Plasma angiopoietin-2 and its association with heart failure in patients with atrial fibrillation.

AIMS: Several biomarkers are associated with clinical outcomes in patients with atrial fibrillation (AF), but a causal relationship has not been established. This study aimed to evaluate angiopoietin-2, a novel candidate biomarker of endothelial inflammation and vascular remodelling, in patients with AF. METHODS AND RESULTS: Angiopoietin-2 was measured in plasma obtained from patients with AF treated with aspirin monotherapy (exploration cohort, n = 2987) or with oral anticoagulation (validation cohort, n = 13 079). Regression models were built to assess the associations between angiopoietin-2, clinical characteristics, and outcomes. In both cohorts, plasma angiopoietin-2 was independently associated with AF on the baseline electrocardiogram and persistent/permanent AF, age, history of heart failure, female sex, tobacco use/smoking, body mass index, renal dysfunction, diabetes, and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Angiopoietin-2 was independently associated with subsequent hospitalization for heart failure after adjusting for age, creatinine, and clinical characteristics in the exploration cohort [c-index 0.79, 95% confidence interval (CI) 0.75-0.82; third vs. first quartile, hazard ratio (HR) 1.74, 95% CI 1.26-2.41] and in the validation cohort (c-index 0.76, 95% CI 0.74-0.78; HR 1.58, 95% CI 1.37-1.82). In both cohorts, the association persisted when also adjusting for NT-proBNP (P ≤ 0.001). In full multivariable models also adjusted for NT-proBNP, angiopoietin-2 did not show statistically significant associations with ischaemic stroke, cardiovascular and all-cause death, or major bleeding that were consistent across the two cohorts. CONCLUSIONS: In patients with AF, plasma levels of angiopoietin-2 were independently associated with subsequent hospitalization for heart failure and provided incremental prognostic value to clinical risk factors and NT-proBNP.

Biomarkers and heart failure events in patients with atrial fibrillation in the ARISTOTLE trial evaluated by a multi-state model.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF) often coexist. We investigated the prognostic impact of biomarkers on the development of HF and death in patients with AF and different left ventricular systolic function considering the influence of competing events. METHODS: The study included 11,818 patients with AF from the ARISTOTLE trial who at entry had information on history of HF, an estimate of left ventricular function and plasma samples for determination of biomarkers representing cardiorenal dysfunction (NT-proBNP, troponin T, cystatin C) and inflammation (GDF-15, IL-6, CRP). Patients were categorized into: (I) HF with reduced ejection fraction (HFrEF, n = 2,048), (II) HF with preserved ejection fraction (HFpEF, n = 2,520), and (III) No HF (n = 7,250). Biomarker associations with HF hospitalization and death were analyzed using a multi-state model accounting also for repeated events. RESULTS: Baseline levels of NT-proBNP, troponin T, cystatin C, GDF-15, IL-6, and CRP were highest in HFrEF and lowest in No HF. During median 1.9 years follow-up, 546 patients were hospitalized at least once for HF and 819 died. Higher levels of all investigated biomarkers were associated with both outcomes (all P< .0001), with highest event rates in HFrEF and lowest in No HF. The associations remained after adjustments and were more pronounced for first than for recurrent events. CONCLUSIONS: In anticoagulated patients with AF, biomarkers indicating cardiorenal dysfunction and inflammation improve the identification of patients at risk of developing HF or worsening of already existing HF. These biomarkers might be useful for targeting novel HF therapies in patients with AF.

Using multimarker screening to identify biomarkers associated with cardiovascular death in patients with atrial fibrillation.

