B-type natriuretic peptide for incident atrial fibrillation—The Heinz Nixdorf Recall Study

Biomarkers for predicting atrial fibrillation: An explorative sub-analysis of the randomised SCREEN-AF trial

BACKGROUND

Atrial fibrillation (AF) is a common treatable risk factor for stroke. Screening for paroxysmal AF in general practice is difficult, but biomarkers might help improve screening strategies.

OBJECTIVES

We investigated six blood biomarkers for predicting paroxysmal AF in general practice.

METHODS

This was a pre-specified sub-study of the SCREEN-AF RCT done in Germany. Between 12/2017-03/2019, we enrolled ambulatory individuals aged 75 years or older with a history of hypertension but without known AF. Participants in the intervention group received active AF screening with a wearable patch, continuous ECG monitoring for 2x2 weeks and usual care in the control group. The primary endpoint was ECG-confirmed AF within six months after randomisation. High-sensitive Troponin I (hsTnI), brain natriuretic peptide (BNP), N-terminal pro-B-type natriuretic peptide (NT-pro BNP), N-terminal pro atrial natriuretic peptide (NT-ANP), mid-regional pro atrial natriuretic peptide (MR-pro ANP) and C-reactive protein (CRP) plasma levels were investigated at randomisation for predicting AF within six months after randomisation.

RESULTS

Blood samples were available for 291 of 301 (96.7%) participants, including 8 with AF (3%). Five biomarkers showed higher median results in AF-patients: BNP 78 vs. 41 ng/L (p = 0.012), NT-pro BNP 273 vs. 186 ng/L (p = 0.029), NT-proANP 4.4 vs. 3.5 nmol/L (p = 0.027), MR-pro ANP 164 vs. 125 pmol/L (p = 0.016) and hsTnI 7.4 vs. 3.9 ng/L (p = 0.012). CRP levels were not different between groups (2.8 vs 1.9 mg/L, p = 0.1706).

CONCLUSION

Natriuretic peptide levels and hsTnI are higher in patients with AF than without and may help select patients for AF screening, but larger trials are needed.

No Detectable Differences in microRNA Plasma Levels between Diabetic Hypertensive Patients with and without Incident Subclinical Atrial Fibrillation

Background: Long-term rhythm monitoring (LTRM) can detect undiagnosed atrial fibrillation (AF) in patients at risk of AF and stroke. Circulating microRNAs (miRNAs), which have been shown to play a role in atrial electrical and structural remodelling, could help to select patients who would benefit most from LTRM. The aim of this study was to investigate whether patients with diabetes mellitus (DM) and hypertension and screen-detected subclinical AF (SCAF) using an insertable cardiac monitor (ICM) have significantly different plasma baseline levels of five selected miRNAs playing a role in the modulation of atrial electrical and structural remodelling (miR-21-5p, miR-29b-3p, miR-150-5p, miR-328-3p, and miR-432-5p) compared to those without SCAF. Methods: This study was performed at the outpatient clinic of a secondary academic teaching hospital between December 2013 and November 2015. Eligible patients were ≥65 years of age with DM and hypertension but without known heart diseases. All patients received an ICM. On the day of ICM implantation, blood samples for the measurement of plasma levels of the five miRNAs were drawn. In this post hoc analysis, we investigated their expression by reverse transcription-quantitative polymerase chain reaction. MiRNA plasma levels in patients with and without newly detected SCAF were compared. Results: We included 82 consecutive patients (median age of 71.3 years (IQR 67.4-75.1)), who were followed for a median of 588 days (IQR: 453-712 days). Seventeen patients (20.7%) had ICM-detected SCAF. Plasma levels of miR-328-3p, miR-29b-3p, miR-21-5p, miR-432-5p, and miR-150-5p were slightly but not significantly different in patients with incident SCAF compared with patients without. Conclusions: In patients with hypertension and DM, newly detected SCAF was not significantly associated with changes in expression levels of miR-21-5p, miR-29b-3p, miR-150-5p, miR-328-3p, and miR-432-5p.

Association of soluble suppression of tumorigenicity 2 protein with new-onset atrial fibrillation in patients with acute ST-segment elevation myocardial infarction undergoing primary PCI

Background

Previous studies have indicated that the soluble suppression of tumorigenicity 2 protein (sST2) is associated with new-onset atrial fibrillation (NOAF) in patients diagnosed with coronary artery disease (CAD). However, the predictive value of sST2 in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has not been well studied.

Methods

A total of 580 patients with STEMI undergoing primary PCI were consecutively recruited between January 2021 and January 2023. These patients were then categorized into two groups: the NOAF group and the no NOAF groups based on the presence of NOAF during admission. The concentration of sST2 in blood samples was measured in all patients. The clinical data from the two groups were prospectively analyzed to investigate the predictive factors of NOAF in patients with STEMI undergoing primary PCI.

Results

A total of 41 (7.1%) patients developed NOAF. The presence of NOAF has been found to be associated with various factors, including age, diabetes mellitus, hypertension, the left atrial (LA) diameter, N-terminal pro-brain natriuretic peptide, C-reactive protein (CRP), sST2, a Killip class of ≥2, and a final TIMI flow grade of <3. After including multiple factors, it was observed that LA diameter, CRP, sST2, a Killip class of ≥2, and a final TIMI flow grade of <3 remained significant risk factors for developing NOAF. The receiver operating characteristic (ROC) curve showed the following findings: (1) when the LA diameter exceeded 38.5 mm, the sensitivity and specificity values were observed to be 67.2% and 68.2%, respectively, and the area under the ROC curve (AUC) was 0.683 [95% confidence interval (CI): 0.545-0.732; p = 0.003]; (2) when the CRP level exceeded 8.59, the sensitivity and specificity values were observed to be 68.6% and 69.2%, respectively, and the AUC was 0.713 (95% CI: 0.621-0.778; p < 0.001); and (3) when the sST2 value exceeded 53.3, the sensitivity and specificity values were 79.2% and 68.7%, respectively, and the AUC was 0.799 (95% CI: 0.675-0.865; p < 0.001).

