflammatory biomarkers compared to noninfected controls which may play a role in CVD risk stratification. We undertook a systematic review of inflammatory and cardiac biomarkers in people with HCV infection with a focus on the effect of CHC on serum levels of these markers and their utility as predictors of CVD in this population. Medline, EMBASE, and Cochrane databases were searched for relevant articles until June 2019. A total of 2430 results were reviewed with 115 studies included. Our review revealed that HCV infection significantly alters serum levels of markers of inflammation, endothelial function, and cardiac dysfunction prior to HCV treatment, and some of which may change in response to HCV therapy. Current risk stratification tools for development of CVD in the general population may not account for the increased inflammatory markers that appear to be elevated among HCV‐infected patients contributing to increased CVD risk.

Natriuretic peptide-guided treatment for the prevention of cardiovascular events in patients without heart failure

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. Early intervention for those with high cardiovascular risk is crucial in improving patient outcomes. Traditional prevention strategies for CVD have focused on conventional risk factors, such as overweight, dyslipidaemia, diabetes, and hypertension, which may reflect the potential for cardiovascular insult. Natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro B-type natriuretic peptide (NT-proBNP), are well-established biomarkers for the detection and diagnostic evaluation of heart failure. They are of interest for CVD prevention because they are secreted by the heart as a protective response to cardiovascular stress, strain, and damage. Therefore, measuring NP levels in patients without heart failure may be valuable for risk stratification, to identify those at highest risk of CVD who would benefit most from intensive risk reduction measures.

OBJECTIVES

To assess the effects of natriuretic peptide (NP)-guided treatment for people with cardiovascular risk factors and without heart failure.

SEARCH METHODS

Searches of the following bibliographic databases were conducted up to 9 July 2019: CENTRAL, MEDLINE, Embase, and Web of Science. Three clinical trial registries were also searched in July 2019.

SELECTION CRITERIA

We included randomised controlled trials enrolling adults with one or more cardiovascular risk factors and without heart failure, which compared NP-based screening and subsequent NP-guided treatment versus standard care in all settings (i.e. community, hospital).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts and selected studies for inclusion, extracted data, and evaluated risk of bias. Risk ratios (RRs) were calculated for dichotomous data, and mean differences (MDs) with 95% confidence intervals (CIs) were calculated for continuous data. We contacted trial authors to obtain missing data and to verify crucial study characteristics. Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, two review authors independently assessed the quality of the evidence and GRADE profiler (GRADEPRO) was used to import data from Review Manager to create a 'Summary of findings' table.

MAIN RESULTS

We included two randomised controlled trials (three reports) with 1674 participants, with mean age between 64.1 and 67.8 years. Follow-up ranged from 2 years to mean 4.3 years.For primary outcome measures, effect estimates from a single study showed uncertainty for the effect of NP-guided treatment on cardiovascular mortality in patients with cardiovascular risk factors and without heart failure (RR 0.33, 95% CI 0.04 to 3.17; 1 study; 300 participants; low-quality evidence). Pooled analysis demonstrated that in comparison to standard care, NP-guided treatment probably reduces the risk of cardiovascular hospitalisation (RR 0.52, 95% CI 0.40 to 0.68; 2 studies; 1674 participants; moderate-quality evidence). This corresponds to a risk of 163 per 1000 in the control group and 85 (95% CI 65 to 111) per 1000 in the NP-guided treatment group.When secondary outcome measures were evaluated, evidence from a pooled analysis showed uncertainty for the effect of NP-guided treatment on all-cause mortality (RR 0.90, 95% CI 0.60 to 1.35; 2 studies; 1354 participants; low-quality evidence). Pooled analysis indicates that NP-guided treatment probably reduces the risk of all-cause hospitalisation (RR 0.83, 95% CI 0.75 to 0.92; 2 studies; 1354 participants; moderate-quality evidence). This corresponds to a risk of 601 per 1000 in the control group and 499 (95% CI 457 to 553) per 1000 in the NP-guided treatment group. The effect estimate from a single study indicates that NP-guided treatment reduced the risk of ventricular dysfunction (RR 0.61, 95% CI 0.41 to 0.91; 1374 participants; high-quality evidence). The risk in this study's control group was 87 per 1000, compared with 53 (95% CI 36 to 79) per 1000 with NP-guided treatment. Results from the same study show that NP-guided treatment does not affect change in NP level at the end of follow-up, relative to standard care (MD -4.06 pg/mL, 95% CI -15.07 to 6.95; 1 study; 1374 participants; moderate-quality evidence).

AUTHORS' CONCLUSIONS

This review shows that NP-guided treatment is likely to reduce ventricular dysfunction and cardiovascular and all-cause hospitalisation for patients who have cardiovascular risk factors and who do not have heart failure. Effects on mortality and natriuretic peptide levels are less certain. Neither of the included studies were powered to evaluate mortality. Available evidence shows uncertainty regarding the effects of NP-guided treatment on both cardiovascular mortality and all-cause mortality; very low event numbers resulted in a high degree of imprecision in these effect estimates. Evidence also shows that NP-guided treatment may not affect NP level at the end of follow-up.As both trials included in our review were pragmatic studies, non-blinding of patients and practices may have biased results towards a finding of equivalence. Further studies with more adequately powered sample sizes and longer duration of follow-up are required to evaluate the effect of NP-guided treatment on mortality. As two trials are ongoing, one of which is a large multi-centre trial, it is hoped that future iterations of this review will benefit from larger sample sizes across a wider geographical area.

Sympathetic and renin-angiotensin-aldosterone system activation in heart failure with preserved, mid-range and reduced ejection fraction

BACKGROUND

Evidence of sympathetic and renin-angiotensin-aldosterone system activation provided a rationale for neurohormonal antagonism in heart failure with reduced ejection fraction (HFrEF), while no data are available in patients with milder degree of systolic dysfunction. We aimed to investigate neurohormonal function in HF with preserved and mid-range EF (HFpEF/HFmrEF).

