Hemostatic markers are associated with the risk and prognosis of atrial fibrillation: the ARIC study

Development and validation a nomogram for predicting new-onset postoperative atrial fibrillation following pulmonary resection

BACKGROUND

The new-onset postoperative atrial fibrillation (NOPAF) following pulmonary resection is a common clinical concern. The aim of this study was to construct a nomogram to intuitively predict the risk of NOPAF and offered protective treatments.

METHODS

Patients who underwent pulmonary resection between January 2018 and December 2020 were consecutively enrolled. Forward stepwise multivariable logistic regression analyses were used to screen independent predictors, and a derived nomogram model was built. The model performance was evaluated in terms of calibration, discrimination and clinical utility and validated with bootstrap resampling.

RESULTS

A total of 3583 patients who met the research criteria were recruited for this study. The incidence of NOPAF was 1.507% (54/3583). A nomogram, composed of five independent predictors, namely age, admission heart rate, extent of resection, laterality, percent maximum ventilation volume per minute (%MVV), was constructed. The concordance index (C-index) was 0.811. The nomogram showed substantial discriminative ability, with an area under the receiver operating characteristic curve of 0.811 (95% CI 0.758-0.864). Moreover, the model shows prominent calibration performance and higher net clinical benefits.

CONCLUSION

We developed a novel nomogram that can predict the risk of NOPAF following pulmonary resection, which may assist clinicians predict the individual probability of NOPAF and perform available prophylaxis. By using bootstrap resampling for validation, the optimal discrimination and calibration were demonstrated, indicating that the nomogram may have clinical practicality.

Platelet-to-Lymphocyte Ratio as an Independent Factor Associated With Atrial Tachyarrhythmia

Objective To investigate the relationship between the presence of atrial tachyarrhythmia (AT) and the platelet-to-lymphocyte ratio (PLR), which is a recently described inflammatory marker. Methods A total of 149 patients with AT and 187 healthy volunteers were included in this study. Complete blood count, serum lipids, and serum creatinine were tested, and dynamic electrocardiograms were performed routinely in all subjects. Student's t-test, Mann-Whitney U test, logistic regression analysis, and receiver operating characteristic curve analysis were used for statistical analysis. Results In the AT group, the proportions of patients with diabetes, hypertension, and coronary heart disease were higher than those in the control group. Higher blood platelet, low-density lipoprotein, neutrophil-to-lymphocyte ratio, and PLR were detected in the AT group. In addition, haemoglobin, lymphocytes, and the fastest ventricular rate were significantly lower in the AT group. Higher PLR was identified as independently associated with the presence of AT. When a cut-off value of 119.47 was used, the sensitivity and specificity of PLR for predicting AT were 79.2% and 81.3%, respectively. Conclusion Elevated PLR was associated with AT, suggesting that it might be useful in the future as an adjunct biomarker for the detection of the disease.

von Willebrand factor, ADAMTS-13, and thrombospondin 1 in relation to clinical outcomes in elderly patients with a recent myocardial infarction

Background

von Willebrand factor (VWF) multimers are cleaved by A disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS-13) into less active fragments. Thrombospondin 1 (TSP-1) competes with VWF's cleavage site, protecting it from degradation. Low ADAMTS-13 and high VWF have been associated with cardiovascular disease and atrial fibrillation (AF).

Objectives

We aimed to investigate whether VWF, ADAMTS-13, and TSP-1 are associated with clinical outcome.

Methods

Elderly patients with a recent myocardial infarction (MI) (n = 1027) were followed for 2 years. Blood was collected 2 to 8 weeks after the MI for ADAMTS-13, VWF, and TSP-1 measures. The primary endpoints (major adverse cardiovascular events; n = 210) included the first event of MI, stroke, heart failure hospitalization, coronary revascularization, and all-cause death. Total mortality was also registered (n = 56). The secondary endpoint was new-onset AF (n = 43).

Results

Concentrations of VWF, ADAMTS-13, and TSP-1 did not intercorrelate. The risk of major adverse cardiovascular events was altered in patients with VWF ≥ median (hazard ratio [HR], 1.4; 95% CI, 1.0-1.8; P = .03) and ADAMTS-13 ≥ median (HR, 0.7; 95% CI, 0.5-0.9; P = .02); however, it was not significant in adjusted models. VWF and ADAMTS-13 were significantly associated with total mortality, with a HR of 2.7 (95% CI, 1.6-4.6; P < .001) for VWF (Q4 vs. Q1-Q3) and HR of 0.3 (95% CI, 0.2-0.5; P < .001) for ADAMTS-13 (Q2-4 vs. Q1). The associations persisted in multivariable analysis, but the significance disappeared for VWF after correcting for high-sensitivity C-reactive protein. The risk of new-onset AF was lower in patients with VWF ≥ median (HR, 0.5; 95% CI, 0.3-1.0; P = .04]), and this was still significant after adjustments.

Conclusion

Although low ADAMTS-13 predicted death, the cardiovascular risk associated with VWF and ADAMTS-13 was weaker than previously reported. Low VWF is associated with new-onset AF and needs further research.

The association of coagulation and atrial fibrillation: a systematic review and meta-analysis

AIMS

While atrial fibrillation (AF) is suggested to induce a prothrombotic state, increasing thrombotic risk, it is also hypothesized that coagulation underlies AF onset. However, conclusive evidence is lacking. With this systematic review and meta-analysis, we aimed to summarize and combine the evidence on the associations between coagulation factors with AF in both longitudinal and cross-sectional studies.

METHODS AND RESULTS

We systematically searched for longitudinal cohort and cross-sectional studies investigating AF and thrombosis. For longitudinal studies, pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. For cross-sectional studies, we determined pooled standardized mean differences (SMDs) and 95% CIs. A total of 17 longitudinal and 44 cross-sectional studies were included. In longitudinal studies, we found significant associations between fibrinogen (HR 1.05, 95% CI 1.00-1.10), plasminogen activator inhibitor 1 (PAI-1) (HR 1.06, 95% CI 1.00-1.12), and D-dimer (HR 1.10, 95% CI 1.02-1.19) and AF incidence. In cross-sectional studies, we found significantly increased levels of fibrinogen (SMD 0.47, 95% CI 0.20-0,74), von Willebrand factor (SMD 0.96, 95% CI 0.28-1.66), P-selectin (SMD 0.31, 95% CI 0.08-0.54), ß-thromboglobulin (SMD 0.82, 95% CI 0.61-1.04), Platelet Factor 4 (SMD 0.42, 95% CI 0.12-0.7), PAI-1 (1.73, 95% CI 0.26-3.19), and D-dimer (SMD 1.74, 95% CI 0.36-3.11) in AF patients, as opposed to controls.

CONCLUSION

These findings suggest that higher levels of coagulation factors are associated with prevalent and incident AF. These associations are most pronounced with prevalent AF in cross-sectional studies. Limited evidence from longitudinal studies suggests a prothrombotic state underlying AF development.

Progress of Pathogenesis in Pediatric Multifocal Atrial Tachycardia

Multifocal atrial tachycardia (MAT) is defined as irregular P-P, R-R, and P-R intervals, isoelectric baseline between P waves, and ventricular rate over 100 beats/min. Although the prognosis of pediatric MAT in most patients is favorable, adverse outcomes of MAT have been reported, such as cardiogenic death (3%), respiratory failure (6%), or persistent arrhythmia (7%), due to delayed diagnosis and poorly controlled MAT. Previous studies demonstrated that pediatric MAT is associated with multiple enhanced automatic lesions located in the atrium or abnormal automaticity of a single lesion located in the pulmonary veins via multiple pathways to trigger electrical activity. Recent studies indicated that pediatric MAT is associated with the formation of a re-entry loop, abnormal automaticity, and triggering activity. The occurrence of pediatric MAT is affected by gestational disease, congenital heart disease, post-cardiac surgery, pulmonary hypertension, and infectious diseases, which promote MAT via inflammation, redistribution of the autonomic nervous system, and abnormal ion channels. However, the pathogenesis of MAT needs to be explored. This review is aimed to summarize and analyze the pathogenesis in pediatric MAT.

