Prognostic role of high-sensitivity cardiac troponin T in patients with nonischemic dilated cardiomyopathy

A Case Study and Literature Review of the Diagnosis of Danon Disease in Patients Presenting Only with Severe Cardiac Symptoms

The clinical manifestations of Danon disease, which result from the primary deficiency of the lysosome-associated membrane protein 2 gene, include cardiomyopathy, skeletal myopathy, and different degrees of intellectual disability that vary greatly among patients. The present study reports on two cases of Danon disease in two patients who only presented cardiac symptoms. Cardiac symptoms usually occur in adolescence and during a patient's twenties, and most patients die from heart failure. However, the lab results from these cases suggested that other systems were involved, despite no other clinical symptoms. Significantly, the two patients had elevated serum cardiac troponin I, which often manifests in the acute cardiac phase, especially in severely affected patients with rapidly fatal outcomes. Danon disease is a multi-system involvement disease. Therefore, clinicians must be aware of its complexity when evaluating newly diagnosed patients due to its vastly different clinical course and prognosis and the importance of multidisciplinary management.

Different expression and prognostic value of troponin in ischemic cardiomyopathy and non-ischemic dilated cardiomyopathy

BACKGROUND

Early risk stratification of patients with ischemic cardiomyopathy (ICM) and non-ischemic dilated cardiomyopathy (NIDCM) may be beneficial for therapies.

METHODS

We retrospectively enrolled all patients admitted for acute heart failure (HF) between January 2019 and December 2021 in Zhongshan Hospital Fudan University, dividing them according to etiology (ICM or NIDCM). Cardiac troponin T (TNT) concentration was compared between two groups. Risk factors for positive TNT and in-hospital all-cause mortality were investigated with regression analysis.

RESULTS

A total of 1525 HF patients were enrolled, including 571 ICM and 954 NIDCM. The TNT positive patients were not different between the two groups (41.3% in ICM group vs. 37.8% in NIDCM group, P = 0.215). However, the TNT value in ICM group were significantly higher than that in NIDCM group (0.025 (0.015-0.053) vs. 0.020 (0.014-0.041), P = 0.001). NT-proBNP was independently associated with TNT in both ICM and NIDCM group. Although the in-hospital all-cause mortality did not show much difference between the two groups (1.1% vs. 1.9%, P = 0.204), the NIDCM diagnosis was associated with reduced risk of mortality after multiple adjustments (OR 0.169, 95% CI 0.040-0.718, P = 0.016). Other independent risk factors included the level of NT-proBNP (OR 8.260, 95% CI 3.168-21.533, P < 0.001), TNT (OR 8.118, 95% CI 3.205-20.562, P < 0.001), and anemia (OR 0.954, 95% CI 0.931-0.978, P < 0.001). The predictive value of TNT and NT-proBNP for all-cause mortality was similar. However, the best cutoff values of TNT for mortality were different between ICM and NIDCM groups, which were 0.113 ng/mL and 0.048 ng/mL, respectively.

CONCLUSION

The TNT level was higher in ICM patient than that in NIDCM patients. TNT was an independent risk factor for in-hospital all-cause mortality for both ICM and NIDCM patients, although the best cutoff value was higher in ICM patients.

Clinical implications of cardiac troponin-I in patients with hypertensive crisis visiting the emergency department

OBJECTIVES

Cardiac troponin-I (cTnI) is a representative marker of myocardial injury. Elevation of cTnI is frequently observed in patients with hypertensive crisis, but few studies have examined its prognostic significance in hypertensive crisis. We aimed to determine whether cTnI could predict all-cause mortality in patients with hypertensive crisis visiting the emergency department (ED).

METHODS

This observational study included patients aged ≥18 years who visited an ED between 2016 and 2019 for hypertensive crisis, defined as systolic blood pressure (BP) ≥180 mmHg and/or diastolic BP ≥110 mmHg. Among 6467 patients, 3938 who underwent a cTnI assay were analysed.

RESULTS

Among the 3938 patients, 596 (15.1%) had cTnI levels above the 99th percentile upper reference limit (elevated cTnI >40 ng/L) and 600 (15.2%) had cTnI levels between the detection limit (≥10 ng/L) and the 99th percentile upper reference limit (detectable cTnI). The 3-year all-cause mortality in the elevated, detectable and undetectable cTnI groups were 41.6%, 36.5% and 12.8%, respectively. After adjusting for confounding variables, elevated cTnI patients (adjusted hazard ratio [HR], 2.01; 95% confidence interval [CI], 1.61-2.52) and detectable cTnI patients (adjusted HR, 1.64; 95% CI, 1.32-2.04) showed a significantly higher risk of 3-year all-cause mortality than did patients with undetectable cTnI.

CONCLUSIONS

In patients with hypertensive crisis, elevated cTnI levels provide useful prognostic information and permit the early identification of patients with an increased risk of death. Moreover, putatively normal but detectable cTnI levels also significantly correlated with a higher risk of all-cause mortality. Intensive treatment and follow-up strategies are needed for patients with hypertensive crisis with elevated and detectable cTnI levels.Key messagesCardiac troponin-I level was an independent prognostic factor for all-cause mortality in patients with hypertensive crisis.Detectable but normal range cardiac troponin-I, which was considered clinically insignificant, also had a prognostic impact on all-cause mortality comparable to elevated cardiac troponin-I levels.

Left ventricular strain patterns and their relationships with cardiac biomarkers in hypertrophic cardiomyopathy patients with preserved left ventricular ejection fraction

Aims

This study aims to assess left ventricular (LV) function in hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction (LVEF) by LV strain patterns based on cardiac magnetic resonance feature tracking (CMR-FT) and to explore the relationships between LV strain patterns and cardiac biomarkers in these patients, such as cardiac troponin (cTnT) and N-terminal prohormone of the brain natriuretic peptide (NT-proBNP).

Methods

A total of 64 HCM patients with preserved LVEF and 33 healthy people were included in this study. All subjects underwent contrast-enhanced CMR, and all patients took blood tests for cTnT and NT-proBNP during hospitalization.

Results

Despite the absence of a significant difference in LVEF between HCM patients and healthy controls, almost all global and segmental strains in radial, circumferential, and longitudinal directions in the HCM group deteriorated significantly as compared to controls (p < 0.05). Moreover, some global and segmental strains correlated significantly with NT-proBNP and cTnT in HCM patients, and the best correlations were global radial strain (GRS) (r = -0.553, p < 0.001) and mid-ventricular radial strain (MRS) (r = -0.582, p < 0.001), respectively, with a moderate correlation. The receiver operating characteristic (ROC) results showed that among the LV deformation parameters, GRS [area under the curve (AUC), 0.76; sensitivity, 0.49; specificity, 1.00], MRS (AUC, 0.81; sensitivity, 0.77; specificity, 0.79) demonstrated greater diagnostic accuracy to predict elevated NT-proBNP, and abnormal cTnT, respectively. Their cut-off values were 21.17 and 20.94%, respectively. Finally, all global strains demonstrated moderate, good, and excellent intra- and inter-observer reproducibility.