Conclusion

sST2 has been identified as an independent predictor of NOAF in patients with STEMI undergoing PCI.

Role of Cardiac Natriuretic Peptides in Heart Structure and Function

Cardiac natriuretic peptides (NPs), atrial NP (ANP) and B-type NP (BNP) are true hormones produced and released by cardiomyocytes, exerting several systemic effects. Together with C-type NP (CNP), mainly expressed by endothelial cells, they also exert several paracrine and autocrine activities on the heart itself, contributing to cardiovascular (CV) health. In addition to their natriuretic, vasorelaxant, metabolic and antiproliferative systemic properties, NPs prevent cardiac hypertrophy, fibrosis, arrhythmias and cardiomyopathies, counteracting the development and progression of heart failure (HF). Moreover, recent studies revealed that a protein structurally similar to NPs mainly produced by skeletal muscles and osteoblasts called musclin/osteocrin is able to interact with the NPs clearance receptor, attenuating cardiac dysfunction and myocardial fibrosis and promoting heart protection during pathological overload. This narrative review is focused on the direct activities of this molecule family on the heart, reporting both experimental and human studies that are clinically relevant for physicians.

Circulating biomarkers, echocardiographic parameters, and incident subclinical atrial fibrillation in patients with diabetes and hypertension

BACKGROUND

Long-term rhythm monitoring (LTRM) can detect undiagnosed atrial fibrillation (AF) in patients at high risk of AF and stroke. Biomarkers and echocardiographic parameters could, however, help identify patients benefitting most from LTRM. The aim of this study was to investigate, whether circulating biomarkers of cardiac and vascular function (brain natriuretic peptide (BNP), cardiac troponin I (cTnI), copeptin, and mid-regional proadrenomedullin (MR-proADM)) and echocardiographic parameters were associated with incident subclinical AF (SCAF) in a population at high risk of stroke in the presence of AF. For this purpose, we investigated individuals ≥65 years of age with hypertension and diabetes mellitus, but no history or symptoms of AF or other cardiovascular disease (CVD).

METHODS

We included 82 consecutive patients (median age 71.3 years (IQR 67.4-75.1)). All patients received an insertable cardiac monitor (ICM) and were followed for a median of 588 days (IQR 453-712). On the day of ICM implantation, a comprehensive echocardiogram and blood samples were obtained.

RESULTS

During a median follow-up of 588 days (IQR: 453-712 days), incident SCAF occurred in 17 patients (20.7%) with a median time to first-detected episode of 91 days (IQR 41-251 days). MR-proADM (median 0.87 nmol/L (IQR 0.76-1.02) vs 0.78 nmol/L (IQR 0.68-0.98)) and copeptin (median 13 pmol/L (IQR 9-17) vs 8 pmol/L (IQR 4-18)) levels were insignificantly higher in patients with incident SCAF. BNP and cTnI concentrations and echocardiographic parameters were similar in the two groups.

CONCLUSIONS

MR-proADM, BNP, cTnI, copeptin, and several echocardiographic parameters were not associated with incident SCAF in this cohort of patients with hypertension and diabetes, but without any underlying CVD.

Incidence of Atrial Fibrillation in Persons with Very High Serum Levels of N-Terminal Pro-B-Type Natriuretic Peptide: The Multi-Ethnic Study of Atherosclerosis

Objective

While persons in the upper fourth or fifth of the distribution of serum levels of N-terminal pro-B type natriuretic peptide (NT-proBNP) are at a sharply increased risk of developing atrial fibrillation, their absolute risk of this condition (about 20 per 1000 per year) is not clearly high enough to justify prevention or early detection measures. We sought to determine whether the incidence of atrial fibrillation among persons with VERY high levels of NT-proBNP might be sufficiently high to warrant further action.

Design and Setting

Among persons enrolled in the Multi-Ethnic Study of Atherosclerosis, we documented rates of new onset atrial fibrillation in those with increasingly high serum levels of NT-proBNP.

Results

There was a monotonic increase in the incidence of atrial fibrillation with increasing serum level of NT-proBNP, reaching rates of about 50–70 cases per 1000 person-years among those in the upper 3.1% of the distribution (above 422 pg/mL). In this group the incidence tended to be somewhat higher still among persons who were at increased risk of atrial fibrillation for other reasons (eg older age), but in no subgroup did the incidence reach 100 per 1000 person-years.

Conclusion

Serum levels of NT-proBNP have a considerable ability to predict the development of atrial fibrillation. However, the value of screening middle aged and older adults for these levels hinges largely on the ability of interventions in screen-positive people to lead to a reduced incidence of atrial fibrillation and its complications.