Immunothrombosis and new-onset atrial fibrillation in the general population: the Rotterdam Study

Background

Atrial fibrillation (AF) is the most common age-related cardiac arrhythmia. The etiology underlying AF is still largely unknown. At the intersection of the innate immune system and hemostasis, immunothrombosis may be a possible cause of atrial remodeling, and therefore be an underlying cause of AF.

Methods

From 1990 to 2014, we followed participants aged 55 and over, free from AF at inclusion. Immunothrombosis factors fibrinogen, von Willebrand factor, ADAMTS13, and neutrophil extracellular traps (NETs) levels were measured at baseline. Participants were followed until either onset of AF, loss-to-follow-up, or reaching the end-date of 01-01-2014. Cox proportional hazard modelling was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusted for cardiovascular risk factors.

Results

We followed 6174 participants (mean age 69.1 years, 57% women) for a median follow-up time of 12.8 years. 364 men (13.7%, incidence rate 13.0/1000 person-years) and 365 women (10.4%, incidence rate 8.9/1000 person-years) developed AF. We found no significant association between markers of immunothrombosis and new-onset AF after adjusting for cardiovascular risk factors [HR 1.00 (95% CI 0.93–1.08) for fibrinogen, 1.04 (0.97–1.12) for von Willebrand factor, 1.00 (1.00–1.01) for ADAMTS13, and 1.01 (0.94–1.09) for NETs]. In addition, we found no differences in associations between men and women.

Conclusion

We found no associations between markers of immunothrombosis and new-onset AF in the general population. Inflammation and immunothrombosis may be associated with AF through other cardiovascular risk factors or predisposing conditions of AF. Our findings challenge the added value of biomarkers in AF risk prediction.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01938-4.

Von Willebrand Factor, Factor VIII, and Other Acute Phase Reactants as Biomarkers of Inflammation and Endothelial Dysfunction in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGvHD) is an immune mediated late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Discovery of adequate biomarkers could identify high-risk patients and provide an effective pre-emptive intervention or early modification of therapeutic strategy, thus reducing prevalence and severity of the disease among long-term survivors of alloHSCT. Inflammation, endothelial injury, and endothelial dysfunction are involved in cGvHD development. Altered levels of acute phase reactants have shown a strong correlation with the activity of several immune mediated disorders and are routinely used in clinical practice. Since elevated von Willebrand factor (VWF) and factor VIII (FVIII) levels have been described as acute phase reactants that may indicate endothelial dysfunction and inflammation in different settings, including chronic autoimmune diseases, they could serve as potential candidate biomarkers of cGvHD. In this review we focused on reported data regarding VWF and FVIII as well as other markers of inflammation and endothelial dysfunction, evaluating their potential role in cGvHD.

Coagulation factor VIII: Relationship to cardiovascular disease risk and whole genome sequence and epigenome-wide analysis in African Americans

BACKGROUND

Prospective studies have suggested higher factor VIII (FVIII) levels are an independent risk factor for coronary heart disease (CHD) and stroke. However, limited information, including on genetic and epigenetic contributors to FVIII variation, is available specifically among African Americans (AAs), who have higher FVIII levels than Europeans.

OBJECTIVES

We measured FVIII levels in ~3400 AAs from the community-based Jackson Heart Study and assessed genetic, epigenetic, and epidemiological correlates of FVIII, as well as incident cardiovascular disease (CVD) associations.

METHODS

We assessed cross-sectional associations of FVIII with CVD risk factors as well as incident CHD, stroke, heart failure, and mortality associations. We additionally assessed associations with TOPMed whole genome sequencing data and an epigenome-wide methylation array.

RESULTS

Our results confirmed associations between FVIII and risk of incident CHD events and total mortality in AAs; mortality associations were largely independent of traditional risk factors. We also demonstrate an association of FVIII with incident heart failure, independent of B-type natriuretic peptide. Two genomic regions were strongly associated with FVIII (ABO and VWF). The index variant at VWF is specific to individuals of African descent and is distinct from the previously reported European VWF association signal. Epigenome-wide association analysis showed significant FVIII associations with several CpG sites in the ABO region. However, after adjusting for ABO genetic variants, ABO CpG sites were not significant.

CONCLUSIONS

Larger sample sizes of AAs will be required to discover additional genetic and epigenetic contributors to FVIII phenotypic variation, which may have consequences for CVD health disparities.

Prognostic value of von Willebrand factor for patients with atrial fibrillation: a meta-analysis of prospective cohort studies

BACKGROUND

It is unknown whether an abnormal level of von Willebrand factor (vWF) is correlated with the prognosis of patients with atrial fibrillation (AF) and current findings are controversial. This meta-analysis aimed to evaluate the association between vWF levels and the clinical prognosis of patients with AF.

METHODS

We searched prospective cohort studies on PubMed, Embase, Web of Science, Cochrane Library and WanFang databases for vWF and adverse events of AF from inception of the databases to July 2019. The risk ratios of all-cause death, cardiovascular death, major adverse cardiac events (MACE), stroke and bleeding prognosis in patients with AF were analysed using a fixed-effects model or random-effects model, and all included studies were evaluated with heterogeneity and publication bias analysis.

RESULTS

Twelve studies which included 7449 patients with AF were used in the meta-analysis. The average age was 71.3 years and the average follow-up time was 3.38 years. The analysis found that high vWF levels were associated with increased risks of all-cause death (RR 1.56; 95% CI 1.16 to 2.11, p=0.00400), cardiovascular death (RR 1.91; 95% CI 1.20 to 3.03, p=0.00600), MACE (RR 1.83; 95% CI 1.28 to 2.62, p=0.00090), stroke (RR 1.69; 95% CI 1.08 to 2.64, p=0.02000) and bleeding (RR 2.01; 95% CI 1.65 to 2.45, p<0.00001) in patients with AF.

CONCLUSIONS

vWF is a risk factor for poor prognosis of AF, and patients with higher vWF levels have a higher risk of all-cause death, cardiovascular death, MACE, stroke and bleeding.

Straight to the heart: Pleiotropic antiarrhythmic actions of oral anticoagulants

Mechanistic understanding of atrial fibrillation (AF) pathophysiology and the complex bidirectional relationship with thromboembolic risk remains limited. Oral anticoagulation is a mainstay of AF management. An emerging concept is that anticoagulants may themselves have potential pleiotropic disease-modifying effects. We here review the available evidence for hemostasis-independent actions of the oral anticoagulants on electrical and structural remodeling, and the inflammatory component of the vulnerable substrate.

Correlation between Fibrinogen and White Matter Hyperintensities among Nondiabetic Individuals with Noncardiogenic Ischemic Stroke

OBJECTIVE

The aim of the present study is to confirm the correlation between fibrinogen and the severity of cerebral white matter hyperintensities (WMHs) among nondiabetic patients with noncardiogenic acute ischemic stroke.

PATIENTS AND METHODS

A cross-sectional study of 170 consecutive patients with noncardiogenic acute ischemic stroke who underwent magnetic resonance imaging and vascular imaging was conducted. WMHs were classified into periventricular hyperintensity (PVH) and deep and subcortical WMH (DSWMH) using Fazekas rating scale. After adjustment for fibrinogen and other vascular risk factors, we determined which factors were independent of WMHs.

RESULTS

After adjustment for the vascular risk factors, prior ischemic stroke (odds ratio [OR] 4.153, 95% confidence interval [CI] 1.077-16.020, P = .039), fibrinogen level (OR 2.114, 95% CI 1.034-4.322, P = .040), and glycosylated hemoglobin A1c (OR .633, 95% CI .423-.947, P = .026) were independently and positively associated with PVH (P < .05); prior ischemic stroke (OR 2.841, 95% CI 1.469-5.493, P = .002), lipoprotein(a) (OR 1.002, 95% CI 1.000-1.005, P = .047), and fibrinogen levels (OR 1.788, 95% CI 1.170-2.732, P = .007) were independently and positively associated with DSWMH (P < .05).