Conclusion

LV strain patterns can be used to assess the subclinical cardiac function of HCM patients on the merit of being more sensitive than LVEF. In addition, LV strain patterns can detect serious HCM patients and may be helpful to non-invasively predict elevated NT-proBNP and cTnT.

Pediatric and adult dilated cardiomyopathy are distinguished by distinct biomarker profiles

BACKGROUND

Emerging evidence suggests that pediatric and adult dilated cardiomyopathy (DCM) represent distinct diseases. Few diagnostic tools exist for pediatric cardiologists to assess clinical status and prognosis. We hypothesized that pediatric DCM would have a unique biomarker profile compared to adult DCM and controls.

METHODS

We utilized a DNA aptamer array (SOMAScan) to compare biomarker profiles between pediatric and adult DCM. We simultaneously measured 1310 plasma proteins and peptides from 39 healthy children (mean age 3 years, interquartile range (IQR) 1-14), 39 ambulatory subjects with pediatric DCM (mean age 2.7 years, IQR 1-13), and 40 ambulatory adults with DCM (mean age 53 years, IQR 46-63).

RESULTS

Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics. We identified 20 plasma peptides and proteins that were increased in pediatric DCM compared to age- and sex-matched controls. Unbiased multidimensionality reduction analysis suggested previously unrecognized heterogeneity among pediatric DCM subjects. Biomarker profile analysis identified four subgroups of pediatric DCM with distinguishing clinical characteristics.

CONCLUSIONS

These findings support the emerging concept that pediatric and adult DCM are distinct disease entities, signify the need to develop pediatric-specific biomarkers for disease prognostication, and challenge the paradigm that pediatric DCM should be viewed as a single disease.

IMPACT

Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics and outcomes. Our findings suggest that pediatric DCM may be a heterogeneous disease with various sub-phenotypes, including differing biomarker profiles and clinical findings. These data provide prerequisite information for future prospective studies that validate the identified pediatric DCM biomarkers, address their diagnostic accuracy and prognostic significance, and explore the full extent of heterogeneity amongst pediatric DCM patients.

Well-Known and Novel Serum Biomarkers for Risk Stratification of Patients with Non-ischemic Dilated Cardiomyopathy

Non-ischemic dilated cardiomyopathy encompasses a wide spectrum of myocardial disorders, characterized by left ventricular dilatation with systolic impairment and increased risk of sudden cardiac death. In spite of all the therapeutic progress that has been made in recent years, dilated cardiomyopathy continues to be an important cause of cardiac transplant, being associated with an enormous cost burden for health care systems worldwide. Predicting the prognosis of patients with dilated cardiomyopathy is essential to individualize treatment. Late gadolinium enhancement-cardiac magnetic resonance imaging, microvolt T-wave alternans, and genetic testing have emerged as powerful tools in predicting sudden cardiac death occurrence and maximizing patient's selection. Despite all these new diagnostic modalities, additional tests to complement or replace current tools are required for better risk stratification. Therefore, biomarkers are an easy and important tool that can help to detect patients at risk of adverse cardiovascular events. Additionally, identifying potential biomarkers involved in dilated cardiomyopathy can provide us important information regarding the diagnostic, prognostic, risk stratification, and response to treatment for these patients. Many potential biomarkers have been studied in patients with dilated cardiomyopathy, but only a few have been adopted in current practice. Therefore, the aim of our review is to provide the clinicians with an update on the well-known and novel biomarkers that can be useful for risk stratification of patients with non-ischemic dilated cardiomyopathy.

The prognostic role of high-sensitivity cardiac troponin T over time in ischemic and non-ischemic heart failure

INTRODUCTION

High-sensitivity cardiac troponin T (hs-cTnT) as a prognostic biomarker can be detected in patients with heart failure (HF).

AIM

This study focuses on hs-cTnT to evaluate its prognostic role in ischemic heart failure (IHF) and non-ischemic heart failure (NIHF).

MATERIAL AND METHODS

One hundred and sixty patients with HF were divided into IHF and NIHF groups. Hs-cTnT measured at baseline, 2-5 h, 6-24 h and 24 h-7 d after admission was analyzed by generalized estimating equations. Patients were followed up for 1 year at the endpoint events of re-hospitalization for HF and all-cause death that was tested by the Kaplan-Meier method and the Cox regression method.

RESULTS

Hs-cTnT varied significantly over time, first increasing and then decreasing in IHF while showing a continuously elevated trend in NIHF. Patients with hs-cTnT levels > 0.014 ng/ml had a significantly higher re-hospitalization rate compared with those with hs-cTnT levels ≤ 0.014 ng/ml (23.7% vs. 7.0%, p < 0.05). Adjusted for age, New York Heart Association class, N-terminal pro-B-type natriuretic peptide, and left ventricular ejection fraction, baseline hs-cTnT was independently associated with re-hospitalization and all-cause death in HF (p < 0.05). Optimal hs-cTnT cut-off of 0.0275 ng/ml was derived to predict the re-hospitalization and death in IHF (AUC = 0.709, 95% CI: 0.561-0.856, sensitivity: 76.9%, specificity: 63.5%, p < 0.05).

CONCLUSIONS

Hs-cTnT varying over time is an important risk factor for the prognosis of patients with IHF and NIHF.

Are troponin and B-type natriuretic peptides useful biomarkers for the diagnosis of systemic sclerosis heart involvement? A systematic literature review

BACKGROUND

Systemic sclerosis (SSc) heart involvement (SHI) is a leading cause of SSc-associated mortality and once clinically overt, carries a very poor prognosis. There remain no established diagnostic criteria for SHI. This study aimed to systematically review the literature regarding the role of cardiac troponin (cTn) and B-type natriuretic peptide (BNP) or N-terminal B-type natriuretic peptide (NT-proBNP) in the diagnosis of SHI.

METHODS

A comprehensive search of the MEDLINE (Ovid), EMBASE and Pubmed databases was performed to identify adult human studies of at least 10 SSc patients with a primary focus of SHI that included data on cTn and BNP or NT-proBNP results. Only cohort studies and case-controlled studies were identified and the quality of the evidence presented in each study was assessed according to the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

Of the 2742 studies identified by the database search, 12 articles fulfilled the study inclusion criteria. Three out of four studies evaluating SHI using cardiac magnetic resonance imaging found no association between cardiac biomarkers and imaging changes. By comparison echocardiographic abnormalities, cardiac arrhythmias and congestive cardiac failure were more likely to be associated with elevated cardiac biomarkers. Comparison of results between studies was limited by the highly heterogenous definitions of SHI and inclusion criteria employed across studies.

