High-sensitivity cardiac troponin I and risk of incident atrial fibrillation hospitalisation in an Australian community-based cohort: The Busselton health study

The Role of Biochemical Cardiac Markers in Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Proteins are a component of cardiac biomarkers containing cell structures that are released into the circulation when a myocardial injury occurs. They are essential in the diagnosis, risk assessment, and treatment of patients who have chest pain, are thought to have acute coronary syndrome, or are experiencing acute heart failure exacerbations. There are numerous biochemical cardiac markers, but this article summarizes the basic role of major biochemical cardiac markers, including cardiac natriuretic peptides, cardiac troponins, C-reactive protein (CRP), creatine kinase-MB, heart-type fatty acid-binding protein, ischemia-modified albumin, lipoprotein (a), osteopontin (OPN), and soluble suppression of tumorigenicity 2 (sST2), in AF. Atrial natriuretic peptide may serve as an indicator of atrial integrity, which may help to select appropriate treatment approaches for AF. Higher levels of N-terminal pro-B-type natriuretic peptide and brain natriuretic peptide are predictive of incidental AF. Increased troponin T release may indicate better clinical results following AF ablation. Similarly, CRP increases the risk of the AF-increasing calcium (Ca) influx in atrial myocytes, but not because of atrial fibrosis. Patients with postoperative AF have lower FABP3 gene expression in the atrium. Lipoprotein (a) (Lp[a]) may play a causative role in the onset of AF and impact various cardiac tissues. Clinical trials for Lp(a)-lowering drugs should assess their impact on preventing AF. Also, OPN was highly expressed in the circulation of AF patients and further increased with the progression of AF. sST2 was a reliable predictor of new-onset AF and can improve the accuracy of the AF risk model. There is a greater chance that these cardiac biomarkers might be employed to enhance clinical risk stratification in AF.

Risk prediction of atrial fibrillation and its complications in the community using hs troponin I

AIMS

Atrial fibrillation (AF) is becoming increasingly common. Traditional cardiovascular risk factors (CVRF) do not explain all AF cases. Blood-based biomarkers reflecting cardiac injury such as high-sensitivity troponin I (hsTnI) may help close this gap.

METHODS

We investigated the predictive ability of hsTnI for incident AF in 45,298 participants (median age 51.4 years, 45.0% men) across European community cohorts in comparison to CVRF and established biomarkers (C-reactive protein, N-terminal pro B-type natriuretic peptide).

RESULTS

During a median follow-up of 7.7 years, 1734 (3.8%) participants developed AF. Those in the highest hsTnI quarter (≥4.2 ng/L) had a 3.91-fold (95% confidence interval (CI) 3.30, 4.63; p < .01) risk for developing AF compared to the lowest quarter (<1.4 ng/L). In multivariable-adjusted Cox proportional hazards models a statistically significant association was seen between hsTnI and AF (hazard ratio (HR) per 1 standard deviation (SD) increase in log10(hsTnI) 1.08; 95% CI 1.01, 1.16; p = .03). Inclusion of hsTnI did improve model discrimination (C-index CVRF 0.811 vs. C-index CVRF and hsTnI 0.813; p < .01). Higher hsTnI concentrations were associated with heart failure (HR per SD 1.37; 95% CI 1.12, 1.68; p < .01) and overall mortality (HR per SD 1.24; 95% CI 1.09, 1.41; p < .01).

CONCLUSION

hsTnI as a biomarker of myocardial injury does not improve prediction of AF incidence beyond classical CVRF and NT-proBNP. However, it is associated with the AF-related disease heart failure and mortality likely reflecting underlying subclinical cardiovascular impairment.

Ultrasensitive Troponin I and Incident Cardiovascular Disease

BACKGROUND

To examine the association of ultrasensitive cTnI (cardiac troponin I) with incident cardiovascular disease events (CVDs) in the primary prevention setting.

METHODS

cTnI was analyzed in the baseline plasma (2008-2012) of CVD-free volunteers from the Paris Prospective Study III using a novel ultrasensitive immunoassay (Simoa Troponin-I 2.0 Kit, Quanterix, Lexington) with a limit of detection of 0.013 pg/mL. Incident CVD hospitalizations (coronary heart disease, stroke, cardiac arrhythmias, deep venous thrombosis or pulmonary embolism, heart failure, or arterial aneurysm) were validated by critical review of the hospital records. Hazard ratios were estimated per log-transformed SD increase of cTnI in Cox models using age as the time scale.

RESULTS

The study population includes 9503 participants (40% women) aged 59.6 (6.3) years. cTnI was detected in 99.6% of the participants (median value=0.63 pg/mL, interquartile range, 0.39-1.09). After a median follow-up of 8.34 years (interquartile range, 8.0-10.07), 516 participants suffered 612 events. In fully adjusted analysis, higher cTnI (per 1 SD increase of log cTnI) was significantly associated with CVD events combined (hazard ratio, 1.18 [1.08-1.30]). Among all single risk factors, cTnI had the highest discrimination capacity for incident CVD events (C index=0.6349). Adding log cTnI to the SCORE 2 (Systematic Coronary Risk Evaluation) risk improved moderately discriminatory capacity (C index 0.698 versus 0.685; bootstrapped C index difference: 0.0135 [95% CI, 0.0131-0.0138]), and reclassification of the participants (categorical net reclassification index, 0.0628 [95% CI, 0.023-0.102]). Findings were consistent using the US pooled cohort risk equation.

