Comparison of C-reactive protein levels in patients who do and do not develop atrial fibrillation during electrophysiologic study

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Serum High-Sensitivity C-Reactive Protein Levels and the Risk of Atrial Fibrillation in Japanese Population: the Circulatory Risk in Communities Study

AIM

This study aimed to investigate the association between the serum high-sensitivity C-reactive protein (hs-CRP) levels and incident atrial fibrillation risk in the general Japanese population, who have lower hs-CRP levels than the Western population, and assess whether the association is modified by sex, overweight, hypertension, and smoking status.

METHODS

We conducted a prospective study in 6517 Japanese men and women aged 40-79 years without atrial fibrillation at baseline and enrolled in the Circulatory Risk in Communities Study (2002-2008). The hs-CRP levels were measured using the latex particle-enhanced immunonephelometric assay. Atrial fibrillation was identified using standard 12-lead electrocardiograms and information on physician-diagnosed atrial fibrillation history from the follow-up surveys. We used a Cox proportional hazard regression stratified by community.

RESULTS

During a median follow-up of 11 years, 127 new cases of atrial fibrillation (74 and 53 cases among men and women, respectively) were found. Compared to the lowest quintile of hs-CRP levels, the multivariable hazard ratios (95% confidence intervals) were 2.54 (1.17-5.50), 2.28 (1.06-4.93), 2.92 (1.37-6.23), and 2.77 (1.30-5.91) for the second, third, fourth, and fifth (highest) quintiles, respectively. There was no significant effect modification by sex, overweight, hypertension, and smoking status (P for interaction ＞0.05).

CONCLUSIONS

Elevated hs-CRP levels were significantly associated with increased risk of atrial fibrillation in the Japanese population. The association of hs-CRP levels with incident atrial fibrillation did not vary according to sex, overweight, hypertension status, or smoking status.

Biomarkers Associated with Stroke Risk in Atrial Fibrillation

Background:

Atrial fibrillation (AF) is associated with an increased risk of cardioembolic stroke. The risk of cardioembolism is not adequately reduced with the administration of oral anticoagulants, since a number of patients continue to experience thromboembolic events despite receiving treatment. Therefore, identification of a circulating biomarker to identify these high-risk patients would be clinically beneficial.

Objective:

In the present article, we aim to review the available data regarding use of biomarkers to predict cardioembolic stroke in patients with AF.

Methods:

We performed a thorough search of the literature in order to analyze the biomarkers identified thus far and critically evaluate their clinical significance.

Results:

A number of biomarkers have been proposed to predict cardioembolic stroke in patients with AF. Some of them are already used in the clinical practice, such as d-dimers, troponins and brain natriuretic peptide. Novel biomarkers, such as the inflammatory growth differentiation factor-15, appear to be promising, while the role of micro-RNAs and genetics appear to be useful as well. Even though these biomarkers are associated with an increased risk for thromboembolism, they cannot accurately predict future events. In light of this, the use of a scoring system, that would incorporate both circulating biomarkers and clinical factors, might be more useful.

Conclusions:

Recent research has disclosed several biomarkers as potential predictors of cardioembolic stroke in patients with AF. However, further research is required to establish a multifactorial scoring system that will identify patients at high-risk of thromboembolism, who would benefit from more intensive treatment and monitoring.

Biomarkers and arrhythmia recurrence following radiofrequency ablation of atrial fibrillation

Objective

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and radiofrequency catheter ablation of AF (RCAAF) has become increasingly popular. Cardiac stress and inflammation have been associated with AF. This study was performed to determine whether the pre- or post-AF ablation levels of high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP) are predictive of AF recurrence.

Methods

This multicenter prospective cohort study involved patients undergoing RCAAF in Switzerland and Canada. The primary endpoint was the recurrence of AF or atrial flutter at 6 months.

Results

Of 202 patients, 195 completed follow-up (age, 57.5 ± 9 years; mean left ventricular ejection fraction, 62%; mean left atrial size, 19.4 cm²). Patients with AF recurrence had larger atrial surfaces and longer total RCAAF times. Both the pre-ablation hs-CRP level and 1-day post-RCAAF NT-proBNP level were significantly associated with an increased risk of recurrence.

