Quantifying the Release of Biomarkers of Myocardial Necrosis from Cardiac Myocytes and Intact Myocardium

Assessment of cardiovascular risk and physical activity: the role of cardiac-specific biomarkers in the general population and athletes

The first part of this Inter-Society Document describes the mechanisms involved in the development of cardiovascular diseases, particularly arterial hypertension, in adults and the elderly. It will also examine how consistent physical exercise during adolescence and adulthood can help maintain blood pressure levels and prevent progression to symptomatic heart failure. The discussion will include experimental and clinical evidence on the use of specific exercise programs for preventing and controlling cardiovascular diseases in adults and the elderly. In the second part, the clinical relevance of cardiac-specific biomarkers in assessing cardiovascular risk in the general adult population will be examined, with a focus on individuals engaged in sports activities. This section will review recent studies that suggest a significant role of biomarkers in assessing cardiovascular risk, particularly the presence of cardiac damage, in athletes who participate in high-intensity sports. Finally, the document will discuss the potential of using cardiac-specific biomarkers to monitor the effectiveness of personalized physical activity programs (Adapted Physical Activity, APA). These programs are prescribed for specific situations, such as chronic diseases or physical disabilities, including cardiovascular diseases. The purposes of this Inter-Society Document are the following: 1) to discuss the close pathophysiological relationship between physical activity levels (ranging from sedentary behavior to competitive sports), age categories (from adolescence to elderly age), and the development of cardiovascular diseases; 2) to review in detail the experimental and clinical evidences supporting the role of cardiac biomarkers in identifying athletes and individuals of general population at higher cardiovascular risk; 3) to stimulate scientific societies and organizations to develop specific multicenter studies that may take into account the role of cardiac biomarkers in subjects who follow specific exercise programs in order to monitor their cardiovascular risk.

Interpretation of elevated baseline concentrations and serial changes of high-sensitivity cardiac troponin T in confirmed muscular dystrophies

AIMS

Concentrations of high-sensitivity cardiac troponin T (hs-cTnT) are frequently elevated in stable patients with confirmed muscle dystrophies. However, sparse information is available on the interpretation of serial concentration changes.

METHODS

Hs-cTnT was collected in 35 stable outpatients with confirmed skeletal muscle dystrophies at 0 and 1 h and after 6-12 months during scheduled outpatient visits. We simulated the effectiveness of the European Society of Cardiology (ESC) 0/1 h algorithm and assessed biological variation at 6-12 months using two established methods: reference change value (RCV) and minimal important difference (MID).

RESULTS

Median baseline hs-cTnT concentrations were 34.4 ng/L [inter-quartile range (IQR): 17.5-46.2], and values > 99th percentile upper limit of normal were present in 34 of 35 patients. All patients were stable without cardiovascular adverse events during a follow-up of 6.6 months (IQR: 6-7). Median concentration change was 1.9 ng/L (IQR: 0.7-3.2) and 0.8 ng/L (IQR: 0-7.0) at 60 min and 6-9 months, respectively. Applying the criteria of the ESC 0/1 h algorithm for triage of suspected acute coronary syndrome (ACS) showed poor overall effectiveness of baseline hs-cTnT values. No patient would qualify for rule-out based on hs-cTnT less than the limit of detection, whereas five cases would qualify for rule-in based on hs-cTnT ≥ 52 ng/L. Biological variabilities at 6-12 months per MID and RCV were 1.2 ng/L [95% confidence interval (CI): 0.7-2.1] and 28.6% (95% CI: 27.9-29.6), respectively. A total of 8 (22.9%) and 25 (71.4%) cases exceeded the biological variation range, suggesting some additional myocardial damage.

CONCLUSIONS

The high prevalence of elevated hs-cTnT could negatively impact the effectiveness of rule-out and rule-in strategies based on a single hs-cTnT value. Knowledge of the physiological and biological variation of hs-cTnT after 6-12 months is helpful to detect the progression of cardiac involvement or to search for cardiac complications including but not limited to arrhythmias that may trigger acute or chronic myocardial damage.

Evaluating Biomarkers as Tools for Early Detection and Prognosis of Heart Failure: A Comprehensive Review

There is a high prevalence of heart failure (HF) worldwide, which has significant consequences for healthcare costs, patient death and quality of life. Therefore, there has been much focus on finding and using biomarkers for early diagnosis, prognostication and therapy of HF. This overview of the research presents a thorough examination of the current state of HF biomarkers and their many uses. Their function in diagnosing HF, gauging its severity and monitoring its response to therapy are all discussed. Particularly promising in HF diagnosis and risk stratification are the cardiac-specific biomarkers, B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide. Markers of oxidative stress, extracellular matrix, renal function, inflammation and cardiac peptides have shown promise in evaluating HF severity and prognosis. MicroRNAs and insulin-like growth factor are two emerging biomarkers that have shown potential in helping with HF diagnosis and prognosis.

Insights into the Novel Cardiac Biomarker in Acute Heart Failure: Mybp-C

(1) Background: Given its high cardiac specificity and its capacity to directly assess the cardiac function, cardiac myosin-binding protein (MyBP-C) is a promising biomarker in patients with acute heart failure (AHF). The aim of our study was to investigate the clinical utility of this novel marker for diagnosis and short-term prognosis in subjects with AHF. (2) Methods: We measured plasma levels of MyBP-C at admission in 49 subjects (27 patients admitted with AHF and 22 controls). (3) Results: The plasma concentration of MyBP-C was significantly higher in patients with AHF compared to controls (54.88 vs. 0.01 ng/L, p < 0.001). For 30-day prognosis, MyBP-C showed significantly greater AUC (0.972, p < 0.001) than NT-proBNP (0.849, p = 0.001) and hs-TnI (0.714, p = 0.047). In a multivariate logistic regression analysis, an elevated level of MyBP-C was the best independent predictor of 30-day mortality (OR = 1.08, p = 0.039) or combined death/recurrent 30-days rehospitalization (OR = 1.12, p = 0.014). (4) Conclusions: Our data show that circulating MyBP-C is a sensitive and cardiac-specific biomarker with potential utility for the accurate diagnosis and prognosis of AHF.

