Troponin I as a predictor of coronary heart disease and mortality in 70-year-old men: a community-based cohort study

What Do We Know So Far About Ventricular Arrhythmias and Sudden Cardiac Death Prediction in the Mitral Valve Prolapse Population? Could Biomarkers Help Us Predict Their Occurrence?

PURPOSE OF THE REVIEW

To summarize currently available data on the topic of mitral valve prolapse (MVP) and its correlation to the occurrence of atrial and ventricular arrhythmias. To assess the prognostic value of several diagnostic methods such as transthoracic echocardiography, transesophageal echocardiography, cardiac magnetic resonance, cardiac computed tomography, electrocardiography, and electrophysiology concerning arrhythmic episodes. To explore intra and extracellular biochemistry of the cardiovascular system and its biomarkers as diagnostic tools to predict rhythm disturbances in the MVP population.

RECENT FINDINGS

MVP is a common and mainly benign valvular disorder. It affects 2-3% of the general population. MVP is a heterogeneous and highly variable phenomenon with three structural phenotypes: myxomatous degeneration, fibroelastic deficiency, and forme fruste. Exercise intolerance, supraventricular tachycardia, and chest discomfort are the symptoms that are often paired with psychosomatic components. Though MVP is thought to be benign, the association between isolated MVP without mitral regurgitation (MR) or left ventricle dysfunction, with ventricular arrhythmia (VA) and sudden cardiac death (SCD) has been observed. The incidence of SCD in the MVP population is around 0.6% per year, which is 6 times higher than the occurrence of SCD in the general population. Often asymptomatic MVP population poses a challenge to screen for VA and prevent SCD. Therefore, it is crucial to carefully assess the risk of VA and SCD in patients with MVP with the use of various tools such as diagnostic imaging and biochemical and genetic screening.

Cardiac troponin I as predictor for cardiac and other mortality in the German randomized lung cancer screening trial (LUSI)

Cardiac Troponin I (cTnI) could be used to identify individuals at elevated risk of cardiac death in lung cancer (LC) screening settings. In a population-based, randomized LC screening trial in Germany ("LUSI" study) serum cTnI was measured by high-sensitivity assay in blood samples collected at baseline, and categorized into unquantifiable/low (< 6 ng/L), intermediate (≥ 6-15 ng/L), and elevated (≥ 16 ng/L). Cox proportional-hazard models were used to estimate risk of all-cause and cardiac mortality with cTnI levels. After exclusion criteria, 3653 participants were included for our analyses, of which 82.4% had low, 12.8% intermediate and 4.8% elevated cTnI, respectively. Over a median follow up of 11.87 years a total of 439 deaths occurred, including 67 caused by cardiac events. Within the first 5 years after cTnI measurement, intermediate or elevated cTnI levels showed approximately 1.7 (HR = 1.69 [95% CI 0.57-5.02) and 4.7-fold (HR = 4.66 [1.73-12.50]) increases in risk of cardiac death relative to individuals with unquantifiable/low cTnI, independently of age, sex, smoking and other risk factors. Within this time interval, a risk model based on age, sex, BMI, smoking history and cTnI showed a combined area under the ROC curve (AUC) of 73.6 (58.1-87.3), as compared to 70.4 (53.3-83.5) for a model without cTnI. Over the time interval of > 5-10 years after blood donation, the relative risk associations with cTnI and were weaker. cTnI showed no association with mortality from any other (non-cardiac) cause. Our findings show that cTnI may be of use for identifying individuals at elevated risk specifically of short-term cardiac mortality in the context of LC screening.

The ABC-Stroke Risk Score and Effects of Atrial Fibrillation Screening on Stroke Prevention: Results From the Randomized LOOP Study

BACKGROUND

The ABC-stroke score is a risk scheme for prediction of stroke or systemic embolism (SE) in atrial fibrillation (AF). This study sought to examine whether the score could be useful in predicting stroke in AF-naïve individuals and risk stratifying for AF screening.

METHODS AND RESULTS

The LOOP (Atrial Fibrillation Detected by Continuous ECG Monitoring Using Implantable Loop Recorder to Prevent Stroke in High-Risk Individuals) study randomized 6004 AF-naïve individuals aged 70 to 90 years with stroke risk factors to either screening with an implantable loop recorder and anticoagulation upon detection of new-onset AF episodes ≥6 minutes, or usual care. A total of 5781 participants had available ABC-stroke score at baseline and were included in this secondary analysis: 4170 (72.1%) with an estimated stroke/SE risk ≤1%/year versus 1611 (27.9%) with an estimated stroke/SE risk >1%/year. Having an annual ABC-stroke risk >1% was associated with stroke/SE, stroke/SE/cardiovascular death, and all-cause death (hazard ratio, 1.82 [95% CI, 1.44-2.21], 2.17 [95% CI, 1.80-2.62], and 2.19 [95% CI, 1.87-2.56], respectively). For screening with implantable loop recorder versus usual care, no significant reduction in these study outcomes was obtained in any ABC-stroke risk groups (P>0.0500 for all), with no signal toward interaction (Pinteraction>0.2500 for all). Similar findings were yielded when assessing the ABC-stroke score as a continuous variable.

CONCLUSIONS

In an elderly, AF-naïve population with additional stroke risk factors, a higher ABC-stroke score could identify individuals with increased stroke risk. However, this risk score may not be useful in pinpointing those more likely to benefit from AF screening and subsequent preventive treatment. These findings should be considered as hypothesis generating and warrant further study.

REGISTRATION

URL: https://www.clinicaltrials.gov; unique identifier: NCT02036450.

Association between troponin level and medium-term mortality in 20 000 hospital patients

INTRODUCTION

Cardiac troponin (cTn) concentrations above the manufacturer recommended upper limit of normal (ULN) are frequently seen in hospital patients without a clinical presentation consistent with type 1 myocardial infarction, and the significance of this is uncertain. The aim of this study was to assess the relationship between medium-term mortality and cTn concentration in a large consecutive hospital population, regardless of whether there was a clinical indication for performing the test.

METHOD

This prospective observational study included 20 000 consecutive in-hospital and outpatient patients who had a blood test for any reason at a large teaching hospital, and in whom a hs-cTnI assay was measured, regardless of the original clinical indication. Mortality was obtained via NHS Digital.

RESULTS

A total of 20 000 patients were included in the analysis and 18 282 of these (91.4%) did not have a clinical indication for cardiac troponin I (cTnI) testing. Overall, 2825 (14.1%) patients died at a median of 809 days. The mortality was significantly higher if the cTnI concentration was above the ULN (45.3% vs 12.3% p<0.001 log rank). Multivariable Cox analysis demonstrated that the log10 cTnI concentration was independently associated with mortality (HR 1.76 (95% CI 1.65 to 1.88)). Landmark analysis, excluding deaths within 30 days, showed the relationship between cTnI concentration and mortality persisted.

CONCLUSION

In a large, unselected hospital population, in 91.4% of whom there was no clinical indication for testing, cTnI concentration was independently associated with medium-term cardiovascular and non-cardiovascular mortality in the statistical model tested.