Usefulness of Post-Procedural Plasma Brain Natriuretic Peptide Levels to Predict Recurrence After Catheter Ablation of Atrial Fibrillation in Patients With Left Ventricular Systolic Dysfunction

Catheter ablation (CA) of atrial fibrillation (AF) improves cardiac function, resulting in a decrease in plasma brain natriuretic peptide (BNP) levels in patients with reduced left ventricular ejection fraction (LVEF). This study sought to examine the pre-procedural and post-procedural correlations between BNP levels and cardiac function and the associations between the BNP levels and recurrence after CA in patients with AF and reduced LVEF. Of 3142 consecutive patients who underwent first-time CA of AF at our institute, a total of 217 patients with LVEF <50% were enrolled. Significant decrease in BNP levels (from a median of 198 [interquartile range 113 to 355] to 47.7 [22.7 to 135] pg/ml, p <0.001) and improvement in LVEF (from 39±9% to 61±16%, p <0.001) were observed 3 months after CA. There was a linear correlation between log-transformed BNP levels and cardiac measures (LVEF: r = -0.64; LV end-diastolic volume: r = 0.25; LV end-systolic volume: r = 0.43; left atrial volume: r = 0.52; all p <0.001). During a median follow-up of 35 months, AF recurrence after a 3-month blanking period was observed in 80 patients (37%). Cox proportional hazard regression analysis after adjustment for cardiac measures significant in univariate analysis revealed that early recurrence within the blanking period (hazard ratio, 4.88; 95% confidence interval, 2.89 to 8.25) and elevated post-procedural BNP levels (2.02 per unit log increase; 1.14 to 3.56) were significant predictors of AF recurrence, but pre-procedural BNP was not. In conclusion, post-procedural BNP levels at the end of the blanking period predicted subsequent AF recurrence in patients with reduced LVEF, independent of early recurrence.

Anaphylaxis-induced atrial fibrillation and anesthesia: Pathophysiologic and therapeutic considerations

Atrial fibrillation is the most common cardiac arrhythmia in western society affecting more than 35 million individuals worldwide annually. It is a common postoperative complication and may also occur spontaneously during general and local anesthesia administration. Aging, diabetes mellitus, hypertension, and cardiovascular diseases including cardiomyopathies, congenital cardiac anomalies, heart failure, myocardial ischemia, pericarditis, previous cardiac surgery, vascular disease, and valvular heart disease are some correlated factors. Beyond age, increased incidence of atrial fibrillation has been correlated to autoimmune system activation as it is the underlying mechanism of persistent atrial fibrillation development. Current research supports an association between the complement system activation and lymphocyte-pro-inflammatory cytokines release with the cardiac conduction system and atrial fibrosis. The loss of CD28 antigen from CD4+ CD28+ T lymphocytes seems to play a major role in atrial fibrillation development and prognosis. Except atrial fibrillation, a variety of additional electrocardiographic changes, resembling those with digitalis intoxication may accompany anaphylaxis and particularly Kounis syndrome. Histamine is one well-known mediator in allergic and inflammatory conditions as physiologically regulates several cardiovascular and endothelial functions with arrhythmogenic potential. The increased oxidative stress, measured by the redox potentials of glutathione, has been correlated with atrial fibrillation incidence and prevalence. The use of antazoline, a first-generation antihistamine agent used for rapid conversion of recent-onset atrial fibrillation in patients with preserved left ventricular function and for rapid atrial fibrillation termination during accessory pathway ablation denotes that anaphylaxis-induced histamine production could be the cause of atrial fibrillation at least in some instances. The anaphylaxis diagnosis in anesthesia can be challenging owing to the absence of cutaneous manifestetions such as flushing, urticaria, or angioedema. Anticoagulation for stroke prevention, rate and rhythm control medications, invasive methods such as radiofrequency ablation or cryoablation of pulmonary veins as well surgical ablation constitute the treatment basis of atrial fibrillation. Understanding the underlying mechanisms of atrial fibrillation by cardiologists, anesthesiologists and surgeons, as well as potential treatments, to optimize care is of paramount importance.

Electrocardiographic Left Atrial Abnormality and B-Type Natriuretic Peptide in a General Japanese Population: NIPPON DATA2010

AIMS

P-wave terminal force in lead V1 (PTFV1) is an electrocardiogram marker of increased left atrial pressure and may be a noninvasive and early detectable marker for future cardiovascular events in the general population compared to serum B-type natriuretic peptide (BNP) concentration. The clinical significance of PTFV1 in the contemporary general population is an area of unmet need. We aimed to demonstrate the correlation between PTFV1 and BNP concentrations in a contemporary representative Japanese population.

METHODS

Among 2,898 adult men and women from 300 randomly selected districts throughout Japan (NIPPON DATA2010), we analyzed 2,556 participants without cardiovascular disease (stroke, myocardial infarction, and atrial fibrillation). Elevated BNP was defined as a value of ≥ 20 pg/mL based on the definition from the Japanese Circulation Society guidelines.

RESULTS

In total, 125 (4.9%) participants had PTFV1. Participants with PTFV1 were older with a higher prevalence of hypertension, major electrocardiographic findings, and elevated BNP concentrations (13.5 [6.9, 22.8] versus 7.8 [4.4, 14.5] pg/mL; P＜0.001). After adjustment for confounders, PTFV1 was correlated with elevated BNP (odds ratio, 1.66; 95% confidence interval, 1.05-2.62; P=0.030). This correlation was consistent among various subgroups and was particularly evident in those aged ＜65 years or those without a history of hypertension.

CONCLUSIONS

In the contemporary general population cohort, PTFV1 was independently related to high BNP concentration. PTFV1 may be an alternative marker to BNP in identifying individuals at a higher risk of future cardiovascular events in the East Asian population.