Pathophysiological mechanisms underlying increased circulating cardiac troponin in noncardiac surgery: a narrative review

Assay-specific increases in circulating cardiac troponin are observed in 20-40% of patients after noncardiac surgery, depending on patient age, type of surgery, and comorbidities. Increased cardiac troponin is consistently associated with excess morbidity and mortality after noncardiac surgery. Despite these findings, the underlying mechanisms are unclear. The majority of interventional trials have been designed on the premise that ischaemic cardiac disease drives elevated perioperative cardiac troponin concentrations. We consider data showing that elevated circulating cardiac troponin after surgery could be a nonspecific marker of cardiomyocyte stress. Elevated concentrations of circulating cardiac troponin could reflect coordinated pathological processes underpinning organ injury that are not necessarily caused by ischaemia. Laboratory studies suggest that matching of coronary artery autoregulation and myocardial perfusion-contraction coupling limit the impact of systemic haemodynamic changes in the myocardium, and that type 2 ischaemia might not be the likeliest explanation for cardiac troponin elevation in noncardiac surgery. The perioperative period triggers multiple pathological mechanisms that might cause cardiac troponin to cross the sarcolemma. A two-hit model involving two or more triggers including systemic inflammation, haemodynamic strain, adrenergic stress, and autonomic dysfunction might exacerbate or initiate acute myocardial injury directly in the absence of cell death. Consideration of these diverse mechanisms is pivotal for the design and interpretation of interventional perioperative trials.

Cardiovascular risk evaluation in pregnancy: focus on cardiac specific biomarkers

Despite the evidence demonstrating the clinical utility of cardiac specific biomarkers in improving cardiovascular risk evaluation in several clinical conditions, even the most recent reviews and guidelines fail to consider their measurement in order to enhance the accuracy of the evaluation of cardiovascular risk in pregnant women. The aim of this review article was to examine whether the assay of cardiac specific biomarkers can enhance cardiovascular risk evaluation in pregnant women, first by reviewing the relationships between the physiological state of pregnancy and cardiac specific biomarkers. The clinical relevance of brain natriuretic peptide (BNP)/NT-proBNP and high-sensitivity cardiac troponin I/high-sensitivity cardiac troponin T (hs-cTnI/hs-cTnT) assay in improving cardiovascular risk evaluation is examined based on the results of clinical studies on subjects with normal and those with complicated pregnancy. Finally, the analytical approaches and clinical objectives related to cardio specific biomarkers are advocated in order to allow an early and more accurate evaluation of cardiovascular risk in pregnant women.

Translational bioinformatics approach to combat cardiovascular disease and cancers

Bioinformatics is an interconnected subject of science dealing with diverse fields including biology, chemistry, physics, statistics, mathematics, and computer science as the key fields to answer complicated physiological problems. Key intention of bioinformatics is to store, analyze, organize, and retrieve essential information about genome, proteome, transcriptome, metabolome, as well as organisms to investigate the biological system along with its dynamics, if any. The outcome of bioinformatics depends on the type, quantity, and quality of the raw data provided and the algorithm employed to analyze the same. Despite several approved medicines available, cardiovascular disorders (CVDs) and cancers comprises of the two leading causes of human deaths. Understanding the unknown facts of both these non-communicable disorders is inevitable to discover new pathways, find new drug targets, and eventually newer drugs to combat them successfully. Since, all these goals involve complex investigation and handling of various types of macro- and small- molecules of the human body, bioinformatics plays a key role in such processes. Results from such investigation has direct human application and thus we call this filed as translational bioinformatics. Current book chapter thus deals with diverse scope and applications of this translational bioinformatics to find cure, diagnosis, and understanding the mechanisms of CVDs and cancers. Developing complex yet small or long algorithms to address such problems is very common in translational bioinformatics. Structure-based drug discovery or AI-guided invention of novel antibodies that too with super-high accuracy, speed, and involvement of considerably low amount of investment are some of the astonishing features of the translational bioinformatics and its applications in the fields of CVDs and cancers.

Absence of visible infarction on cardiac magnetic resonance imaging despite the established diagnosis of myocardial infarction by 4th Universal Definition of Myocardial Infarction

AIMS

Myocardial scarring due to acute myocardial infarction (AMI) can be visualized by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging. However, a recent study revealed a group of Type 1 AMI patients with undetectable myocardial injury on LGE. This study aims to describe these cases in detail and explore possible explanations for this new phenomenon.

METHODS AND RESULTS

A total of 137 patients diagnosed with either ST-elevation myocardial infarction (STEMI) or non-ST-elevation myocardial infarction (non-STEMI) diagnosed according to the 4th Universal Definition of Myocardial Infarction underwent LGE-CMR after invasive coronary angiography. Fourteen of them (10.2%) showed no LGE and were included in the final study population. Most patients presented with acute chest pain, 3 patients were diagnosed as STEMI, and 11 as non-STEMI. Peak high-sensitive cardiac troponin T ranged from 45 to 1173 ng/L. A culprit lesion was identified in 12 patients. Severe coronary stenoses were found in five patients, while seven patients had subtotal to total coronary artery occlusion. Percutaneous coronary intervention was performed in 10 patients, while 2 patients required coronary artery bypass grafting and no intervention was required in 2 patients. Cardiac magnetic resonance was performed 30 (4-140) days after the initial presentation. Most patients showed preserved left ventricular ejection fraction on CMR. No alternative reasons for the rise/fall of high-sensitive cardiac troponin T were found.

CONCLUSION

The absence of LGE on CMR in patients with Type 1 AMI is a new finding. While insufficient spatial resolution of LGE imaging, delayed CMR performance, spontaneous reperfusion, and coronary collaterals may provide some explanations, further investigations are required to fully understand this phenomenon.