Association between high-sensitive cardiac troponin level and coronary artery disease: A systematic review and meta-analysis

Background and objectives

Previous studies suggest a link between high-sensitive cardiac troponin (hs-cTn) levels and coronary artery disease (CAD). However, the nature of this relationship is disputed. To address this, we conducted a study to gather and assess evidence on the association between hs-cTn and CAD prediction.

Data sources

Studies were systematically searched and collected from four databases and different types of gray literature to cover all available evidence. After the screening, the selected articles' quality and risk of bias assessment were evaluated.

Synthesis method

Meta-analysis calculated std. mean difference on the extracted data. Furthermore, heterogeneity, sensitivity, subgroups, and publication bias analyses were assessed.

Results

Twenty-two studies were included in this systematic review, with a total of 844 cases and 2101 control people. The results of the meta-analysis on nine studies showed a significant and positive association between hs-cTn levels and CAD (pooled std. mean difference = 0.44; 95% confidence interval = 0.14-0.73; p < 0.003), with no publication bias (p = 0.9170). Among subgroups, std. mean differences were notably different only when the data were stratified by region or risk of bias; however, subgroup analysis could not determine the source of heterogeneity.

Conclusions

Available prospective studies indicate a strong association of hs-cTn with the risk of CAD and significant improvements in CAD prediction. Further investigations in both molecular and clinical fields with proper methodology and more detailed information are needed to discover more evidence and underlying mechanisms to clear the interactive aspects of hs-cTn level in CAD patients.

Label-Free, Portable, and Color-Indicating Cholesteric Liquid Crystal Test Kit for Acute Myocardial Infarction by Spectral Analysis and Naked-Eye Observation

The early diagnosis of acute myocardial infarction is difficult in patients with nondiagnostic characteristics. Acute myocardial infarction with chest pain is associated with increased mortality. This study developed a portable test kit based on cholesteric liquid crystals (CLCs) for the rapid detection of AMI through eye observation at home. The test kit was established on dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride-coated substrates covered by a CLC-binding antibody. Cardiac troponin I (cTnI) is a major biomarker of myocardial cellular injury in human blood. The data showed that the concentration of cTnI was related to light transmittance in a positive way. The proposed CLC test kit can be operated with a smartphone; therefore, it has high potential for use as a point-of-care device for home testing. Moreover, the CLC test kit is an effective and innovative device for the rapid testing of acute myocardial infarction-related diseases through eye observation, spectrometer, or even smartphone applications.

The Predictive Power of the 14-51 Ng/L High Sensitive Troponin T (hsTnT) Values for Predicting Cardiac Revascularization in a Clinical Setting

Background: high sensitive Troponin T (hsTnT) values between 14−50 ng/L represent a challenge in diagnosing acute coronary syndrome (ACS) at the Emergency Department (ED). The European Society for Cardiology (ESC) recommends a second hsTnT measurement 3 h later to distinguish between ACS and other causes depending on the Δ hsTnT. Our study aims to evaluate the predictive power this approach in a clinical setting by following patients presenting at the ED with hsTnT values 14−51 ng/L. Materials and methods: patients presenting with chest pain or dyspnea and a hsTnT value between 14 and 50 ng/L at the Erasmus MC ED in 2012−2013 were included and retrospectively monitored for 90 days after initial presentation for the occurrence of a cardiac revascularization. Patient records were reviewed according to the standing protocol, which depended on the Δ hsTnT. The “event-group” consists of patients receiving cardiac revascularization within 90 days after the ED visit, whereas the “no event-group” consisted of patients without revascularization. Results: a total of 889 patients patient records were reviewed. After excluding out-of-hospital-cardia-arrests (60), non-cardiological chest pain (373) and incomplete follow-up (100), 356 patients remained for final analysis. In 207 patients, a second hsTnT was actually performed (58%). From these 207 patients, 68 (33%) had a Δ hsTnT ≥7 ng/L. In these patients, 37 (54%) experienced an event within 90 days. In the 139 patients with a Δ hsTnT < 7 ng/L, 23 (17%) presented with an event within 90 days. Conclusion: our study demonstrated a sensitivity of 62%, a specificity of 79%, a positive predicted value (PPV) of 54% and a negative predictive value (NPV) of 83% for using a 3-h Δ hsTnT ≥7 ng/L cut-off, related to risk of an event in 90 days following ED presentation.

Circulating cardiac biomarkers improve risk stratification for incident cardiovascular disease in community dwelling populations

Background

Plasma cardiac markers may assist in prediction of incident cardiovascular disease.

Methods

The incremental value of cardiac Troponins (T and I) and NT-proBNP added to risk factors in the PREDICT score for incident cardiovascular disease (CVD) in primary care, was assessed in 4102 asymptomatic participants in a randomised controlled trial of Vitamin D (ViDA). Findings were corroborated in 2528 participants in a separate community-based observational registry of CVD-free volunteers (HVOLS).

Findings

Hazard ratios for first cardiovascular events adjusted for PREDICT risk factors, comparing fifth to first quintiles of marker plasma concentrations, were 2.57 (95% CI 1.47-4.49); 3.01 (1.66-5.48) and 3.38 (2.04-5.60) for hs-cTnI, hs-cTnT and NT-proBNP respectively. The C statistic for discrimination of the primary endpoint increased from 0.755 to 0.771 (+0.016, p = 0.01). Cardiac marker data correctly reclassified risk upwards in 6.7% of patients and downwards in 3.3%. These findings were corroborated by results from HVOLS.

Interpretation

Increments in plasma cardiac biomarkers robustly and reproducibly predicted increased hazard of incident CVD, independent of established risk factors, in two community-dwelling populations. Cardiac markers may augment risk assessment for onset of CVD in primary care.

Funding

ViDA was funded by the Health Research Council of New Zealand (grant 10/400) and the Accident Compensation Corporation. HVOLS was funded by the Health Research Council of NZ Programme Grants (grants 02/152 and 08/070) and by grants from the Heart Foundation of NZ and the Christchurch Heart Institute Trust. Roche Diagnostics provided in-kind support for NT-proBNP and hs-cTnT assays and Abbott Laboratories for hs-cTnI assays.

A Real Pandora's Box in Pandemic Times: A Narrative Review on the Acute Cardiac Injury Due to COVID-19

The intricate relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the cardiovascular system is an extensively studied pandemic topic, as there is an ever-increasing amount of evidence that reports a high prevalence of acute cardiac injury in the context of viral infection. In patients with Coronavirus disease 2019, COVID-19, a significant increase in serum levels of cardiac troponin or other various biomarkers was observed, suggesting acute cardiac injury, thus predicting both a severe course of the disease and a poor outcome. Pathogenesis of acute cardiac injury is not yet completely elucidated, though several mechanisms are allegedly involved, such as a direct cardiomyocyte injury, oxygen supply-demand inequity caused by hypoxia, several active myocardial depressant factors during sepsis, and endothelial dysfunction due to the hyperinflammatory status. Moreover, the increased levels of plasma cytokines and catecholamines and a significantly enhanced prothrombotic environment may lead to the destabilization and rupture of atheroma plaques, subsequently triggering an acute coronary syndrome. In the present review, we focus on describing the epidemiology, pathogenesis, and role of biomarkers in the diagnosis and prognosis of patients with acute cardiac injury in the setting of the COVID-19 pandemic. We also explore some novel therapeutic strategies involving immunomodulatory therapy, as well as their role in preventing a severe form of the disease, with both the short-term outcome and the long-term cardiovascular sequelae being equally important in patients with SARS-CoV-2 induced acute cardiac injury.