CONCLUSION

There are insufficient data to draw definitive conclusions about the role of cTn and BNP / NT-proBNP in the diagnosis of SHI. Currently available literature suggests that cardiac biomarkers may have some role, in conjunction with other diagnostic modalities, in identifying SHI; however, this remains a much-needed area of clinical research.

Elevation of high-sensitivity cardiac troponin T and left ventricular remodelling in hypertrophic cardiomyopathy

Aims

Hypertrophic cardiomyopathy (HCM) is generally associated with mild disability and normal life expectancy. On the other hand, once the end‐stage phase of HCM characterized by left ventricular (LV) ejection fraction < 50% is established, patients with this subtype have a poor prognosis. This study clarifies the clinical parameters associated with progression to end‐stage HCM.

Methods and results

We retrospectively studied 157 HCM patients (age 59.9 ± 14.2 years, 104 men) with preserved LV systolic function in whom subsequent echocardiographic data were obtained for a period of >1 year. HCM progressed to end‐stage HCM in 13 patients (8.3%) of the 157 patients during a mean follow‐up period of 6.3 ± 2.8 years. Compared with patients who did not reach end‐stage HCM at the last evaluation, patients with progression to the end‐stage phase had lower ejection fraction, larger LV size, more enlarged left atrial diameter, longer follow‐up period, and higher frequency of an elevated concentration of high‐sensitivity cardiac troponin T (hs‐cTnT; >0.014 ng/mL) at registration. Multivariate analysis revealed that elevated hs‐cTnT was a significant predictor independent of lower LV ejection fraction for progression to end‐stage HCM. Furthermore, in patients with elevated hs‐cTnT levels, LV ejection fraction became significantly lower, LV end‐diastolic diameter increased, and LV wall thickness decreased during the follow‐up period, whereas those parameters did not change in the normal hs‐cTnT group.

Conclusions

In patients with HCM, an elevated hs‐cTnT was associated with progression of LV remodelling, and this biomarker can be useful for predicting progression to the end‐stage phase.

Is the true clinical value of high-sensitivity troponins as a biomarker of risk? The concept that detection of high-sensitivity troponin 'never means nothing'

INTRODUCTION

High-sensitivity troponin (hs-cTn) assays are central to the diagnosis of myocardial infarction (MI). Their increased sensitivity has facilitated rapid pathways for the exclusion of MI. However, hs-cTn is now more readily detectable in patients without symptoms typical of MI, in whom a degree of myocardial injury is assumed. Recently, the practice of using the 99^th centile of hs-cTn as a working 'upper reference limit' has been challenged. There is increasing evidence that hs-cTn may provide useful prognostic information, regardless of any suspicion of MI, and as such these assays may have potential as a general biomarker for mortality. This raises the concept that detection of hs-cTn 'never means nothing.'

AREAS COVERED

In this review, we will evaluate the evidence for the use of hs-cTn assays outside their common clinical indication to rule out or diagnose acute MI.

EXPERT OPINION

The data presented suggest that hs-cTn testing may in the future have a generalized role as a biomarker of mortality risk and may be used less as a test for ruling in acute MI, but will remain a frontline test to exclude that diagnosis in ED. Further, the data suggest that the detection of hs-cTn 'never means nothing.'

Classic and Novel Biomarkers as Potential Predictors of Ventricular Arrhythmias and Sudden Cardiac Death

Sudden cardiac death (SCD), most often induced by ventricular arrhythmias, is one of the main reasons for cardiovascular-related mortality. While coronary artery disease remains the leading cause of SCD, other pathologies like cardiomyopathies and, especially in the younger population, genetic disorders, are linked to arrhythmia-related mortality. Despite many efforts to enhance the efficiency of risk-stratification strategies, effective tools for risk assessment are still missing. Biomarkers have a major impact on clinical practice in various cardiac pathologies. While classic biomarkers like brain natriuretic peptide (BNP) and troponins are integrated into daily clinical practice, inflammatory biomarkers may also be helpful for risk assessment. Indeed, several trials investigated their application for the prediction of arrhythmic events indicating promising results. Furthermore, in recent years, active research efforts have brought forward an increasingly large number of “novel and alternative” candidate markers of various pathophysiological origins. Investigations of these promising biological compounds have revealed encouraging results when evaluating the prediction of arrhythmic events. To elucidate this issue, we review current literature dealing with this topic. We highlight the potential of “classic” but also “novel” biomarkers as promising tools for arrhythmia prediction, which in the future might be integrated into clinical practice.

Plasma levels of melatonin in dilated cardiomyopathy

BACKGROUND

Melatonin is a multifunctional indolamine and has a cardioprotective role in a variety of cardiovascular processes via antioxidant, anti-inflammatory, antihypertensive, antithrombotic, and antilipemic effects. It has been reported that lower levels of circulating melatonin are significantly associated with a higher risk of acute myocardial infarction (AMI) and later cardiac remodeling. However, levels of melatonin in patients with dilated cardiomyopathy (DCM) and associations between melatonin levels and cardiac function remain unclear.

METHODS AND RESULTS

We measured and compared plasma levels of melatonin in 61 control subjects, 81 AMI patients, and 77 DCM patients. Plasma levels of melatonin were progressively decreased from 71.9 pg/mL in the control group to 52.6 pg/mL in the DCM group and 21.9 pg/mL in the AMI group. Next, we examined associations of melatonin levels with parameters of laboratory data, echocardiography, and right-heart catheterization. In the DCM patients, circulating melatonin showed significant correlations with both high-sensitivity troponin T (R = -0.422, P < 0.001) and cardiac output (R = 0.431, P = 0.003), but not with B-type natriuretic peptide (BNP), left ventricular ejection fraction (LVEF), pulmonary artery wedge pressure, or pulmonary artery pressure.

CONCLUSION

Patients with not only AMI but also DCM had lower circulating melatonin levels. Circulating melatonin levels appear to correlate with myocardial injury and cardiac output in DCM patients.

Redefining biomarkers in heart failure

Heart failure (HF) is the end result of many different cardiac and non-cardiac abnormalities leading to a complex clinical entity. In this view, the use of biomarkers in HF should be deeply reconsidered; indeed, the same biomarker may carry a different significance in patients with preserved or reduced EF. The aim of this review is to reconsider the role of biomarkers in HF, based on the different clinical characteristics of this syndrome. The role of cardiac and non-cardiac biomarkers will be reviewed with respect of the different clinical manifestations of this syndrome.

The usefulness of selected biomarkers in aortic regurgitation

BACKGROUND

The aim of the study was to investigate the prognostic value of selected biomarkers in patients with aortic regurgitation undergoing valve surgery.

METHODS

A prospective study was conducted on a group of consecutive patients with hemodynamically significant aortic regurgitation that underwent elective aortic valve surgery. The primary endpoint was 30-day mortality and any major adverse event within 30 days.