AIMS: Atrial fibrillation (AF) is associated with higher mortality. Biomarkers may improve the understanding of key pathophysiologic processes in AF that lead to death. Using a new multiplex analytic technique, we explored the association between 268 biomarkers and cardiovascular (CV) death in anticoagulated patients with AF. METHODS AND RESULTS: A case-cohort design with 1.8- to 1.9-year follow-up. The identification cohort included 517 cases and 4057 randomly selected patients from ARISTOTLE. The validation cohort included 277 cases and 1042 randomly selected controls from RE-LY. Plasma collected at randomization was analysed with conventional immunoassays and the OLINK proximity extension assay panels: CVDII, CVDIII, and Inflammation. Association between biomarkers and CV death was evaluated using Random Survival Forest, Boruta, and adjusted Cox-regression analyses. The biomarkers most strongly and consistently associated with CV death were as follows (hazard ratio for inter-quartile comparison [95% CI]): N-terminal pro-B-type natriuretic peptide [NT-proBNP; 1.63 (1.37-1.93)], cardiac troponin T [cTnT-hs; 1.60 (1.35-1.88)], interleukin-6 [IL-6; 1.29 (1.13-1.47)], growth differentiation factor-15 [GDF-15; 1.30 (1.10-1.53)], fibroblast growth factor 23 [FGF-23; 1.21 (1.10-1.33)], urokinase receptor [uPAR; 1.38 (1.16-1.64)], trefoil factor 3 [TFF3; 1.27 (1.10-1.46)], tumour necrosis factor receptor 1 [TNFR1; 1.21 (1.01-1.45)], TNF-related apoptosis-inducing ligand receptor 2 [TRAILR2; 1.18 (1.04-1.34)], and cathepsin L1 [CTSL1; 1.22 (1.07-1.39)]. CONCLUSION: In this comprehensive screening of 268 biomarkers in anticoagulated patients with AF, the underlying mechanisms most strongly associated with CV death were cardiorenal dysfunction (NT-proBNP, cTnT-hs, CTSL1, TFF3), oxidative stress (GDF-15), inflammation (IL-6, GDF-15), calcium balance, vascular and renal dysfunction (FGF-23), fibrinolysis (suPAR), and apoptosis (TNFR1, TRAILR2). These findings provide novel insights into pathophysiologic aspects associated with CV death in AF. CLINICALTRIALS.GOV IDENTIFIER: NCT00412984 and NCT00262600.

Screening of Multiple Biomarkers Associated With Ischemic Stroke in Atrial Fibrillation.

Background To explore the pathophysiological features of ischemic stroke in patients with atrial fibrillation (AF), we evaluated the association between 268 plasma proteins and subsequent ischemic stroke in 2 large AF cohorts receiving oral anticoagulation. Methods and Results A case-cohort sample of patients with AF from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial, including 282 cases with ischemic stroke or systemic embolism and a random sample of 4124 without these events, during 1.9 years of follow-up was used for identification. Validation was provided by a similar case-cohort sample of patients with AF from the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, including 149 cases with ischemic stroke/systemic embolism and a random sample of 1062 without these events. In plasma obtained before randomization, 268 unique biomarkers were measured with OLINK proximity extension assay panels (CVD II, CVD III, and Inflammation) and conventional immunoassays. The association between biomarkers and outcomes was evaluated by random survival forest and adjusted Cox regression. According to random survival forest or Cox regression analyses, the biomarkers most strongly and consistently associated with ischemic stroke/systemic embolism were matrix metalloproteinase-9, NT-proBNP (N-terminal pro-B-type natriuretic peptide), osteopontin, sortilin, soluble suppression of tumorigenesis 2, and trefoil factor-3. The corresponding hazard ratios (95% CIs) for an interquartile difference were as follows: 1.18 (1.00-1.38), 1.55 (1.28-1.88), 1.28 (1.07-1.53), 1.19 (1.02-1.39), 1.23 (1.05-1.45), and 1.19 (0.97-1.45), respectively. Conclusions In patients with AF, of 268 unique biomarkers, the 6 biomarkers most strongly associated with subsequent ischemic stroke/systemic embolism represent fibrosis/remodeling (matrix metalloproteinase-9 and soluble suppression of tumorigenesis 2), cardiac dysfunction (NT-proBNP), vascular calcification (osteopontin), metabolism (sortilin), and mucosal integrity/ischemia (trefoil factor-3). Registration URL: https://www.clinicaltrials.gov. Unique Identifiers: NCT00412984 and NCT00262600.

Angiotensin-converting enzyme 2 (ACE2) levels in relation to risk factors for COVID-19 in two large cohorts of patients with atrial fibrillation.

AIMS: The global COVID-19 pandemic is caused by the SARS-CoV-2 virus entering human cells using angiotensin-converting enzyme 2 (ACE2) as a cell surface receptor. ACE2 is shed to the circulation, and a higher plasma level of soluble ACE2 (sACE2) might reflect a higher cellular expression of ACE2. The present study explored the associations between sACE2 and clinical factors, cardiovascular biomarkers, and genetic variability. METHODS AND RESULTS: Plasma and DNA samples were obtained from two international cohorts of elderly patients with atrial fibrillation (n = 3999 and n = 1088). The sACE2 protein level was measured by the Olink Proteomics® Multiplex CVD II96 × 96 panel. Levels of the biomarkers high-sensitive cardiac troponin T (hs-cTnT), N-terminal probrain natriuretic peptide (NT-proBNP), growth differentiation factor 15 (GDF-15), C-reactive protein, interleukin-6, D-dimer, and cystatin-C were determined by immunoassays. Genome-wide association studies were performed by Illumina chips. Higher levels of sACE2 were statistically significantly associated with male sex, cardiovascular disease, diabetes, and older age. The sACE2 level was most strongly associated with the levels of GDF-15, NT-proBNP, and hs-cTnT. When adjusting for these biomarkers, only male sex remained associated with sACE2. We found no statistically significant genetic regulation of the sACE2 level. CONCLUSIONS: Male sex and clinical or biomarker indicators of biological ageing, cardiovascular disease, and diabetes are associated with higher sACE2 levels. The levels of GDF-15 and NT-proBNP, which are associated both with the sACE2 level and a higher risk for mortality and cardiovascular disease, might contribute to better identification of risk for severe COVID-19 infection.