METHODS

Three cohorts (n = 189/each) of stable HFpEF, HFmrEF and HFrEF patients were selected (median age 70, 67 and 67 years; male 56%, 73% and 74%, respectively). Patients received a baseline clinical assessment including plasma renin activity (PRA), aldosterone, catecholamines, and N-terminal fraction of pro-B-type natriuretic peptide (NT-proBNP) assays, and were followed-up for all-cause death.

RESULTS

Neuroendocrine profile was similar between HFpEF and HFmrEF, while all neurohormones except epinephrine were higher in HFrEF than in HFmrEF (NT-proBNP 2332 ng/L, IQR 995-5666 vs 575 ng/L, 205-1714; PRA 1.7 ng/mL/h, 0.4-5.6 vs 0.6 ng/mL/h, 0.2-2.6; aldosterone 153 ng/L, 85-246 vs 113 ng/L, 72-177; norepinephrine 517 ng/L, 343-844 vs 430 ng/L, 259-624; all p < 0.001, epinephrine 31 ng/L, 10-63 vs 25 ng/L, 10-44; p = 0.319). These findings were unrelated to treatment heterogeneity. Ten percent of HFpEF patients had elevated PRA, aldosterone and norepinephrine vs. 8% in HFmrEF and 21% in HFrEF. During a 5-year follow-up, survival decreased with the number of neurohormones elevated (HFpEF: log-rank 7.8, p = 0.048; HFmrEF: log-rank 11.8, p = 0.008; HFrEF: log-rank 8.1, p = 0.044).

CONCLUSIONS

Neurohormonal activation is present only in a subset of patients with HFpEF and HFmrEF, and may hold clinical significance. Neurohormonal antagonism may be useful in selected HFpEF/HFmrEF population.

The impact of aerobic exercise training with vascular occlusion in patients with chronic heart failure

AIMS

This study aimed to evaluate the impact of aerobic exercise training with vascular occlusion in patients with chronic heart failure.

METHODS AND RESULTS

Thirty patients with post-infarction heart failure were randomized to an interventional exercise group (IG; n = 15) or a control exercise group (CG; n = 15). Exercise was performed at an intensity of 40-70% of the peak VO2 /W for 6 months. Patients in the IG remained seated on the saddle of the cycle ergometer with their feet on the pedals. Pneumatic tourniquets were applied to the proximal ends of their thighs with appropriate pressure resulting in a 40-80 mmHg increase in the systolic blood pressure that is required for vascular occlusion (208.7 ± 7.4 mmHg). We evaluated the safety and efficacy of the intervention and its effect on exercise capacity and serum BNP levels. There were no significant differences between the IG and CG in patient characteristics at study entry. Peak VO2 /W in the IG significantly increased compared with that in the CG; the change in the serum BNP levels was significantly larger in the IG than in the CG.

CONCLUSIONS

These results suggest that aerobic exercise training with vascular occlusion can improve exercise capacity and serum BNP levels in patients with chronic heart failure.

Methods for the evaluation of biomarkers in patients with kidney and liver diseases: multicentre research programme including ELUCIDATE RCT

Background

Protein biomarkers with associations with the activity and outcomes of diseases are being identified by modern proteomic technologies. They may be simple, accessible, cheap and safe tests that can inform diagnosis, prognosis, treatment selection, monitoring of disease activity and therapy and may substitute for complex, invasive and expensive tests. However, their potential is not yet being realised.

Design and methods

The study consisted of three workstreams to create a framework for research: workstream 1, methodology – to define current practice and explore methodology innovations for biomarkers for monitoring disease; workstream 2, clinical translation – to create a framework of research practice, high-quality samples and related clinical data to evaluate the validity and clinical utility of protein biomarkers; and workstream 3, the ELF to Uncover Cirrhosis as an Indication for Diagnosis and Action for Treatable Event (ELUCIDATE) randomised controlled trial (RCT) – an exemplar RCT of an established test, the ADVIA Centaur® Enhanced Liver Fibrosis (ELF) test (Siemens Healthcare Diagnostics Ltd, Camberley, UK) [consisting of a panel of three markers – (1) serum hyaluronic acid, (2) amino-terminal propeptide of type III procollagen and (3) tissue inhibitor of metalloproteinase 1], for liver cirrhosis to determine its impact on diagnostic timing and the management of cirrhosis and the process of care and improving outcomes.

Results

The methodology workstream evaluated the quality of recommendations for using prostate-specific antigen to monitor patients, systematically reviewed RCTs of monitoring strategies and reviewed the monitoring biomarker literature and how monitoring can have an impact on outcomes. Simulation studies were conducted to evaluate monitoring and improve the merits of health care. The monitoring biomarker literature is modest and robust conclusions are infrequent. We recommend improvements in research practice. Patients strongly endorsed the need for robust and conclusive research in this area. The clinical translation workstream focused on analytical and clinical validity. Cohorts were established for renal cell carcinoma (RCC) and renal transplantation (RT), with samples and patient data from multiple centres, as a rapid-access resource to evaluate the validity of biomarkers. Candidate biomarkers for RCC and RT were identified from the literature and their quality was evaluated and selected biomarkers were prioritised. The duration of follow-up was a limitation but biomarkers were identified that may be taken forward for clinical utility. In the third workstream, the ELUCIDATE trial registered 1303 patients and randomised 878 patients out of a target of 1000. The trial started late and recruited slowly initially but ultimately recruited with good statistical power to answer the key questions. ELF monitoring altered the patient process of care and may show benefits from the early introduction of interventions with further follow-up. The ELUCIDATE trial was an ‘exemplar’ trial that has demonstrated the challenges of evaluating biomarker strategies in ‘end-to-end’ RCTs and will inform future study designs.

Conclusions

The limitations in the programme were principally that, during the collection and curation of the cohorts of patients with RCC and RT, the pace of discovery of new biomarkers in commercial and non-commercial research was slower than anticipated and so conclusive evaluations using the cohorts are few; however, access to the cohorts will be sustained for future new biomarkers. The ELUCIDATE trial was slow to start and recruit to, with a late surge of recruitment, and so final conclusions about the impact of the ELF test on long-term outcomes await further follow-up. The findings from the three workstreams were used to synthesise a strategy and framework for future biomarker evaluations incorporating innovations in study design, health economics and health informatics.