Serum N-terminal pro-B-type natriuretic peptide as a predictor for future development of atrial fibrillation in a general population: the Hisayama Study

BACKGROUND

Biomarkers for predicting future development of atrial fibrillation (AF) have not been fully established in general populations. The aim of this study was to assess the predictive ability of serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) for the development of AF.

METHODS AND RESULTS

A total of 3126 community-dwelling Japanese subjects aged ≥ 40 years without a history of AF in 2002 were followed up for a median of 10.2 years. Serum NT-proBNP levels at baseline were divided into four categories (≤ 54, 55-124, 125-299, and ≥ 300 pg/mL) according to the current guidelines and prior reports. The hazard ratios for the development of AF were estimated using a Cox proportional hazards model. During the follow-up period, 153 subjects developed new-onset AF. The age- and sex-adjusted cumulative incidence of AF increased significantly with higher serum NT-proBNP levels (p < 0.001 for trend). The association remained significant after adjustment for known risk factors for AF and cardiovascular disease (hazard ratio [95% confidence interval]: ≤ 54 pg/mL: 1.00 [reference]; 55-124 pg/mL: 1.72 [1.00-2.97]; 125-299 pg/mL: 3.95 [2.23-6.98]; ≥ 300 pg/mL: 8.51 [4.48-16.17]; p < 0.001 for trend). Furthermore, incorporation of serum NT-proBNP levels into the model consisting of known risk factors for AF and cardiovascular disease significantly improved the predictive ability for developing AF (Harrell's c-statistics: 0.828 to 0.844, p = 0.01; continuous net reclassification improvement: 0.41, p < 0.001; integrated discrimination improvement: 0.031, p < 0.001).

CONCLUSIONS

Serum NT-proBNP levels can be a risk biomarker for predicting future development of AF in a general Japanese population.

The value of brain natriuretic peptide in the prosthetic valve thrombosis

: We aimed to investigate how prosthetic valve thrombosis (PVT) affects brain natriuretic peptide (BNP) levels and how BNP changes following thrombolytic therapy. The study included 70 consecutive patients with left-sided mechanical PVT who received thrombolytic therapy. The patients were divided into two groups, namely obstructive thrombus (n = 42) and nonobstructive thrombus (NOT, n = 28). BNP levels of patients were assessed before and after thrombolytic therapy. BNP levels were higher in obstructive thrombus group than NOT group in whole study population, in patients with mitral PVT and in patients with aortic PVT [325.0 (189.5-496.0) vs. 84.0 (44.5-140.0), P < 0.001, 323.0 (193-449.0) vs. 59.0 (37.0-131.0), P < 0.001 and 321.0 (132.0-525.0) vs. 99.0 (60.5-173.0), P < 0.001]. BNP levels were positively correlated with transmitral and transaortic mean gradients, and negatively correlated with mitral valve area (r: 0.374, P = 0.013; r: 0.432, P = 0.035 and; r: -0.642, P < 0.001, respectively). BNP values above 165 pg/ml may predict the presence of obstructive thrombus with a sensitivity of 88.0%, and a specificity of 79.0% (AUC = 0.928, 95% confidence interval: 0.871-0.986, P < 0.001). Following thrombolytic therapy, BNP levels (pg/ml) significantly decreased from 325.0 (189.5-496.0) to 137.0 (101.7-224.5), P < 0.001, in all patients with obstructive thrombus, from 323.0 (193.0-449.0) to 129.0 (98.0-223.0), P < 0.001, in patients with only mitral obstructive thrombus and from 321.0 (132.0-525.0) to 181.0 (99.0-217.5), P < 0.001, in patients with only aortic obstructive thrombus. BNP levels are significantly higher in prosthetic valve patients with obstructive thrombus than in those with NOT and decrease in patients with obstructive thrombus after thrombolytic therapy. A cut off value of BNP of at least 165.0 pg/ml was found to discriminate obstructive thrombus from NOT.

Reduced left atrial cardiomyocyte PITX2 and elevated circulating BMP10 predict atrial fibrillation after ablation

BACKGROUNDGenomic and experimental studies suggest a role for PITX2 in atrial fibrillation (AF). To assess if this association is relevant for recurrent AF in patients, we tested whether left atrial PITX2 affects recurrent AF after AF ablation.METHODSmRNA concentrations of PITX2 and its cardiac isoform, PITX2c, were quantified in left atrial appendages (LAAs) from patients undergoing thoracoscopic AF ablation, either in whole LAA tissue (n = 83) or in LAA cardiomyocytes (n = 52), and combined with clinical parameters to predict AF recurrence. Literature suggests that BMP10 is a PITX2-repressed, atrial-specific, secreted protein. BMP10 plasma concentrations were combined with 11 cardiovascular biomarkers and clinical parameters to predict recurrent AF after catheter ablation in 359 patients.RESULTSReduced concentrations of cardiomyocyte PITX2, but not whole LAA tissue PITX2, were associated with AF recurrence after thoracoscopic AF ablation (16% decreased recurrence per 2-(ΔΔCt) increase in PITX2). RNA sequencing, quantitative PCR, and Western blotting confirmed that BMP10 is one of the most PITX2-repressed atrial genes. Left atrial size (HR per mm increase [95% CI], 1.055 [1.028, 1.082]); nonparoxysmal AF (HR 1.672 [1.206, 2.318]), and elevated BMP10 (HR 1.339 [CI 1.159, 1.546] per quartile increase) were predictive of recurrent AF. BMP10 outperformed 11 other cardiovascular biomarkers in predicting recurrent AF.CONCLUSIONSReduced left atrial cardiomyocyte PITX2 and elevated plasma concentrations of the PITX2-repressed, secreted atrial protein BMP10 identify patients at risk of recurrent AF after ablation.TRIAL REGISTRATIONClinicalTrials.gov NCT01091389, NL50069.018.14, Dutch National Registry of Clinical Research Projects EK494-16.FUNDINGBritish Heart Foundation, European Union (H2020), Leducq Foundation.