Smartphone and home-based liquid crystal sensor for rapid screening of acute myocardial infarction by naked-eye observation and image analysis

An early diagnosis of acute myocardial infarction (AMI) or thrombosis is complicated in patients with non-diagnostic features. AMI or thrombosis patients with chest pain are unintentionally discharged and have increased mortality. The study aimed to develop a smartphone biomedical sensor as a rapid test for AMI or thrombosis by naked-eye observation. The system was built on dimethyloctadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP)-coated glass substrates, which refers to a nematic liquid crystal (LC)-binding antibody. One of the main biomolecules, cardiac troponin I (cTnI), is a substance in blood in people whose bodies are vulnerable to suffering a myocardial infarction or thrombosis. The other medium, LC, is a sensing biomaterial as an earlier detection method of ameliorating the disadvantages of older methods. Results revealed that the density of cTnI was positively correlated with the coefficient of light transmittance, and it has a high chance of being developed as a point-of-care device for a home inspection as it can be operated with a smartphone. As discussed above, the nematic LC is an effective and innovative healthcare method as a rapid test for diagnosis of AMI or thrombosis related diseases by naked-eye observation.

Poor outcome among patients undergoing myocardial perfusion imaging with intermediate-zone troponin

BACKGROUND

Intermediate zone troponin elevation is defined as one to five times the upper limit of normal. Approximately half the patients presenting with chest pain to the emergency department have initial intermediate zone troponin.

OBJECTIVES

We aimed to investigate the long-term outcome of patients hospitalized with chest pain and intermediate zone troponin elevation.

METHODS

We investigated 8269 patients hospitalized in a tertiary center with chest pain. All patients had serial measurements of troponin during hospitalization. Patients were divided into three groups based on their initial troponin levels: negative troponin (N = 6112), intermediate zone troponin (N = 1329) and positive troponin (N = 828). All patients underwent myocardial perfusion imaging (MPI) as part of the initial evaluation.

RESULTS

Mean age of the study population was 68 ± 11, of whom 36% were women. Patients with an intermediate zone troponin were older, more likely to be males, and with significantly more cardiovascular co-morbidities. Multivariate analysis adjusted for age, gender, cardiovascular risk factors, and abnormal MPI result found that patients with intermediate zone troponin had a 70% increased risk of re-hospitalization at 1 year (HR 1.70, 95%CI 1.48-1.96, p-value < 0.001) and 5.3 times higher risk of total mortality at 1-year (HR 5.33, 95%CI 3.65-7.78, p-value < 0.001). sub-group analysis found that among the intermediate zone troponin group, patients with double intermediate zone troponin had the poorest outcome.

CONCLUSIONS

Intermediate zone troponin elevation is an independent risk factor associated with adverse outcomes and therefore patients with an initial value in this range should be closely monitored and aggressively managed.

Cardioprotective Effect of Glycyrrhizin on Myocardial Remodeling in Diabetic Rats

Myocardial fibrosis is one of the major complications of long-term diabetes. Hyperglycemia induced cardiomyocyte atrophy is a frequent pathophysiological indicator of diabetic heart. The objective of this study was to investigate the cardioprotective effect of glycyrrhizin (GLC) on myocardial damage in diabetic rats and assess the anti-inflammatory and anti-fibrotic effect of GLC. Our study demonstrates that hyperglycemia can elevate cardiac atrophy in diabetic animals. Type 2 diabetic fatty and the lean control rats were evaluated for cardiac damage and inflammation at 8-12 weeks after the development of diabetes. Western blot and immunohistochemical studies revealed that gap junction protein connexin-43 (CX43), cardiac injury marker troponin I, cardiac muscle specific voltage gated sodium channel NaV1.5 were significantly altered in the diabetic heart. Furthermore, oxidative stress mediator receptor for advanced glycation end-products (RAGE), as well as inflammatory mediator phospho-p38 MAPK and chemokine receptor CXCR4 were increased in the diabetic heart whereas the expression of nuclear factor erythroid-2-related factor 2 (Nrf2), the antioxidant proteins that protect against oxidative damage was reduced. We also observed an increase in the expression of the pleiotropic cytokine, transforming growth factor beta (TGF-β) in the diabetic heart. GLC treatment exhibited a decrease in the expression of phospho-p38 MAPK, RAGE, NaV1.5 and TGF-β and it also altered the expression of CX43, CXCR4, Nrf2 and troponin I. These observations suggest that GLC possesses cardioprotective effects in diabetic cardiac atrophy and that these effects could be mediated through activation of Nrf2 and inhibition of CXCR4/SDF1 as well as TGF-β/p38MAPK signaling pathway.

Prognostic performance of troponin in COVID-19: A diagnostic meta-analysis and meta-regression

BACKGROUND

Cardiac injury is frequently encountered in patients with coronavirus disease 2019 (COVID-19) and is associated with increased risk of mortality. Elevated troponin may signify myocardial damage and is predictive of mortality. This study aimed to assess the prognostic value of troponin above the 99th percentile upper reference limit (URL) for mortality, and factors affecting the relationship.

METHODS

A comprehensive literature search of PubMed (MEDLINE), Scopus and Embase was undertaken, from inception of the databases until 16 December 2020. The key exposure was elevated serum troponin, defined as troponin (of any type) above the 99th percentile URL. The outcome was mortality due to any cause.

RESULTS

In total, 12,262 patients from 13 studies were included in this systematic review and meta-analysis. The mortality rate was 23% (20-26%). Elevated troponin was observed in 31% (23-38%) of patients. Elevated troponin was associated with increased mortality [odds ratio (OR) 4.75, 95% confidence interval (CI) 4.07-5.53; P < 0.001; I² = 19.9%]. Meta-regression showed that the association did not vary with age (P = 0.218), male gender (P = 0.707), hypertension (P = 0.182), diabetes (P = 0.906) or coronary artery disease (P = 0864). The association between elevated troponin and mortality had sensitivity of 0.55 (0.44-0.66), specificity of 0.80 (0.71-0.86), positive likelihood ratio of 2.7 (2.2-3.3), negative likelihood ratio of 0.56 (0.49-0.65), diagnosis odds ratio of 5 (4-5) and area under the curve of 0.73 (0.69-0.77). The probability of mortality was 45% in patients with elevated troponin and 14% in patients with non-elevated troponin.

CONCLUSION

Elevated troponin was associated with mortality in patients with COVID-19 with 55% sensitivity and 80% specificity.