Trial registration

Current Controlled Trials ISRCTN74815110, UKCRN ID 9954 and UKCRN ID 11930.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 6, No. 3. See the NIHR Journals Library website for further project information.

NT-proBNP and Echocardiographic Parameters in Patients with Acute Heart Failure

Aim. The aim of this study was to analyse the relation between clinical, haemodynamic and X-ray parameters and plasma NT-proBNP level in pts with symptoms of left ventricular dysfunction. Methods. The plasma NT-proBNP levels, chest x-ray, transthoracic 2-d and Doppler echocardiography were performed at the time of admission in a group of 96 consecutive patients (mean age 68 ± 11 years) with symptoms of acute heart failure. NT-proBNP levels were assessed with the use of commercial tests (Roche Diagnostics). Results. All patients have significant increase in NT-proBNP (8 000 ± 9 000 pg/mL vs. controls 90 ± 80 pg/mL, p < 0.001). The group of all patients has shown a significant increase in cardiothoracic ratio (CTR, 0.6 ± 0.1, vs. 0.4 ± 0.1, p <0.001), left atrium diameter (LAD, 4.4 ± 0.8 cm, vs.3.5 ± 0.4 cm, p <0.01). Left ventricular ejection fraction (LVEF) was decreased (37 ± 15%, vs. 64 ± 5%, p <0.001). In patients with acute heart failure, NT-proBNP significantly correlated with end-systolic and end-diastolic left ventricle diameters, ejection fraction, vena cava inferior diameter and plasma creatinine levels. Conclusion. Increased plasma NT-proBNP level is influenced by the clinical severity of acute heart failure and correlates with LVEF and IVCD. NT-proBNP can serve as a marker for the clinical severity of the disease.

Profiling B-Type Natriuretic Peptide Cleavage Peptidoforms in Human Plasma by Capillary Electrophoresis with Electrospray Ionization Mass Spectrometry

B-type Natriuretic Peptide (BNP) is a biologically active circulating hormone. Plasma concentrations of BNP are routinely used in the diagnosis of heart failure, and the intravenous infusion of recombinant BNP can be used for heart failure treatment. Like many bioactive polypeptides, multiple plasma enzymes are known to cleave circulating BNP, and as part of the CVD-B/D-HPP mandate, we sought to develop a technique capable of profiling these catabolic processes in plasma. We used a neutral-coated capillary electrophoresis-electrospray ionization (CESI) separation system coupled with high-resolution mass spectrometry to profile the proteolysis of exogenous recombinant BNP_1-32 in plasma. Our method utilizes electrokinetic injection of minimally processed plasma samples to simultaneously monitor the dynamic generation and breakdown of at least five BNP peptidoforms in plasma. By integrating multisegment injection, our method can produce a multipoint BNP proteolytic profile for one sample within an hour. We envision applying this method to assess the potential relation between plasma-based BNP proteolysis and heart failure as well as a means of monitoring BNP bioavailability after therapeutic infusion.

Influence of apelin-12 on troponin levels and the rate of MACE in STEMI patients

BACKGROUND

During acute myocardial infarction, phosphorylated TnI levels, Ca²⁺ sensitivity and ATPase activity are decreased in the myocardium, and the subsequent elevation in Ca²⁺ levels activates protease I (caplain I), leading to the proteolytic degradation of troponins. Concurrently, the levels of apelin and APJ expression are increased by limiting myocardial injury.

METHODS

In this prospective observational study, 100 consecutive patients with ST-elevation acute myocardial infarction were included. Patients meeting the following criteria were included in our study: (1) continuous chest pain lasting for >30 min, (2) observation of ST-segment elevation of more than 2 mm in two adjacent leads by electrocardiography (ECG), (3) increased cardiac troponin I levels, and (4) patients who underwent reperfusion therapy. We evaluated the levels of apelin-12 and troponin I on the first and seventh days after reperfusion therapy in all patients.

RESULTS

Apelin-12 was inversely correlated with troponin I levels (Spearman's correlation = -0.40) with a p value <0.001. There was variability in the apelin values on the seventh day (Kruskal-Wallis test) based on major adverse cardiac events (MACE) (p = 0.012). Using ROC curve analyses, a cut-off value of >2.2 for the association of apelin with MACE was determined, and the AUC was 0.71 (95% CI, 0.58-0.84). Survival analysis using the Kaplan-Meier method showed a lower rate of MACE among patients with apelin levels >2.2 (p = 0.002), and the ROC curve analysis showed a statistically significant difference in the area under the curve (p = 0.004).

CONCLUSION

The influence of apelin levels on troponin levels in the acute phase of STEMI is inversely correlated, whereas in the non-acute phase, low apelin values were associated with a high rate of MACE.

Improved LFIAs for highly sensitive detection of BNP at point-of-care

Heart failure (HF) has become a major cause of morbidity and mortality with a significant global economic burden. Although well-established clinical tests could provide early diagnosis, access to these tests is limited in developing countries, where a relatively higher incidence of HF is present. This has prompted an urgent need for developing a cost-effective, rapid and robust diagnostic tool for point-of-care (POC) detection of HF. Lateral flow immunoassay (LFIA) has found widespread applications in POC diagnostics. However, the low sensitivity of LFIA limits its ability to detect important HF biomarkers (e.g., brain natriuretic peptide [BNP]) that are normally present in low concentration in blood. To address this issue, we developed an improved LFIA by optimizing the gold nanoparticle (GNP)–antibody conjugate conditions (e.g., the conjugate pH and the amount of added antibody), the diameter of GNP and the concentration of antibody embedded on the test line and modifying the structure of test strip. Through these improvements, the proposed test strip enabled the detection of BNP down to 0.1 ng/mL within 10–15 min, presenting ~15-fold sensitivity enhancement over conventional lateral flow assay. We also successfully applied our LFIA in the analysis of BNP in human serum samples, highlighting its potential use for clinical assessment of HF. The developed LFIA for BNP could rapidly rule out HF with the naked eye, offering tremendous potential for POC test and personalized medicine.