RESULTS

The study group included 205 consecutive patients who underwent replacement or repair of the aortic valve. The primary endpoint occurred in 72 patients. At multivariate analysis red cell distribution width (RDW; p = 0.03) and high-sensitivity troponin T (hs-TnT; p = 0.02) remained independent predictors of the major complications including death.

CONCLUSIONS

Elevated preoperative RDW and hs-TnT were associated with a poorer outcome following aortic valve surgery.

Heterogeneity in a large pedigree with Danon disease: Implications for pathogenesis and management

BACKGROUND

Danon disease is an X-linked disturbance of autophagy manifesting with cognitive impairment and disordered heart and skeletal muscle. After a period of relative stability, patients deteriorate rapidly and may quickly become ineligible for elective heart transplantation - the only life-saving therapy.

METHODS

We report a large pedigree with diverse manifestations of Danon disease in hemizygotes and female heterozygotes.

RESULTS

Malignant cardiac arrhythmias requiring amiodarone treatment induced thyroid disease in two patients; intractable thyrotoxicosis, which enhances autophagy, caused the death of a 21year-old man. Our patients also had striking elevation of serum troponin I during the accelerated phase of their illness (p<0.01) and rising concentrations heralded cardiac decompensation. We argue for changes to cardiac transplantation eligibility criteria.

CONCLUSION

Danon disease causes hypertrophic cardiomyopathy - here we propose a common pathophysiological basis for the metabolic and structural effects of this descriptive class of heart disorders. We also contend that troponin I may have prognostic value and merits exploration for clinical decision-making including health warning bracelets. Rapamycin (Sirolimus®), an approved immunosuppressant which also influences autophagy, may prove beneficial. In the interim, while new treatments are developed, a revaluation of cardiac transplantation eligibility criteria is warranted.

How is cardiac troponin released from injured myocardium?

Cardiac troponin I and cardiac troponin T are nowadays the criterion biomarkers for the laboratory diagnosis of acute myocardial infarction due to their very high sensitivities and specificities for myocardial injury. However, still many aspects of their degradation, tissue release and elimination from the human circulation are incompletely understood. Myocardial injury may be caused by a variety of different mechanisms, for example, myocardial ischaemia, inflammatory and immunological processes, trauma, drugs and toxins, and myocardial necrosis is preceded by a substantial reversible prelethal phase. Recent experimental data in a pig model of myocardial ischaemia demonstrated cardiac troponin release into the circulation from apoptotic cardiomyocytes as an alternative explanation for clinical situations with increased cardiac troponin without any other evidence for myocardial necrosis. However, the comparably lower sensitivities of all currently available imaging modalities, including cardiac magnetic resonance imaging for the detection of particularly non-focal myocardial necrosis in patients, has to be considered for cardiac troponin test result interpretation in clinical settings without any other evidence for myocardial necrosis apart from increased cardiac troponin concentrations as well.

Diagnostic utility of cardiac troponin T level in patients with cardiac amyloidosis

AIM

The aim of this study was to evaluate the diagnostic utility of high-sensitivity cardiac troponin T (hs-cTnT) levels in discriminating cardiac amyloidosis from patients with cardiac hypertrophy caused by aetiologies other than cardiac amyloidosis.

METHODS AND RESULTS

Serum hs-cTnT levels were measured in 96 patients with cardiac amyloidosis (light chain: 23, wild-type transthyretin amyloidosis: 40, and mutated transthyretin amyloidosis: 33), and 91 patients with other causes of cardiac hypertrophy who were confirmed to have no cardiac amyloidosis by endomyocardial biopsy (control group). The diagnostic utility and cut-off value of hs-cTnT were evaluated by receiver operating characteristic analysis. The median hs-cTnT levels were higher in cardiac amyloidosis than the control group [0.048 (0.029-0.073) vs. 0.016 (0.010-0.031) ng/mL; P < 0.001]. High levels of hs-cTnT were suggestive of cardiac amyloidosis (cut-off value: 0.0312 ng/mL, sensitivity: 0.74, specificity: 0.76, area under the curve: 0.788; 95% confidence interval: 0.723-0.854, P < 0.001), compared with brain natriuretic peptide and E/e' ratio. The hs-cTnT levels were also useful in differentiating each type of amyloidosis from the control group. Multivariate analysis identified log hs-cTnT as an independent diagnostic factor for cardiac amyloidosis (odds ratio: 2.22; 95% confidence interval: 1.30-3.80; P = 0.004).

CONCLUSIONS

High serum levels of hs-cTnT are highly suggestive of cardiac amyloidosis, allowing its differentiation from cardiac hypertrophy of other aetiologies. Further refined diagnostic approaches that include imaging modalities and histopathological examination are needed for these patients to avoid underdiagnosis of cardiac amyloidosis.

Moving sum of number of positive patient result as a quality control tool

Background:

Recently, the total prostate-specific antigen (PSA) assay used in a laboratory had a positive bias of 0.03 μg/L, which went undetected. Consequently, a number of post-prostatectomy patients with previously undetectable PSA concentrations (defined as <0.03 μg/L in that laboratory) were being reported as having detectable PSA, which suggested poorer prognosis according to clinical guidelines.

Methods:

Through numerical simulations, we explored (1) how a small bias may evade the detection of routine quality control (QC) procedures with specific reference to the concentration of the QC material, (2) whether the use of ‘average of normals’ approach may detect such a small bias, and (3) describe the use of moving sum of number of patient results with detectable PSA as an adjunct QC procedure.

Results:

The lowest QC level (0.86 μg/L) available from a commercial kit had poor probability (<10%) of a bias of 0.03 μg/L regardless of QC rule (i.e. 1:2S, 2:2S, 1:3S, 4:1S) used. The average number of patient results affected before error detection (ANPed) was high when using the average of normals approach due to the relatively wide control limits. By contrast, the ANPed was significantly lower for the moving sum of number of patient results with a detectable PSA approach.

Conclusions:

Laboratory practitioners should ensure their QC strategy can detect small but critical bias, and may require supplementation of ultra-low QC levels that are not covered by commercial kits with in-house preparations. The use of moving sum of number of patient results with a detectable result is a helpful adjunct QC tool.