Advances in research on molecular markers in immune checkpoint inhibitor-associated myocarditis

Immune checkpoint inhibitors (ICIs) play a crucial role in the immunotherapy of malignant tumors, preventing immune evasion by tumor cells and activating autoimmune cells to eliminate the tumor. Despite their proven effectiveness in antitumor therapy, potential immune-related adverse effects must be recognized, particularly ICI-associated myocarditis (ICIAM). ICIAM is the most lethal form of organ immunotoxicity, with a significant impact on short-term mortality. However, ICIAM is predominantly asymptomatic or mildly nonspecific. It is difficult to diagnose, especially due to the lack of unique molecular markers. This article aims to provide a comprehensive overview of the progress made in identifying molecular markers for ICIAM.

Long-term prognostic value of high-sensitivity cardiac troponin-I in patients with idiopathic dilated cardiomyopathy

Our objective was to evaluate the long-term prognostic value of high-sensitivity cardiac troponin-I (hs-cTn-I) in idiopathic dilated cardiomyopathy (DCM). First, patients were divided into an end-event group (n = 55) and a non-end-event group (n = 67). Then, patients were included in the subgroup analysis to compare the diagnostic value of brain natriuretic peptide (BNP) and hs-cTn-I in different populations. hs-cTn-I and BNP concentrations were higher in the end-event group. The Cox regression analysis indicated that high hs-cTn-I was a risk factor for poor long-term prognosis. Receiver operating characteristic analysis showed that the area under the curve (AUC) for hs-cTn-I to predict end events was 0.751, and the AUC for BNP was 0.742. The correlation analysis suggested that hs-cTn-I was related to the percentage change in left ventricular internal diameter at end-diastolic and left ventricular ejection fraction. Subgroup analysis showed that compared with BNP, hs-cTn-I was more suitable for predicting end events in patients with preserved renal function (AUC: 0.853 vs 0.712, P = 0.04). In conclusion, hs-cTn-I is a potential biomarker for evaluating long-term prognosis in idiopathic DCM, and its predictive value is higher than that of BNP in patients with preserved renal function.

Measurement of Cardiac-Specific Biomarkers in the Emergency Department: New Insight in Risk Evaluation

The aim of this article review is to analyze some models and clinical issues related to the implementation of accelerated diagnostic protocols based on specific cardiac biomarkers in patients admitted to the emergency department (ED) with symptoms compatible with acute cardiac disorders. Four specific clinical issues will be discussed in detail: (a) pathophysiological and clinical interpretations of circulating hs-cTnI and hs-cTnT levels; (b) the clinical relevance and estimation of the biological variation of biomarkers in patients admitted to the ED with acute and severe diseases; (c) the role and advantages of the point-of-care testing (POCT) methods for cardiac-specific biomarkers in pre-hospital and hospital clinical practice; and (d) the clinical role of specific cardiac biomarkers in patients with acute heart failure (AHF). In order to balance the risk between a hasty discharge versus the potential harms caused by a cardiac assessment in patients admitted to the ED with suspected acute cardiovascular disease, the measurement of specific cardiac biomarkers is essential for the early identification of the presence of myocardial dysfunction and/or injury and to significantly reduce the length and costs of hospitalization. Moreover, specific cardiac biomarkers (especially hs-cTnI and hs-cTnT) are useful predictors of mortality and major adverse cardiovascular events (MACE) in patients admitted to the ED with suspected acute cardiovascular disease. To guide the implementation of the most rapid algorithms for the diagnosis of Non-ST-Elevation Myocardial Infarction (NSTEMI) into routine clinical practice, clinical scientific societies and laboratory medicine societies should promote collaborative studies specifically designed for the evaluation of the analytical performance and, especially, the cost/benefit ratio resulting from the use of these clinical protocols and POCT methods in the ED clinical practice.

Variability of cardiac troponin levels in normal subjects and in patients with cardiovascular diseases: analytical considerations and clinical relevance

In accordance with all the most recent international guidelines, the variation of circulating levels of cardiac troponins I and T, measured with high-sensitivity methods (hs-cTnI and hs-cTnT), should be used for the detection of acute myocardial injury. Recent experimental and clinical evidences have demonstrated that the evaluation of hs-cTnI and hs-cTnT variations is particularly relevant: a) for the differential diagnosis of Acute Coronary Syndromes (ACS) in patients admitted to the Emergency Department (ED); b) for the evaluation of cardiovascular risk in patients undergoing major cardiac or non-cardiac surgery, and in asymptomatic subjects of the general population aged >55 years and with co-morbidities; c) for the evaluation of cardiotoxicity caused by administration of some chemotherapy drugs in patients with malignant tumors. The aim of this document is to discuss the fundamental statistical and biological considerations on the intraindividual variability of hs-cTnI and hs-cTnT over time in the same individual. Firstly, it will be discussed in detail as the variations of circulating levels strictly depend not only on the analytical error of the method used but also on the intra-individual variability of the biomarker. Afterwards, the pathophysiological interpretation and the clinical relevance of the determination of the variability of the hs-cTnI and hs-cTnT values ​​ in patients with specific clinical conditions are discussed. Finally, the evaluation over time of the variation in circulating levels of hs-cTnI and hs-cTnT is proposed for a more accurate estimation of cardiovascular risk in asymptomatic subjects from the general population.

New Insights in the Era of Clinical Biomarkers as Potential Predictors of Systemic Therapy-Induced Cardiotoxicity in Women with Breast Cancer: A Systematic Review

Cardiotoxicity induced by breast cancer therapies is a potentially serious complication associated with the use of various breast cancer therapies. Prediction and better management of cardiotoxicity in patients receiving chemotherapy is of critical importance. However, the management of cancer therapy-related cardiac dysfunction (CTRCD) lacks clinical evidence and is based on limited clinical studies.

AIM

To provide an overview of existing and potentially novel biomarkers that possess a promising predictive value for the early and late onset of CTRCD in the clinical setting.