Proteomics Profiling and Risk of New-Onset Atrial Fibrillation: Framingham Heart Study

Background

Prior studies relating proteomics markers to incident AF screened for limited numbers of proteins.

Methods and Results

We performed proteomics assays among participants from the Framingham Heart Study Offspring attending their fifth examination. Plasma protein levels (n=1373) were measured by the SOMAscan proteomic profiling platform. We used robust inference for the Cox proportional hazards model to relate each protein level with incident AF. In addition, we examined the association between AF‐related genetic loci and levels of proteins associated with AF. Our study included 1885 participants (mean age 55±10 years, 54% women) who had proteomic profiles measured. A total of 349 participants developed AF during follow‐up (mean follow‐up 18.3 years). We observed that 8 proteins were significantly associated with incident AF after adjusting for age, sex, technical covariates, and correction for multiple testing (P<0.05/1373=3.6×10⁻⁵). After additional adjustments for clinical factors associated with AF, ADAMTS13 and N‐terminal pro‐B‐type natriuretic peptide remained significantly associated with the risk of incident AF (hazard ratio, 0.78; 95% CI, 0.70–0.88; and 1.44; 95% CI, 1.22–1.70, respectively; P<3.6×10⁻⁵ for both). None of the 8 proteins were encoded by genes at AF‐related genetic loci previously identified by genome‐wide association studies.

Conclusions

We identified 8 proteins associated with risk of incident AF after adjustment for age and sex; 2 proteins were associated with AF after adjustment for AF risk factors. Future studies are needed to replicate our findings, identify whether the markers are mechanistically related to AF development, and whether they are clinically useful for identification of future AF risk.

Atrial Tissue Pro-Fibrotic M2 Macrophage Marker CD163+, Gene Expression of Procollagen and B-Type Natriuretic Peptide

Background

Atrial tissue fibrosis is linked to inflammatory cells, yet is incompletely understood. A growing body of literature associates peripheral blood levels of the antifibrotic hormone BNP (B‐type natriuretic peptide) with atrial fibrillation (AF). We investigated the relationship between pro‐fibrotic tissue M2 macrophage marker Cluster of Differentiation (CD)163+, atrial procollagen expression, and BNP gene expression in patients with and without AF.

Methods and Results

In a cross‐sectional study design, right atrial tissue was procured from 37 consecutive, consenting, stable patients without heart failure or left ventricular systolic dysfunction, of whom 10 had AF and 27 were non‐AF controls. Samples were analyzed for BNP and fibro‐inflammatory gene expression, as well as fibrosis and CD163+. Primary analyses showed strong correlations (all P<0.008) between M2 macrophage CD163+ staining, procollagen gene expression, and myocardial BNP gene expression across the entire cohort. In secondary analyses without multiplicity adjustments, AF patients had greater left atrial volume index, more valve disease, higher serum BNP, and altered collagen turnover markers versus controls (all P<0.05). AF patients also showed higher atrial tissue M2 macrophage CD163+, collagen volume fraction, gene expression of procollagen 1 and 3, as well as reduced expression of the BNP clearance receptor NPRC (all P<0.05). Atrial procollagen 3 gene expression was correlated with fibrosis and BNP gene expression was correlated with serum BNP.

Conclusions

Elevated atrial tissue pro‐fibrotic M2 macrophage CD163+ is associated with increased myocardial gene expression of procollagen and anti‐fibrotic BNP and is higher in patients with AF. More work on modulation of BNP signaling for treatment and prevention of AF may be warranted.

Brain Natriuretic Peptide and Discovery of Atrial Fibrillation After Stroke

Background and Purpose—

Diagnosing paroxysmal atrial fibrillation (pAF) can be challenging after acute ischemic stroke. Enhanced and prolonged Holter-ECG monitoring (EPM) improves the detection rate but is not feasible for all patients. We hypothesized that brain natriuretic peptide (BNP) may help to identify patients with stroke at high risk for pAF to select patients for EPM more effectively.

Methods—

Patients with acute cerebral ischemia ≥60 years presenting in sinus rhythm and without history of AF were included into a prospective, randomized multicenter study to receive either EPM (3× 10-day Holter-ECG) or usual stroke care diagnostic work-up. BNP plasma levels were measured on randomization and 3 months thereafter. Levels were compared between patients with and without pAF detected by means of EPM or usual care. Furthermore, the number needed to screen for EPM depending on BNP cut offs was calculated.

Results—

A total of 398 patients were analyzed. In 373 patients (93.7%), BNP was measured at baseline and in 275 patients (69.1%) after 3 months. pAF was found in 27 patients by means of EPM and in 9 patients by means of usual care ( P =0.002). Median BNP was higher in patients with pAF as compared to patients without AF in both study arms at baseline (57.8 versus 28.3 pg/mL in the EPM arm, P =0.0003; 46.2 versus 27.7 pg/mL, P =0.28 in the control arm) and after 3 months (74.9 versus 31.3 pg/mL, P =0.012 in the EPM arm, 99.3 versus 26.3 pg/mL, P =0.02 in the control arm). Applying a cut off of 100 pg/mL, the number needed to screen was reduced from 18 by usual care to 3 by EPM.