High sensitivity troponin, analytical advantages, clinical benefits and clinical challenges - An update

The measurement of cardiac troponin (cTn) by a high sensitivity method now represents the standard method for cTn measurement in the laboratory. High sensitivity method are not measuring a novel form of troponin but have undergone methodological improvement in assay sensitivity to allow both very low level detection and repeat measurements at low levels with very low degrees of analytical imprecision. The methods identify additional patients with myocardial injury who would benefit from evidence-based interventions. Rapid predictive algorithms utilising measurement on admission as well as short sampling periods (1-2 h) allow much more rapid categorisation of patients to appropriate clinical pathways. The shift in the diagnosis from traditional "cardiac enzymes" to troponin based on the 99th percentile has accounted for the majority of the detection of myocardial injury in patients without acute coronary syndromes. These patients have a worse prognosis irrespective of the underlying cause of their hospital admission. The appropriate management strategy in this group, beyond managing the underlying problem, remains to be defined. Measurement of cTn in otherwise asymptomatic individuals may have a role for patient selection for preventive treatment or for patients monitoring. Clinical trials in this area are awaited.

Impact of polysubstance use on high-sensitivity cardiac troponin I over time in homeless and unstably housed women

INTRODUCTION

The use of controlled substances like cocaine increases the risk of cardiovascular disease (CVD) and myocardial infarction (MI). However, outside of alcohol and tobacco, substance use is not included in CVD risk assessment tools. We identified the effects of using multiple substances (nicotine/cotinine, cannabis, alcohol, cocaine, methamphetamine, heroin and other opioids) on cardiac injury measured by high-sensitivity troponin (hsTnI) in homeless and unstably housed women.

METHODS

We recruited 245 homeless and unstably housed women from shelters, free meal programs and street encampments. Participants completed six monthly study visits. Adjusting for traditional CVD risk factors, we examined longitudinal associations between substance use and hsTnI.

RESULTS

Median participant age was 53 years and 74 % were ethnic minority women. At baseline, 76 % of participants had hypertension, 31 % were HIV-positive, 8% had a history of a prior MI and 12 % of prior stroke. The most commonly used substances were cotinine/nicotine (80 %), cannabis (68 %) and cocaine (66 %). HsTnI exceeding the 99th percentile (14.7 ng/L) - a level high enough to signal possible MI - was observed in 14 participants during >1 study visit (6%). In adjusted analysis, cocaethylene and fentanyl were significantly associated with higher hsTnI levels.

CONCLUSIONS

Fentanyl use and the co-use of cocaine and alcohol are associated with myocardial injury, suggesting that the use of these substances may act as long-term cardiac insults. Whether risk counseling on these specific substances and/or including their use in CVD risk stratification would improve CVD outcomes in populations where substance use is high merits further investigation.

Type 2 myocardial infarction: is it a geriatric syndrome?

Type 2 myocardial infarctions (T2-MI) is a type of necrosis that results from reduced oxygen supply and/or increased demand secondary to other causes unrelated to acute coronary atherothrombosis. The development and implementation of sensitive and high-sensitivity cardiac necrosis marker and the age-related increase of comorbidity lead to a boost of the frequency of T2-MI. T2-MI is often a complication of a high degree of clinical frailty in older adults, emerging as a "geriatric syndrome". Age-related non-cardiovascular causes may be the triggering factors and are strongly associated with the diagnosis, treatment, and prognosis of T2-MI. To date, there are no guidelines on management of this pathology in advancing age. Patient-centered approach and comprehensive geriatric assessment play a key role in the diagnosis, therapy and prognosis of geriatric patients with T2-MI.

Multiple Biomarker Use for Detection of Adverse Events in Patients Presenting with Symptoms Suggestive of Acute Coronary Syndrome

Background: We investigated multiple biomarkers of various pathophysiologic pathways to determine their relationships with adverse outcomes in patients presenting with symptoms of acute coronary syndrome.

Methods: We obtained plasma specimens from 457 patients on admission and measured 7 biomarkers: myeloperoxidase (MPO), soluble CD40 ligand (CD40L), placental growth factor (PlGF), metalloproteinase-9 (MMP-9), high-sensitivity C-reactive protein (hsCRP), cardiac troponin I (cTnI), and N-terminal pro-B-type natriuretic peptide (NT-proBNP). We used the Modification of Diet in Renal Disease formula to calculate the estimated glomerular filtration rate (eGFR). Endpoints were cardiac events (myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, cardiac death) and all-cause mortality. We estimated cumulative event rates over a 4-month period with the Kaplan–Meier method and relative risk (RR) with the Cox proportional hazards model.

Results: Patients with increased PlGF, NT-proBNP, hsCRP, or cTnI or decreased eGFR had 11% to 20% higher all-cause mortality rates than patients with concentrations within reference intervals: 20.4% (eGFR), 16.0% (PlGF), 15.8% (hsCRP), 12.7% (NT-proBNP), and 11.3% (cTnI; all P ≤0.03). No differences in mortality rates were observed between those with increased vs normal concentrations of MPO, CD40L, or MMP-9. Decreased eGFR (RR 3.4, P = 0.004) and increased NT-proBNP (RR 7.9, P = 0.04) were independently predictive of mortality, and PlGF (RR 2.0, P = 0.08) approached significance. Patients with increased NT-proBNP (12.3%) or cTnI (33.8%) had higher cardiac event rates (each P &lt;0.02), with increased MPO (11.1%) showing a trend (P = 0.09). Patients in whom both cTnI and MPO were increased had a cardiac event rate of 43%.

Conclusion: Multiple biomarkers that are likely indicative of different underlying pathophysiologic mechanisms are independently predictive of increased risk for adverse events in patients with acute coronary syndrome.

A liquid-crystal-based immunosensor for the detection of cardiac troponin I

Cardiac troponin I (cTnI) is one of the most sensitive and specific markers of myocardial cell injury. In this study, a label-free biosensor that utilizes the birefringence property of liquid crystal (LC) for the detection of cTnI is demonstrated.

Association Between Circulating Troponin Concentrations, Left Ventricular Systolic and Diastolic Functions, and Incident Heart Failure in Older Adults

Importance

Cardiac troponin is associated with incident heart failure and greater left ventricular (LV) mass. Its association with LV systolic and diastolic functions is unclear.

Objectives

To define the association of high-sensitivity cardiac troponin T (hs-cTnT) with LV systolic and diastolic functions in the general population, and to evaluate the extent to which that association accounts for the correlation between hs-cTnT concentration and incident heart failure overall, heart failure with preserved LV ejection fraction (LVEF; HFpEF), and heart failure with LVEF less than 50%.

Design, Setting, and Participants

This analysis of the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing epidemiologic cohort study in US communities, included participants without cardiovascular disease (n = 4111). Available hs-cTnT measurements for participants who attended ARIC Study visits 2 (1990 to 1992), 4 (1996 to 1998), and 5 (2011 to 2013) were assessed cross-sectionally against echocardiographic measurements taken at visit 5 and against incident health failure after visit 5. Changes in hs-cTnT concentrations from visits 2 and 4 were also examined. Data analyses were performed from August 2017 to July 2018.

Main Outcomes and Measures

Cardiac structure and function by echocardiography at visit 5, and incident heart failure during a median 4½ years follow-up after visit 5.