N-terminal pro-B-type natriuretic peptide in amniotic fluid of fetuses with known or suspected cardiac load

Background

Myocardial dysfunction occurs in a variety of fetal disorders. Findings from adult cardiology, where n-terminal pro-B-type natriuretic peptide (nt-proBNP) is an established biomarker of left ventricular dysfunction have been extended to fetal life. Since fetal blood sampling is technically challenging we investigated amniotic fluid nt-proBNP for its suitability to diagnose fetal myocardial dysfunction.

Methods

Ultrasound, Doppler examination and echocardiography was applied to classify cases and controls. Amniotic fluid nt-proBNP to amniotic fluid total protein ratio was calculated and compared to the gestational age-dependent reference intervals. In a subset of cases, fetal and maternal plasma nt-proBNP levels were determined.

Results

Specimen from 391 fetuses could be analyzed (171 cases, 220 controls). There was a high correlation between amniotic fluid and fetal blood nt-proBNP levels (r = 0.441 for cases; r = 0.515 for controls), whereas no correlation could be detected between maternal and fetal (blood and amniotic fluid) nt-proBNP concentrations. Specificity and positive likelihood ratio of amniotic fluid nt-proBNP to amniotic fluid total protein ratio were high (0.97 and 4.3, respectively).

Conclusion

Amniotic fluid nt-proBNP measurement allows diagnostic confirmation of fetal myocardial dysfunction. It may serve as a useful adjunct in addition and correlation to existing tests of myocardial function, particularly in the context of invasive fetal therapy, where access to the amniotic cavity is part of the procedure.

Genetic variability in the system of natriuretic B peptide and principal toxicological parameters in workers exposed to lead

The study was aimed at evaluating the influence of selected polymorphisms of natriuretic peptide B precursor (NPPB) and natriuretic peptide receptor C (NPR3) genes on blood lead concentration (Pb-B) and blood zinc protoporphyrin concentration (ZnPP) in persons occupationally exposed to lead. Investigations were conducted on 360 persons (mean age: 44.49±9.62years), workers exposed to lead compounds. The analysis examined four polymorphisms of BNP gene, i.e.,: rs198388, rs198389, rs632793, and rs6676300; as well as one polymorphism of receptor C for natriuretic peptides, i.e., rs1421811. Heterozygosity in locus rs632793 of NPPB gene may result in higher concentrations of Pb-B, while allele A in locus rs632793 of NPPB gene seems to determine higher concentrations of ZnPP in persons occupationally exposed to lead. Workers exposed to lead and carrying allele C in locus rs198388 of NPPB gene, particularly in the heterozygotic setup, seem to be predisposed to present higher concentrations of ZnPP. Carriership of A allele in locus rs198389 of NPPB gene probably determines higher concentrations of ZnPP in study group. In summary, among persons occupationally exposed to lead, certain relationships were demonstrated between rs632793, rs198388 and rs198389 polymorphisms of NPPB gene and principal toxicological parameters characterizing exposure to lead.

Factors affecting N-terminal pro-brain natriuretic peptide elevation in the acute phase of Kawasaki disease

BACKGROUND

The aim of this study was to investigate the clinical significance and factors that affect N-terminal pro-brain natriuretic peptide (NT-proBNP) elevation in the acute phase of Kawasaki disease (KD) despite the absence of apparent cardiac complications.

METHODS

The laboratory and echocardiography results of 44 KD patients in the acute and subacute phases were reviewed.

RESULTS

With preserved cardiac function, median NT-proBNP was significantly elevated in the acute phase compared with the subacute phase (343 pg/mL, IQR, 162-1182 pg/mL vs 98 pg/mL, IQR, 61-205 pg/mL, respectively; P < 0.0001). The respective levels of tumor necrosis factor (TNF)-α, soluble TNF receptor (sTNFR)1, and sTNFR2 were also significantly elevated in the acute phase compared with the subacute phase: TNF-α, 3.3 pg/mL (IQR, 2.6-4.8 pg/mL) versus 2.4 pg/mL (IQR 1.9-4.0 pg/mL; P < 0.01), sTNFR1, 2741 pg/mL (IQR, 2080-3183 pg/mL) versus 976 pg/mL (IQR, 814-1247 pg/mL; P < 0.0001), sTNFR2, 5644 pg/mL (IQR, 4693-7520 pg/mL) versus 3169 pg/mL (IQR, 2132-3878 pg/mL; P < 0.0001). Log-transformed NT-proBNP was correlated with TNF-α (r = 0.29, P = 0.056), sTNFR1 (r = 0.60, P < 0.0001), and sTNFR2 (r = 0.65, P < 0.0001). TNF-α was correlated with sTNFR1 (r = 0.35, P = 0.02) and sTNFR2 (r = 0.51, P < 0.001).

CONCLUSION

Tumor necrosis factor-α may cause NT-proBNP elevation in the acute phase of KD, and NT-proBNP level may be an indicator of TNF-α activity.

Natriuretic peptides as biomarkers of cardiac endocrine function in heart failure: new challenges and perspectives

Several studies indicated that B-type natriuretic peptide (BNP) assay is able to detect patients even in the early phases of heart failure (HF), when the myocardial remodeling process may be still reversible. BNP assay may assist the physician to initiate appropriate and prompt pharmacological treatments. However, clinical relevance and result interpretation of BNP assay for the guide of therapy or in particular clinical conditions, such as renal failure or treatment with inhibitors of enzymes degrading BNP in HF patients, are still debated. The aim of this article is to discuss some still controversial issues concerning the clinical use of measurement of cardiac natriuretic peptides, and also to provide a general overview and some perspectives related to pathophysiological mechanisms of HF.

Neprilysin Inhibition in Heart Failure with Reduced Ejection Fraction: A Clinical Review

There has been a 10-year hiatus in the approval of a new pharmacotherapy for patients with chronic heart failure with a reduced ejection fraction (HFrEF). Combining an angiotensin receptor blocker, valsartan, with sacubitril, an inhibitor of neprilysin, results in increasing levels of natriuretic peptides that counterbalance high circulating levels of neurohormones in HFrEF. This has resulted in the development of a new agent, LCZ696. A comprehensive overview of LCZ696, its pharmacology, its role in the pathophysiology of HFrEF, completed and future clinical trial information, specific critical issues, and the place of LCZ696 in HFrEF therapy are presented.