CONCLUSIONS

Our study demonstrated that prior ischemic stroke and higher fibrinogen are associated with WMHs, regardless of PVH and DSWMH, in nondiabetic patients with noncardiogenic acute ischemic stroke. In addition, lipoprotein(a) might be an independent predictor of DSWMH in patients with noncardiogenic acute ischemic stroke.

The prothrombotic state in atrial fibrillation: pathophysiological and management implications

Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia and is associated with significant morbidity and mortality. There is plenty of evidence available to support the presence of a prothrombotic or hypercoagulable state in AF, but the contributory factors are multifactorial and cannot simply be explained by blood stasis. Abnormal changes in atrial wall (anatomical and structural, as ‘vessel wall abnormalities’), the presence of spontaneous echo contrast to signify abnormal changes in flow and stasis (‘flow abnormalities’), and abnormal changes in coagulation, platelet, and other pathophysiologic pathways (‘abnormalities of blood constituents’) are well documented in AF. The presence of these components therefore fulfils Virchow’s triad for thrombogenesis. In this review, we present an overview of the established and professed pathophysiological mechanisms for thrombogenesis in AF and its management implications.

Is von Willebrand factor associated with stroke and death at mid-term in patients with non-valvular atrial fibrillation?

BACKGROUND

Heart failure and atrial fibrillation share common mechanisms that may contribute to hypercoagulability and thrombotic risk. Elevated von Willebrand factor (vWF) concentration has been associated with increased risk of thromboembolism and cardiovascular events.

AIM

To investigate whether increased vWF plasma concentration predicts occurrence of a composite endpoint (all-cause death and stroke) in patients with non-valvular atrial fibrillation (NVAF).

METHODS

We prospectively studied 122 patients (mean age 70±14years; 46% men) hospitalized with NVAF, and followed over a median (interquartile range) of 5.4 (2.3-9.0)years. Cox proportional models were used to estimate the association of vWF concentration with time to stroke and death.

RESULTS

Forty-three patients (35%) had at least a stroke or died during the 5-year follow-up. Kaplan-Meier curves using vWF plasma concentration tertiles (≤191IU/dL;>191 to≤295IU/dL;>295IU/dL) showed that vWF plasma concentrations discriminated groups of patients with higher cardiovascular event rates (log-rank P=0.01). In the multivariable analysis, higher vWF concentrations (middle tertile hazard ratio [HR] 4.59, 95% confidence interval [CI] 1.55-13.50 [P=0.006]; upper tertile HR 4.10, 95% CI 1.43-11.75 [P=0.009]), age≥75years (HR 5.02, 95% CI 1.53-16.49; P=0.008), heart failure (HR 2.05, 1.01-4.19; P=0.048), C-reactive protein, log₂ per unit increase (HR 1.29, 95% CI 1.04-1.61; P=0.021), no warfarin at discharge (HR 4.96, 95% CI 2.02-12.20; P<0.0001) and no aspirin at discharge (HR 4.41, 95% CI 1.71-11.97; P=0.002) were independently associated with an increased risk of stroke and all-cause death, whereas female sex was a protective factor (HR 0.35, 0.16-0.78; P=0.01).

CONCLUSIONS

High vWF plasma concentrations may discriminate patients with NVAF at greater risk of stroke or all-cause death.

Prognostic value of von Willebrand factor in patients with atrial fibrillation: A meta-analysis

BACKGROUND

Studies on the prognostic role of von Willebrand factor (vWF) in patients with atrial fibrillation (AF) are conflicting. This meta-analysis aimed to evaluate the association of elevated circulating vWF level with adverse outcomes in patients with AF.

METHODS

PubMed and Embase were used to search literature through August 2017. Prospective observational studies that evaluated the association of elevated vWF level with major adverse cardiac events (MACEs) and all-cause mortality in patients with AF were deemed eligible. The MACEs included death, stroke/transient ischemic attack, heart failure, myocardial infarction, and systemic/peripheral embolism.

RESULTS

A total of 6 studies were included this meta-analysis. Patients with AF with the highest vWF level were independently associated with greater risk of MACEs (risk ratio [RR] 2.20; 95% confidence intervals [CI] 1.61-3.01) and all-cause mortality (RR 1.63; 95% CI 1.39-1.91). Subgroup analysis showed that the prognostic role of higher vWF level was consistently observed in each defined subgroups.

CONCLUSION

Patients with AF with elevated vWF level are independently associated with a higher risk of MACEs and all-cause mortality. However, more well-designed prospective studies are needed to confirm these findings.

Association between Fibrinogen and Leukoaraiosis in Patients with Ischemic Stroke and Atrial Fibrillation

BACKGROUND

Leukoaraiosis (LA), a surrogate of cerebral small-vessel diseases (CSVD), has been increasingly recognized because of its high prevalence and strong prognostic value in stroke. But the mechanism of LA is incompletely clarified. Fibrinogen is a crucial role in coagulation cascade and inflammation. There are inconsistent reports on the association of fibrinogen with LA in the general population. We aimed to investigate the association between fibrinogen and LA in patients with stroke and atrial fibrillation (AF), which was not ever reported before.

METHODS

Patients with ischemic stroke and AF were prospectively and consecutively recruited. Clinico-demographic data and fibrinogen levels were collected within 48 hours from stroke onsets and analyzed according to the presence and distribution of LA (periventricular hyperintensity [PVH] and deep white matter hyperintensity).

RESULTS

Of 186 patients (34.4% male; mean age, 68.76 ± 12.76 years) enrolled, 134 patients (72.0%) presented with LA. Elevated fibrinogen levels were associated with higher presence of LA (P = .005) and PVH (P = .002). After adjustment for the confounders, the fibrinogen levels were independently correlated with LA and PVH (all P <.05). Patients with elevated fibrinogen levels (≥3.5 g/L) were more likely to present with LA and PVH, with the odds ratios of 14.037 (95% confidence interval [CI] 2.588-76.131) and 12.567 (95% CI 2.572-61.395), respectively.

CONCLUSION

This study found that fibrinogen was independently and positively associated with LA and PVH in patients with stroke and AF. These results provide further evidence for the key role of fibrinogen in LA, even the total CSVD burden.

Stroke or left atrial thrombus prediction using antithrombin III and mean platelet volume in patients with nonvalvular atrial fibrillation

BACKGROUND

CHADS₂ (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke) and CHA₂ DS₂ -VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke, vascular disease, age 65 to 74 years, sex category) scores showed just moderate discrimination ability in predicting thromboembolic complications in patients with nonvalvular atrial fibrillation (AF).

HYPOTHESIS

To determine the association of antithrombin III (AT-III) deficiency and mean platelet volume (MPV) with the development of stroke or left atrial (LA) thrombus in patients with AF.

METHODS

AT-III and MPV were analyzed in 352 patients with AF. The primary endpoint was a composite of ischemic stroke event and incidental LA thrombus.

RESULTS

There were 50 events (14.2%) during a mean 35.4 months of follow-up. A significantly higher stroke or LA thrombus rate was observed in the low-AT-III group (<70%) than that in the high-AT-III group (≥70%). A significantly higher stroke or LA thrombus rate was observed in the high-MPV group (≥7.0 fL) than that in the low-MPV group (<7.0 fL). AF patients with an MPV ≥7.0 fL and AT-III deficiency had higher stroke or LA thrombus risk than those without an MPV ≥7.0 fL and AT-III deficiency. In the Cox proportional hazard analysis, high MPV was found to be an independent predictor of stroke or LA thrombus risk (hazard ratio: 6.408; 95% confidence interval: 2.874-14.286). Although AT-III deficiency was not an independent predictor of stroke or LA thrombus risk, a trend was observed.