METHODS

A systematic review of published studies searching for promising biomarkers for the prediction of CTRCD in patients with breast cancer was undertaken according to PRISMA guidelines. A search strategy was performed using PubMed, Google Scholar, and Scopus for the period 2013-2023. All subjects were >18 years old, diagnosed with breast cancer, and received breast cancer therapies.

RESULTS

The most promising biomarkers that can be used for the development of an alternative risk cardiac stratification plan for the prediction and/or early detection of CTRCD in patients with breast cancer were identified.

CONCLUSIONS

We highlighted the new insights associated with the use of currently available biomarkers as a standard of care for the management of CTRCD and identified potentially novel clinical biomarkers that could be further investigated as promising predictors of CTRCD.

Anthracyclines and Biomarkers of Myocardial Injury: The Effect of Remote Ischemic Conditioning

Background

Remote ischemic conditioning (RIC) has been beneficial in laboratory studies of anthracycline cardiotoxicity, but its effects in patients is not established.

Objectives

The authors studied the effect of RIC on cardiac biomarkers and function during and after anthracycline chemotherapy.

Methods

The ERIC-Onc study (Effect of Remote Ischaemic Conditioning in Oncology Patients; NCT02471885) was a randomized, single-blind, sham-controlled study of RIC at each chemotherapy cycle. The primary endpoint was troponin T (TnT) during chemotherapy and up to 1 year. Secondary outcomes included cardiac function, major adverse cardiovascular events (MACE), and MACE or cancer death. Cardiac myosin-binding-protein C (cMyC) was investigated in parallel with TnT.

Results

The study was prematurely halted after the evaluation of 55 patients (RIC n = 28, sham n = 27). Biomarkers increased from baseline to cycle 6 of chemotherapy for all patients (median TnT 6 [IQR: 4-9] ng/L to 33 [IQR: 16-36)] ng/L; P ≤ 0.001; cMyC 3 (IQR: 2-5) ng/L to 47 (IQR: 18-49) ng/L; P ≤ 0.001). Mixed-effects regression analysis for repeated measures showed no difference in TnT between the 2 groups (RIC vs sham, mean difference 3.15 ng/L; 95% CI: -0.04 to 6.33; P = 0.053), or cMyC (RIC vs sham, mean difference 4.17 ng/L; 95% CI: -0.12 to 8.45; P = 0.056). There were more MACE and cancer deaths in the RIC group (11 vs 3; HR: 0.25; 95% CI: 0.07-0.90; P = 0.034), with more cancer deaths (8 vs 1; HR: 0.21; 95% CI: 0.04-0.95; P = 0.043) at 1 year.

Conclusions

TnT and cMyC significantly increased during anthracycline chemotherapy with 81% having a TnT ≥14 ng/L at cycle 6. RIC did not affect the rise in biomarkers, but there was a small increase in early cancer deaths, possibly related to the greater proportion of patients with metastatic disease randomized to the RIC group (54%vs 37%). (Effect of Remote Ischaemic Conditioning in Oncology Patients [ERIC-ONC]; NCT02471885).

Inflammageing and Cardiovascular System: Focus on Cardiokines and Cardiac-Specific Biomarkers

The term "inflammageing" was introduced in 2000, with the aim of describing the chronic inflammatory state typical of elderly individuals, which is characterized by a combination of elevated levels of inflammatory biomarkers, a high burden of comorbidities, an elevated risk of disability, frailty, and premature death. Inflammageing is a hallmark of various cardiovascular diseases, including atherosclerosis, hypertension, and rapid progression to heart failure. The great experimental and clinical evidence accumulated in recent years has clearly demonstrated that early detection and counteraction of inflammageing is a promising strategy not only to prevent cardiovascular disease, but also to slow down the progressive decline of health that occurs with ageing. It is conceivable that beneficial effects of counteracting inflammageing should be most effective if implemented in the early stages, when the compensatory capacity of the organism is not completely exhausted. Early interventions and treatments require early diagnosis using reliable and cost-effective biomarkers. Indeed, recent clinical studies have demonstrated that cardiac-specific biomarkers (i.e., cardiac natriuretic peptides and cardiac troponins) are able to identify, even in the general population, the individuals at highest risk of progression to heart failure. However, further clinical studies are needed to better understand the usefulness and cost/benefit ratio of cardiac-specific biomarkers as potential targets in preventive and therapeutic strategies for early detection and counteraction of inflammageing mechanisms and in this way slowing the progressive decline of health that occurs with ageing.

Cardiac troponins: Mechanisms of release and role in healthy and diseased subjects

The cardiac troponins (cTns), cardiac troponin C (cTnC), cTnT, and cTnI are key elements of myocardial apparatus, fixed as protein complex on the thin filament of sarcomere and are involved in the regulation of excitation-contraction coupling of cardiomyocytes in the presence of Ca²⁺ . Circulating cTnT and cTnI (cTns) increase following cardiac tissue necrosis, and they are consolidated biomarkers of acute myocardial infarction (AMI). However, the use of high sensitivity (hs)-immunoassay tests for cTnT and cTnI has made it possible to identify a multitude of other clinical conditions associated with increased circulating levels of cTns. cTns can be measured also in the peripheral circulation of healthy subjects or athletes, suggesting that different mechanisms are involved in the release of cTns in the blood independently of cardiac cell necrosis. In this review, the molecular/cellular mechanisms involved in cTns release in blood and the exploitation of cTnI and cTnT as biomarkers of cardiac adverse events, in addition to cardiac necrosis, are discussed.