Results

Of the 6538 eligible participants, 4111 (62.9%) without cardiovascular disease were included. Among these participants, 2586 (62.9%) were female, and the mean (SD) age was 75 (5) years. Median (interquartile range) hs-cTnT concentration at visit 5 was 9 (7-14) ng/L and was detectable in 3946 participants (96.0%). After adjustment for demographic and clinical covariates, higher hs-cTnT levels were associated with greater LV mass index (adjusted mean [SE] for group 1: 33.8 [0.5] vs group 5: 40.1 [0.4]; P for trend < .001) and with worse diastolic function, including lower tissue Doppler imaging e' (6.00 [0.07] vs 5.54 [0.06]; P for trend < .001), higher E/e' ratio (11.4 [0.2] vs 12.9 [0.1]; P for trend < .001), and greater left atrial volume index (23.4 [0.4] vs 26.4 [0.3]; P for trend < .001), independent of LV mass index; hs-cTnT level was not associated with measures of LV systolic function. Accounting for diastolic function attenuated the association of hs-cTnT concentration with incident HFpEF by 41% and the association with combined heart failure with midrange and reduced ejection fraction combined (LVEF <50) by 17%. Elevated hs-cTnT concentration and diastolic dysfunction were additive risk factors for incident heart failure. For any value of late-life hs-cTnT levels, longer duration of detectable hs-cTnT from midlife to late life was associated with greater LV mass in late life but not with worse LV systolic or diastolic function.

Conclusions and Relevance

This study shows that higher hs-cTnT concentrations were associated with worse diastolic function, irrespective of LV mass, but not with systolic function; these findings suggest that high levels of hs-cTnT may serve as an early marker of subclinical alterations in diastolic function that may lead to a predisposition to heart failure.

Cardiac Troponin I and Risk of Cardiac Events in Patients With Heart Failure and Preserved Ejection Fraction

BACKGROUND

Levels of cTn (cardiac troponin) are frequently elevated in patients with heart failure (HF) and reduced ejection fraction (EF) and correlate with the risk for mortality. However, factors associated with high cTn concentrations and the association with cardiovascular events in patients with HF and preserved EF are unclear.

METHODS AND RESULTS

Of 1767 subjects with symptomatic HF with preserved EF from the Americas part of the TOPCAT trial (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial), 236 underwent baseline measurements of high-sensitivity (hs) cTnI using the Abbott Architect STAT assay. Baseline factors correlated with hs-cTnI levels were assessed in stepwise linear regression models and the association between hs-cTnI and adjudicated study outcomes was examined in Cox models. The median hs-cTnI concentration at baseline was 6.3 ng/L (interquartile range, 3.4-12.9 ng/L) with levels detectable in 99.2% of patients. Higher hs-cTnI concentrations were associated with male sex, black race, lower estimated glomerular filtration rate and higher NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. After multivariable adjustment, higher concentrations of hs-cTnI were associated with greater risk for the composite of cardiovascular death or HF hospitalization (69 events during mean follow-up 2.6±1.5 years): hazard ratio 1.42 (95% CI, 1.20-1.69), P<0.001 per doubling of hs-cTnI. Compared with those in the lowest quartile of hs-cTnI, patients in the highest quartile demonstrated a nearly 5-fold higher risk of cardiovascular death and HF hospitalization (hazard ratio 4.85 [1.99-11.83], P=0.001). There was no interaction between hs-cTnI and spironolactone treatment with regard to the primary composite end point (interaction P=0.94).

CONCLUSIONS

In ambulatory patients with HF with preserved EF, levels of hs-cTnI are higher in male patients with black race, lower estimated glomerular filtration rate, and higher NT-proBNP. As in those with HF and reduced EF, higher hs-cTnI levels are independently associated with risk for cardiovascular death and HF hospitalization.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT00094302.

Performance of Coronary Risk Scores Among Patients With Chest Pain in the Emergency Department

BACKGROUND

Both the modified History, Electrocardiogram, Age, Risk factors and Troponin (HEART) score and the Emergency Department Assessment of Chest pain Score (EDACS) can identify patients with possible acute coronary syndrome (ACS) at low risk (<1%) for major adverse cardiac events (MACE).

OBJECTIVES

The authors sought to assess the comparative accuracy of the EDACS (original and simplified) and modified HEART risk scores when using cardiac troponin I (cTnI) cutoffs below the 99th percentile, and obtain precise MACE risk estimates.

METHODS

The authors conducted a retrospective study of adult emergency department (ED) patients evaluated for possible ACS in an integrated health care system between 2013 and 2015. Negative predictive values for MACE (composite of myocardial infarction, cardiogenic shock, cardiac arrest, and all-cause mortality) were determined at 60 days. Reclassification analyses were used to assess the comparative accuracy of risk scores and lower cTnI cutoffs.

RESULTS

A total of 118,822 patients with possible ACS were included. The 3 risk scores' accuracies were optimized using the lower limit of cTnI quantitation (<0.02 ng/ml) to define low risk for 60-day MACE, with reclassification yields ranging between 3.4% and 3.9%, while maintaining similar negative predictive values (range 99.49% to 99.55%; p = 0.27). The original EDACS identified the largest proportion of patients as low risk (60.6%; p < 0.0001).

CONCLUSIONS

Among ED patients with possible ACS, the modified HEART score, original EDACS, and simplified EDACS all predicted a low risk of 60-day MACE with improved accuracy using a cTnI cutoff below the 99th percentile. The original EDACS identified the most low-risk patients, and thus may be the preferred risk score.

Identification of acute myocardial infarction in elderly patients using optimized highly sensitive troponin I thresholds

Purpose: Established diagnostic thresholds for high-sensitivity cardiac troponins (hs-cTn) might not apply for elderly patients as they are elevated irrespective of the presence of an acute myocardial infarction (AMI). Aim of the present study was to investigate hs-cTnI in elderly patients with suspected AMI and to calculate optimized diagnostic cutoffs. Material and methods: Data from a prospective multi-centre study and from a second independent prospective single-centre cohort study were analysed. A number of 2903 patients were eligible for further analysis. Patients > 70 years were classified as elderly. hs-cTnI was measured upon admission. Results: Around 34.7% of 2903 patients were classified as elderly. Around 22.5% of elderly patients were finally diagnosed with AMI. Elderly patients had higher hs-cTnI levels at admission irrespective of the final diagnosis (p < 0.001). According to the AUROC, hs-cTnI was a strong marker for detection of AMI in elderly patients. Application of the 99th percentile cutoffs showed a substantially lower specificity in elderly. By using optimized thresholds, specificity was improved to levels as in younger patients in both cohorts but accompanied with a decrease in sensitivity. Conclusions: hs-cTnI levels have a lower specificity for detecting AMI in elderly patients. This lower specificity can be improved by using hs-cTnI thresholds optimized for elderly patients.