CONCLUSIONS

High MPV and AT-III deficiency were predictive markers for stroke or LA thrombus. Their predictive power for stroke was independent of antiplatelet treatment, anticoagulation therapy, and a high CHA₂ DS₂ -VASc score in patients with AF.

Intracardiac Hemostasis and Fibrinolysis Parameters in Patients with Atrial Fibrillation

AIMS

To identify intracardiac hemostasis or fibrinolysis abnormalities, which are associated with atrial fibrillation (AF) and increase the risk of thromboembolism.

PATIENTS AND METHODS

Patient group consisted of 24 patients with AF and control group included 14 individuals with other supraventricular tachycardia undergoing transcatheter radiofrequency ablation. Blood samples were drawn from the femoral vein (FV), left atrium (LA), and left atrial appendage (LAA) before the ablation procedure. Fibrinogen, factor VIII (FVIII) and factor XIII activity, von Willebrand factor (VWF) antigen, thrombin-antithrombin (TAT) complex, quantitative fibrin monomer (FM), plasminogen, α₂-plasmin inhibitor, plasmin-α₂-antiplasmin (PAP) complex, PAI-1 activity, and D-dimer were measured from all samples.

RESULTS

Levels of FVIII and VWF were significantly elevated in the FV and LA of AF patients as compared to controls. TAT complex, FM, PAP complex, and D-dimer levels were significantly elevated in the LA as compared to FV samples in case of both groups, indicating a temporary thrombotic risk associated with the catheterization procedure.

CONCLUSIONS

None of the investigated hemostasis or fibrinolysis parameters showed significant intracardiac alterations in AF patients as compared to non-AF controls. AF patients have elevated FVIII and VWF levels, most likely due to endothelial damage, presenting at both intracardiac and systemic level.

Systemic Inflammation and Arrhythmogenesis: A Review of Mechanistic and Clinical Perspectives

In the recent decades, systemic inflammation, as a clinical phenomenon, has been the focus of extensive research particularly with regard to its potential association with a variety of cardiovascular diseases including atherogenesis and acute coronary syndromes. Within this context, there also exists a potential link between systemic inflammation and cardiac arrhythmogenesis in various aspects. Accordingly, systemic inflammation response as measured with inflammation markers (cytokines, etc) has been investigated in the setting of well-known cardiac arrhythmias including atrial fibrillation and ventricular tachycardia. Based on current literature, clinical utility of these markers might potentially yield important prognostic implications in the setting of certain arrhythmogenic conditions. On the other hand, there exists limited data regarding therapeutic implications including clinical benefit of primary anti-inflammatory agents (corticosteroids, colchicine, etc) in the setting of arrhythmia management. The present review primarily aims to discuss potential triggers and fundamental mechanisms of inflammation-related arrhythmias along with a particular emphasis on clinical implications of systemic inflammation in the setting of cardiac arrhythmogenesis.

Are cardiovascular risk factors also associated with the incidence of atrial fibrillation? A systematic review and field synopsis of 23 factors in 32 population-based cohorts of 20 million participants

Established primary prevention strategies of cardiovascular diseases are based on understanding of risk factors, but whether the same risk factors are associated with atrial fibrillation (AF) remains unclear. We conducted a systematic review and field synopsis of the associations of 23 cardiovascular risk factors and incident AF, which included 84 reports based on 28 consented and four electronic health record cohorts of 20,420,175 participants and 576,602 AF events. We identified 3-19 reports per risk factor and heterogeneity in AF definition, quality of reporting, and adjustment. We extracted relative risks (RR) and 95 % confidence intervals [CI] and visualised the number of reports with inverse (RR [CI]<1.00), or direct (RR [CI]>1.00) associations. For hypertension (13/17 reports) and obesity (19/19 reports), there were direct associations with incident AF, as there are for coronary heart disease (CHD). There were inverse associations for non-White ethnicity (5/5 reports, with RR from 0.35 to 0.84 [0.82-0.85]), total cholesterol (4/13 reports from 0.76 [0.59-0.98] to 0.94 [0.90-0.97]; 8/13 reports with non-significant inverse associations), and diastolic blood pressure (2/11 reports from 0.87 [0.78-0.96] to 0.92 [0.85-0.99]; 5/11 reports with non-significant inverse associations), and direct associations for taller height (7/10 reports from 1.03 [1.02-1.05] to 1.92 [1.38-2.67]), which are in the opposite direction of known associations with CHD. A systematic evaluation of the available evidence suggests similarities as well as important differences in the risk factors for incidence of AF as compared with other cardiovascular diseases, which has implications for the primary prevention strategies for atrial fibrillation.

Predictive Role of Coagulation, Fibrinolytic, and Endothelial Markers in Patients with Atrial Fibrillation, Stroke, and Thromboembolism: A Meta-Analysis, Meta-Regression, and Systematic Review

Background

The pathophysiological mechanism associated with the higher prothrombotic tendency in atrial fibrillation (AF) is complex and multifactorial. However, the role of prothrombotic markers in AF remains inconclusive.

Material/Methods

We conducted a meta-analysis of observational studies evaluating the association of coagulation activation, fibrinolytic, and endothelial function with occurrence of AF and clinical adverse events. A comprehensive subgroup analysis and meta-regression was performed to explore potential sources of heterogeneity.

Results

A literature search of major databases retrieved 1703 studies. After screening, a total of 71 studies were identified. Pooled analysis showed the association of coagulation markers (D-dimer (weighted mean difference (WMD)=197.67 and p<0.001), fibrinogen (WMD=0.43 and p<0.001), prothrombin fragment 1–2 (WMD=0.53 and p<0.001), antithrombin III (WMD=23.90 and p=0.004), thrombin-antithrombin (WMD=5.47 and p=0.004)); fibrinolytic markers (tissue-type plasminogen activator (t-PA) (WMD=2.13 and p<0.001), plasminogen activator inhibitor (WMD=11.44 and p<0.001), fibrinopeptide-A (WMD=4.13 and p=0.01)); and endothelial markers (von Willebrand factor (WMD=27.01 and p<0.001) and soluble thrombomodulin (WMD=3.92 and p<0.001)) with AF.

Conclusions

The levels of coagulation, fibrinolytic, and endothelial markers have been reported to be significantly higher in AF patients than in SR patients.

Usefulness of HATCH score in the prediction of new-onset atrial fibrillation for Asians

The HATCH score (hypertension <1 point>, age >75 years <1 point>, stroke or transient ischemic attack <2 points>, chronic obstructive pulmonary disease <1 point>, and heart failure <2 points>) was reported to be useful for predicting the progression of atrial fibrillation (AF) from paroxysmal to persistent or permanent AF for patients who participated in the Euro Heart Survey. The goal of the current study was to investigate whether the HATCH score was a useful scheme in predicting new-onset AF. Furthermore, we aimed to use the HATCH scoring system to estimate the individual risk in developing AF for patients with different comorbidities. We used the "Taiwan National Health Insurance Research Database." From January 1, 2000, to December 31, 2001, a total of 670,804 patients older than 20 years old and who had no history of cardiac arrhythmias were enrolled. According to the calculation rule of the HATCH score, 599,780 (score 0), 46,661 (score 1), 12,892 (score 2), 7456 (score 3), 2944 (score 4), 802 (score 5), 202 (score 6), and 67 (score 7) patients were studied and followed for the new onset of AF. During a follow-up of 9.0 ± 2.2 years, there were 9174 (1.4%) patients experiencing new-onset AF. The incidence of AF was 1.5 per 1000 patient-years. The incidence increased from 0.8 per 1000 patient-years for patients with a HATCH score of 0 to 57.3 per 1000 patient-years for those with a HATCH score of 7. After an adjustment for the gender and comorbidities, the hazard ratio (95% confidence interval) of each increment of the HATCH score in predicting AF was 2.059 (2.027-2.093; P < 0.001). The HATCH score was useful in risk estimation and stratification of new-onset AF.

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.