PARP inhibition and postinfarction myocardial remodeling

Coronary artery disease accounts for the greatest proportion of cardiovascular diseases therefore it is the major cause of death worldwide. Its therapeutic importance is indicated by still high mortality of myocardial infarction, which is one of the most severe forms of CVDs. Moreover, the risk of developing heart failure is very high among survivors. Heart failure is accompanied by high morbidity and mortality rate, therefore this topic is in the focus of researchers' interest. After a myocardial infarct, at first ventricular hypertrophy develops as a compensatory mechanism to decrease wall stress but finally leads to left ventricular dilation. This phenomenon is termed as myocardial remodeling. The main characteristics of underlying mechanisms involve cardiomyocyte growth, vessel changes and increased collagen production, in all of which several mechanical stress induced neurohumoral agents, oxidative stress and signal transduction pathways are involved. The long term activation of these processes ultimately leads to left ventricular dilation and heart failure with decreased systolic function. Oxidative stress causes DNA breaks producing the activation of nuclear poly(ADP-ribose) polymerase-1 (PARP-1) enzyme that leads to energy depletion and unfavorable modulation of different kinase cascades (Akt-1/GSK-3β, MAPKs, various PKC isoforms) and thus it promotes the development of heart failure. Therefore inhibition of PARP enzyme could offer a promising new therapeutical approach to prevent the onset of heart failure among postinfarction patients. The purpose of this review is to give a comprehensive summary about the most significant experimental results and mechanisms in postinfarction remodeling.

Association between serum N-terminal pro-B-type natriuretic peptide levels and characteristics of coronary atherosclerotic plaque detected by coronary computed tomography angiography

The aim of the present study was to explore the association between the levels of serum N-terminal pro-B-type natriuretic peptide (NT-pro BNP) and the characteristics of coronary atherosclerotic plaque detected by coronary computed tomography angiography (CCTA), in patients with unstable angina (UA). A total of 202 patients (age range, 47-82 years) were divided into the following three groups: Non-cardiac disease group (57 patients); stable angina pectoris (SAP) group (62 patients); and UA group (83 patients). There were significant differences between the serum NT-pro BNP levels among the three groups (P=0.007). However, in multivariant diagnoses, NT-pro BNP level was not an independent risk factor for UA. The levels of serum NT-pro BNP were observed to be positively correlated with the number of vessels involved (r=0.462; P<0.001), SIS (r=0.475; P<0.001), segment-stenosis score (r=0.453; P<0.001), coronary calcification score (r=0.412; P=0.001), number of obstructive diseases (r=0.346; P<0.001), and the number of segments with non-calcified plaque (r=0.235; P=0.017), mixed plaque (r=0.234; P=0.017) and calcified plaque (r=0.431; P<0.001). The levels of serum NT-pro BNP were significantly higher in patients with UA and left main-left anterior descending (LM-LAD) disease, compared with UA patients without LM-LAD disease (P<0.001). In addition, serum NT-pro BNP was significantly higher in patients with obstructive disease and UA than in those without obstructive disease (P<0.001). The area under the curve of log(NT-pro BNP) was 0.656 (P=0.006; optimal cut-off value, 1.74; sensitivity, 77.6%; specificity, 51.9%). In conclusion, the levels of serum NT-pro BNP are associated with the burden and severity of coronary artery atherosclerotic disease in patients with UA, and may be helpful in risk stratification of patients with UA.

The search for efficient diagnostic and prognostic biomarkers of heart failure

Several biomarkers have been tested for screening, diagnosis and prognosis purposes, as well as to guide treatment in heart failure, but only the assay of circulating B-type natriuretic peptides has widely recognized applications for clinical decision-making. Natriuretic peptides are sensitive in detecting the clinically overt or subclinical myocardial damage, but their plasma levels are increased following every generic insult to the cardiovascular system. Novel biomarkers are required to identify specific pathways of disease progression, such as diverse neurohormonal axes activation, inflammation and fibrogenesis, and to act as a tool for therapeutic tailoring. In this view, Gal-3 and ST-2 assays seem very promising, given their involvement in mechanisms of cardiac fibrosis and their prognostic value.

Biomarkers of Heart Failure with Preserved and Reduced Ejection Fraction

Biomarkers are increaingly being used in the management of heart failure not only for the purpose of screening, diagnosis, and risk stratification, but also as a guide to evaluate the response to treatment in the individual patient and as an entry criterion and/or a surrogate marker of efficacy in clinical trials testing novel drugs. In this chapter, we review the role of established biomarkers for heart failure management, according to the main classification of HF phenotypes, based on the measurement of left ventricular ejection fraction, including heart failure with reduced (<40%), preserved (≥50%), and, as recently proposed, mid-range (40-49%) ejection fraction.

Symptom burden, Metabolic profile, Ultrasound findings, Rhythm, neurohormonal activation, haemodynamics and health-related quality of life in patients with atrial Fibrillation (SMURF): a protocol for an observational study with a randomised interventional component

INTRODUCTION

Atrial fibrillation (AF) is the most common cardiac arrhythmia, with an estimated prevalence of 1.5-2%. It is an independent risk factor for ischaemic stroke and is estimated to cause about 20-25% of all stroke cases. AF has a great impact on health-related quality of life (HRQoL); however, one unresolved issue related to AF is the wide variation in its symptoms.

METHODS AND ANALYSIS

The symptom burden, metabolic profile, ultrasound findings, rhythm, neurohormonal activation, haemodynamics and HRQoL in patients with AF (Symptom burden, Metabolic profile, Ultrasound findings, Rhythm, neurohormonal activation, haemodynamics and health-related quality of life in patients with atrial Fibrillation, SMURF) study is a prospective observational, cohort study, with a randomised interventional part. The aim of the study is to investigate, in patients with AF, the relationship between symptom burden and metabolic aspects, atrial function and different neurohormones, and the effect of radiofrequency ablation (RFA). The interventional part of the study will give an insight into the neurohormonal and intracardiac pressure changes directly after initiation of AF. Consecutive patients with symptomatic AF accepted for treatment with RFA for the first time at Linköping University Hospital are eligible for participation. The enrolment started in January 2012, and a total of 200 patients are to be included into the study, with 45 of them being enrolled into the interventional study with initiation of AF. The sample size of the interventional study is based on a small pilot study with 5 patients induced to AF while 2 served as controls. The results indicated that, in order to find a statistically significant difference, there was a need to include 28 patients; for safety reasons, 45 patients will be included.