Identification of the molecular mechanisms underlying dilated cardiomyopathy via bioinformatic analysis of gene expression profiles

In the present study, gene expression profiles of patients with dilated cardiomyopathy (DCM) were re-analyzed with bioinformatics tools to investigate the molecular mechanisms underlying DCM. Gene expression dataset GSE3585 was downloaded from Gene Expression Omnibus, which included seven heart biopsy samples obtained from patients with DCM and five healthy controls. Differential analysis was performed using a Limma package in R to screen for differentially expressed genes (DEGs). Functional enrichment analysis was subsequently conducted for DEGs using the Database for Annotation, Visualization and Integration Discovery. A protein-protein interaction (PPI) network was constructed using information from Search Tool for the Retrieval of Interacting Genes software. A total of 89 DEGs were identified in the patients with DCM, including 67 upregulated and 22 downregulated genes. Functional enrichment analysis demonstrated that the downregulated genes predominantly encoded chromosomal proteins and transport-related proteins, which were significantly associated with the biological processes of ‘nucleosome assembly’, ‘chromatin assembly’, ‘protein-DNA complex assembly’, ‘nucleosome organization’ and ‘DNA packaging’ (H1 histone family member 0, histone cluster 1 H1c, histone cluster 1 H2bd and H2A histone family member Z). The upregulated genes detected in the present study encoded secreted proteins or phosphotransferase, which were associated with biological processes including ‘cell adhesion’ [connective tissue growth factor (CTGF)], ‘skeletal system development’ [CTGF and insulin-like growth factor binding protein 3 (IGFBP3)], ‘muscle organ development’ (SMAD7) and ‘regulation of cell migration’ [SMAD7, IGFBP3 and insulin receptor (INSR)]. Notably, signal transducer and activator of transcription 3, SMAD7, INSR, CTGF, exportin 1, IGFBP3 and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha were hub nodes with the higher degree in the PPI network. Therefore, the results of the present study suggested that DEGs may alter the biological processes of ‘nucleosome formation’, ‘cell adhesion’, ‘skeletal system development’, ‘muscle organ development’ and ‘regulation of cell migration’ in the development of DCM.

Myocardial ischaemia after hip and knee arthroplasty: incidence and risk factors

PURPOSE

Because the occurrence of postoperative myocardial ischaemia (MI) predicts subsequent cardiac morbidity and mortality, we determined the prevalence of and risk factors for MI in hip and knee arthroplasty patients.

METHODS

High-sensitivity cardiac troponin T (hs-cTnT) was measured on stored samples from postoperative day two in 394 hip and knee arthroplasty patients ≥ 65 years of age enrolled in the Genetics-InFormatics Trial (GIFT).

RESULTS

Fifty-three (13.5 %) participants had MI, of whom only three were diagnosed clinically during their hospitalisation. The risk of MI increased with age [odds ratio (OR) 3.52 per decade, 95 % confidence interval (CI) 2.00-6.19] and diabetes (OR 2.23, 95 % CI 1.04-4.77). MI was rarer with statins (OR 0.74, 95 % CI 0.40-1.35) and more common with hypertension, coronary artery disease and tobacco use, although these were not statistically significant.

CONCLUSIONS

Subclinical MI occurs frequently after arthroplasty. Diabetic and elderly patients are at highest risk.

Implications of Introducing High-Sensitivity Cardiac Troponin T Into Clinical Practice: Data From the SWEDEHEART Registry

BACKGROUND

Cardiac troponin is the preferred biomarker for diagnosing myocardial infarction (MI).

OBJECTIVES

The aim of this study was to examine the implications of introducing high-sensitivity cardiac troponin T (hs-cTnT) into clinical practice and to define at what hs-cTnT level risk starts to increase.

METHODS

We analyzed data from 48,594 patients admitted because of symptoms suggesting an acute coronary syndrome and who were entered into a large national registry. Patients were divided into Group 1, those with hs-cTnT<6 ng/l; Group 2, those with hs-cTnT 6 to 13 ng/l; Group 3, those with hs-cTnT 14 to 49 ng/l (i.e., a group in which most patients would have had a negative cardiac troponin T with older assays); and Group 4, those with hs-cTnT≥50 ng/l.

RESULTS

There were 5,790 (11.9%), 6,491 (13.4%), 10,476 (21.6%), and 25,837 (53.2%) patients in Groups 1, 2, 3, and 4, respectively. In Groups 1 to 4, the proportions with MI were 2.2%, 2.6%, 18.2%, and 81.2%. There was a stepwise increase in the proportion of patients with significant coronary stenoses, left ventricular systolic dysfunction, and death during follow-up. When dividing patients into 20 groups according to hs-cTnT level, the adjusted mortality started to increase at an hs-cTnT level of 14 ng/l.

CONCLUSIONS

Introducing hs-cTnT into clinical practice has led to the recognition of a large proportion of patients with minor cardiac troponin increases (14 to 49 ng/l), the majority of whom do not have MI. Although a heterogeneous group, these patients remain at high risk, and the adjusted mortality rate started to increase at the level of the 99th percentile in healthy controls.

Clinical significance of high-sensitivity cardiac troponin T in patients with dilated cardiomyopathy

Although conventional cardiac troponin T (cTnT) and I (cTnI) markers have been reported to predict adverse outcome in dilated cardiomyopathy (DCM), the usefulness of a new-generation high-sensitivity assay of cardiac troponin T (hs-cTnT) compared with these conventional biomarkers is unclear.We performed clinical evaluation including measurements of troponin markers in 54 patients with DCM under a clinically stable condition. At baseline, the serum concentration of hs-cTnT was 0.014 ± 0.016 ng/mL and 17 (31%) of the patients showed abnormal hs-cTnT values (> 0.014 ng/mL). During a mean follow-up period of 5.1 ± 1.6 years, there were 16 cardiac events: heart failure death in 6 patients, sudden cardiac death in 2 patients, and hospitalization for heart failure in 8 patients. Patients with abnormal hs-cTnT or abnormal cTnT (> 0.01 ng/mL) values had significantly more frequent cardiac events than did those with normal hs-cTnT or cTnT values. On the other hand, abnormal cTnI (> 0.03 ng/mL) value did not reach statistical significance for these adverse events. Multivariate analysis showed that only an abnormal hs-cTnT value was an independent predictor of all cardiac events (HR: 5.68, P = 0.003). When the patients were divided into 4 groups according to the degree of hs-cTnT levels, the clinical course was significantly worse in patients with higher hs-cTnT values.These results suggest that the serum concentration of hs-cTnT provides better risk stratification in DCM patients.

Transport stress induces apoptosis in rat myocardial tissue via activation of the mitogen-activated protein kinase signaling pathways

The present study aimed to elucidate the mechanism of myocardial damage induced by simulated transport stress. Sprague-Dawley rats were subjected to 35 °C and 60 rpm (0.1×g rcf) on a constant temperature shaker. The blood samples were prepared for detection of epinephrine (E), norepinephrine (NE), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and serum cardiac troponin T (cTNT); myocardium samples were prepared for morphological examination and signaling protein quantitative. The result showed that plasma norepinephrine (NE) and epinephrine (E) concentrations increased in all stressed groups (P < 0.01). Levels of serum cardiac troponin T (cTNT) were elevated in both the S2d (P < 0.05) and S3d groups (P < 0.01). The concentration of plasma BNP was increased significantly in S3d group (P < 0.05); the difference in ANP was not remarkable. Morphological observation demonstrated obvious microstructure and ultrastructure damage after simulated transport stress. There was also a significant increase in the number of TUNEL-positive cardiomyocytes in stressed hearts. Western blot analysis found that the mitogen-activated protein kinase (MAPK) pathways were activated by strengthening phosphorylation of ASK-1, JNK, P38 and ERK in rat myocardial tissue after simulated transport stress (P < 0.05, P < 0.01). In addition, the ratio of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins was increased in stressed rats (P < 0.01), and the amount of cleaved-caspase3 increased in all stressed rats (P < 0.01). The expression of cleaved-caspase9 protein was also elevated in S2d and S3d groups (P < 0.01). Consequently simulated transport stress induced obvious myocardial damage, which may be attributed to the activation of caspase 9-mediated mitochondrial apoptotic pathway and MAPK pathways.