Sudden Cardiac Death (SCD) - risk stratification and prediction with molecular biomarkers

Sudden cardiac death (SCD) is a sudden, unexpected death that is caused by the loss of heart function. While SCD affects many patients suffering from coronary artery diseases (CAD) and heart failure (HF), a considerable number of SCD events occur in asymptomatic individuals. Certain risk factors for SCD have been identified and incorporated in different clinical scores, however, risk stratification using such algorithms is only useful for health management rather than for early detection and prediction of future SCD events in high-risk individuals. In this review, we discuss different molecular biomarkers that are used for early detection of SCD. This includes genetic biomarkers, where the majority of them are genomic variants for genes that encode for ion channels. Meanwhile, protein biomarkers often denote proteins that play roles in pathophysiological processes that lead to CAD and HF, notably (i) atherosclerosis that involves oxidative stress and inflammation, as well as (ii) cardiac tissue damage that involves neurohormonal and hemodynamic regulation and myocardial stress. Finally, we outline existing challenges and future directions including the use of OMICS strategy for biomarker discovery and the multimarker panels.

Biomarkers of Atrial Fibrillation in Metabolic Syndrome

Whether the increased atrial fibrillation (AF) risk in metabolic syndrome (MetS) patients is due to the syndrome as a whole or simply the sum of the risks of its individual component parts is still obscure. These two clinical entities share many pathophysiological links and thus distinction between a casual observation and a significant association is difficult. Biomarkers associated with pathogenesis of AF in the context of MetS have the ability to refine future risk prediction. In the present review we identify circulating substances that could be regarded as potential biomarkers for prediction of incident AF, or of cardiovascular events in the setting of AF in patients with MetS. Cardiac myocyte injury and stress markers (troponin and natriuretic peptides), markers of renal function (glomeral filtration rate, cystatin-C), and inflammation markers/mediators (interleukin- 6, CRP) are promising biomarkers of patients with AF and MetS.

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.

Insulin Resistance and Vulnerability to Cardiac Ischemia

Hepatic and myocardial ectopic lipid deposition has been associated with insulin resistance (IR) and cardiovascular risk. Lipid overload promotes increased hepatic oxidative capacity, oxidative stress, and impaired mitochondrial efficiency, driving the progression of nonalcoholic fatty liver disease (NAFLD). We hypothesized that higher lipid availability promotes ischemia-induced cardiac dysfunction and decreases myocardial mitochondrial efficiency. Mice with adipose tissue-specific overexpression of sterol element-binding protein 1c as model of lipid overload with combined NAFLD-IR and controls underwent reperfused acute myocardial infarcts (AMIs). Whereas indexes of left ventricle (LV) contraction were similar in both groups at baseline, NAFLD-IR showed severe myocardial dysfunction post-AMI, with prominent LV reshaping and increased end-diastolic and end-systolic volumes. Hearts of NAFLD-IR displayed hypertrophy, steatosis, and IR due to 18:1/18:1-diacylglycerol-mediated protein kinase Cε (PKCε) activation. Myocardial fatty acid-linked respiration and oxidative stress were increased, whereas mitochondrial efficiency was decreased. In humans, decreased myocardial mitochondrial efficiency of ventricle biopsies related to IR and troponin levels, a marker of impaired myocardial integrity. Taken together, increased lipid availability and IR favor susceptibility to ischemia-induced cardiac dysfunction. The diacylglycerol-PKCε pathway and reduced mitochondrial efficiency both caused by myocardial lipotoxicity may contribute to the impaired LV compensation of the noninfarcted region of the myocardium.

Cardiac Troponin T Concentrations, Reversible Myocardial Ischemia, and Indices of Left Ventricular Remodeling in Patients with Suspected Stable Angina Pectoris: a DOPPLER-CIP Substudy

BACKGROUND

Cardiac troponin T concentrations measured with high-sensitivity assays (hs-cTnT) provide important prognostic information for patients with stable coronary artery disease (CAD). However, whether hs-cTnT concentrations mainly reflect left ventricular (LV) remodeling or recurrent myocardial ischemia in this population is not known.

METHODS

We measured hs-cTnT concentrations in 619 subjects with suspected stable CAD in a prospectively designed multicenter study. We identified associations with indices of LV remodeling, as assessed by cardiac MRI and echocardiography, and evidence of myocardial ischemia diagnosed by single positron emission computed tomography.

RESULTS

Median hs-cTnT concentration was 7.8 ng/L (interquartile range, 4.8–11.6 ng/L), and 111 patients (18%) had hs-cTnT concentrations above the upper reference limit (&gt;14 ng/L). Patients with hs-cTnT &gt;14 ng/L had increased LV mass (144 ± 40 g vs 116 ± 34 g; P &lt; 0.001) and volume (179 ± 80 mL vs 158 ± 44 mL; P = 0.006), lower LV ejection fraction (LVEF) (59 ± 14 vs 62 ± 11; P = 0.006) and global longitudinal strain (14.1 ± 3.4% vs 16.9 ± 3.2%; P &lt; 0.001), and more reversible perfusion defects (P = 0.001) and reversible wall motion abnormalities (P = 0.008). Age (P = 0.009), estimated glomerular filtration rate (P = 0.01), LV mass (P = 0.003), LVEF (P = 0.03), and evidence of reversible myocardial ischemia (P = 0.004 for perfusion defects and P = 0.02 for LV wall motion) were all associated with increasing hs-cTnT concentrations in multivariate analysis. We found analogous results when using the revised US upper reference limit of 19 ng/L.

CONCLUSIONS

hs-cTnT concentrations reflect both LV mass and reversible myocardial ischemia in patients with suspected stable CAD.

Studies towards hcTnI Immunodetection Using Electrochemical Approaches Based on Magnetic Microbeads

Different electrochemical strategies based on the use of magnetic beads are described in this work for the detection of human cardiac troponin I (hcTnI). hcTnI is also known as the gold standard for acute myocardial infarction (AMI) diagnosis according to the different guidelines from the European Society of Cardiology (ESC) and the American College of Cardiology (ACC). Amperometric and voltamperometric sandwich magnetoimmunoassays were developed by biofunctionalization of paramagnetic beads with specific antibodies. These bioconjugates were combined with biotinylated antibodies as detection antibodies, with the aim of testing different electrochemical transduction principles. Streptavidin labeled with horseradish peroxidase was used for the amperometric magnetoimmunoassay, reaching a detectability of 0.005 ± 0.002 µg mL-1 in 30 min. Cadmium quantum dots-streptavidin bioconjugates were used in the case of the voltamperometric immunosensor reaching a detectability of 0.023 ± 0.014 µg mL-1.

Serum Cardiac Troponin T Levels in Asymptomatic Elderly Nursing Home Residents

BACKGROUND

The definition of myocardial infarction relies on elevated troponin levels. However, elevated levels of high sensitive cardiac troponin (hs-cTnT) assays have been reported in elderly patients without acute myocardial infarction. We sought to determine whether elevated hs-cTnT levels have a prognostic value in stable elderly subjects without any acute illness.

METHODS

The study cohort included residents of a nursing home who were asymptomatic without any acute medical problem. Serum hs-cTnT levels were measured, and participants were divided into high and low hs-cTnT groups. We measured hs-cTnT levels of young healthy volunteers as well and compared them with hs-cTnT levels of those nursing home residents.