Association of Different Estimates of Renal Function With Cardiovascular Mortality and Bleeding in Atrial Fibrillation.

Background We compared different methods of estimated glomerular filtration rate (eGFR) and their association with cardiovascular death and major bleeding in 14 980 patients with atrial fibrillation in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. Methods and Results eGFR was calculated using equations based on creatinine (Cockcroft-Gault, Modification of Diet in Renal Disease, and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) and/or cystatin C (CKD-EPICysC and CKD-EPICysC+Creatinine). These 5 eGFR equations, as well as the individual variables that are used in these equations, were assessed for correlation and discriminatory ability for cardiovascular death and major bleeding. The median age was 70.0 years, and 35.6% were women. The median eGFR was highest with Cockcroft-Gault (74.1 mL/min) and CKD-EPICysC (74.2 mL/min), and lowest with Modification of Diet in Renal Disease (66.5 mL/min). Correlation between methods ranged from 0.49 (Cockroft-Gault and CKD-EPICysC) to 0.99 (Modification of Diet in Renal Disease and CKD-EPI). Among the eGFR equations, those based on cystatin C yielded the highest C indices for cardiovascular death and major bleeding: 0.628 (CKD-EPICysC) and 0.612 (CKD-EPICysC+Creatinine), respectively. A model based on the variables within the different eGFR equations (age, sex, weight, creatinine, and cystatin C) yielded the highest discriminatory value for both outcomes, with a C index of 0.673 and 0.656, respectively. Conclusions In patients with atrial fibrillation on anticoagulation, correlation between eGFR calculated using different methods varied substantially. Cystatin C-based eGFRs seem to provide the most robust information for predicting death and bleeding. A model based on the individual variables within the eGFR equations, however, provided the highest discriminatory value. Our findings may help refine risk stratification in patients with atrial fibrillation and define how renal function should be determined in future atrial fibrillation studies. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT00412984.

Serial measurement of interleukin-6 and risk of mortality in anticoagulated patients with atrial fibrillation: Insights from ARISTOTLE and RE-LY trials.

BACKGROUND: The inflammatory biomarker interleukin-6 (IL-6) is associated with mortality in atrial fibrillation (AF). OBJECTIVE: To investigate if repeated IL-6 measurements improve the prognostication for stroke or systemic embolism, major bleeding, and mortality in anticoagulated patients with AF. METHODS: IL-6 levels by ELISA were measured at study entry and at 2 months in 4830 patients in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial with 1.8 years median follow-up. In the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial, IL-6 was measured at study entry, 3, 6, and 12 months in 2559 patients with 2.0 years median follow-up. Associations between a second IL-6 measurement and outcomes, adjusted for baseline IL-6, clinical variables, and other cardiovascular biomarkers, were analyzed by Cox regression. RESULTS: Median IL-6 levels were 2.0 ng/L (interquartile range [IQR] 1.30-3.20) and 2.10 ng/L (IQR 1.40-3.40) at the two time-points in ARISTOTLE, and, in RE-LY, 2.5 ng/L (IQR 1.6-4.3), 2.5 ng/L (IQR 1.6-4.2), 2.4 ng/L (IQR 1.6, 3.9), and 2.4 ng/L (IQR 1.5, 3.9), respectively. IL-6 was associated with mortality; hazard ratios per 50% higher IL-6 at 2 or 3 months, respectively, were 1.32 (95% confidence interval, 1.23-1.41; P < .0001) in ARISTOTLE, and 1.11 (1.01-1.22, P = .0290) in RE-LY; with improved C index from 0.74 to 0.76 in ARISTOTLE, but not in the smaller RE-LY cohort. There were no consistent associations with second IL-6 and stroke or systemic embolism, or major bleeding. CONCLUSIONS: Persistent systemic inflammatory activity, assessed by repeated IL-6 measurements, is associated with mortality independent of established clinical risk factors and other strong cardiovascular biomarkers in anticoagulated patients with AF.

Stepwise mass screening for atrial fibrillation using N-terminal B-type natriuretic peptide: the STROKESTOP II study.