Correlation between extent of myocardial fibrosis assessed by cardiac magnetic resonance and cardiac troponin T release in patients with nonischemic heart failure

Persistently high cardiac troponin T (cTnT) levels reflect myocardial damage in heart failure (HF). The presence and extent of myocardial fibrosis assessed by cardiac magnetic resonance (CMR) and high levels of cTnT predict poor prognosis in various cardiomyopathies. However, the association between myocardial fibrosis and transcardiac cTnT release has not been evaluated. This study investigated the correlation between myocardial fibrosis and transcardiac cTnT release from nonischemic failing myocardium. Serum cTnT levels were measured in aortic root (Ao) and coronary sinus (CS) using highly sensitive assay (detection limit >5 ng/L) in 74 nonischemic patients with HF who underwent CMR. Transcardiac cTnT release (ΔcTnT [CS-Ao]) represented the difference between CS and Ao-cTnT levels. Myocardial fibrosis was quantified by late gadolinium enhancement (LGE) volume and %LGE on CMR. cTnT was detectable in 65 patients (88%), and ΔcTnT (CS-Ao) levels were available (ΔcTnT [CS-Ao] >0 ng/L) in 60 patients (81%). LGE was observed in 42 patients (57%), and ΔcTnT (CS-Ao) levels were available in 41 LGE-positive patients (98%). In patients with available cTnT release, ΔcTnT (CS-Ao) levels were significantly higher in LGE-positive patients than those in LGE-negative patients (4.3 [2.2-5.5] vs 1.5 [0.9-2.6] ng/L; p = 0.001). Log (ΔcTnT [CS-Ao]) levels were correlated with LGE volume (r = 0.460, p = 0.003) and %LGE (r = 0.356, p = 0.03). In conclusion, the amount of transcardiac cTnT release was higher in LGE-positive patients than LGE-negative patients and correlated with the extent of LGE in nonischemic patients with HF. These results suggested that ongoing myocardial damage correlates with the presence and extent of myocardial fibrosis.

Association of high-sensitivity cardiac troponin T and N-terminal pro-brain-type natriuretic peptide with left ventricular structure: J-HOP study

Although both high-sensitivity cardiac troponin T (Hs-cTnT) and N-terminal pro-brain-type natriuretic peptide (NT-proBNP) levels are higher among patients with cardiac structural abnormalities than among those with apparently normal hearts, there is considerable overlap between the groups. The authors evaluated 1336 patients who had ≥1 cardiovascular risk factors, underwent echocardiography, and had Hs-cTnT and NT-proBNP measured and excluded patients with left ventricular (LV) dysfunction. The patients in the highest Hs-cTnT category in quintiles had an increased likelihood of abnormal relative wall thickness compared with those in the lowest category (odds ratio, 1.66; 95% confidence interval, 1.17-2.36; P<.01). However, no such association was found in the category of NT-proBNP. The patients in the highest NT-proBNP category had an increased likelihood of abnormal LV diastolic dimension/body surface area compared with those in the lowest category (odds ratio, 2.11; 95% confidence interval, 1.17-3.79; P<.05). However, no such association was found in the category of Hs-cTnT. The data suggest that the measurement of Hs-cTnT and NT-proBNP might provide information on cardiac structural abnormalities.

High-sensitivity cardiac troponins in everyday clinical practice

High-sensitivity cardiac troponin (hs-cTn) assays are increasingly being used in many countries worldwide, however, a generally accepted definition of high-sensitivity is still pending. These assays enable cTn measurement with a high degree of analytical sensitivity with a low analytical imprecision at the low measuring range of cTn assays (coefficient of variation of < 10% at the 99^th percentile upper reference limit). One of the most important advantages of these new assays is that they allow novel, more rapid approaches to rule in or rule out acute coronary syndromes (ACSs) than with previous cTn assay generations which are still more commonly used in practice worldwide. hs-cTn is also more sensitive for the detection of myocardial damage unrelated to acute myocardial ischemia. Therefore, the increase in early diagnostic sensitivity of hs-cTn assays for ACS comes at the cost of a reduced ACS specificity, because more patients with other causes of acute or chronic myocardial injury without overt myocardial ischemia are detected than with previous cTn assays. As hs-cTn assays are increasingly being adopted in clinical practice and more hs-cTn assays are being developed, this review attempts to synthesize the available clinical data to make recommendations for their everyday clinical routine use.

Relation between soluble ST2, growth differentiation factor-15, and high-sensitivity troponin I and incident atrial fibrillation

BACKGROUND

We investigated whether circulating concentrations of soluble ST2, growth differentiation factor-15 (GDF-15), and high-sensitivity troponin I (hsTnI) are associated with incident atrial fibrillation (AF) and whether these biomarkers improve current risk prediction models including AF risk factors, B-type natriuretic peptide (BNP), and C-reactive protein (CRP).

METHODS

We studied the relation between soluble ST2, GDF-15, and hsTnI and development of AF in Framingham Heart Study participants without prevalent AF. We used Cox proportional hazard regression analysis to examine the relation of incident AF during a 10-year follow-up period with each biomarker. We adjusted for standard AF clinical risk factors, BNP, and CRP.

RESULTS

The mean age of the 3,217 participants was 59 ± 10 years, and 54% were women. During a 10-year follow-up, 242 participants developed AF. In age- and sex-adjusted models, GDF-15 and hsTnI were associated with risk of incident AF; however, after including the AF risk factors and BNP and CRP, only hsTnI was significantly associated with AF (hazard ratio per 1 SD of loge hsTnI, 1.12, 95% CI 1.00-1.26, P = .045). The c statistic of the base model including AF risk factors, BNP, and CRP was 0.803 (95% CI 0.777-0.830) and did not improve by adding individual or all 3 biomarkers. None of the discrimination and reclassification statistics were significant compared with the base model.

CONCLUSION

In a community-based cohort, circulating hsTnI concentrations were associated with incident AF. None of the novel biomarkers evaluated improved AF risk discrimination or reclassification beyond standard clinical AF risk factors and biomarkers.

Plasma high sensitivity troponin T levels in adult survivors of childhood leukaemias: determinants and associations with cardiac function

Background

We sought to quantify plasma high sensitivity cardiac troponin (hs-cTnT) levels, their determinants, and their associations with left ventricular (LV) myocardial deformation in adult survivors of childhood acute leukaemias.