Evaluation of the cardiovascular risk in patients undergoing major non-cardiac surgery: role of cardiac-specific biomarkers

Major adverse cardiovascular events are frequently observed in patients undergoing major non-cardiac surgery during the peri-operative period. At this time, the possibility to predict cardiovascular events remains limited, despite the introduction of several algorithms to calculate the risk of adverse events, mainly death and major adverse cardiovascular events (MACE) based on the clinical history, risk factors (sex, age, lipid profile, serum creatinine) and non-invasive cardiac exams (electrocardiogram, echocardiogram, stress tests). The cardiac-specific biomarkers natriuretic peptides (NPs) and cardiac troponins (cTn) have been proposed as additional tools for risk prediction in the peri-operative period, particularly for the identification of myocardial injury in patients undergoing major non-cardiac surgery. The prognostic information from the measurement of BNP/NT-proBNP and hs-cTn is independent and complementary to other important indicators of risk, also including ECG and imaging techniques. Elevated levels of cardiac-specific biomarkers before surgery are associated with a markedly higher risk of MACE during the peri-operative period. BNP/NT-proBNP and hs-cTn should be measured in all patients during the clinical evaluation before surgery, particularly during intermediate- or high-risk surgery, in patients aged >65 years and/or with comorbidities. Several questions remain to be assessed in dedicated clinical studies, such as how to optimize the management of patients with raised cardiac specific biomarkers before surgery, and whether a strategy based on biomarker measurement improves patient outcomes and is cost-effective.

Multiomics technologies: role in disease biomarker discoveries and therapeutics

 

Medical research has been revolutionized after the publication of the full human genome. This was the major landmark that paved the way for understanding the biological functions of different macro and micro molecules. With the advent of different high-throughput technologies, biomedical research was further revolutionized. These technologies constitute genomics, transcriptomics, proteomics, metabolomics, etc. Collectively, these high-throughputs are referred to as multi-omics technologies. In the biomedical field, these omics technologies act as efficient and effective tools for disease diagnosis, management, monitoring, treatment and discovery of certain novel disease biomarkers. Genotyping arrays and other transcriptomic studies have helped us to elucidate the gene expression patterns in different biological states, i.e. healthy and diseased states. Further omics technologies such as proteomics and metabolomics have an important role in predicting the role of different biological molecules in an organism. It is because of these high throughput omics technologies that we have been able to fully understand the role of different genes, proteins, metabolites and biological pathways in a diseased condition. To understand a complex biological process, it is important to apply an integrative approach that analyses the multi-omics data in order to highlight the possible interrelationships of the involved biomolecules and their functions. Furthermore, these omics technologies offer an important opportunity to understand the information that underlies disease. In the current review, we will discuss the importance of omics technologies as promising tools to understand the role of different biomolecules in diseases such as cancer, cardiovascular diseases, neurodegenerative diseases and diabetes.

SUMMARY POINTS

A 0/1h-algorithm using cardiac myosin-binding protein C for early diagnosis of myocardial infarction

AIMS

Cardiac myosin-binding protein C (cMyC) demonstrated high diagnostic accuracy for the early detection of non-ST-elevation myocardial infarction (NSTEMI). Its dynamic release kinetics may enable a 0/1h-decision algorithm that is even more effective than the ESC hs-cTnT/I 0/1 h rule-in/rule-out algorithm.

METHODS AND RESULTS

In a prospective international diagnostic study enrolling patients presenting with suspected NSTEMI to the emergency department, cMyC was measured at presentation and after 1 h in a blinded fashion. Modelled on the ESC hs-cTnT/I 0/1h-algorithms, we derived a 0/1h-cMyC-algorithm. Final diagnosis of NSTEMI was centrally adjudicated according to the 4th Universal Definition of Myocardial Infarction. Among 1495 patients, the prevalence of NSTEMI was 17%. The optimal derived 0/1h-algorithm ruled-out NSTEMI with cMyC 0 h concentration below 10 ng/L (irrespective of chest pain onset) or 0 h cMyC concentrations below 18 ng/L and 0/1 h increase <4 ng/L. Rule-in occurred with 0 h cMyC concentrations of at least 140 ng/L or 0/1 h increase ≥15 ng/L. In the validation cohort (n = 663), the 0/1h-cMyC-algorithm classified 347 patients (52.3%) as 'rule-out', 122 (18.4%) as 'rule-in', and 194 (29.3%) as 'observe'. Negative predictive value for NSTEMI was 99.6% [95% confidence interval (CI) 98.9-100%]; positive predictive value 71.1% (95% CI 63.1-79%). Direct comparison with the ESC hs-cTnT/I 0/1h-algorithms demonstrated comparable safety and even higher triage efficacy using the 0h-sample alone (48.1% vs. 21.2% for ESC hs-cTnT-0/1 h and 29.9% for ESC hs-cTnI-0/1 h; P < 0.001).

CONCLUSION

The cMyC 0/1h-algorithm provided excellent safety and identified a greater proportion of patients suitable for direct rule-out or rule-in based on a single measurement than the ESC 0/1h-algorithm using hs-cTnT/I.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587.

Cardiac Troponin-T Release After Sport and Differences by Age, Sex, Training Type, Volume, and Intensity: A Critical Review

BACKGROUND

Postexercise release of cardiac troponin (cTn) is a well-known phenomenon, although the influence of various confounders remains unclear. The aim of this critical review was to analyze the postexercise release of cTn according to age, sex, different types of sport, exercise intensity and duration, and training level.

DATA SOURCES

A literature search was performed within the National Library of Medicine using the following keywords: cTn, peak, release, and exercise. The search was further refined by adding the keywords athletes, children/adolescents, and sport.

MAIN RESULTS

For final analysis, 52 studies were included: 43 adult studies, 4 pediatric studies, and 5 with a mixed population of adults and children. Several studies have investigated the kinetics of cTn response after exercise with different biomarkers. The current evidence suggests that sport intensity and duration have significant effects on postexercise cTn elevation, whereas the influence of the type of sport, age, and sex have been not completely defined yet. Most data were obtained during endurance races, whereas evidence is limited (or almost absent), particularly for mixed sports. Data on young adults and professional athletes are limited. Finally, studies on women are extremely limited, and those for non-White are absent.

CONCLUSIONS

Postexercise release of cTn can be observed both in young and master athletes and usually represents a physiological phenomenon; however, more rarely, it may unmask a subclinical cardiac disease. The influence of different confounders (age, sex, sport type/intensity/duration, and training level) should be better clarified to establish individualized ranges of normality for postexercise cTn elevation.