AIMS: To study the prevalence of unknown atrial fibrillation (AF) in a high-risk, 75/76-year-old, population using N-terminal B-type natriuretic peptide (NT-proBNP) and handheld electrocardiogram (ECG) recordings in a stepwise screening procedure. METHODS AND RESULTS: The STROKESTOP II study is a population-based cohort study in which all 75/76-year-old in the Stockholm region (n = 28 712) were randomized 1:1 to be invited to an AF screening programme or to serve as the control group. Participants without known AF had NT-proBNP analysed and were stratified into low-risk (NT-proBNP <125 ng/L) and high-risk (NT-proBNP ≥125 ng/L) groups. The high-risk group was offered extended ECG-screening, whereas the low-risk group performed only one single-lead ECG recording. In total, 6868 individuals accepted the screening invitation of which 6315 (91.9%) did not have previously known AF. New AF was detected in 2.6% [95% confidence interval (CI) 2.2-3.0] of all participants without previous AF. In the high-risk group (n = 3766/6315, 59.6%), AF was diagnosed in 4.4% (95% CI 3.7-5.1) of the participants. Out of these, 18% had AF on their index-ECG. In the low-risk group, one participant was diagnosed with AF on index-ECG. The screening procedure resulted in an increase in known prevalence from 8.1% to 10.5% among participants. Oral anticoagulant treatment was initiated in 94.5% of the participants with newly diagnosed AF. CONCLUSION: N-terminal B-type natriuretic peptide-stratified systematic screening for AF identified 4.4% of the high-risk participants with new AF. Oral anticoagulant treatment initiation was well accepted in the group diagnosed with new AF.

Antithrombotic Therapy after Acute Coronary Syndrome or PCI in Atrial Fibrillation.

BACKGROUND: Appropriate antithrombotic regimens for patients with atrial fibrillation who have an acute coronary syndrome or have undergone percutaneous coronary intervention (PCI) are unclear. METHODS: In an international trial with a two-by-two factorial design, we randomly assigned patients with atrial fibrillation who had an acute coronary syndrome or had undergone PCI and were planning to take a P2Y12 inhibitor to receive apixaban or a vitamin K antagonist and to receive aspirin or matching placebo for 6 months. The primary outcome was major or clinically relevant nonmajor bleeding. Secondary outcomes included death or hospitalization and a composite of ischemic events. RESULTS: Enrollment included 4614 patients from 33 countries. There were no significant interactions between the two randomization factors on the primary or secondary outcomes. Major or clinically relevant nonmajor bleeding was noted in 10.5% of the patients receiving apixaban, as compared with 14.7% of those receiving a vitamin K antagonist (hazard ratio, 0.69; 95% confidence interval [CI], 0.58 to 0.81; P<0.001 for both noninferiority and superiority), and in 16.1% of the patients receiving aspirin, as compared with 9.0% of those receiving placebo (hazard ratio, 1.89; 95% CI, 1.59 to 2.24; P<0.001). Patients in the apixaban group had a lower incidence of death or hospitalization than those in the vitamin K antagonist group (23.5% vs. 27.4%; hazard ratio, 0.83; 95% CI, 0.74 to 0.93; P = 0.002) and a similar incidence of ischemic events. Patients in the aspirin group had an incidence of death or hospitalization and of ischemic events that was similar to that in the placebo group. CONCLUSIONS: In patients with atrial fibrillation and a recent acute coronary syndrome or PCI treated with a P2Y12 inhibitor, an antithrombotic regimen that included apixaban, without aspirin, resulted in less bleeding and fewer hospitalizations without significant differences in the incidence of ischemic events than regimens that included a vitamin K antagonist, aspirin, or both. (Funded by Bristol-Myers Squibb and Pfizer; AUGUSTUS ClinicalTrials.gov number, NCT02415400.).

Outcomes of apixaban versus warfarin in patients with atrial fibrillation and multi-morbidity: Insights from the ARISTOTLE trial.

BACKGROUND: Patients with atrial fibrillation (AF) often have multi-morbidity, defined as ≥3 comorbid conditions. Multi-morbidity is associated with polypharmacy, adverse events, and frailty potentially altering response to anticoagulation. We sought to describe the prevalence of multi-morbidity among older patients with AF and determine the association between multi-morbidity, clinical outcomes, and the efficacy and safety of apixaban compared with warfarin. METHODS: In this post-hoc subgroup analysis of the ARISTOTLE trial, we studied enrolled patients age ≥ 55 years (n = 16,800). Patients were categorized by the number of comorbid conditions at baseline: no multi-morbidity (0-2 comorbid conditions), moderate multi-morbidity (3-5 comorbid conditions), and high multi-morbidity (≥6 comorbid conditions). Association between multi-morbidity and clinical outcomes were analyzed by treatment with a median follow-up of 1.8 (1.3-2.3) years. RESULTS: Multi-morbidity was present in 64% (n = 10,713) of patients; 51% (n = 8491) had moderate multi-morbidity, 13% (n = 2222) had high multi-morbidity, and 36% (n = 6087) had no multi-morbidity. Compared with the no multi-morbidity group, the high multi-morbidity group was older (74 vs 69 years), took twice as many medications (10 vs 5), and had higher CHA2DS2-VASc scores (4.9 vs 2.7) (all P < .001). Adjusted rates per 100 patient-years for stroke/systemic embolism, death, and major bleeding increased with multi-morbidity (Reference no multi-morbidity; moderate multi-morbidity 1.42 [1.24-1.64] and high multi-morbidity 1.92 [1.59-2.31]), with no interaction in relation to efficacy or safety of apixaban. CONCLUSIONS: Multi-morbidity is prevalent among the population with AF; efficacy and safety of apixaban is preserved in this subgroup supporting extension of trial results to the most complex AF patients.