Conclusions—

BNP measured early after ischemic stroke identifies a subgroup of patients with stroke at increased risk for AF, in whom EPM is particularly efficacious.

Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01855035.

B-type natriuretic peptide enhances fibrotic effects via matrix metalloproteinase-2 expression in the mouse atrium in vivo and in human atrial myofibroblasts in vitro

B-type natriuretic peptide (BNP) was approved by the US Food and Drug Administration in 2001 for the treatment of heart failure. However, the effects of BNP in clinical applications are controversial and uncertain. Recently, study indicated that high BNP levels are associated with an increased risk of developing atrial fibrillation. In this study, we investigated the direct effects of BNP on TNF-α-induced atrial fibrosis mice, as well as its effects on human atrial myofibroblasts. We found that injecting TNF-α-induced mice with recombinant human BNP enhanced atrial fibrosis via matrix metalloproteinase-2 (MMP-2) expression and collagen accumulation. Furthermore, we found that BNP stimulated MMP-2 expression in human atrial myofibroblasts. Treatment of human atrial myofibroblasts with cycloheximide had no effect on this outcome; however, treatment of cells with MG132 enhanced BNP-induced MMP-2 expression, indicating that protein stability and inhibition of proteasome-mediated protein degradation pathways are potentially involved. Inhibition of SIRT1 significantly decreased BNP-induced MMP-2 expression. Additionally, confocal and coimmunoprecipitation data indicated that BNP-regulated MMP-2 expression are likely to be mediated through direct interaction with SIRT1, which is thought to deacetylate MMP-2 and to increase its protein stability in human atrial myofibroblasts. Finally, we confirmed that SIRT1 is expressed and cytoplasmically redistributed as well as colocalized with MMP-2 in mouse fibrotic atrial tissue. We suggest a possible fibrosis-promoting role of BNP in the atrium, although the antifibrotic properties of BNP in the ventricle have been reported in previous studies, and that the coordination between MMP-2 and SIRT1 in BNP-induced atrial myofibroblasts participates in atrial fibrosis.

Data-driven discovery and validation of circulating blood-based biomarkers associated with prevalent atrial fibrillation

AIMS

Undetected atrial fibrillation (AF) is a major health concern. Blood biomarkers associated with AF could simplify patient selection for screening and further inform ongoing research towards stratified prevention and treatment of AF.

METHODS AND RESULTS

Forty common cardiovascular biomarkers were quantified in 638 consecutive patients referred to hospital [mean ± standard deviation age 70 ± 12 years, 398 (62%) male, 294 (46%) with AF] with known AF or ≥2 CHA2DS2-VASc risk factors. Paroxysmal or silent AF was ruled out by 7-day ECG monitoring. Logistic regression with forward selection and machine learning algorithms were used to determine clinical risk factors, imaging parameters, and biomarkers associated with AF. Atrial fibrillation was significantly associated with age [bootstrapped odds ratio (OR) per year = 1.060, 95% confidence interval (1.04-1.10); P = 0.001], male sex [OR = 2.022 (1.28-3.56); P = 0.008], body mass index [BMI, OR per unit = 1.060 (1.02-1.12); P = 0.003], elevated brain natriuretic peptide [BNP, OR per fold change = 1.293 (1.11-1.63); P = 0.002], elevated fibroblast growth factor-23 [FGF-23, OR = 1.667 (1.36-2.34); P = 0.001], and reduced TNF-related apoptosis-induced ligand-receptor 2 [TRAIL-R2, OR = 0.242 (0.14-0.32); P = 0.001], but not other biomarkers. Biomarkers improved the prediction of AF compared with clinical risk factors alone (net reclassification improvement = 0.178; P < 0.001). Both logistic regression and machine learning predicted AF well during validation [area under the receiver-operator curve = 0.684 (0.62-0.75) and 0.697 (0.63-0.76), respectively].

CONCLUSION

Three simple clinical risk factors (age, sex, and BMI) and two biomarkers (elevated BNP and elevated FGF-23) identify patients with AF. Further research is warranted to elucidate FGF-23 dependent mechanisms of AF.

Autoimmune activation as a determinant of atrial fibrillation among Turks: A prospective evaluation

Although low-grade inflammation has been linked to the prediction of atrial fibrillation (AF), evidence from some reports suggest that autoimmune activation might potentially be a relevant mechanism. We assessed the predictive value of inflammation and other markers for the risk of incident AF.A score of age-controlled anthropometric, lipid, and nonlipid variables was compared in participants with recorded nonvalvular persistent/permanent AF (n = 110) to those of a nested cohort sample (n = 1126) of the Turkish Adult Risk Factor study. Available values preceding by 2 (±1) years the development of AF were used regarding incident AF (n = 87) in multivariable regression.Comparing age-controlled inflammation and other markers across the 2 groups, low apolipoprotein (apo) B and total cholesterol levels differed highly significantly in each sex. Moreover, low-density lipoprotein (LDL)-cholesterol and fasting insulin concentrations were significantly lower, sex hormone binding globulin (SHBG), glucose and systolic blood pressure higher in women alone, while C-reactive protein levels were similar. A model of multivariable logistic regression analyses for overall AF and 2 models for incident AF demonstrated a consistent inverse predictive value for apoB in each gender [relative risk (RR) 0.44 (95% confidence interval (CI), 95% CI 0.30-0.66], along with age, as main determinants. SHBG in females and waist circumference in males were further significantly associated with initial AF. Never smoking (compared with ever smoking) tended to predict AF.These findings, collectively, are highly consistent with an autoimmune process in which damaged epitope of apoB due to proinflammatory state emerge as a basic mechanism in the development of AF. ApoB level is likely only apparently reduced due to partial escape from assay.