ETHICS AND DISSEMINATION

The SMURF study is approved by the Regional Ethical Review Board at the Faculty of Health Sciences, Linköping, Sweden. The results will be presented through peer-review journals and conference presentation.

TRIAL REGISTRATION NUMBER

NCT01553045; Pre-results.

Levels of N-terminal pro brain natriuretic peptide are enhanced in people with the uncomplicated metabolic syndrome: a case-cohort analysis of the population-based Casale Monferrato study

BACKGROUND

Both metabolic syndrome (MetS) and N-amino terminal fragment of the prohormone B-type natriuretic peptide (NT-proBNP) confer increased risk of cardiovascular diseases (CVD). We assessed if NT-proBNP levels were greater in people with uncomplicated MetS, who had neither CVD/chronic kidney disease (CKD) nor diabetes, as compared with subjects who met none of the defining criteria of the MetS.

METHODS

A case-cohort study from the non-diabetic population-based Casale Monferrato study was performed, after exclusion of all subjects with established CVD, CKD [estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2)], and CRP values ≥3 mg/L. Cases (n = 161) with MetS were compared with all subjects within the cohort (n = 124) who were completely free of any component of the MetS. Serum NT-proBNP was centrally measured by immunoenzymatic assay.

RESULTS

NT-proBNP levels were significantly higher in cases than in control subjects [35.4 (15.5-98.2) vs 24.4 (11.7-49.6) pg/mL, p = 0.014]. In logistic regression analysis, compared with NT-proBNP values in the lower quartiles (≤49.64 pg/mL), higher values conferred odds ratio 4.17 (1.30-13.44) of having the MetS, independently of age, sex, microalbuminuria, CRP, eGFR, and central obesity. This association was evident even after the exclusion of hypertensive subjects. Further adjustment for log-HOMA and diastolic blood pressure did not modify the strength of the association, while central obesity was a negative confounder.

CONCLUSIONS

Compared with people without any component of the MetS, those with uncomplicated MetS, who had neither CVD/CKD nor diabetes, had increased NT-proBNP values, even if they were normotensive and although absolute values were still in the low range. The insulin resistance state did not mediate this association, while central obesity was a negative confounder.

Association between serum level of ubiquinol and NT-proBNP, a marker for chronic heart failure, in healthy elderly subjects

Ubiquinone and ubiquinol represent the oxidized and reduced forms of Coenzyme Q10 (CoQ10). CoQ10 is present in membranes of almost all human tissues and organs, with highest concentration in the heart. In patients with heart failure, serum levels of the N-terminal pro-brain natriuretic peptide (NT-proBNP) are an indicator of disease severity. Here, we investigated the relationship between serum levels of CoQ10 and NT-proBNP in healthy volunteers of an elderly study population (mean age 52 years, n = 871). We found a negative association between serum levels of ubiquinol and NT-proBNP (P < 0.001). Accordingly, the CoQ10 redox state (% oxidized form of CoQ10) is positively associated with serum NT-proBNP level (P < 0.001). Compared to patients who survived a myocardial infarction (n = 21), healthy subjects have lower NT-proBNP level (500.39 ± 631.28 pg/ml vs. 76.90 ± 120.27 pg/ml, P < 0.001), higher ubiquinol serum level (0.43 ± 0.19 µmol/L vs. 0.71 ± 0.32 µmol/L; P < 0.001), and a lower CoQ10 redox state (27.6 ± 13.8% vs. 17.6 ± 10.1%; P < 0.001). Interestingly, ubiquinol supplementation (150 mg/day; 14 day; n = 53) slightly reduces the expression of CLCN6, a gene related to NT-proBNP level. In summary, higher serum levels of ubiquinol are associated with lower serum NT-proBNP levels in healthy elderly subjects. However, to what extent a high serum level of ubiquinol is a protective factor for heart failure remains to be elucidated in prospective studies.

State of the art of immunoassay methods for B-type natriuretic peptides: An update

The aim of this review article is to give an update on the state of the art of the immunoassay methods for the measurement of B-type natriuretic peptide (BNP) and its related peptides. Using chromatographic procedures, several studies reported an increasing number of circulating peptides related to BNP in human plasma of patients with heart failure. These peptides may have reduced or even no biological activity. Furthermore, other studies have suggested that, using immunoassays that are considered specific for BNP, the precursor of the peptide hormone, proBNP, constitutes a major portion of the peptide measured in plasma of patients with heart failure. Because BNP immunoassay methods show large (up to 50%) systematic differences in values, the use of identical decision values for all immunoassay methods, as suggested by the most recent international guidelines, seems unreasonable. Since proBNP significantly cross-reacts with all commercial immunoassay methods considered specific for BNP, manufacturers should test and clearly declare the degree of cross-reactivity of glycosylated and non-glycosylated proBNP in their BNP immunoassay methods. Clinicians should take into account that there are large systematic differences between methods when they compare results from different laboratories that use different BNP immunoassays. On the other hand, clinical laboratories should take part in external quality assessment (EQA) programs to evaluate the bias of their method in comparison to other BNP methods. Finally, the authors believe that the development of more specific methods for the active peptide, BNP1-32, should reduce the systematic differences between methods and result in better harmonization of results.

A multimarker approach to diagnose and stratify heart failure

BACKGROUND

We have previously demonstrated that circulating NT-proBNP is truncated at the N and C termini. Aims of this study are three-fold: firstly to determine whether the NT-proBNP levels correlate with NYHA functional classes when measuring with different antibody pairs; secondly to evaluate the diagnostic potential of ProBNP and; thirdly to investigate whether combining NT-proBNP assays with or without ProBNP would lead to better diagnostic accuracies.