Conclusions

The pre-ablation hs-CRP level and immediate post-ablation NT-proBNP level were markers for atrial arrhythmia recurrence after RCAAF. This confirms growing evidence of the role of inflammation in the pathogenesis of AF. These biomarkers appear to be promising stratification tools for selection and management of patients undergoing RCAAF.

Prediction of New-Onset and Recurrent Atrial Fibrillation by Complete Blood Count Tests: A Comprehensive Systematic Review with Meta-Analysis

Background

Atrial fibrillation (AF) is one of the most critical and frequent arrhythmias precipitating morbidities and mortalities. The complete blood count (CBC) test is an important blood test in clinical practice and is routinely used in the workup of cardiovascular diseases. This systematic review with meta-analysis aimed to determine the strength of evidence for evaluating the association of hematological parameters in the CBC test with new-onset and recurrent AF.

Material/Methods

We conducted a meta-analysis of observational studies evaluating hematologic parameters in patients with new-onset AF and recurrent AF. A comprehensive subgroup analysis was performed to explore potential sources of heterogeneity.

Results

The literature search of all major databases retrieved 2150 studies. After screening, 70 studies were analyzed in the meta-analysis on new-onset AF and 23 studies on recurrent AF. Pooled analysis on new-onset AF showed platelet count (PC) (weighted mean difference (WMD)=WMD of −26.39×10⁹/L and p<0.001), mean platelet volume (MPV) (WMD=0.42 FL and p<0.001), white blood cell (WBC) (WMD=−0.005×10⁹/L and p=0.83), neutrophil to lymphocyte ratio (NLR) (WMD=0.89 and p<0.001), and red blood cell distribution width (RDW) (WMD=0.61% and p<0.001) as associated factors. Pooled analysis on recurrent AF revealed PC (WMD=−2.71×10⁹/L and p=0.59), WBC (WMD=0.20×10⁹/L (95% CI: 0.08 to 0.32; p=0.002), NLR (WMD=0.37 and p<0.001), and RDW (WMD=0.28% and p<0.001).

Conclusions

Hematological parameters have significant ability to predict occurrence and recurrence of AF. Therefore, emphasizing the potential predictive role of hematological parameters for new-onset and recurrent AF, we recommend adding the CBC test to the diagnostic modalities of AF in clinical practice.

Helicobacter pylori infection in Chinese patients with atrial fibrillation

Objective

To explore the relationship between Helicobacter pylori (Hp) infection and atrial fibrillation (AF) in Chinese patients.

Methods

A total of 285 hospitalized patients with AF and 300 patients from Health Screening Center who matched age and sex with AF group were enrolled. AF patients were divided into two groups: the short-standing AF category (less than a year) and the long-standing AF category (more than a year). All patients had laboratory testing of ¹³C urea breath test, high-sensitive C-reactive protein (hs-CRP) and left atrial diameter (LAD). We analyzed the difference of these factors in all groups and explored the correlation between Hp infection and AF using logistic regression analysis.

Results

Both AF groups had more hypertension, diabetes, and Hp infection than the control group. The Hp value and the hs-CRP level in patients with long-standing AF were higher than those in the short-standing AF and the control groups (for Hp value: P<0.001 for both and for hs-CRP level: P=0.003, 0.002, respectively). The LAD of patients in the long-standing AF group was significantly larger than those in the short-standing AF group and control group (P=0.001 and P<0.001, respectively). The values of Hp, hs-CRP, and LAD in the long-standing AF category were significantly higher than those in the short-standing AF category (all P<0.05). After controlling the potential confounders, Hp value ≥4‰, hs-CRP >5 mg/L, and LAD >36 mm were significantly related to long-standing AF.

Conclusion

The values of Hp in patients with long-standing AF were significantly higher than those in short-standing AF and control groups. Hp δ value ≥4‰ is an independent predictor for long-standing AF.

High-sensitivity troponin I for risk assessment in patients with atrial fibrillation: insights from the Apixaban for Reduction in Stroke and other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial

BACKGROUND

High-sensitivity troponin-I (hs-TnI) measurement improves risk assessment for cardiovascular events in many clinical settings, but the added value in atrial fibrillation patients has not been described.