CONCLUSIONS

Ultrasensitive cTnI is an independent marker of CVD events in the primary prevention setting.

Prognostic Value of High-Sensitivity Cardiac Troponin in Women

High-sensitivity cardiac troponin assays have become the gold standard for diagnosing acute and chronic myocardial injury. The detection of troponin levels beyond the 99th percentile is included in the fourth universal definition of myocardial infarction, specifically recommending the use of sex-specific thresholds. Measurable concentrations below the proposed diagnostic thresholds have been shown to inform prognosis in different categories of inpatients and outpatients. However, clinical investigations from the last twenty years have yielded conflicting results regarding the incremental value of using different cut-offs for men and women. While advocates of a sex-specific approach claim it may help reduce gender bias in cardiovascular medicine, particularly in acute coronary syndromes, other groups question the alleged incremental diagnostic and prognostic value of sex-specific thresholds, ultimately asserting that less is more. In the present review, we aimed to synthesize our current understanding of sex-based differences in cardiac troponin levels and to reappraise the available evidence with regard to (i) the prognostic significance of sex-specific diagnostic thresholds of high-sensitivity cardiac troponin assays compared to common cut-offs in both men and women undergoing cardiovascular disease risk assessment, and (ii) the clinical utility of high-sensitivity cardiac troponin assays for cardiovascular disease prevention in women.

Genetically Predicted Cardiac Troponin I Concentrations and Risk of Stroke and Atrial Fibrillation

OBJECTIVES

Observational studies have shown that elevated circulating cardiac troponin I (cTnI) concentrations were linked to higher risk of stroke and atrial fibrillation, but the causality remains unclear. Therefore, we used mendelian randomization to assess the potential causal effects of cTnI concentrations on the risk of stroke, its subtypes and atrial fibrillation.

MATERIALS AND METHODS

The instrumental variables for circulating cTnI concentrations were selected from a genome-wide association study meta-analysis of 48,115 European individuals. We examined the associations of circulating cTnI concentrations with stroke, ischemic stroke, ischemic stroke subtypes (cardioembolic, large artery, small vessel stroke), intracerebral hemorrhage and atrial fibrillation.

RESULTS

Genetically predicted elevated circulating cTnI concentrations were associated with higher risk of cardioembolic stroke (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.20-2.68; P = 0.004), but not associated with large artery stroke, small vessel stroke, total stroke, ischemic stroke and intracerebral hemorrhage. Additionally, we also found that elevated cTnI concentrations were causally linked to higher risk of atrial fibrillation (OR, 1.30; 95% CI, 1.10-1.53; P = 0.003).

CONCLUSIONS

This study provides evidence that genetically predicted circulating cTnI concentrations are causally linked to higher risk of cardioembolic stroke and atrial fibrillation.

Atrial fibrillation: is there a role for cardiac troponin?

Atrial fibrillation (AF) is the most common sustained arrhythmia, and its prevalence rate is expected to be doubled over the next decades. Despite the wide use of biomarkers in the management of different cardiac diseases such as myocardial infarction and heart failure, utilization of biomarkers in AF management is not routinely recommended by current guidelines. There is also growing evidence that higher levels of cardiac-specific troponin, as an intracellular protein involved in cardiomyocyte contraction, may be associated with the risk of incident and recurrent AF and its complications. In the present paper, we review the association between troponin and AF and propose clinical suggestions for use of troponin in the management of AF patients.

Comprehensive Use of Routine Clinical Parameters to Identify Patients at Risk of New-Onset Atrial Fibrillation in Acute Myocardial Infarction

(1) Background: New-onset atrial fibrillation (NOAF) is a significant complication of acute myocardial infarction (AMI). Our study aimed to investigate whether routinely checked clinical parameters aid in NOAF identification in modernly treated AMI patients. (2) Patients and methods: Patients admitted consecutively within 2017 and 2018 to the University Clinical Centre in Gdańsk (Poland) with AMI diagnosis (necrosis evidence in a clinical setting consistent with acute myocardial ischemia) were enrolled. Medical history and clinical parameters were checked during NOAF prediction. (3) Results: NOAF was diagnosed in 106 (11%) of 954 patients and was significantly associated with in-hospital mortality (OR 4.54, 95% CI 2.50-8.33, p < 0.001). Age, B-type natriuretic peptide (BNP), C-reactive protein (CRP), high-sensitivity troponin I, total cholesterol, low-density lipoprotein cholesterol, potassium, hemoglobin, leucocytes, neutrophil/lymphocyte ratio, left atrium size, and left ventricular ejection fraction (LVEF) were associated with NOAF in the univariate logistic analysis, whereas age ≥ 66 yo, BNP ≥ 340 pg/mL, CRP ≥ 7.7 mg/L, and LVEF ≤ 44% were associated with NOAF in the multivariate analysis. (4) Conclusions: NOAF is a multifactorial, significant complication of AMI, leading to a worse prognosis. Simple, routinely checked clinical parameters could be helpful indices of this arrhythmia in current invasively treated patients with AMI.