Natriuretic Peptides and Troponins to Predict Cardiovascular Events in Patients Undergoing Major Non-Cardiac Surgery

Patients undergoing major surgery have a substantial risk of cardiovascular events during the perioperative period. Despite the introduction of several risk scores based on medical history, classical risk factors and non-invasive cardiac tests, the possibility of predicting cardiovascular events in patients undergoing non-cardiac surgery remains limited. The cardiac-specific biomarkers, natriuretic peptides (NPs) and cardiac troponins (cTn) have been proposed as additional tools for risk prediction in the perioperative period. This review paper aims to discuss the value of preoperative levels and perioperative changes in cardiac-specific biomarkers to predict adverse outcomes in patients undergoing major non-cardiac surgery. Based on several prospective observational studies and six meta-analyses, some guidelines recommended the measurement of NPs to refine perioperative cardiac risk estimation in patients undergoing non-cardiac surgery. More recently, several studies reported a higher mortality in surgical patients presenting an elevation in high-sensitivity cardiac troponin T and I, especially in elderly patients or those with comorbidities. This evidence should be considered in future international guidelines on the evaluation of perioperative risk in patients undergoing major non-cardiac surgery.

Biological variation of cardiac myosin-binding protein C in healthy individuals

OBJECTIVES

Cardiac myosin-binding protein C (cMyC) is a novel biomarker of myocardial injury, with a promising role in the triage and risk stratification of patients presenting with acute cardiac disease. In this study, we assess the weekly biological variation of cMyC, to examine its potential in monitoring chronic myocardial injury, and to suggest analytical quality specification for routine use of the test in clinical practice.

METHODS

Thirty healthy volunteers were included. Non-fasting samples were obtained once a week for ten consecutive weeks. Samples were tested in duplicate on the Erenna® platform by EMD Millipore Corporation. Outlying measurements and subjects were identified and excluded systematically, and homogeneity of analytical and within-subject variances was achieved before calculating the biological variability (CVI and CVG), reference change values (RCV) and index of individuality (II).

RESULTS

Mean age was 38 (range, 21-64) years, and 16 participants were women (53%). The biological variation, RCV and II with 95% confidence interval (CI) were: CVA (%) 19.5 (17.8-21.6), CVI (%) 17.8 (14.8-21.0), CVG (%) 66.9 (50.4-109.9), RCV (%) 106.7 (96.6-120.1)/-51.6 (-54.6 to -49.1) and II 0.42 (0.29-0.56). There was a trend for women to have lower CVG. The calculated RCVs were comparable between genders.

CONCLUSIONS

cMyC exhibits acceptable RCV and low II suggesting that it could be suitable for disease monitoring, risk stratification and prognostication if measured serially. Analytical quality specifications based on biological variation are similar to those for cardiac troponin and should be achievable at clinically relevant concentrations.

High-sensitivity cardiac troponins in pediatric population

Apparently healthy children often complain of chest pain, especially after physical exercise. Cardiac biomarker levels are often measured, but the clinical relevance of these assays in children is still debated, even when a cardiac disease is present. Coronary artery disease is exceedingly rare in children, but elevated circulating levels of cardiac troponin I (cTnI) and T (cTnT) in an acute setting may help detect heart failure due to an unknown cardiac disorder, or worsening heart failure, particularly in combination with other biomarkers such as B-type natriuretic peptides. However, the interpretation of biomarkers is often challenging, especially when institutions transition from conventional cTn assays to high-sensitivity (hs-cTn) methods, as well demonstrated in the emergency setting for adult patients. From a clinical perspective, the lack of established reference values in the pediatric age is the main problem limiting the use of hs-cTn methods for the diagnosis and managements of cardiac diseases in infants, children and adolescents. This review aims to discuss the possibility to use hs-cTnI and hs-cTnT to detect cardiac disease and to explore age-related differences in biomarker levels in the pediatric age. We start from some analytical and pathophysiological considerations related to hs-cTn assays. Then, after a systematic literature search, we discuss the current evidence and possible limitations of hs-cTn assay as indicators of cardiac disease in the most frequently cardiac disease in pediatric setting.

Use of high-sensitivity cardiac troponins in the emergency department for the early rule-in and rule-out of acute myocardial infarction without persistent ST-segment elevation (NSTEMI) in Italy

Serial measurements of cardiac troponin are recommended by international guidelines to diagnose myocardial infarction (MI) since 2000. However, some relevant differences exist between the three different international guidelines published between 2020 and 2021 for the management of patients with chest pain and no ST-segment elevation. In particular, there is no agreement on the cut-offs or absolute change values to diagnose non-ST-segment elevation MI (NSTEMI). Other controversial issues concern the diagnostic accuracy and cost-effectiveness of cut-off values for the most rapid algorithms (0 h/1 h or 0 h/2 h) to rule-in and rule-out NSTEMI. Finally, another important point is the possible differences between demographic and clinical characteristics of patients enrolled in multicenter trials compared to those routinely admitted to the Emergency Department in Italy. The Study Group of Cardiac Biomarkers, supported by the Italian Scientific Societies Società Italiana di Biochimica Clinica, Italian Society of the European Ligand Assay Society, and Società Italiana di Patolgia Clinica e Medicina di Laboratorio decided to revise the document previously published in 2013 about the management of patients with suspected NSTEMI, and to provide some suggestions for the use of these biomarkers in clinical practice, with a particular focus on the Italian setting.

Exercise-Induced Cardiac Troponin Elevations: From Underlying Mechanisms to Clinical Relevance

Supplemental Digital Content is available in the text.