Use of Biomarkers to Predict Specific Causes of Death in Patients With Atrial Fibrillation.

BACKGROUND: Atrial fibrillation is associated with an increased risk of death. High-sensitivity troponin T, growth differentiation factor-15, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and interleukin-6 levels are predictive of cardiovascular events and total cardiovascular death in anticoagulated patients with atrial fibrillation. The prognostic utility of these biomarkers for cause-specific death is unknown. METHODS: The ARISTOTLE trial (Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) randomized 18 201 patients with atrial fibrillation to apixaban or warfarin. Biomarkers were measured at randomization in 14 798 patients (1.9 years median follow-up). Cox models were used to identify clinical variables and biomarkers independently associated with each specific cause of death. RESULTS: In total, 1272 patients died: 652 (51%) cardiovascular, 32 (3%) bleeding, and 588 (46%) noncardiovascular/nonbleeding deaths. Among cardiovascular deaths, 255 (39%) were sudden cardiac deaths, 168 (26%) heart failure deaths, and 106 (16%) stroke/systemic embolism deaths. Biomarkers were the strongest predictors of cause-specific death: a doubling of troponin T was most strongly associated with sudden death (hazard ratio [HR], 1.48; P<0.001), NT-proBNP with heart failure death (HR, 1.62; P<0.001), and growth differentiation factor-15 with bleeding death (HR, 1.72; P=0.028). Prior stroke/systemic embolism (HR, 2.58; P>0.001) followed by troponin T (HR, 1.45; P<0.0029) were the most predictive for stroke/ systemic embolism death. Adding all biomarkers to clinical variables improved discrimination for each cause-specific death. CONCLUSIONS: Biomarkers were some of the strongest predictors of cause-specific death and may improve the ability to discriminate among patients' risks for different causes of death. These data suggest a potential role of biomarkers for the identification of patients at risk for different causes of death in patients anticoagulated for atrial fibrillation. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00412984.

N-terminal pro B-type natriuretic peptide in systematic screening for atrial fibrillation.

OBJECTIVE: Screening for atrial fibrillation (AF) in individuals aged 65 and above is recommended by the European Society of Cardiology. Increased levels of the biomarker N-terminal pro B-type natriuretic peptide (NT-proBNP) has in cohort studies been associated with incident AF.The aim of this study was to assess whether NT-proBNP could be useful for AF detection in systematic screening. METHODS: The Strokestop study entailed 7173 Swedish residents aged 75/76 that were screened for AF using twice daily intermittent ECG recordings during 2 weeks. In a substudy of 886 participants, the last 815 consecutive participants and 71 individuals with newly detected AF, levels of NT-proBNP were determined. RESULTS: Participants with newly detected AF (n=96) had a median NT-proBNP of 330 ng/L (IQR 121;634). In individuals without AF (n=742), median NT-proBNP was 171 ng/L (IQR 95;283), p<0.001. The CHA2DS2-VASc parameters did not differ significantly between individuals with newly detected AF and without AF nor between newly detected AF in the NT-proBNP cohort compared with the cohort where NT-proBNP was not assessed. Using an NT-proBNP cut-off of ≥125 ng/L in a non-acute setting yielded a negative predictive value of 92%, meaning that 35% fewer participants would need to be screened when applied to systematic AF screening. Adding weight to NT-proBNP further reduced participants needed to be screened with a preserved sensitivity. CONCLUSIONS: NT-proBNP was increased in individuals with newly detected AF. Prospective studies could clarify if NT-proBNP can be used to correctly select individuals that benefit most from AF screening. CLINICAL TRIALS: ClinicalTrials.gov. Identifier: NCT01593553.