Methods and Results

One hundred adult survivors (57 males) of childhood acute leukaemias, aged 24.1±4.2 years, and 42 age-matched controls (26 males) were studied. Plasma cTnT was determined using a highly sensitive assay. Genotyping of NAD(P)H oxidase and multidrug resistance protein polymorphisms was performed. Left ventricular function was assessed by conventional, three-dimensional, and speckle tracking echocardiography. The medians (interquartile range) of hs-cTnT in male and female survivors were 4.9 (4.2 to 7.2) ng/L and 1.0 (1.0 to 3.5) ng/L, respectively. Nineteen survivors (13 males, 6 females) (19%) had elevated hs-cTnT (>95^th centile of controls). Compared to those without elevated hs-TnT levels, these subjects had received larger cumulative anthracycline dose and were more likely to have leukaemic relapse, stem cell transplant, and cardiac irradiation. Their LV systolic and early diastolic myocardial velocities, isovolumic acceleration, and systolic longitudinal strain rate were significantly lower. Survivors having CT/TT at CYBA rs4673 had higher hs-cTnT levels than those with CC genotype. Functionally, increased hs-cTnT levels were associated with worse LV longitudinal systolic strain and systolic and diastolic strain rates.

Conclusions

Increased hs-cTnT levels occur in a significant proportion of adult survivors of childhood acute leukaemias and are associated with larger cumulative anthracycline dose received, history of leukaemic relapse, stem cell transplant, and cardiac irradiation, genetic variants in free radical metabolism, and worse LV myocardial deformation.

Significance of high-sensitivity cardiac troponin T in hypertrophic cardiomyopathy

OBJECTIVES

This study investigated the significance of the serum high-sensitivity cardiac troponin T (hs-cTnT) marker for prediction of adverse events in hypertrophic cardiomyopathy (HCM).

BACKGROUND

Although serum cardiac troponins as sensitive and specific markers of myocardial injury have become well-established diagnostic and prognostic markers in acute coronary syndrome, the usefulness of hs-cTnT for prediction of cardiovascular events in patients with HCM is unclear.

METHODS

We performed clinical evaluation, including measurements of hs-cTnT in 183 consecutive patients with HCM.

RESULTS

Of 183 HCM patients, 99 (54%) showed abnormal hs-cTnT values (>0.014 ng/ml). During a mean follow-up of 4.1 ± 2.0 years, 32 (32%) of the 99 patients in the abnormal hs-cTnT group, but only 6 (7%) of 84 patients with normal hs-cTnT values, experienced cardiovascular events: cardiovascular deaths, unplanned heart failure admissions, sustained ventricular tachycardia, embolic events, and progression to New York Heart Association functional class III or IV status (hazard ratio [HR]: 5.05, p < 0.001). Abnormal hs-cTnT value remained an independent predictor of these cardiovascular events after multivariate analysis (HR: 3.23, p = 0.012). Furthermore, in the abnormal hs-cTnT group, overall risk increased with an increase in hs-cTnT value (HR: 1.89/hs-cTnT 1 SD increase in the logarithmic scale, 95% confidence interval: 1.13 to 3.15; p = 0.015 [SD: 0.59]).

CONCLUSIONS

In patients with HCM, an abnormal serum concentration of hs-cTnT is an independent predictor of adverse outcome, and a higher degree of abnormality in hs-cTnT value is associated with a greater risk of cardiovascular events.

Diagnostic and prognostic biomarkers in acute myocarditis. Interleukin-10

Acute myocarditis is a major inflammatory heart disease with a variety of clinical courses from the acute to chronic phases represented by unexpected circulatory deterioration during hospitalization and progression to dilated cardiomyopathy. Predicting these disease courses is important for patient management. However, biomarkers have not been fully investigated. In addition, clinical profiles including symptoms, serological data, and electrocardiographic findings in acute myocarditis often mimic more common disorders such as coronary artery disease, which have reduced the diagnostic accuracy of acute myocarditis. These issues hamper the development of safer and earlier therapeutic interventions specific for acute myocarditis. Against this background, identifying simple prognostic and diagnostic biomarkers would contribute dramatically to the improvement in outcomes. Interleukin-10 may be a strong candidate for an excellent biomarker.

Utility of combination of cardiac magnetic resonance imaging and high-sensitivity cardiac troponin T assay in diagnosis of inflammatory cardiomyopathy

We evaluated the clinical utility of cardiac magnetic resonance imaging (CMR) combined with a novel high-sensitivity troponin T assay (hs-cTnT) in the diagnosis of inflammatory cardiomyopathy. CMR, measurement of hs-cTnT, and endomyocardial biopsy were performed in 42 patients with dilated cardiomyopathy and a short-term history of heart failure (median 2 months, interquartile range 1 to 3.5). The patients were followed up for 25 ± 9 months for events. Endomyocardial biopsy revealed myocarditis in 15 subjects (36%). The sensitivity, specificity, and diagnostic accuracy of the individual CMR tissue parameters for myocardial inflammation was 40%, 96%, and 76% for early gadolinium enhancement, 87%, 44%, and 60% for late gadolinium enhancement, 47%, 89%, and 74% for pericardial effusion, and 67%, 85%, and 79% for any 2 of the criteria simultaneously, respectively. An assessment of myocardial edema on T(2)-weighted imaging and/or hs-cTnT assay were inadequate for the diagnosis. The extent of late gadolinium enhancement and increased hs-cTnT concentration were significant predictors of a composite end point of cardiac death, urgent heart transplantation, and hospitalization for worsening heart failure (hazard ratio 1.1, 95% confidence interval 1.0 to 1.2, per percentage of left ventricular mass; and hazard ratio 2.2, 95% confidence interval 1.4 to 3.5, per ln ng/L; p = 0.008 and p = 0.001, respectively). In conclusion, the results of the present study have demonstrated a modest performance for CMR and a limited use of the hs-cTnT assay in the diagnosis of inflammatory cardiomyopathy. Nonetheless, in these patients, CMR and/or hs-cTnT assessment seems to be useful for the prediction of the clinical outcome.

Current applications of cardiac troponin T for the diagnosis of myocardial damage

Biochemical markers of myocardial injury play an important role in the diagnosis of cardiovascular diseases. Measurement of cardiac biomarkers is one of the most important diagnostic tests in acute myocardial infarction (AMI), heart failure, and other cardiovascular disorders. Recently, the European Society of Cardiology, the American College of Cardiology Foundation, the American Heart Association, and the World Heart Federation have published a consensus definition of AMI that includes a detailed guideline for the assessment of biochemical markers in suspected disease. The cardiac troponins (cTI and cTnT) were recommended as preferred markers of myocardial necrosis in this setting. Herein, we review cardiac troponin biochemistry, the performance characteristics of cTnT assays, and optimal utilization of troponin in patients with proven or possible cardiovascular disease. We also discuss the use of troponin tests, with emphasis on cTnT, in different clinical situations in which its levels may be elevated.