Serological assessment of cardiac troponins (cTn) is the gold standard to assess myocardial injury in clinical practice. A greater magnitude of acutely or chronically elevated cTn concentrations is associated with lower event-free survival in patients and the general population. Exercise training is known to improve cardiovascular function and promote longevity, but exercise can produce an acute rise in cTn concentrations, which may exceed the upper reference limit in a substantial number of individuals. Whether exercise-induced cTn elevations are attributable to a physiological or pathological response and if they are clinically relevant has been debated for decades. Thus far, exercise-induced cTn elevations have been viewed as the only benign form of cTn elevations. However, recent studies report intriguing findings that shed new light on the underlying mechanisms and clinical relevance of exercise-induced cTn elevations. We will review the biochemical characteristics of cTn assays, key factors determining the magnitude of postexercise cTn concentrations, the release kinetics, underlying mechanisms causing and contributing to exercise-induced cTn release, and the clinical relevance of exercise-induced cTn elevations. We will also explain the association with cardiac function, correlates with (subclinical) cardiovascular diseases and exercise-induced cTn elevations predictive value for future cardiovascular events. Last, we will provide recommendations for interpretation of these findings and provide direction for future research in this field.

Myocardial infarction with non-obstructive coronary artery disease

As a result of the increased use of coronary angiography in acute myocardial infarction in the last two decades, myocardial infarction with non-obstructive coronary arteries (MINOCA) has received growing attention in everyday clinical practice. At the same time, research interest in MINOCA has increased significantly. MINOCA is a heterogeneous disease entity seen in 5-10% of all patients with myocardial infarction, especially in women. Clinically, MINOCA may be difficult to distinguish from other non-ischaemic conditions that can cause similar symptoms and myocardial injury. There is still some confusion around the diagnosis, investigation and management of patients with MINOCA. The present review summarises the current knowledge of MINOCA regarding epidemiology, pathophysiology, investigation, and treatment, with a special focus on imaging modalities. In addition, remaining important knowledge gaps are highlighted.

Cardiac troponin and defining myocardial infarction

The 4th Universal Definition of Myocardial Infarction has stimulated considerable debate since its publication in 2018. The intention was to define the types of myocardial injury through the lens of their underpinning pathophysiology. In this review, we discuss how the 4th Universal Definition of Myocardial Infarction defines infarction and injury and the necessary pragmatic adjustments that appear in clinical guidelines to maximize triage of real-world patients.

Prognostically relevant periprocedural myocardial injury and infarction associated with percutaneous coronary interventions: a Consensus Document of the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

A substantial number of chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI) experience periprocedural myocardial injury or infarction. Accurate diagnosis of these PCI-related complications is required to guide further management given that their occurrence may be associated with increased risk of major adverse cardiac events (MACE). Due to lack of scientific data, the cut-off thresholds of post-PCI cardiac troponin (cTn) elevation used for defining periprocedural myocardial injury and infarction, have been selected based on expert consensus opinions, and their prognostic relevance remains unclear. In this Consensus Document from the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI), we recommend, whenever possible, the measurement of baseline (pre-PCI) cTn and post-PCI cTn values in all CCS patients undergoing PCI. We confirm the prognostic relevance of the post-PCI cTn elevation >5× 99th percentile URL threshold used to define type 4a myocardial infarction (MI). In the absence of periprocedural angiographic flow-limiting complications or electrocardiogram (ECG) and imaging evidence of new myocardial ischaemia, we propose the same post-PCI cTn cut-off threshold (>5× 99th percentile URL) be used to define prognostically relevant ‘major’ periprocedural myocardial injury. As both type 4a MI and major periprocedural myocardial injury are strong independent predictors of all-cause mortality at 1 year post-PCI, they may be used as quality metrics and surrogate endpoints for clinical trials. Further research is needed to evaluate treatment strategies for reducing the risk of major periprocedural myocardial injury, type 4a MI, and MACE in CCS patients undergoing PCI.

Diagnostic algorithms for non-ST-segment elevation myocardial infarction: open issues

The use of serial measurement of cardiac troponin (cTn) is recommended by international guidelines for the diagnosis of myocardial infarction (MI) since 2000. This article focuses on factors influencing temporal changes in high-sensitive cTn (hs)-cTn and the impact of these factors on the diagnosis of non-ST-segment elevation MI (NSTEMI). The recommendations proposed by three different international guidelines published in 2020-2021 for the management of acute coronary syndromes (ACS) in patients presenting without persistent ST-segment elevation (NSTE) show some discrepancies. In particular, there is no agreement among these guidelines about cut-off or absolute change values to be used for the rule-in, especially regarding the use of sex-specific cut-off values. Furthermore, there are no sufficient evidences on the diagnostic accuracy and cost effectiveness related to cut-off values suggested for algorithms to be used by some hs-cTnI methods.

Systems biology in cardiovascular disease: a multiomics approach

Omics techniques generate large, multidimensional data that are amenable to analysis by new informatics approaches alongside conventional statistical methods. Systems theories, including network analysis and machine learning, are well placed for analysing these data but must be applied with an understanding of the relevant biological and computational theories. Through applying these techniques to omics data, systems biology addresses the problems posed by the complex organization of biological processes. In this Review, we describe the techniques and sources of omics data, outline network theory, and highlight exemplars of novel approaches that combine gene regulatory and co-expression networks, proteomics, metabolomics, lipidomics and phenomics with informatics techniques to provide new insights into cardiovascular disease. The use of systems approaches will become necessary to integrate data from more than one omic technique. Although understanding the interactions between different omics data requires increasingly complex concepts and methods, we argue that hypothesis-driven investigations and independent validation must still accompany these novel systems biology approaches to realize their full potential.

Cardiac biomarkers for outcome prediction in infant bronchiolitis: Too soon to discard troponin?

BACKGROUND

Acute bronchiolitis, usually caused by the respiratory syncytial virus, is the most common cause of severe respiratory distress in infants. The clinical relevance of cardiac biomarkers for diagnosis and prognosis of bronchiolitis in infants is still controversial.

AIM

This Editorial discuss the results of a recent on the clinical relevance of cardiac specific biomarkers, NT-proBNP and cardiac troponin I (cTnI) in 40 infants with bronchiolitis, 37% requiring admission in the ICU.

RESULTS

NT-proBNP levels were significantly associated with prolonged hospitalization and duration of oxygen therapy, while cTnI levels, measured with high-sensitivity (hs) methods, did not. Furthermore NT-proBNP was significantly correlated with left and right ventricular functional echocardiographic parameters, while hs-cTnI was not associated with any echocardiographic parameter.