METHODS AND RESULTS

At randomization, hs-TnI was analyzed in 14 821 atrial fibrillation patients in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial comparing apixaban with warfarin. The associations between hs-TnI concentrations and clinical outcomes were evaluated by using adjusted Cox analysis. The hs-TnI assay detected troponin (≥1.3 ng/L) in 98.5% patients, 50% had levels >5.4, 25% had levels >10.1, and 9.2% had levels ≥23 ng/L (the 99th percentile in healthy individuals). During a median of 1.9 years follow-up, annual rates of stroke or systemic embolism ranged from 0.76% in the lowest hs-TnI quartile to 2.26% in the highest quartile (>10.1 ng/L). In multivariable analysis, hs-TnI was significantly associated with stroke or systemic embolism, adjusted hazard ratio 1.98 (1.42-2.78), P=0.0007. hs-TnI was also significantly associated with cardiac death; annual rates ranged from 0.40% to 4.24%, hazard ratio 4.52 (3.05-6.70), P<0.0001, in the corresponding groups, and for major bleeding hazard ratio 1.44 (1.11-1.86), P=0.0250. Adding hs-TnI levels to the CHA2DS2VASc score improved c-statistics from 0.629 to 0.653 for stroke or systemic embolism, and from 0.591 to 0.731 for cardiac death. There were no significant interactions with study treatment.

CONCLUSIONS

Troponin-I is detected in 98.5% and elevated in 9.2% of atrial fibrillation patients. The hs-TnI level is independently associated with a raised risk of stroke, cardiac death, and major bleeding and improves risk stratification beyond the CHA2DS2VASc score. The benefits of apixaban in comparison with warfarin are consistent regardless of hs-TnI levels.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00412984.

High-sensitivity troponin T and risk stratification in patients with atrial fibrillation during treatment with apixaban or warfarin

OBJECTIVES

The aim of this study was to evaluate the prognostic value of high-sensitivity troponin T (hs-TnT) in addition to clinical risk factors and the CHA2DS2VASc (congestive heart failure, hypertension, 75 years of age and older, diabetes mellitus, previous stroke or transient ischemic attack, vascular disease, 65 to 74 years of age, female) risk score in patients with atrial fibrillation (AF).

BACKGROUND

The level of troponin is a powerful predictor of cardiovascular events and mortality.

METHODS

A total of 14,897 patients with AF were randomized to treatment with apixaban or warfarin in the ARISTOTLE (Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) trial. The associations between baseline hs-TnT levels and outcomes were evaluated using adjusted Cox regression models.

RESULTS

Levels of hs-TnT were measurable in 93.5% of patients; 75% had levels >7.5 ng/l, 50% had levels >11.0 ng/l, and 25% had levels >16.7 ng/l. During a median 1.9-year period, the annual rates of stroke or systemic embolism ranged from 0.87% in the lowest hs-TnT quartile to 2.13% in the highest hs-TnT quartile (adjusted hazard ratio [HR]: 1.94; 95% confidence interval [CI]: 1.35 to 2.78; p = 0.0010). The annual rates in the corresponding groups ranged from 0.46% to 4.24% (adjusted HR: 4.31; 95% CI: 2.91 to 6.37; p < 0.0001) for cardiac death and from 1.26% to 4.21% (adjusted HR: 1.91; 95% CI: 1.43 to 2.56; p = 0.0001) for major bleeding. Adding hs-TnT levels to the CHA2DS2VASc score improved the C statistic from 0.620 to 0.635 for stroke or systemic embolism (p = 0.0226), from 0.592 to 0.711 for cardiac death (p < 0.0001), and from 0.591 to 0.629 for major bleeding (p < 0.0001). Apixaban reduced rates of stroke, mortality, and bleeding regardless of the hs-TnT level.

CONCLUSIONS

Levels of hs-TnT are often elevated in patients with AF. The hs-TnT level is independently associated with an increased risk of stroke, cardiac death, and major bleeding and improves risk stratification beyond the CHA2DS2VASc risk score. The benefits of apixaban as compared with warfarin are consistent regardless of the hs-TnT level. (Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation [ARISTOTLE]; NCT00412984).

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.

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.