Associations between blood coagulation markers, NT-proBNP and risk of incident heart failure in older men: The British Regional Heart Study

AIMS

Chronic heart failure (HF) is associated with activation of blood coagulation but there is a lack of prospective studies on the association between coagulation markers and incident HF in general populations. We have examined the association between the coagulation markers fibrinogen, von Willebrand Factor (VWF), Factors VII, VIII and IX, D-dimer, activated protein C (APC) and activated partial thromboplastin time (aPPT) with NT-proBNP and incident HF.

METHODS AND RESULTS

Prospective study of 3366 men aged 60-79years with no prevalent HF, myocardial infarction or venous thrombosis and who were not on warfarin, followed up for a mean period of 13years, in whom there were 203 incident HF cases. D-dimer and vWF were significantly and positively associated with NT-proBNP (a marker of neurohormonal activation and left ventricular wall stress) even after adjustment for age, lifestyle characteristics, renal dysfunction, atrial fibrillation (AF) and inflammation (C-reactive protein). By contrast Factor VII related inversely to AF and NT-proBNP even after adjustment. No association was seen however between the coagulation markers VWF, Factor VII, Factor VIII, Factor IX, D-dimer, APC resistance or aPPT with incident HF in age-adjusted analyses. Fibrinogen was associated with incident HF but this was abolished after adjustment for HF risk factors.

CONCLUSION

Coagulation activity is not associated with the development of HF. However D-dimer and vWF were significantly associated with NT-proBNP, suggesting that increased coagulation activity is related to cardiac stress; and the increased coagulation seen in HF patients may in part be a consequence of neurohormonal activation.

Association of platelet activation markers with recurrence of atrial fibrillation after pulmonary vein isolation

Atrial fibrillation (AF) is known to cause platelet activation. AF and its degree of thrombogenesis could be associated with monocyte-platelet aggregates (MPAs). We investigated on whether the content of MPAs or other platelet activation markers is associated with the recurrence of AF after pulmonary vein isolation (PVI). A total of 73 patients with symptomatic AF underwent PVI. After 6 months, all patients were evaluated for episodes of AF recurrence. At the same time, flow-cytometric quantification analyses were performed to determine the content of MPAs. Further platelet activation parameters were detected by using either cytometric bead arrays or quantitative immunological determination. Patients with recurrent AF (n = 20) compared to individuals without AF relapse (n = 53) were associated with an increased content of MPAs (43 ± 3% vs. 33 ± 2%, p = 0.004), as well as an increased CD41 expression on monocytes (191 ± 20 vs. 113 ± 6, p = 0.001). The level of the soluble platelet activation markers such as D-dimer, sCD40L, and sP-selectin did not differ between these groups. The content of MPAs correlated weakly with the level of sCD40L (r = 0.26, p = 0.03), but not with sP-selectin and D-dimer, whereas sP-selectin and sCD40L correlated with each other (r = 0.38, p = 0.001). Only the cellular marker of platelet activation, the content of MPAs, was increased in patients with recurrent AF after PVI. In contrast, soluble markers remained unaltered. These data indicate a distinct mechanism and level of platelet activation in AF. The clinical relevance of MPAs in identifying AF recurrence or in guiding the therapy with anticoagulants remains to be elucidated.

Circulating biomarkers and incident ischemic stroke in the Framingham Offspring Study

OBJECTIVE

We related a panel of inflammatory biomarkers to risk of incident ischemic stroke (IIS) in a community-dwelling sample.

METHODS

Stroke-free Framingham offspring attending examination cycle 7 (1998-2001) had 15 circulating inflammatory biomarkers measured. Cox proportional hazard models were used to calculate the hazard ratios (HRs) of IIS per SD increment of each biomarker. Model 1 included age and sex. Model 2 additionally adjusted for systolic blood pressure, hypertension treatment, current smoking, diabetes, cardiovascular disease, and atrial fibrillation. The continuous net reclassification improvement was used to assess the improvement in IIS risk prediction of statistically significant biomarkers from our main analysis over traditional stroke risk factors.

RESULTS

In 3,224 participants (mean age 61 ± 9 years, 54% women), 98 experienced IIS (mean follow-up of 9.8 [±2.2] years). In model 1, ln-C-reactive protein (ln-CRP) (HR 1.28, 95% confidence interval [CI] 1.04-1.56), ln-tumor necrosis factor receptor 2 (ln-TNFR2) (HR 1.33, 95% CI 1.09-1.63), ln-total homocysteine (ln-tHcy) (HR 1.32, 95% CI 1.11-1.58), and vascular endothelial growth factor (VEGF) (HR 1.25, 95% CI 1.07-1.46) were associated with risk of IIS. All associations, except for ln-CRP, remained significant in model 2 (ln-TNFR2: HR 1.24, 95% CI 1.02-1.51; ln-tHcy: HR 1.20, 95% CI 1.01-1.43; and VEGF: HR 1.21, 95% CI 1.04-1.42). The addition of these 4 biomarkers to the clinical Framingham Stroke Risk Profile score improved stroke risk prediction (net reclassification improvement: 0.34, 0.12-0.57; p < 0.05).

CONCLUSIONS

Higher levels of 4 biomarkers-CRP, tHcy, TNFR2, and VEGF-increased risk of IIS and improved the predictive ability of the Framingham Stroke Risk Profile score. Further research is warranted to explore their role as potential therapeutic targets.

Decreased Activity of the Protein C Anticoagulant Pathway in the Early Hours of Paroxysmal Atrial Fibrillation

BACKGROUND

Increased coagulation activity has been established in paroxysmal atrial fibrillation (PAF), but data on the anticoagulant system are scarce.

PURPOSE

To examine the protein C anticoagulant pathway in the early hours of the disease.

MATERIALS AND METHODS

Fifty-one patients (26 men and 25 women; mean age 59.84 ± 1.60 years) and 52 controls (26 men and 26 women; mean age 59.50 ± 1.46 years) were selected for the study. Protein C antigen and its activity, total protein S, free protein S and its activity, soluble forms of endothelial protein C receptor (sEPCR), and thrombomodulin (sTM) were examined in the plasma.

RESULTS

The indicators were studied in patients between the 2nd and the 24th hour after the onset of arrhythmia. Levels of protein C were significantly elevated in patients compared to controls (111.40% ± 6.66% vs 94.83% ± 4.47%; P = .039). Protein C activity showed significant reduction in PAF (73.13% ± 5.80% vs 103.3% ± 3.80%; P < .001). Total protein S levels did not differ significantly (108.20% ± 4.07% vs 102.40% ± 3.65%; P = .30). Free protein S (76.81% ± 6.01% vs 122.10% ± 3.97%; P < .001) and its activity (71.39% ± 6.27% vs 119.50% ± 6.54%; P < .001) were reduced in patients. Higher levels of sEPCR (203.10 ± 10.33 vs 133.10 ± 7.37 ng/mL; P < .001) and sTM (6.50±0.40 vs 4.48±0.28 ng/mL; P < .001) were measured in PAF.

CONCLUSION

Protein C activity is reduced still in the first hours (until the 24th hour) of PAF clinical manifestation, determining reduced activity of the anticoagulant pathway as a whole. The established low levels of free protein S and its activity as well as low sEPCR and sTM levels are a possible explanation of the changes in protein C activity.

Evaluating the Atrial Myopathy Underlying Atrial Fibrillation: Identifying the Arrhythmogenic and Thrombogenic Substrate

Atrial disease or myopathy forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. Current diagnostic approaches in patients with AF focus on identifying clinical predictors with the evaluation of left atrial size by echocardiography serving as the sole measure specifically evaluating the atrium. Although the atrial substrate underlying AF is likely developing for years before the onset of AF, there is no current evaluation to identify the preclinical atrial myopathy. Atrial fibrosis is 1 component of the atrial substrate that has garnered recent attention based on newer MRI techniques that have been applied to visualize atrial fibrosis in humans with prognostic implications regarding the success of treatment. Advanced ECG signal processing, echocardiographic techniques, and MRI imaging of fibrosis and flow provide up-to-date approaches to evaluate the atrial myopathy underlying AF. Although thromboembolic risk is currently defined by clinical scores, their predictive value is mediocre. Evaluation of stasis via imaging and biomarkers associated with thrombogenesis may provide enhanced approaches to assess risk for stroke in patients with AF. Better delineation of the atrial myopathy that serves as the substrate for AF and thromboembolic complications might improve treatment outcomes. Furthermore, better delineation of the pathophysiologic mechanisms underlying the development of the atrial substrate for AF, particularly in its earlier stages, could help identify blood and imaging biomarkers that could be useful to assess risk for developing new-onset AF and suggest specific pathways that could be targeted for prevention.