Application of Biomarkers for Risk Stratification in Patients with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation is the most common sustained arrhythmia and an important contributor to cardiovascular morbidity and mortality. Several strategies have been proposed for prediction of outcomes and individualization of treatments to better balance the benefits of stroke prevention and risks of bleeding during anticoagulation. CONTENT: The availability of analytically more specific and sensitive methods to measure circulating biomarkers of cellular and organ stress and dysfunction has led to testing of their utility in several cardiovascular conditions. In patients with atrial fibrillation, biomarkers of myocardial injury (troponin) and cardiovascular stress and dysfunction (natriuretic peptides, growth differentiation factor 15), myocardial fibrosis (galectin-3), renal dysfunction (creatinine, cystatin C), inflammation (C-reactive protein, cytokines) and coagulation activity (d-dimer) have been found associated with underlying pathophysiology, clinical outcomes and effects of treatment. Measurements of these markers might therefore expand the understanding of the pathophysiology, improve risk assessment and optimize treatment in individual patients with atrial fibrillation. SUMMARY: Biomarkers for risk stratification have potential roles as tools for evaluation of patients with atrial fibrillation and for selection of the best treatment strategies to prevent stroke, major bleeding, and mortality.

NT-proBNP is a powerful predictor for incident atrial fibrillation - Validation of a multimarker approach.

BACKGROUND: Biomarkers may be of value to identify individuals at risk of developing atrial fibrillation (AF). Using a multimarker approach, this study investigated if the biomarkers; NT-proBNP, high-sensitivity cardiac troponin (hs-cTn), growth differentiation factor-15 (GDF-15), cystatin C and high-sensitivity C-reactive protein (CRP) are independent predictors for incident AF. METHODS: Blood samples were collected from 883 individuals in the Uppsala Longitudinal Study of Adult Men (ULSAM) and 978 individuals in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Participants were followed for 10-13years with n=113 incident AF cases in ULSAM and n=148 in PIVUS. The associations between biomarkers and incident AF were analysed in Cox proportional hazards regression models. RESULTS: The hazard ratio (HR) for incident AF was significant for all five biomarkers in unadjusted analyses in both cohorts. Only NT-proBNP remained significant when adjusting for cardiovascular risk factors and the other biomarkers (HR (1SD) 2.05 (1.62-2.59) (ULSAM) and 1.56 (1.30-1.86) (PIVUS), both p<0.001). The C-index improved from 0.64 to 0.69 in ULSAM and from 0.62 to 0.68 in PIVUS, by adding NT-proBNP to cardiovascular risk factors (both p<0.001). The C-index of the CHARGE-AF risk score increased from 0.62 to 0.68 (ULSAM) and 0.60 to 0.66 (PIVUS) by addition of NT-proBNP (p<0.001). CONCLUSIONS: Using a multimarker approach NT-proBNP was the strongest predictor of incident AF in two cohorts, and improved risk prediction when added to traditional risk factors. NT-proBNP significantly improved the predictive ability of the novel CHARGE-AF risk score, although the predictive value remained modest.

The novel biomarker-based ABC (age, biomarkers, clinical history)-bleeding risk score for patients with atrial fibrillation: a derivation and validation study.

BACKGROUND: The benefit of oral anticoagulation in atrial fibrillation is based on a balance between reduction in ischaemic stroke and increase in major bleeding. We aimed to develop and validate a new biomarker-based risk score to improve the prognostication of major bleeding in patients with atrial fibrillation. METHODS: We developed and internally validated a new biomarker-based risk score for major bleeding in 14,537 patients with atrial fibrillation randomised to apixaban versus warfarin in the ARISTOTLE trial and externally validated it in 8468 patients with atrial fibrillation randomised to dabigatran versus warfarin in the RE-LY trial. Plasma samples for determination of candidate biomarker concentrations were obtained at randomisation. Major bleeding events were centrally adjudicated. The predictive values of biomarkers and clinical variables were assessed with Cox regression models. The most important variables were included in the score with weights proportional to the model coefficients. The ARISTOTLE and RE-LY trials are registered with ClinicalTrials.gov, numbers NCT00412984 and NCT00262600, respectively. FINDINGS: The most important predictors for major bleeding were the concentrations of the biomarkers growth differentiation factor-15 (GDF-15), high-sensitivity cardiac troponin T (cTnT-hs) and haemoglobin, age, and previous bleeding. The ABC-bleeding score (age, biomarkers [GDF-15, cTnT-hs, and haemoglobin], and clinical history [previous bleeding]) score yielded a higher c-index than the conventional HAS-BLED and the newer ORBIT scores for major bleeding in both the derivation cohort (0·68 [95% CI 0·66-0·70] vs 0·61 [0·59-0·63] vs 0·65 [0·62-0·67], respectively; ABC-bleeding vs HAS-BLED p<0·0001 and ABC-bleeding vs ORBIT p=0·0008). ABC-bleeding score also yielded a higher c-index score in the the external validation cohort (0·71 [95% CI 0·68-0·73] vs 0·62 [0·59-0·64] for HAS-BLED vs 0·68 [0·65-0·70] for ORBIT; ABC-bleeding vs HAS-BLED p<0·0001 and ABC-bleeding vs ORBIT p=0·0016). A modified ABC-bleeding score using alternative biomarkers (haematocrit, cTnI-hs, cystatin C, or creatinine clearance) also outperformed the HAS-BLED and ORBIT scores. INTERPRETATION: The ABC-bleeding score, using age, history of bleeding, and three biomarkers (haemoglobin, cTn-hs, and GDF-15 or cystatin C/CKD-EPI) was internally and externally validated and calibrated in large cohorts of patients with atrial fibrillation receiving anticoagulation therapy. The ABC-bleeding score performed better than HAS-BLED and ORBIT scores and should be useful as decision support on anticoagulation treatment in patients with atrial fibrillation. FUNDING: BMS, Pfizer, Boehringer Ingelheim, Roche Diagnostics.