Serial Measurement of Cardiac Troponin T Using a Highly Sensitive Assay in Patients With Chronic Heart Failure

Background—

Cardiac troponins are emerging as important prognostic markers in chronic cardiovascular conditions like stable coronary artery disease or chronic heart failure (HF). Less is known about the relation between serial measurements of high-sensitivity cardiac troponin T (hs-cTnT) and future events in HF. We determined the association between changes over time in hs-cTnT and outcome in patients with chronic HF.

Methods and Results—

We analyzed 5284 patients with chronic HF from 2 independent randomized clinical trials, the Valsartan Heart Failure Trial (Val-HeFT) (n=4053) and the Gruppo Italiano per lo Studio della Sopravvivenza nell'Insufficienza Cardiaca–Heart Failure (GISSI-HF) trial (n=1231). hs-cTnT was measured at randomization and after 3 months (GISSI-HF) or 4 months of follow-up (Val-HeFT). The association between changes over time of hs-cTnT and various outcomes was tested in multivariable models. In both studies, increases in hs-cTnT levels over time were associated with age, diabetes mellitus, worsening of renal function (reduction in estimated glomerular filtration rate), and baseline and increases in N-terminal pro-brain natriuretic peptide concentrations. Increases in hs-cTnT concentrations were associated with all-cause mortality (incidence rates, 8.19 [7.51–8.88] and 6.79 [5.98–7.61] per 100 person-years in Val-HeFT and GISSI-HF, respectively, with hazard ratios [95% confidence intervals] of 1.59 [1.39–1.82] and 1.88 [1.50–2.35]) after adjustment for conventional risk factors and baseline levels of hs-cTnT and N-terminal pro-brain natriuretic peptide. Changes in hs-cTnT concentration modestly improved prognostic discrimination beyond baseline values for fatal outcomes only.

Conclusions—

Despite very low circulating concentrations, changes in hs-cTnT concentrations over time are robust predictors of future cardiovascular events in patients with chronic HF but add limited prognostic discrimination.

Clinical Trial Registration—

http://www.clinicaltrials.gov . Unique identifier: NCT00336336.

Prognostic value of serial measurements of highly sensitive cardiac troponin I in stable outpatients with nonischemic chronic heart failure

BACKGROUND

Cardiac troponin I (cTnI) is a useful biomarker in patients with chronic heart failure (CHF), and a highly sensitive cTnI (hs-cTnI) commercial assay has become available. However, the prognostic role of serial measurements of hs-cTnI in stable outpatients with CHF remains unknown.

METHODS

At entry to the study, we evaluated 95 stable outpatients with nonischemic CHF showing a serum hs-cTnI (Centaur TnI-Ultra [Siemens Medical Solution Diagnostics, New York, NY], lower limit of detection 0.006 ng/mL) value ≥0.006 ng/mL. To evaluate the role of repetitive measurements of hs-cTnI, we performed echocardiography and measured serum levels of cTnI and N-terminal proBNP at baseline and 6 months later and then prospectively followed up these patients for 4.25 years.

RESULTS

During long-term follow-up, there were 27 cardiac deaths. On multivariate analyses, high plasma N-terminal pro-brain natriuretic peptide (≥711 pg/mL, P = .0008), high serum hs-cTnI at baseline (≥0.03 ng/mL, P = .0011), and an increase in hs-cTnI (Δhs-cTnI ≥0 ng/mL, P = .022) after 6 months were independent significant prognostic predictors. The hazard ratio for mortality of patients with high hs-cTnI (≥0.03 ng/mL) and an increase in hs-cTnI (Δhs-cTnI ≥0 ng/mL) was 3.59 (95% CI 1.3-9.9, P = .014) compared with that of those with high hs-cTnI (≥0.03 ng/mL) and a decrease in hs-cTnI (Δhs-cTnI <0 ng/mL).

CONCLUSIONS

These findings indicated that not only the serum concentration of hs-cTnI at baseline but also an increase in hs-cTnI were independent and useful prognostic predictors in patients with nonischemic CHF.

Troponin elevation in conditions other than acute coronary syndromes

Acute coronary syndromes comprise a large spectrum of clinical conditions ranging from unstable angina pectoris to acute ST-elevation myocardial infarction. Chest pain is usually the major symptom of atherosclerotic heart disease; however, it may be challenging to diagnose correctly, especially in the emergency department, because of the ambiguous way that pain is characterized by some patients. Cardiac troponins are sensitive and specific biomarkers used in the diagnosis of myocardial infarction that are released into the bloodstream when cardiac myocytes are damaged by acute ischemia or any other mechanism. They are the cornerstone for the diagnosis, risk assessment, prognosis, and determination of antithrombotic and revascularization strategies. However, troponin elevation indicates the presence, not the mechanism, of myocardial injury. There are many clinical conditions other than myocardial infarction that cause troponin elevation; thus, the physician should be aware of the wide spectrum of disease states that may result in troponin elevation and have a clear understanding of the related pathophysiology to effectively make a differential diagnosis. This review focuses on causes of troponin elevation other than acute coronary syndromes.

Soluble lectin-like oxidized LDL receptor-1 and high-sensitivity troponin T as diagnostic biomarkers for acute coronary syndrome. Improved values with combination usage in emergency rooms

BACKGROUND

Although highly sensitive assays for troponin T (hs-TnT) have been developed, the sensitivity and specificity of hs-TnT for diagnosing acute coronary syndrome (ACS) remains imperfect. We evaluated the diagnostic value of a new biomarker of plaque vulnerability (soluble lectin-like oxidized low-density lipoprotein receptor-1, sLOX-1) as compared with hs-TnT in the emergency room (ER).

METHODS AND RESULTS

Plasma sLOX-1 and serum hs-TnT levels were measured in 200 consecutive patients presenting with chest symptoms and ECG abnormalities in the ER (116 ST elevation ACS [STEACS], 44 non-ST elevation ACS [NSTEACS], 40 non-ACS). The non-ACS group consisted of patients with cardiovascular diseases such as coronary spastic angina pectoris, pulmonary thromboembolism, perimyocarditis and takotsubo cardiomyopathy. Levels of sLOX-1 and hs-TnT were significantly higher in STEACS and NSTEACS than in non-ACS patients. The receiver-operating characteristic (ROC) curves of sLOX-1 and hs-TnT for detecting ACS, using the non-ACS patients as negative references, showed that the area under the curve (AUC) values of sLOX-1 and hs-TnT were 0.769 and 0.739, respectively. In the lower hs-TnT (<0.0205ng/ml) subgroup, the AUC value of the ROC curve of sLOX-1 for detecting ACS was 0.869.

CONCLUSIONS

The diagnostic value for ACS was comparable between sLOX-1 and hs-TnT, and the accuracy of ACS diagnosis appeared to improve when sLOX-1 and hs-TnT were measured in combination.