Association of sST2 and hs-CRP levels with new-onset atrial fibrillation in coronary artery disease

BACKGROUND

The data on biomarkers as predictors of atrial fibrillation (AF) in patients with coronary artery disease (CAD) are limited.

METHODS

A total of 1946 patients with CAD were recruited to the ARTEMIS study. At baseline, the study patients underwent clinical and echocardiographic examinations and had laboratory tests. The patients (n=1710) with the information about the occurrence of new-onset AF during the follow-up were included in the present analysis.

RESULTS

During 5.7±1.5years of follow-up, 143 (8.4%) patients developed a new-onset AF. Higher values of soluble ST2 (sST2) (20.2±10.8 vs. 17.5±7.2ng/mL, p=0.005), high-sensitivity troponin T (hs-TnT) (11.9±10.2 vs. 10.3±8.3ng/L, p=0.005), high-sensitivity C-reactive protein (hs-CRP) (3.3±5.9 vs. 2.0±4.4mg/L, p<0.001) and brain natriuretic peptide (BNP) (85.6±77.5 vs. 64.9±73.5ng/L, p<0.001) had significant associations with the occurrence of new-onset AF. In the Cox clinical hazards model, higher age (p=0.004), greater weight (p=0.045), larger left atrial diameter (p=0.001), use of asthma/chronic obstructive pulmonary disease medication (p=0.001) and lack of cholesterol lowering medication (p=0.008) had a significant association with the increased risk of AF. When the biomarkers were tested in the Cox clinical hazards model, sST2 (HR=1.025, 95% CI=1.007-1.043, p=0.006) and hs-CRP (HR=1.027, 95% CI=1.008-1.047, p=0.006) retained their significant power in predicting AF.

CONCLUSION

A biomarker of fibrosis, sST2, and a biomarker of inflammation, hs-CRP, predict the risk of occurrence of new-onset AF in patients with CAD. These biomarkers contributed to the discrimination of the AF risk model, but did not improve it markedly.

Impact of B-Type Natriuretic Peptide Level on Risk Stratification of Thromboembolism and Death in Patients With Nonvalvular Atrial Fibrillation - The Hokuriku-Plus AF Registry

BACKGROUND

B-type natriuretic peptide (BNP) may be a predictor of stroke risk in patients with nonvalvular atrial fibrillation (NVAF); because heart failure is associated with the incidence of stroke in AF patients. However, limited data exist regarding the association between BNP at baseline and risks of thromboembolic events (TE) and death in NVAF patients. Methods and Results: We prospectively studied 1,013 NVAF patients (725 men, 72.8±9.7 years old) from the Hokuriku-plus AF Registry to determine the relationship between BNP at baseline and prognosis among Japanese NVAF patients. During the follow-up period (median, 751 days); 31 patients experienced TE and there were 81 cases of TE/all-cause death. For each endpoint we constructed receiver-operating characteristic curves that gave cutoff points of BNP for TE (170 pg/mL) and TE/all-cause death (147 pg/mL). Multivariate analysis with the Cox-proportional hazards model indicated that high BNP was significantly associated with risks of TE (hazard ratio [HR] 3.86; 95% confidence interval [CI] 1.83-8.67; P=0.0003) and TE/all-cause death (HR 2.27; 95% CI 1.45-3.56; P=0.0003). Based on the C-index and net reclassification improvement, the addition of BNP to CHA2DS2-VASc statistically improved the prediction of TE.

CONCLUSIONS

In a real-world cohort of Japanese NVAF patients, high BNP was significantly associated with TE and death. Plasma BNP might be a useful biomarker for these adverse clinical events.

Association of pre-ablation level of potential blood markers with atrial fibrillation recurrence after catheter ablation: a meta-analysis

Aims

The meta-analysis was aimed to search for candidate blood markers whose pre-ablation level was associated with atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA).

Methods and results

A systematic literature search of PubMed, EMBASE, Springer Link, Web of Science, Wiley-Cochrane library, and supplemented with Google scholar search engine was performed. Thirty-six studies covering 11 blood markers were qualified for this meta-analysis. Compared with the nonrecurrence group, the recurrence group had increased pre-ablation level of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), interleukin-6 (IL-6), C-reactive protein, low density lipoprotein (LDL), and tissue inhibitor of metal loproteinase-2 (TIMP-2) [standardized mean difference (95% confidence interval): 0.37 (0.13-0.61), 0.77 (0.40-1.14), 1.25 (0.64-1.87), 0.37 (0.21-0.52), 0.35 (0.10-0.60), 0.24 (0.07-0.42), 0.17 (0.00-0.34), respectively], while no statistical difference of pre-ablation level of white blood cell, total cholesterol, triglyceride, and transforming growth factor-β1 was found. Subgroup analysis demonstrated that ANP was associated with AF recurrence in participants who had no concomitant structural heart diseases (SHD); however, not in participants who had SHD, C-reactive protein was associated with AF recurrence in Asian studies, whereas not in European studies.

Conclusion

Increased pre-ablation level of ANP, BNP, NT-pro-BNP, IL-6, C-reactive protein, LDL, and TIMP-2 was associated with greater risk of AF recurrence after RFCA.