METHODS

Plasma samples were collected from healthy controls (n=52) and HF patients (n=46). Customized AlphaLISA® immunoassays were developed and validated to measure the concentrations of proBNP and NT-proBNP (with antibodies targeting 13-45, 13-76, 28-76). The diagnostic performance and predictive value of proBNP and NT-proBNP assays and their combinations were evaluated.

RESULTS

Plasma proBNP assay showed acceptable diagnostic performance. NT-proBNP13-76 assay is useful in diagnosing and stratifying HF patients. The diagnostic performance of NT-proBNP13-76 demonstrated improvement over commercial NT-proBNP tests. The combination of NT-proBNP13-76 with NT-proBNP28-76 assays gave the best diagnostic assay performance.

CONCLUSION

Our results demonstrate that while there is major heterogeneity in circulating NT-proBNP, specific epitopes of the peptides are extraordinarily stable, providing ideal targets for clinically useful diagnostic assays. Future new clinical diagnostic clinical trials should include a multimarker approach rather than using a single marker to diagnose HF.

Ceramide is upregulated and associated with mortality in patients with chronic heart failure

BACKGROUND

Ceramide is involved in apoptosis, inflammation, and stress responses, which are among the pathogenic components of chronic heart failure (CHF). However, no one has documented the levels of ceramide itself in CHF or determined its potential prognostic value.

METHODS

In this study we recruited patients with heart failure consecutively from the hospital, of whom 423 stable patients were eventually selected to participate in this study after an observation period of at least 3 months after hospital discharge. All patents were followed up for all-cause death to December 31, 2013.

RESULTS

Plasma ceramide levels were increased stepwise with New York Heart Association functional class (I, 5.32 ± 1.98; II, 5.81 ± 1.63; III, 6.14 ± 2.14; IV, 6.66 ± 2.61 ng/mL). During a mean follow-up of 4.4 years (interquartile range: 3.5-5.3 years), a total of 200 CHF patients died. The optimal threshold value of ceramide was 6.05 ng/mL. Ceramide levels as continuous and as dichotomous variables are risk factors for mortality in CHF (adjusted hazard ratio, 1.31; 95% confidence interval, 1.16-1.47; P < 0.001 and adjusted hazard ratio, 2.07, 95% confidence interval, 1.53-2.81; P < 0.001, respectively). When ceramide levels were combined with conventional CHF risk factors, the area under the curve increased from 0.68 (0.63-0.72) to 0.72 (0.68-0.76); P = 0.047. The continuous net reclassification index and integrated discrimination improvement index were 17.2% (5.0-29.9%; P = 0.027) and 0.04 (0.01-0.08; P = 0.020), respectively.

CONCLUSIONS

Plasma ceramide levels were increased and correlated with the severity of CHF, and were an independent risk factor of mortality in patients with CHF and reduced left ventricular systolic function. Ceramide levels might provide additional predictive value after conventional risk assessment.

Reference intervals for N-terminal pro-B-type natriuretic peptide in amniotic fluid between 10 and 34 weeks of gestation

BACKGROUND

In adult and pediatric cardiology, n-terminal pro-B-type natriuretic peptide (nt-proBNP) serves as biomarker in the diagnosis and management of cardiovascular dysfunction. Elevated levels of circulating nt-proBNP are present in fetal conditions associated with myocardial pressure or volume load. Compared to fetal blood sampling, amniocentesis is technically easier and can be performed from early pregnancy onwards. We aimed to investigate amniotic fluid (AF) nt-proBNP concentrations in normal pregnancies between 10 and 34 weeks of gestation.

METHODS

Nt-proBNP and total protein (TP) was measured in AF by chemiluminescence assay (photometry, respectively). To adjust for a potential dilutional effect, the AF-nt-proBNP/AF-TP ratio was analyzed. Reference intervals were constructed by regression modeling across gestational age.

RESULTS

132 samples were analyzed. A negative correlation between AF-nt-proBNP/AF-TP ratio and gestational age was observed. Curves for the mean and the 5% and 95% reference interval between 10 and 34 weeks of gestation were established.

CONCLUSION

In normal pregnancy, nt-proBNP is present in AF and decreases during gestation. Our data provide the basis for research on AF-nt-proBNP as biomarker in fetal medicine.

Biomarkers of activation of renin-angiotensin-aldosterone system in heart failure: how useful, how feasible?

Renin-angiotensin-aldosterone system (RAAS), participated by kidney, liver, vascular endothelium, and adrenal cortex, and counter-regulated by cardiac endocrine function, is a complex endocrine system regulating systemic functions, such as body salt and water homeostasis and vasomotion, in order to allow the accomplishment of physiological tasks, such as orthostasis, physical and emotional stimuli, and to react towards the hemorrhagic insult, in tight conjunction with other neurohormonal axes, namely the sympathetic nervous system, the endothelin and vasopressin systems. The systemic as well as the tissue RAAS are also dedicated to promote tissue remodeling, particularly relevant after damage, when chronic activation may configure as a maladaptive response, leading to fibrosis, hypertrophy and apoptosis, and organ dysfunction. RAAS activation is a fingerprint of systemic arterial hypertension, kidney dysfunction, vascular atherosclerotic disease, and is definitely an hallmark of heart failure, which rapidly shifts from organ disease to a disorder of neurohormonal regulatory systems. Chronic RAAS activation is an indirect or direct target of most effective pharmacological treatments in heart failure, such as beta-blockers, inhibitors of angiotensin converting enzyme, angiotensin receptor blockers, direct renin inhibitors, and mineralocorticoid receptor blockers. Biomarkers of RAAS activation are available, with different feasibility and accuracy, such as plasma renin activity, renin, angiotensin II, and aldosterone, which all accompany the increasing clinical severity of heart failure disease, and are well recognized prognostic factors, even in patients with optimal therapy. Polymorphisms influencing the expression and activity of RAAS pathways have been recognized as clinically relevant biomarkers, likely influencing either the individual clinical phenotype, or the response to drugs. This solid, growing evidence strongly suggests the rationale for the use of biomarkers of the RAAS activation, as a guide to tailor individual therapy in the current practice, and their implementation as a rule-in marker for future trials on novel drugs in the heart failure setting.