Biomarkers of inflammation and risk of cardiovascular events in anticoagulated patients with atrial fibrillation.

OBJECTIVE: Atrial fibrillation (AF) is a risk factor for stroke and mortality and the prothrombotic state has been linked to inflammation. In this study we evaluated the relationship between inflammatory biomarkers at baseline and future risk of cardiovascular events in the Apixaban for Reduction In Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial. METHODS: The ARISTOTLE trial randomised 18,201 patients with AF to apixaban or warfarin. Interleukin 6 (IL-6) and C reactive protein (CRP) were analysed in plasma obtained at randomisation from 14,954 participants, and median follow-up was 1.9 years. Association between quartile groups of IL-6 and CRP and outcomes were analysed by Cox regression adjusted for clinical risk factors and other cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). RESULTS: The IL-6 median level was 2.3 ng/L (IQR 1.5-3.9), median CRP level was 2.2 mg/L (1.0-4.8). IL-6 and CRP were significantly associated with all-cause mortality independent of clinical risk factors and other biomarkers (HR (95% CI) 1.93 (1.57 to 2.37) and 1.49 (1.24 to 1.79), respectively, Q4 vs Q1). IL-6 was associated with myocardial infarction, cardiovascular mortality, and major bleeding beyond clinical risk factors but not in the presence of cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). Neither inflammatory biomarker was associated with stroke/systemic embolism. Risk prediction for stroke, death and major bleeding was not improved by IL-6 or CRP when added to clinical risk factors and the other cardiovascular biomarkers (NT-proBNP, troponin, GDF-15, cystatin C). CONCLUSIONS: In patients with AF on anticoagulation, after accounting for clinical risk factors and other biomarkers, biomarkers of inflammation were significantly associated with an increased risk of mortality. However, there were no associations with the risk of stroke or major bleeding. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT00412984 post-results.

Interleukin-6 and C-reactive protein and risk for death and cardiovascular events in patients with atrial fibrillation.

BACKGROUND: Inflammation has been associated with cardiovascular disease and the burden of atrial fibrillation (AF). In this study we evaluate inflammatory biomarkers and future cardiovascular events in AF patients in the RE-LY study. METHODS: Interleukin-6 (IL-6), C-reactive protein (CRP) (n = 6,187), and fibrinogen (n = 4,893) were analyzed at randomization; outcomes were evaluated by Cox models and C-statistics. RESULTS: Adjusted for clinical risk factors IL-6 was independently associated with stroke or systemic embolism (P = .0041), major bleedings (P = .0001), vascular death (P < .0001), and a composite thromboembolic outcome (ischemic stroke, systemic embolism, myocardial infarction, pulmonary embolism and vascular death) (P < .0001). CRP was independently related to myocardial infarction (P = .0047), vascular death (P = .0004), and the composite thromboembolic outcome (P = .0001). When further adjusted for cardiac (troponin and N-terminal fragment B-type natriuretic peptide [NT-proBNP]) and renal (cystatin-C) biomarkers on top of clinical risk factors IL-6 remained significantly related to vascular death (P < .0001), major bleeding (P < .0170) and the composite thromboembolic outcome (P < .0001), and CRP to myocardial infarction (.0104). Fibrinogen was not associated with any outcome. C-index for stroke or systemic embolism increased from 0.615 to 0.642 (P = .0017) when adding IL-6 to the clinically used CHA2DS2-VASc risk score with net reclassification improvement of 28%. CONCLUSION: In patients with AF, IL-6 is related to higher risk of stroke and major bleeding, and both markers are related to higher risk of vascular death and the composite of thromboembolic events independent of clinical risk factors. Adjustment for cardiovascular biomarkers attenuated the prognostic value, although IL-6 remained related to mortality, the composite of thromboembolic events, and major bleeding, and CRP to myocardial infarction.

Efficacy and safety of dabigatran compared with warfarin in relation to baseline renal function in patients with atrial fibrillation: a RE-LY (Randomized Evaluation of Long-term Anticoagulation Therapy) trial analysis.