Hemostatic Factors, APOL1 Risk Variants, and the Risk of ESRD in the Atherosclerosis Risk in Communities Study

BACKGROUND AND OBJECTIVES

Hemostatic factors have been associated with kidney function decline, and evidence suggests stronger effects among African Americans. The presence of APOL1 renal risk variants, common in African Americans, might partly underlie this risk difference.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 13,337 participants in the Atherosclerosis Risk in Communities study were followed from 1987-1989 until 2010. Participants were categorized into three groups by ancestry and APOL1 risk status: European Americans (n=10,206), African Americans with zero or one APOL1 risk allele (n=2,733), and African Americans with two APOL1 risk alleles (n=398). ESRD events were ascertained through linkage to the US Renal Data System. Cox regression was used to estimate the risk for ESRD associated with hemostatic factors (factor VIIc, factor VIIIc, fibrinogen, von Willebrand factor, protein C, and antithrombin III).

RESULTS

There were 232 cases of ESRD over 21.5 years (European Americans, 119; African Americans with zero or one APOL1 risk allele, 94; African Americans with two APOL1 risk alleles, 19). In unadjusted and adjusted analysis of the overall population, higher levels of all hemostatic factors, except antithrombin III, were significantly associated with ESRD (all P<0.05). Factor VIIc had the strongest association (per one interquartile range; adjusted hazard ratio, 1.46; 95% confidence interval, 1.21 to 1.76). With the exception of fibrinogen, the risk associated with each hemostatic factor was stronger in African Americans with two APOL1 risk alleles compared with the other two groups. Statistically significant interactions were seen for factor VIIIc and protein C (interaction between those with two APOL1 risk allele and the other two groups: P<0.02 for factor VIIIc and <0.04 for protein C).

CONCLUSIONS

Higher levels of factor VIIc, VIIIc, fibrinogen, von Willebrand factor, and protein C were associated with ESRD risk, with a significantly stronger association of factor VIIIc and protein C in African Americans with two APOL1 risk alleles.

Assessment of the Diagnostic Value of Plasma Levels, Activities, and Their Ratios of von Willebrand Factor and ADAMTS13 in Patients with Cerebral Infarction

BACKGROUND AND OBJECTIVES

Raised levels of von Willebrand factor (VWF) and reduced levels of a disintegrin and a metalloproteinase with a thrombospondin type I motif, member 13 (ADAMTS13) activity are associated with thrombosis. We aimed to investigate the relationships between plasma levels of VWF and ADAMTS13, their ratios, and the occurrence of cerebral infarction and to understand the roles of VWF and ADAMTS13 in cerebral infarction.

METHODS

Ninety-four patients with cerebral infarction and 103 controls were analyzed. Plasma levels of VWF antigen (VWF: Ag), VWF ristocetin cofactor activity (VWF: Rcof), and VWF collagen binding activity (VWF: CB) were measured by enzyme-linked immunosorbent assay (ELISA). The ADAMTS13 activity (ADAMTS13) was measured with FRETS-VWF73. The relationship between plasma levels and ratios of VWF and ADAMTS13 and the occurrence of cerebral infarction were analyzed.

RESULTS

Patients with cerebral infarction displayed higher VWF: Ag and VWF: Rcof levels and lower ADAMTS13, VWF: CB/VWF: Ag, ADAMTS13/VWF: Ag, and ADAMTS13/VWF: Rcof levels compared to controls (P < .01). The highest quartiles of VWF: Ag (odds ratio [OR] = 5.11, 95% confidence interval [CI], 1.49-17.50) and VWF: Rcof (OR = 5.04, 95% CI, 1.62-15.66) and the lowest quartiles of VWF: CB/VWF: Ag (OR = 5.91, 95% CI, 1.95-17.93), ADAMTS13/VWF: Ag (OR = 9.11, 95% CI, 2.49-33.33), and ADAMTS13/VWF: Rcof (OR = 3.73, 95% CI, 1.39-10.03) are associated with cerebral infarction.

CONCLUSIONS

An association was found between reduced levels of VWF: CB/VWF: Ag, ADAMTS13/VWF: Ag, and ADAMTS13/VWF: Rcof ratios and cerebral infarction. Our data suggest that increased levels of VWF and reduced levels of ADAMTS13 activity may contribute to the pathogenesis of cerebral infarction.

Association of hemostatic markers with atrial fibrillation: a meta-analysis and meta-regression

BACKGROUND

There is growing evidence that indicates the presence of a prothrombotic state in atrial fibrillation (AF). However, the role of hemostatic markers in AF remains inconclusive.

METHODS

We conducted a meta-analysis of observational studies to evaluate the association between hemostatic markers and AF. A meta-regression was performed to explore potential sources of heterogeneity.

RESULTS

A total of 59 studies met our inclusion criteria for the meta-analysis. For platelet activation, increased circulating platelet factor-4, β-thromboglobulin (BTG) and P-selectin were significantly higher in AF cases compared with controls (standardized mean difference [SMD][95% confidence interval (CI)]: 1.72[0.96-2.49], 1.61[1.03-2.19] and 0.50[0.23-0.77], respectively). For coagulation activation, increased levels of plasma D-dimer, fibrinogen, thrombin-antithrombin, prothrombin fragment 1+2, and antithrombin-III were significantly associated with AF (SMD[95% CI]: 1.82[1.38-2.26], 0.72[0.55-0.89], 0.42[0.13-0.72], 1.00 [0.00-1.99] and 1.38[0.16-2.60], respectively). For fibrinolytic function, tissue-type plasminogen activator and plasminogen activator inhibitor-1 were significantly increased in AF cases compared with controls (SMD[95% CI]: 0.86[0.04-1.67] and 0.87[0.28-1.47], respectively) but the associations became nonsignificant after performing subgroup analysis by anticoagulants treatment status. For endothelial function, increased von Willebrand factor was significantly associated with AF (SMD, 0.79; 95% CI, 0.60-0.99); however, no association was observed for soluble thrombomodulin (SMD, 0.60; 95% CI, -0.13-1.33).

CONCLUSIONS

Increased circulating hemostatic factors (PF-4, BTG, P-selectin, D-dimer, fibrinogen, TAT, F1+2, AT- III, and vWf) are significantly associated with AF. Future research is necessary to elucidate the precise mechanism of the prothrombotic state and how hemostatic markers promote thromboembolism in AF.

sRAGE, inflammation, and risk of atrial fibrillation: results from the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

Advanced glycation end products (AGEs) may cause inflammation by binding to their cellular receptors (RAGE). Soluble RAGE (sRAGE) acts as a decoy receptor for AGEs and may prevent inflammation. Chronic low-grade inflammation is a risk factor for cardiovascular disease, including atrial fibrillation (AF).

METHODS

We studied 1,068 participants in a subsample of the Atherosclerosis Risk in Communities (ARIC) Study who had baseline measurements of sRAGE (mean age 56, 60% female, 21% Black). Inflammation was assessed using measurements of high sensitivity C-reactive protein (hsCRP), fibrinogen, gamma-glutamyl transferase (GGT) and white blood cell (WBC) count. AF events were identified using ECG data, hospitalization discharge codes, and linkage to the National Death Index.