Biomarkers in Atrial Fibrillation: Pathogenesis and Clinical Implications

Biomarkers derived from the key components of the pathophysiology of atrial fibrillation (AF) and its complications have the potential to play an important role in earlier characterization of AF phenotype and in risk prediction of adverse clinical events, which may translate into improved management strategies. C-reactive protein, natriuretic peptides, cardiac troponins, growth differentiation factor-15, and fibroblast growth factor-23 have been shown to be the most promising biomarkers in AF. Some biomarkers have already been included in clinical risk scores to predict postoperative AF, thromboembolism, major bleeding, and death. Considerably more work is needed to bring these novel biomarkers into routine clinical management of patients with AF.

Q. M. Muskens A, Boersma E, de Groot NMS, Brundel BJJM. Evaluating Serum Heat Shock Protein Levels as Novel Biomarkers for Atrial Fibrillation

Background: Staging of atrial fibrillation (AF) is essential to understanding disease progression and the accompanied increase in therapy failure. Blood-based heat shock protein (HSP) levels may enable staging of AF and the identification of patients with higher risk for AF recurrence after treatment. Objective: This study evaluates the relationship between serum HSP levels, presence of AF, AF stage and AF recurrence following electrocardioversion (ECV) or pulmonary vein isolation (PVI). Methods: To determine HSP27, HSP70, cardiovascular (cv)HSP and HSP60 levels, serum samples were collected from control patients without AF and patients with paroxysmal atrial fibrillation (PAF), persistent (PeAF) and longstanding persistent (LSPeAF) AF, presenting for ECV or PVI, prior to intervention and at 3-, 6- and 12-months post-PVI. Results: The study population (n = 297) consisted of 98 control and 199 AF patients admitted for ECV (n = 98) or PVI (n = 101). HSP27, HSP70, cvHSP and HSP60 serum levels did not differ between patients without or with PAF, PeAF or LSPeAF. Additionally, baseline HSP levels did not correlate with AF recurrence after ECV or PVI. However, in AF patients with AF recurrence, HSP27 levels were significantly elevated post-PVI relative to baseline, compared to patients without recurrence. Conclusions: No association was observed between baseline HSP levels and the presence of AF, AF stage or AF recurrence. However, HSP27 levels were increased in serum samples of patients with AF recurrence within one year after PVI, suggesting that HSP27 levels may predict recurrence of AF after ablative therapy.

High-sensitivity troponin and the risk of atrial fibrillation in chronic kidney disease: Results from the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Patients with chronic kidney disease (CKD) are at an increased risk of atrial fibrillation (AF). There is a need for novel biomarkers to reliably and accurately predict AF in this population. High-sensitivity troponin (HsTP) allows the detection of low troponin concentrations. The utility of HsTP for evaluating the risk of AF in CKD has not been established.

OBJECTIVE

We sought to explore the association between HsTP and the risk of incident AF in CKD.

METHODS

The Chronic Renal Insufficiency Cohort is a prospective cohort of 3939 individuals with mild to moderate CKD. HsTP was measured at study enrollment. Patients with a history of AF were excluded. Patients were followed for new-onset AF, and the association between HsTP and incident AF was examined using the Cox regression model.

RESULTS

A total of 3217 participants were included. Over a median follow-up period of 7.1 years (interquartile range 5.0-8.4 years), 252 patients developed new-onset AF (12 events per 1000 person-years of follow-up). The incidence of new-onset AF was 2.46%, 7.06%, and 11.5% at 3, 6, and 9 years, respectively. Compared with the lowest quartile of HsTP, patients in the third quartile of HsTP (hazard ratio 2.40; 95% confidence interval 1.58-3.65; P < .001) and the fourth quartile of HsTP (hazard ratio 4.43; 95% confidence interval 2.98-6.59; P < .001) had a higher incidence of AF.

CONCLUSION

HsTP levels are associated with an increased risk of AF in patients with mild to moderate CKD. This association remains significant despite adjustment for traditional AF risk factors and chronic renal disease.

Prognostication of clinical outcomes in diabetes mellitus: Emerging role of cardiac biomarkers

Type 2 diabetes mellitus (T2DM) remains substantial health problem and one of the most prevalent metabolic diseases worldwide. The impact of T2DM on CV mortality and morbidity is embedded through a nature evolution of the disease and is modulated by numerous risk factors, such as hypertension, obesity, dyslipidemia. There is large body of evidence regarding use of the cardiac biomarkers to risk stratification at higher CV risk individuals who belongs to general population and cohort with established CV disease. Although T2DM patients have higher incidence of cardiac and vascular complications than the general population, whether cardiac biomarkers would be effective to risk stratification of the T2DM is not fully understood. The aim of the review is to summarize our knowledge regarding clinical implementation of cardiac biomarkers in risk assessment for T2DM patients. The role of natriuretic peptides, soluble ST2, galectin-3, growth differentiation factor-15, and cardiac troponins are widely discussed.