BACKGROUND: Renal impairment increases the risk of stroke and bleeding in patients with atrial fibrillation. In the Randomized Evaluation of Long-Term Anticoagulant Therapy (RELY) trial, dabigatran, with ≈80% renal elimination, displayed superiority over warfarin for prevention of stroke and systemic embolism in the 150-mg dose and significantly less major bleeding in the 110-mg dose in 18 113 patients with nonvalvular atrial fibrillation. This prespecified study investigated these outcomes in relation to renal function. METHODS AND RESULTS: Glomerular filtration rate was estimated with the Cockcroft-Gault, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Modification of Diet in Renal Disease (MDRD) equations in all randomized patients with available creatinine at baseline (n=17 951), and cystatin C-based glomerular filtration rate was estimated in a subpopulation with measurements available (n=6190). A glomerular filtration rate ≥80, 50 to <80, and <50 mL/min was estimated in 32.6%, 47.6%, and 19.8% and in 21.6%, 59.6%, and 18.8% of patients based on Cockcroft-Gault and CKD-EPI, respectively. Rates of stroke or systemic embolism, major bleeding, and all-cause mortality increased as renal function decreased. The rates of stroke or systemic embolism were lower with dabigatran 150 mg and similar with 110 mg twice daily compared with warfarin, without significant heterogeneity in subgroups defined by renal function (interaction P>0.1 for all). For the outcome of major bleeding, there were significant interactions between treatment and renal function according to CKD-EPI and MDRD equations, respectively (P<0.05). The relative reduction in major bleeding with either dabigatran dose compared with warfarin was greater in patients with glomerular filtration rate ≥80 mL/min. CONCLUSIONS: The efficacy of both dosages of dabigatran was consistent with the overall trial irrespective of renal function. However, with the CKD-EPI and MDRD equations, both dabigatran dosages displayed significantly lower rates of major bleeding in patients with glomerular filtration rate ≥80 mL/min. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00262600.

Biomarkers in atrial fibrillation: a clinical review.

Assessment of atrial fibrillation (AF)-associated stroke risk is at present mainly based on clinical risk scores such as CHADS2 and CHA2DS2-VASc, although these scores provide only modest discrimination of risk for individual patients. Biomarkers derived from the blood may help refine risk assessment in AF for stroke outcomes and for mortality. Recent studies of biomarkers in AF have shown that they can substantially improve risk stratification. Cardiac biomarkers, such as troponin and natriuretic peptides, significantly improve risk stratification in addition to current clinical risk stratification models. Similar findings have recently been described for markers of renal function, coagulation, and inflammation in AF populations based on large randomized prospective clinical trials or large community-based cohorts. These new findings may enable development of novel tools to improve clinical risk assessment in AF. Biomarkers in AF may also improve the understanding of the pathophysiology of AF further as well as potentially elucidate novel treatment targets. This review will highlight novel associations of biomarkers and outcomes in AF as well as recent progress in the use of biomarkers for risk stratification.

Efficacy of apixaban when compared with warfarin in relation to renal function in patients with atrial fibrillation: insights from the ARISTOTLE trial.

AIMS: Atrial fibrillation (AF) is common among patients with impaired renal function. Apixaban, a novel oral anticoagulant with partial renal excretion, was compared with warfarin and reduced the rate stroke, death and bleeding in the ARISTOTLE trial. We evaluated these outcomes in relation to renal function. METHODS AND RESULTS: Baseline glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations as well as cystatin C measurements. According to baseline Cockcroft-Gault, there were 7518 patients (42%) with an estimated GFR (eGFR) of >80 mL/min, 7587 (42%) between >50 and 80 mL/min, and 3017 (15%) with an eGFR of ≤50 mL/min. The rate of cardiovascular events and bleeding was higher at impaired renal function (≤80 mL/min). Apixaban was more effective than warfarin in preventing stroke or systemic embolism and reducing mortality irrespective of renal function. These results were consistent, regardless of methods for GFR estimation. Apixaban was associated with less major bleeding events across all ranges of eGFRs. The relative risk reduction in major bleeding was greater in patients with an eGFR of ≤50 mL/min using Cockcroft-Gault {hazard ratio (HR) 0.50 [95% confidence interval (CI) 0.38-0.66], interaction P = 0.005} or CKD-EPI equations [HR 0.48 (95% CI 0.37-0.64), interaction P = 0.003]. CONCLUSION: In patients with AF, renal impairment was associated with increased risk of cardiovascular events and bleeding. When compared with warfarin, apixaban treatment reduced the rate of stroke, death, and major bleeding, regardless of renal function. Patients with impaired renal function seemed to have the greatest reduction in major bleeding with apixaban.