Potential Biological Markers of Atrial Fibrillation: A Chance to Prevent Cryptogenic Stroke

Stroke affects millions of people all over the world, causing death and disability. The most frequent type of this disease is ischemic stroke, which can be caused by different factors. In approximately 25 percent of cases, no obvious cause can be found. Recent observations have shown that paroxysmal atrial fibrillation could be responsible for a significant number of cryptogenic stroke events. Short- or long-lasting ECG monitoring could help with the diagnosis of transient arrhythmias. Unfortunately, these techniques either are expensive or require good patient compliance. An alternative option is the identification of biological markers that are specific for atrial fibrillation and can be used to predict arrhythmia. In this review, we give a summary of the recent advances in the research of arrhythmia markers. Based on their structure and function, we differentiated four groups of biomarkers: markers of inflammation, markers of fibrosis, markers with hormonal activity, and other markers. In spite of intensive researches, the optimal biological marker is still not available, but there are some promising markers, like NT-proBNP/BNP.

Amino terminal pro brain natriuretic peptide predicts all-cause mortality in patients with chronic obstructive pulmonary disease: Systematic review and meta-analysis

Natriuretic peptides (NPs) are a family of prognostic biomarkers in patients with heart failure (HF). HF is one of the most frequent comorbidities in patients with chronic obstructive pulmonary disease (COPD). However, the prognostic role of NP in COPD patients remains unclear. The aim of this meta-analysis was to evaluate the relation between NP and all-cause mortality in COPD patients. We performed a systematic review and meta-analysis of observational studies assessing prognostic implications of elevated NP levels on all-cause mortality in COPD patients. Nine studies were considered for qualitative analysis for a total of 2788 patients. Only two studies focused on Mid Regional-pro Atrial Natriuretic Peptide (MR-proANP) and brain natriuretic peptide (BNP), respectively, but seven studies focused on pro-BNP (NT-proBNP) and were included in the quantitative analysis. Elevated NT-proBNP values were related to increased risk of all-cause mortality in COPD patients both with and without exacerbation (hazard ratio (HR): 2.87, p < 0.0001 and HR: 3.34, p = 0.04, respectively). The results were confirmed also after meta-regression analysis for confounding factors (previous cardiovascular history, hypertension, HF, forced expiratory volume at 1 second and mean age). NT-proBNP may be considered a reliable predictive biomarker of poor prognosis in patients with COPD.

Optimal Duration of Monitoring for Atrial Fibrillation in Cryptogenic Stroke: A Nonsystematic Review

Atrial fibrillation (AF) is the most common form of cardiac arrhythmias and an independent risk factor for stroke. Despite major advances in monitoring strategies, clinicians tend to miss the diagnoses of AF and especially paroxysmal AF due mainly to its asymptomatic presentation and the rather limited duration dedicated for monitoring for AF after a stroke, which is 24 hours as per the current recommended guidelines. Hence, determining the optimal duration of monitoring for paroxysmal atrial fibrillation after acute ischemic stroke remains a matter of debate. Multiple trials were published in regard to this matter using both invasive and noninvasive monitoring strategies for different monitoring periods. The data provided by these trials showcase strong evidence suggesting a longer monitoring strategy beyond 24 hours is associated with higher detection rates of AF, with the higher percentage of patients detected consequently receiving proper secondary stroke prevention with anticoagulation and thus justifying the cost-effectiveness of such measures. Overall, we thus conclude that increasing the monitoring duration for AF after a cryptogenic stroke to at least 72 hours will indeed enhance the detection rates, but the cost-effectiveness of this monitoring strategy compared to longer monitoring durations is yet to be established.

Discovery of New Risk Markers for Ischemic Stroke Using a Novel Targeted Proteomics Chip

BACKGROUND AND PURPOSE

Emerging technologies have made it possible to simultaneously evaluate a large number of circulating proteins as potential new stroke risk markers.

METHODS

We explored associations between 85 cardiovascular proteins, assessed by a proteomics chip, and incident ischemic stroke in 2 independent cohorts of elderly (Prospective Investigation of the Vasculature in Uppsala Seniors [PIVUS]: n=977; 50% women, mean age=70.1 years, 71 fatal/nonfatal ischemic stroke events during 10.0 years; and Uppsala Longitudinal Study in Adult Men [ULSAM]: n=720, mean age=77.5 years, 75 ischemic stroke events during 9.5 years). The proteomics chip uses 2 antibodies for each protein and a polymerase chain reaction step to achieve a high-specific binding and the possibility to measure multiple proteins in parallel, but gives no absolute concentrations.

RESULTS

In PIVUS, 16 proteins were related to incident ischemic stroke using a false discovery rate of 5%. Of these, N-terminal pro-B-type natriuretic peptide (P=0.0032), adrenomedullin (P=0.018), and eosinophil cationic protein (P=0.0071) were replicated in ULSAM after adjustment for established stroke risk factors. In predefined secondary meta-analyses of individual data, interleukin-27 subunit α, growth/differentiation factor 15, urokinase plasminogen activator surface receptor, tumor necrosis factor receptor superfamily member 6, macrophage colony-stimulating factor 1, and matrix metalloproteinase-7 were also potential risk markers for ischemic stroke after adjustment for multiple comparisons (P<0.0006). The addition of N-terminal pro-B-type natriuretic peptide, adrenomedullin, and eosinophil cationic protein to a model with established risk factors increased the C-statistic from 0.629 to 0.689 (P=0.001).

CONCLUSIONS

Our data suggest that large-scale proteomics analysis is a promising way of discovering novel biomarkers that could substantially improve the prediction of ischemic stroke.