RESULTS

Fifty-seven nursing home residents and 14 young volunteers were included in the study. The average age of nursing home residents was 83 ± 14 years, compared with 37 ± 3 years of the volunteers. Levels of hs-cTnT were significantly higher in the elderly compared with the volunteers (0.02 ± 0.016 ng/mL vs 0.005 ± 0.0003 ng/mL; P < .001); accordingly, we chose a cutoff of 0.02 ng/mL hs-cTnT and divided the 57 patients into 2 subgroups for further evaluation. After adjustment for age, gender, and glomerular filtration rate, the hs-cTnT was still an independent predictor of 1-year mortality (relative risk 2.04 [95% conficence interval, 2.009-29.45], P = .003).

CONCLUSIONS

Mild elevations of hs-cTnT levels are common in elderly patients, and hs-cTnT level is an independent marker of mortality risk in this population. For patients older than 70 years, a different hs-cTnT cutoff is required (eg, higher than 0.014 ng/mL).

Biomarkers to Predict Cardiovascular Death

This article reviews biomarkers that have been shown to identify subjects at increased risk for cardiovascular death within the general population, in those with established coronary artery disease, and in those with heart failure. Use of biomarkers for risk stratification for sudden cardiac death continues to evolve. It seems that a multimarker strategy for risk stratification using simple measures of circulating proteins and usual clinical risk factors, particularly in patients with known coronary artery disease, can be used to identify patients at near-term risk of death. Whether similar strategies in the general population will prove to be cost-effective needs to be investigated.

Prognostic Significance of Elevated Cardiac Troponin in Acute Gastrointestinal Bleeding

BACKGROUND

Acute gastrointestinal bleeding (AGIB) is responsible for over 140,000 hospitalizations annually. Cardiovascular-related deaths account for 30% of the patients surviving the initial episode of AGIB. The purpose of this study was to identify the impact of elevated troponin on short-term mortality and length of stay (LOS) of these patients.

METHODS

From July 2013 to July 2016, 290 patients admitted with a diagnosis of AGIB and who had cardiac troponin I measured within 24 h of presentation were retrospectively reviewed. Clinical variables including 30-day mortality, 30-day readmission and LOS were then compared between the groups of troponin elevation and no troponin elevation.

RESULTS

The overall 30-day mortality among patients with AGIB was 6.5% (19/290). Cardiac troponin was elevated in 10% of patients (29/290). Among patients with normal troponin, 5% (13/261) died within 30 days. In patients with troponin elevation, 21% died in the same period (6/29, P = 0.001). The LOS was also higher in patients with troponin elevation (6 vs. 5 days, P = 0.02). There was no difference in 30-day readmission among the two groups. Past history of coronary artery disease, congestive heart failure, hypertension, aspirin use and elevated creatinine was more common in patients with troponin elevation. On multivariate analysis, troponin elevation on presentation is associated with increased mortality (odds: 5.50, CI: 1.73 - 17.47, P = 0.004).

CONCLUSION

In patients admitted to the inpatient service with AGIB, elevated troponin I on presentation is associated with high short-term mortality and longer hospital stay.

Age-related remodeling of the JAK/STAT/SOCS signaling pathway and associated myocardial changes: From histological to molecular level

BACKGROUND

The cellular and molecular mechanisms implicated in age-associated changes in myocardial structure are of paramount importance since they cause profound alterations in the functional response and represent targets for alleviating age-related pathologies. One of these mechanisms is the JAK/STAT/SOCS signaling pathway.

AIM OF THE STUDY

The present study is designed to elucidate age-dependent changes of the myocardium to provide morphological basis displaying the pathogenesis of myocardial hypertrophy, fibrosis and inflammation with aging.

MATERIAL AND METHODS

Thirty male Sprague Dawley rats aged; 6, 30 and 36 months were used in this study. The animals were divided into three age groups, young adult, senile and very senile rats, respectively. The heart weight/body weight ratio was determined. The heart was subjected to gross morphologic examination, microscopic examination using H&E and Masson's trichrome stains and immunohistochemical examination for detection of JAK, pSTAT3, α-SMA, β-MHC and CD45. Western blotting was also carried out to detect SOCS genes. Real-time PCR was used to detect the inflammatory markers TNFα and IL1β and the hypertrophy marker α-SKA. Biochemical analysis of cardiac troponin I and creatine kinase-MB was done. Quantitative histomorphometric estimations included estimation of cardiac myocyte cross sectional area, estimation of the area percent of collagen fibers in Masson's trichrome stained sections and determination of optical density in immunostained sections. Electron microscopic examination was done to determine capillary density.

RESULTS

Jak and pSTAT3 were predominantly localized to the nuclei and exhibited progressive decline with aging, while SOCS3 activity displayed an age-related increase. The aged myocardium displayed profound age associated structural changes as well as myocardial hypertrophy, fibrosis and inflammation in senile and very senile rats.

CONCLUSION

The age-related modifications in the JAK/STAT/SOCS signaling as well as the age-associated pathological changes in myocardial structure are of particular interest as they provide further insight in age-associated heart pathologies and represent potential targets for cardioprotective and therapeutic approaches.

High Sensitivity Troponins Discriminate Different Morphologies of Coronary Artery Plaques Being Assessed by Coronary Computed Tomography Angiography

BACKGROUND

This study evaluates the association between high sensitivity troponin I (hsTnI) and T (hsTnT) and the morphology of coronary artery plaques detected by coronary computed tomography angiography (CCTA) in patients with suspected coronary artery disease (CAD).

METHODS

Patients undergoing CCTA were prospectively enrolled. CCTA was indicated by a low to intermediate pretest probability for CAD during routine clinical care. Within 24 hours of CCTA examination, peripheral blood samples were taken to measure hsTnI, hsTnT, and N-terminal probrain natriuretic peptide (NT-proBNP).

RESULTS

A total of 99 patients were enrolled with 43% without CAD, 9% with noncalcified plaques, 28% with calcified plaques, and 19% with mixed type plaque lesions. Both hsTnI and hsTnT levels were able to discriminate significantly between the groups, especially in the presence of mixed coronary plaques (AUC range: 0.741-0.752; p = 0.0001). In multivariate logistic regression models, hsTnT, but not hsTnI, was still significantly associated with mixed coronary plaque morphology (odds ratio = 8.968; 95% CI 1.999-40.241; p = 0.004).

CONCLUSIONS

Both hsTnI and hsTnT are able to discriminate between different coronary artery plaques morphologies, whereas hsTnT was significantly associated with mixed coronary plaques in patients with suspected CAD. This trial is registered with NCT03074253.

Prognostic Value of High-Sensitivity Cardiac Troponin T Compared with Risk Scores in Stable Cardiovascular Disease

BACKGROUND

Risk stratification of patients with cardiovascular disease remains challenging despite consideration of risk scores.

METHODS

We aimed to evaluate the prognostic performance of high-sensitivity cardiac troponin T in a low-risk outpatient population presenting for nonsecondary and secondary prevention. All-cause mortality, a composite of all-cause mortality, acute myocardial infarction, and stroke (end point 2), and a composite of all-cause mortality, acute myocardial infarction, stroke and rehospitalization for acute coronary syndrome, and decompensated heart failure (end point 3) were defined. The prognostic performance of high-sensitivity cardiac troponin T on index visit was compared with the PROCAM score and 3 FRAMINGHAM subscores.