RESULTS

Compared to the highest quartile (>1272.4 pg/mL), the lowest quartile of sRAGE (<714 pg/mL) was associated with higher baseline levels of inflammation (hsCRP ≥3 mg/L: OR=2.21 [95% CI 1.41-3.49], fibrinogen ≥400 mg/dL: OR=4.31 [95% CI 1.50-12.41], GGT ≥36 U/L in women and ≥61 U/L in men: OR=5.22 [95% CI 2.66-10.22], WBC >6.2×10⁹/L: OR=2.38 [95% CI 1.52-3.72]). sRAGE was not prospectively associated with 6-year change in inflammatory markers (hsCRP or GGT). There was no significant association of sRAGE and risk of AF (HR 1.49 [95% CI: 0.80-2.78] for the 1st vs. 4th quartile of sRAGE).

CONCLUSIONS

sRAGE was strongly inversely associated with markers of inflammation at baseline, but not prospectively. sRAGE was not significantly associated with incident AF. This supports a role for sRAGE in attenuating current inflammation, but it remains unclear whether sRAGE plays a role in the development of AF.

Von Willebrand Factor Plasma Levels Variability In Nonvalvular Atrial Fibrillation

Atrial Fibrillation (AF) is the most common cardiac arrhythmia of clinical significance; it increases the risk of mortality due to stroke. The mechanisms behind cerebral thromboembolism in AF are associated with a prothrombotic state, demonstrated by higher levels of von Willebrand Factor (vWF), a multimeric glycoprotein that plays a crucial role in platelet adhesion and aggregation and it has been proposed as a biomarker of endothelial dysfunction. Plasma vWF levels are elevated in patients with nonvalvular Atrial Fibrillation (NVAF) associated to the presence of cardiovascular risk factors. The variability in vWF plasma levels in healthy subjects has a wide distribution, but there is no description available of the variability in AF patients and among types of AF. The aim of this study was to determine the variability of vWF plasma concentrations in patients with NVAF, associated to cardiovascular risk factors. Search strategy included PubMed and Ovid. Keywords used were "Atrial Fibrillation" and "von Willebrand Factor". It includes original articles, with analysis of plasma vWF levels by ELISA, without acute stroke. Review articles and meta-analysis were excluded. Reviewed studies include 22 trials and 6542 patients with nonvalvular AF associated to cardiovascular disease risk factors: age, sex, hypertension, heart failure, diabetes mellitus, prior stroke, coronary artery disease. Variability in vWF plasma levels was wide, with minimum values of 77 IU/dl and maximum values of 245 IU/dl and a mean of 146 IU/dl. Age of patients ranged between 54 and 78 years, and the percentage of males ranged between 23% and 80%. According to type of AF vWF levels were as follows, in paroxysmal AF: 92-264 IU/dl; persistent AF: 76-234 IU/dl; permanent AF: 91-247 IU/dl. The variability in vWF plasma levels is affected by risk factors and the AF type, however vWF levels in AF patients are higher when compared with healthy subjects.

Conventional rapid latex agglutination in estimation of von Willebrand factor: method revisited and potential clinical applications

Measurement of von Willebrand factor antigen (VWF : Ag) levels is usually performed in a specialised laboratory which limits its application in routine clinical practice. So far, no commercial rapid test kit is available for VWF : Ag estimation. This paper discusses the technical aspect of latex agglutination method which was established to suit the purpose of estimating von Willebrand factor (VWF) levels in the plasma sample. The latex agglutination test can be performed qualitatively and semiquantitatively. Reproducibility, stability, linearity, limit of detection, interference, and method comparison studies were conducted to evaluate the performance of this test. Semiquantitative latex agglutination test was strongly correlated with the reference immunoturbidimetric assay (Spearman's rho = 0.946, P < 0.001, n = 132). A substantial agreement (κ = 0.77) was found between qualitative latex agglutination test and the reference assay. Using the scoring system for the rapid latex test, no agglutination is with 0% VWF : Ag (control negative), 1+ reaction is equivalent to <20% VWF : Ag, and 4+ reaction indicates >150% VWF : Ag (when comparing with immunoturbidimetric assay). The findings from evaluation studies suggest that latex agglutination method is suitable to be used as a rapid test kit for the estimation of VWF : Ag levels in various clinical conditions associated with high levels and low levels of VWF : Ag.

Association of inflammatory and hemostatic markers with stroke and thromboembolic events in atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) increases the risk of stroke and thromboembolic events. Recently, biomarkers have been proposed as a practical tool to predict adverse outcomes in patients with AF. The prognostic value of inflammatory and hemostatic markers in AF has been widely studied; however, the results of previous studies have been inconclusive.

METHODS

We conducted a systematic review and meta-analysis to evaluate the association of inflammatory and hemostatic markers with stroke and thromboembolic events in patients with AF.

RESULTS

A total of 27 studies including 22,176 participants met our inclusion criteria for the systematic review. Our meta-analysis determined that elevated circulating plasminogen activator inhibitor-1 (PAI-1) and thrombin-antithrombin (TAT) were significantly associated with increased risk of stroke in patients with AF (standardized mean difference [SMD], 0.89; 95% confidence interval [CI], 0.20-1.59 and 1.43; 95% CI, 0.40-2.47, respectively). Higher levels of D-dimer were associated with increased subsequent thromboembolic event risk with a pooled hazard ratio of 2.90 (95% CI, 1.22-6.90) for cohort studies and an SMD of 0.93 (95% CI, 0.36-1.50) for case-control studies. There was also very limited evidence indicating that other biomarkers-such as interleukin-6, von Willebrand factor, P-selectin, and mean platelet volume-could predict adverse outcomes in AF.

CONCLUSIONS

In conclusion, increased circulating PAI-1 and TAT levels were significantly associated with subsequent stroke in patients with AF, and high levels of D-dimer were associated with thromboembolic events in AF. Further epidemiologic studies are needed to accumulate more evidence on the prognostic role of inflammatory and hemostatic markers in AF.

Haemostatic factors, lipoproteins and long-term mortality in a multi-ethnic population of Gujarati, African-Caribbean and European origin

OBJECTIVES

To examine the relations between haemostatic factors and lipoproteins with mortality in British Europeans, African-Caribbeans (AfC) and Gujarati Indians.

METHODS

A prospective cohort study of 331 subjects (40-79 years), followed-up over 26 years for mortality. Apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), factor VII coagulant activity (FVIIc), fibrinogen and von Willebrand Factor (vWF) were measured at baseline in 118 Europeans, 100 AfC and 113 Gujaratis. Aortic pulse wave velocity (aPWV) was measured in 174 participants.

RESULTS

147 (44.4%) subjects died during a median of 24 years follow-up with 69 cardiovascular deaths. Women at baseline had higher, and AfC males the lowest FVIIc and Apo-A1 levels. Baseline age-sex and ethnicity adjusted FVIIc levels were higher in those who died (131.0 vs. 117.4%; P = 0.048). In similarly adjusted partial correlations, Apo-A1 was inversely related to arterial stiffness (ρ = -0.23, P = 0.04). Over the 26 years follow-up, participants below the median (i.e. with lower concentration) of FVIIc, Fibrinogen, Apo-B and vWF had better survival rates than those with higher concentrations; those with higher concentrations of Apo-A1 had better survival. In Cox multivariable regression analyses including sex, ethnicity and aPWV, independently increased risk of all-cause mortality came only from SBP (per 5 mmHg); P = 0.011), age (per year); P < 0.0001 and FVIIc at 7% (per 10-unit; HR 1.07 (1.02, 1.12); P = 0.008. Separately, Apo-A1 (HR 0.12 (0.02, 0.75; P = 0.029) was independently associated with a very significant 88% reduction in all-cause mortality.

CONCLUSIONS

Despite a relatively small sample size, long-term follow-up suggests an independent effect of the prothrombotic state (via FVIIc) and apo-A1 (a constituent of HDL) on mortality.