Clinical implications of normal B-type natriuretic peptide levels in patients with severe chronic heart failure

Background: High plasma B-type natriuretic peptide (BNP) levels in patients with severe chronic heart failure (CHF) often indicate poor ventricular function and poor prognosis. However, in some such patients plasma BNP levels are normal.

Objective: To investigate the clinical implications of BNP levels in patients with severe CHF.

Methods: Fifty-seven patients with severe CHF were divided into group A (13 normal plasma BNP level) and 44 patients (high plasma BNP levels) group B. Diuretics, angiotensin-converting enzyme inhibitors (or angiotensin II receptor antagonist, e.g., metoprolol) and digitalis were used as conventional treatment. The clinical characteristics of all patients in two groups were analyzed and compared.

Results: At the first admission, left ventricular end diastolic diameter in group B was significantly lower than group A (p < 0.05), and the plasma BNP level in group B was significantly higher than group A (p < 0.05). When metoprolol was used, 6 and 5 patients in group A and B could not tolerate the initial dose. In other cases using metoprolol at average maximum tolerance dose of metoprolol 12.5-6.25 and 24.20-11.22 mg/day in group A and B, respectively, there was a significant difference between them (p < 0.05). There were no significant differences in plasma BNP levels between two groups during stable period. The plasma BNP level in group B during acute worsening stage was significantly higher than in the remission stage (962.73-165.00 ng/L vs 876.24-167.70 ng/L, p < 0.05). However, there was no significant difference between group A (74.03-11.18 ng/L) and group B (71.38-11.68 ng/L) (p > 0.05). The mobility of group A was higher than group B (11/12 vs 6/44, p < 0.05). Logistic regression analysis showed that, the plasma BNP level was the independent risk factor for predicting cardiac death (regression coefficient, 3.817; OR, 45.488; 95% CI, 5.322ʺ388.791).

Conclusion: In patients with severe CHF, normal plasma BNP level suggests depletion of BNP secretion and further deterioration of cardiac function, indicating a poor prognosis.

Are levels of NT-proBNP and SDMA useful to determine diastolic dysfunction in chronic kidney disease and renal transplant patients?

BACKGROUND

The aim of the study was to determine the clinical usefulness of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and symmetric dimethylarginine (SDMA) for detection of renal and left ventricular (LV) diastolic dysfunction in chronic kidney disease (CKD) patients and renal transplant (RT) recipients.

METHODS

We included 98 CKD and 44 RT patients. We assessed LV function using pulsed-wave Doppler ultrasound. Diastolic dysfunction was defined when the E:A ratio was <1.

RESULTS

Independent predictors of NT-proBNP levels were age, creatinine, and albumin in CKD patients and age and urea in RT patients. Determinants of SDMA in CKD patients were glomerular filtration rate (GFR) and NT-proBNP and creatinine in RT patients. In RT patients with diastolic dysfunction, NT-proBNP and SDMA were significantly higher than in patients without diastolic dysfunction (F = 7.478, P < 0.011; F = 2.631, P < 0.017). After adjustment for GFR, the differences were not seen. In CKD patients adjusted NT-proBNP and SDMA values for GFR were not significantly higher in patients with diastolic dysfunction than in patients without diastolic dysfunction.

CONCLUSIONS

NT-proBNP is useful for detection of LV diastolic dysfunction in RT recipients. When evaluating both NT-proBNP and SDMA it is necessary to consider GFR as a confounding factor.

Changes in NT-proBNP in young children with congenital heart malformations

OBJECTIVE

We measured serum NT-proBNP levels in 2 groups of young patients (0-36 months) with congestive heart failure (CHF) secondary to congenital heart malformations (CHM).

METHODS

The first group included 23 patients prior to surgery for heart malformations. The second group included 12 patients with CHM within 24 hours post-operation. NT-proBNP levels were measured by an enzyme-linked immunosorbent immunoassay (ELISA) using the Chem Well 2910 (Awareness Technology Inc.) automated analyzer.

RESULTS

NT-proBNP values were 4 times higher in patients with unoperated CHM compared to healthy controls (P < 0.001), and 12 times higher in patients with CHM 24 hours after surgery compared to controls (P = 0.0001).

CONCLUSIONS

These results demonstrated significant changes in NT-proBNP concentrations before and after surgery to correct congenital heart malformations.

Prevalence and treatment of heart failure in Swedish nursing homes

Background

Since the burden of care for elderly patients with heart failure (HF) can be decreased by therapeutic measures, it is important that such patients are identified correctly. This study explores the prevalence of HF in nursing homes in Sweden, with special consideration of the risk of failure to diagnose HF in the study population. A second aim is to explore medication and the adherence to guidelines for the treatment of HF.

Methods

429 patients from 11 nursing homes were included during 2008–2011. Information about diagnoses and medications from patient records, blood samples, questionnaire responses and blood pressure measurements were collected. The baseline characteristics of the patients, their medications and one-year mortality were identified and then compared regarding HF diagnosis and B-type natriuretic peptide (BNP) levels. A BNP level of >100 ng/L was used to identify potential cases of HF.

Results

The point prevalence of HF diagnosis in the medical records in the study population was 15.4%. With the recommended cut-off value for BNP, up to 196 subjects in the study population (45.7%) qualified for further screening of potential HF.

The subjects in the HF and non-HF groups were similar with the exception of mean age, BNP levels and Mini Mental State Examination results which were higher in the HF group, and the eGFR and blood pressure, which were lower when HF. The subjects with higher BNP values were older and had lower eGFR, Hb, diastolic blood pressure and BMI. The subjects with HF diagnoses were in many cases not treated according to the guidelines. Loop diuretics were often used without concomitant ACE inhibitors or angiotensin receptor blockers. The subjects without HF diagnoses in the medical records at inclusion but with BNP values >100 ng/L had less appropriate HF medication. The one-year mortality was 52.9% in the population with HF.

Conclusions

Our study suggests that the estimated prevalence of HF in nursing homes in Sweden would increase if BNP measurements were used to select patients for further examinations. The pharmacological treatment of HF varied substantially, as did adherence to guidelines.