RESULTS

In 693 patients with a median follow-up of 796 days, we observed 16 deaths, 32 patients with end point 2, and 83 patients with end point 3. All risk scores performed better in the prediction of all-cause mortality in nonsecondary prevention (area under the curve [AUC]: PROCAM: 0.922 vs 0.523, P = .001, consistent for all other scores). In secondary prevention, high-sensitivity cardiac troponin T outperformed all risk scores in the prediction of all-cause mortality (ΔAUC: PROCAM: 0.319, P <.001, consistent for all other scores) and performed superiorly in the prediction of end point 2 compared with the PROCAM, FRAMINGHAM-Coronary Heart Disease, and FRAMINGHAM-Hard Coronary Heart Disease scores (ΔAUC: PROCAM: 0.176, P = .047, consistent for FRAMINGHAM-Coronary Heart Disease and FRAMINGHAM-Hard Coronary Heart Disease). In nonsecondary prevention, we observed a comparable prognostic performance of high-sensitivity cardiac troponin T and multivariable risk scores. Our findings on the prediction of all-cause mortality compared with the FRAMINGHAM-Hard Coronary Heart Disease score were confirmed in an independent validation cohort on 2046 patients.

CONCLUSIONS

High-sensitivity troponin T provides excellent risk stratification regarding all-cause mortality and all-cause mortality, acute myocardial infarction, and stroke in a secondary prevention cohort in whom risk scores perform poorly.

Higher prevalence of detectable troponin I among cocaine-users without known cardiovascular disease

BACKGROUND

While cocaine use is an established risk factor for acute cardiovascular complications, associations between cocaine use and markers of cardiac injury outside of acute hospital presentation remain poorly characterized. We leveraged advances in cardiac troponin (cTnI) testing to assess low but clinically meaningful levels of cardiac injury among cocaine users and non-users.

METHODS

We conducted a case control study comparing cTnI levels by the presence of cocaine among patients presenting for non-cardiac care in an urban safety net hospital. Samples were chosen sequentially among those for which urine drug screens were ordered by providers hospital-wide.

RESULTS

During 2015, 14% of all hospital drug screens ordered were cocaine-positive. Among unique persons providing cocaine-positive (N=100) and cocaine-negative (N=100) samples, 37% were female, 45% were African-American and the median age was 51. Detectable cTnI (> 0.02ng/mL) was observed in 21 samples (11%). It was more common in subjects using cocaine (Adjusted OR=2.81; 95% CI=1.03-7.65), but not other drugs. Moreover, there was a significant correlation between concentrations of cTnI and the cocaine metabolite, benzoylecgonine (Spearman Correlation=0.34, p<0.01).

CONCLUSIONS

Among urban safety net hospital patients, 11% had detectable cTnI, and cTnI concentration was significantly correlated with benzoylecgonine concentration. While these preliminary results require additional confirmation, they suggest the potential utility of considering cocaine use as more than just an episodic exposure leading to acute cardiac events. The consideration of cocaine use as an ongoing chronic exposure leading to subclinical cardiac injury may improve risk-stratification and patient outcomes in populations where cocaine use is high.

Evaluation of Serial High Sensitivity Troponin T Levels in Individuals Without Overt Coronary Heart Disease Following Exercise Stress Testing

BACKGROUND

Detectable levels of high sensitivity (cardiac) troponin T (HsTnT), occur in the majority of patients with stable coronary heart disease (CHD), and often in 'healthy' individuals. Extreme physical activity may lead to marked elevations in creatine kinase MB and TnT levels. However, whether HsTnT elevations occur commonly after exercise stress testing (EST), and if so, whether this has clinical significance, needs clarification.

METHODS

To determine whether HsTnT levels become elevated after EST (Bruce protocol) to ≥95% of predicted maximum heart rate in presumed healthy subjects without overt CHD, we assayed HsTnT levels for ∼5h post-EST in 105 subjects (median age 37 years).

RESULTS

Pre-EST HsTnT levels <5 ng/L were present in 31/32 (97%) of females and 52/74 (70%) of males. Post-EST, 13 (12%) subjects developed HsTnT levels >14 ng/L, with troponin elevation occurring at least three hours post-EST. Additionally, a detectable ≥ 50% increase in HsTnT levels (4.9→9ng/L) occurred in 28 (27%) of subjects who during EST achieved ≥ 95% of their predicted target heart rate. The median age of the subjects with HsTnT elevations to > 14ng/L post-EST was higher than those without such elevation (42 and 36 years respectively; p=0.038). At a median follow-up of 13 months no adverse events were recorded.

CONCLUSION

The current study demonstrates that detectable elevations occur in HsTnT post-EST in 'healthy' subjects without overt CHD. Future studies should evaluate the clinical significance of detectable elevations in post-EST HsTnT with long-term follow-up for adverse cardiac events.

Application of Biomarkers for Risk Stratification in Patients with Atrial Fibrillation

BACKGROUND

Atrial fibrillation is the most common sustained arrhythmia and an important contributor to cardiovascular morbidity and mortality. Several strategies have been proposed for prediction of outcomes and individualization of treatments to better balance the benefits of stroke prevention and risks of bleeding during anticoagulation.

CONTENT

The availability of analytically more specific and sensitive methods to measure circulating biomarkers of cellular and organ stress and dysfunction has led to testing of their utility in several cardiovascular conditions. In patients with atrial fibrillation, biomarkers of myocardial injury (troponin) and cardiovascular stress and dysfunction (natriuretic peptides, growth differentiation factor 15), myocardial fibrosis (galectin-3), renal dysfunction (creatinine, cystatin C), inflammation (C-reactive protein, cytokines) and coagulation activity (d-dimer) have been found associated with underlying pathophysiology, clinical outcomes and effects of treatment. Measurements of these markers might therefore expand the understanding of the pathophysiology, improve risk assessment and optimize treatment in individual patients with atrial fibrillation.

SUMMARY

Biomarkers for risk stratification have potential roles as tools for evaluation of patients with atrial fibrillation and for selection of the best treatment strategies to prevent stroke, major bleeding, and mortality.

Strategies to overcome misdiagnosis of type 1 myocardial infarction using high sensitive cardiac troponin assays

High sensitive cardiac troponin assays have become the gold standard in the diagnosis of an acute type 1 myocardial infarction (MI) in the absence of ST-segment elevation. Several acute or chronic conditions that impact cardiac troponin levels in the absence of a MI might lead to a misdiagnosis of MI. For example, patients with impaired renal function as well as elderly patients often present with chronically increased cardiac troponin levels. Therefore, the diagnosis of MI type 1 based on the 99th percentile upper limit of normal threshold is more difficult in these patients. Different diagnostic approaches might help to overcome this limitation of reduced MI specificity of sensitive troponin assays. First, serial troponin measurement helps to differentiate chronic from acute troponin elevations. Second, specific diagnostic cut-offs, optimized for a particular patient group, like elderly patients, are able to regain specificity. Such an individualized use and interpretation of sensitive cardiac troponin measurements improves diagnostic accuracy and reduces the amount of misdiagnosed MI type 1.