The multiscale backbone of the human phenotype network based on biological pathways

Background

Networks are commonly used to represent and analyze large and complex systems of interacting elements. In systems biology, human disease networks show interactions between disorders sharing common genetic background. We built pathway-based human phenotype network (PHPN) of over 800 physical attributes, diseases, and behavioral traits; based on about 2,300 genes and 1,200 biological pathways. Using GWAS phenotype-to-genes associations, and pathway data from Reactome, we connect human traits based on the common patterns of human biological pathways, detecting more pleiotropic effects, and expanding previous studies from a gene-centric approach to that of shared cell-processes.

Results

The resulting network has a heavily right-skewed degree distribution, placing it in the scale-free region of the network topologies spectrum. We extract the multi-scale information backbone of the PHPN based on the local densities of the network and discarding weak connection. Using a standard community detection algorithm, we construct phenotype modules of similar traits without applying expert biological knowledge. These modules can be assimilated to the disease classes. However, we are able to classify phenotypes according to shared biology, and not arbitrary disease classes. We present examples of expected clinical connections identified by PHPN as proof of principle.

Conclusions

We unveil a previously uncharacterized connection between phenotype modules and discuss potential mechanistic connections that are obvious only in retrospect. The PHPN shows tremendous potential to become a useful tool both in the unveiling of the diseases’ common biology, and in the elaboration of diagnosis and treatments.

Airflow obstruction, lung function, and incidence of atrial fibrillation: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Reduced low forced expiratory volume in 1 second (FEV1) is reportedly associated with an increased risk of atrial fibrillation (AF). Extant reports do not provide separate estimates for never smokers or for blacks, who incongruously have lower AF incidence than whites.

METHODS AND RESULTS

We examined 15 004 middle-aged blacks and whites enrolled in the Atherosclerosis Risk in Communities (ARIC) cohort study. Standardized spirometry data were collected at the baseline examination. Incident AF was identified from the first among the following: International Classification of Diseases codes for AF on hospital discharge records or death certificates or 12-lead ECGs performed during 3 triennial follow-up visits. Over an average follow-up of 17.5 years, a total of 1691 participants (11%) developed new-onset AF. The rate of incident AF was inversely associated with FEV1 in each of the 4 race and sex groups. After multivariable adjustment for traditional cardiovascular disease risk factors and height, hazard ratios of AF comparing the lowest with the highest quartile of FEV1 were 1.37 (95% confidence interval, 1.02-1.83) for white women, 1.49 (95% confidence interval, 1.16-1.91) for white men, 1.63 (95% confidence interval, 1.00-2.66) for black women, and 2.36 (95% confidence interval, 1.30-4.29) for black men. The above associations were observed across all smoking status categories. Moderate/severe airflow obstruction (FEV1/forced vital capacity <0.70 and FEV1 < 80% of predicted value) was also associated with higher AF incidence.

CONCLUSIONS

In this large population-based study with a long-term follow-up, reduced FEV1 and obstructive respiratory disease were associated with a higher AF incidence after adjustment for measured confounders.

Effect of Oral Anticoagulant Therapy on Coagulation Activity and Inflammatory Markers in Patients with Atrial Fibrillation Undergoing Ablation: A Randomized Comparison between Dabigatran and Warfarin

Atrial fibrillation (AF) is associated with inflammatory and hypercoagulability state. Previous studies evaluated the safety and efficacy of dabigatran and warfarin in prevention of thrombothic complications. This study was intended to assess the influence of these drugs on hemostatic and inflammatory markers among patient underwent pulmonary vein ablation. A total of 100 patients with AF who underwent catheter ablation were randomized to treatment with dabigatran (D) 110 mg twice daily or warfarin (W) adjusted to an international normalized ratio (INR) of 2.0 to 3.0 for 3 months after ablation procedure. C - reactive protein (CRP), D-dimer, prothrombin fragment F1 + 2 (F1 + 2), were measured at baseline before ablation procedures, after 30 days and after 90 days of treatment. After 3 months, the D-dimer was 164.9 ± 48.9 in Dabigatran and 197.2 ± 58.6 in warfarin group, F1 + 2 was 0.4 ± 0.2 in dabigatran and 0.8 ± 0.2 in warfarin group and CRP level was 1.8 ± 1.6 in Dabigatran and 5.1 ± 5 in warfarin group. (All p-values < 0.05) The results showed that treatment with dabigatran made greater changes in the serum level of CRP, D-dimer, F1 + 2. The pattern of changes in serum CRP levels D-dimer, F1 + 2 is much faster and with a greater slope in the dabigatran group.

Inflammatory biomarkers as risk factors for future atrial fibrillation. An eleven-year follow-up of 6315 men and women: the Tromsø study

BACKGROUND

Inflammatory biomarkers are reported as risk factors for atrial fibrillation (AF), but their impact is uncertain.

OBJECTIVE

We investigated the associations between inflammatory biomarkers and future AF in a large general cohort.

METHODS

Available markers were white blood cells (WBCs) with subgroups, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and osteoprotegerin (OPG). A total of 6315 men and women from a population survey in Tromsø, Norway in 1994 to 1995 were followed for a mean of 10.9 years. Mean age at baseline was 60 years. Measurements of height, weight, blood pressure, heart rate, total cholesterol, high-density lipoprotein (HDL) cholesterol, WBC count, and information on diabetes, angina, myocardial infarction, and antihypertensive treatment, were obtained at baseline. Fibrinogen, hs-CRP, and OPG were obtained at a follow-up visit. The outcome measure was first-ever AF, documented on an electrocardiogram. The Cox proportional hazards regression model was used to estimate hazard ratios of AF.

RESULTS

In the multivariable analysis, adjusted for traditional cardiovascular risk factors and other inflammatory biomarkers, hs-CRP was associated with AF in men only (hazard ratio = 1.14 for a 1 SD increase; 95% CI, 1.02-1.28). There was a significant increase in AF across quartiles of WBCs in men (P = 0.007) and in the total study population (P = 0.004). OPG was associated with AF in patients free of coronary heart disease at baseline. Fibrinogen and subgroups of WBCs showed no significant association with AF.

CONCLUSION

This population-based cohort study showed that hs-CRP was independently associated with AF in men, but apparently not in women, and that patients with WBCs in the upper quartile had increased risk of AF.

Prognostic value of plasma von Willebrand factor and its cleaving protease ADAMTS13 in patients with atrial fibrillation

BACKGROUND

The von Willebrand factor (vWF) is essential for platelet adhesion and arterial thrombosis. It is degraded into less active multimers by ADAMTS13. Patients with atrial fibrillation (AF) exhibit higher plasma vWF and lower ADAMTS13 antigen levels. The vWF/ADAMTS13-ratio might help to estimate the pro-thrombotic risk of patients with AF. We therefore investigated whether a high ratio of vWF/ADAMTS13, independently of clinical risk scores, predicts major adverse cardiovascular events (MACE) in patients with AF.

METHODS

This prospective longitudinal single center study included 269 patients with AF. Blood samples were analyzed for vWF and ADAMTS13-antigen concentration by means of enzyme-linked immunoassay kits.

RESULTS

After adjustment for all univariable predictors for MACE (p ≤ 0.1), ADAMTS13≤49.77% (HR 1.833 (95% CI 1.089-3.086); p=0.023) and vWF/ADAMTS13-ratio>27.57 (HR 2.174 (95% CI 1.238-3.817); p=0.007) remained independently associated with outcome. vWF>1434.92 mU/ml (HR 1.539 (95% CI 0.883-2.682); p=0.128) alone failed to independently predict MACE. In patients with low and intermediate risk for MACE according to the CHADS2-score the addition of high vWF/ADAMTS13-ratio levels (>27.57) had significant impact on the patients' outcome.

CONCLUSION

A high ratio of vWF/ADAMTS13 independently predicts MACE in patients with AF. Therefore, vWF and its cleaving protease ADAMTS13 might play an important role in the development and perpetuation of vascular disease in AF patients. This might be a novel target for future treatment strategies or an additional help for risk stratification in AF patients.