DISCUSSION

Recent results confirm that NT-proBNP assay has a crucial role in the diagnosis, prognosis and follow-up of patients with cardiac disease not only in adult, but even in pediatric age). On the other hand, the clinical usefulness of assay of hs-cTnI and hs-cTnT in pediatric cardiology, at present time, may be greatly limited by the lack of reliable reference intervals.

CONCLUSIONS

Further well-designed multi-center studies are needed to more accurately evaluate the clinical relevance of cardio-specific biomarkers, and in particular of hs-cTnI and hs-cTnT assay, on prognosis of infants with bronchiolitis.

Pre-treatment high-sensitivity troponin T for the short-term prediction of cardiac outcomes in patients on immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are an emerging option for several advanced metastatic cancers, but may have cardiotoxic effects. The prognostic value of high-sensitivity troponin T (hs-TnT) before treatment start has never been investigated.

MATERIALS AND METHODS

Thirty consecutive patients underwent measurement of hs-TnT before starting ICI therapy (pembrolizumab, 23%; nivolumab, 12%; atezolizumab, 6%; durvalumab, 5%). The primary endpoint of cardiovascular death, stroke or transient ischaemic attack, pulmonary embolism and new-onset heart failure, and the secondary endpoint of progression of cardiac involvement according to the CARDIOTOX classification were evaluated after 3 months from the first cycle.

RESULTS

Patients (median age 68 years, 77% men, 13% with coronary artery disease, 90% current or former smokers, 67% overweight or obese and 43% hypertensive) had a median hs-TnT of 12 ng/L (interquartile interval 8-23). The primary endpoint occurred only in patients with hs-TnT ≥ 14 ng/L at baseline. Therefore, only patients who had hs-TnT ≥ 14 ng/L before the first cycle died had a stroke/TIA or new-onset HF. Furthermore, nine out of 13 patients with the secondary endpoint (progression of cardiac disease) had hs-TnT ≥ 14 ng/L before the first cycle (P = .012). AUC values were 0.909 for the primary endpoint and 0.757 for the secondary endpoint. The best cut-off was 14 ng/L for both the primary (100% sensitivity, 73% specificity) and secondary endpoints (sensitivity 75%, specificity 77%).

CONCLUSIONS

In patients on ICIs, baseline hs-TnT predicts a composite cardiovascular endpoint and the progression of cardiac involvement at 3 months, with 14 ng/L as the best cut-off.

Kinetics, Moderators and Reference Limits of Exercise-Induced Elevation of Cardiac Troponin T in Athletes: A Systematic Review and Meta-Analysis

Background: Kinetics, moderators and reference limits for exercise-induced cardiac troponin T (cTnT) elevations are still unclear. Methods: A systematic review of published literature was conducted adhering to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Studies reporting high-sensitivity cardiac troponin T (hs-cTnT) concentrations before and after a bout of exercise in athletes were included and analyzed. The final dataset consisted of 62 estimates from 16 bouts in 13 studies of 5-1,002 athletes (1,421 in total). Meta-analysis was performed using general linear mixed modeling and Bayesian inferences about effect magnitudes. Modifying fixed-effect moderators of gender, age, baseline level, exercise duration, intensity and modalities were investigated. Simulation was used to derive 99th percentile with 95% limits of upper reference ranges for hs-cTnT of athletic populations. Results: The mean and upper reference limits of hs-cTnT before exercise were 4.4 and 19 ng.L-1. Clear increases in hs-cTnT ranging from large to very large (factor changes of 2.1-7.5, 90% compatibility limits, ×/÷1.3) were evident from 0.7 through 25 h, peaking at 2.9 h after the midpoint of a 2.5-h bout of running, when the mean and upper reference limit for hs-cTnT were 33 and 390 ng L-1. A four-fold increase in exercise duration produced a large clear increase (2.4, ×/÷1.7) in post-exercise hs-cTnT. Rowing exercise demonstrated an extremely large clear reduction (0.1 ×/÷2.4). Conclusions: The kinetics of cTnT elevation following exercise, the positive effect of exercise duration, the impact of exercise modality and 99th upper reference limits for athletic populations were reasonably well defined by this meta-analysis.

Cardiac myosin-binding protein C in the diagnosis and risk stratification of acute heart failure

AIMS

Cardiac myosin-binding protein C (cMyC) seems to be even more sensitive in the quantification of cardiomyocyte injury vs. high-sensitivity cardiac troponin, and may therefore have diagnostic and prognostic utility.

METHODS AND RESULTS

In a prospective multicentre diagnostic study, cMyC, high-sensitivity cardiac troponin T (hs-cTnT), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) plasma concentrations were measured in blinded fashion in patients presenting to the emergency department with acute dyspnoea. Two independent cardiologists centrally adjudicated the final diagnosis. Diagnostic accuracy for acute heart failure (AHF) was quantified by the area under the receiver operating characteristic curve (AUC). All-cause mortality within 360 days was the prognostic endpoint. Among 1083 patients eligible for diagnostic analysis, 51% had AHF. cMyC concentrations at presentation were higher among AHF patients vs. patients with other final diagnoses [72 (interquartile range, IQR 39-156) vs. 22 ng/L (IQR 12-42), P < 0.001)]. cMyC's AUC was high [0.81, 95% confidence interval (CI) 0.78-0.83], higher than hs-cTnT's (0.79, 95% CI 0.76-0.82, P = 0.081) and lower than NT-proBNP's (0.91, 95% CI 0.89-0.93, P < 0.001). Among 794 AHF patients eligible for prognostic analysis, 28% died within 360 days; cMyC plasma concentrations above the median indicated increased risk of death (hazard ratio 2.19, 95% CI 1.66-2.89; P < 0.001). cMyC's prognostic accuracy was comparable with NT-proBNP's and hs-cTnT's. cMyC did not independently predict all-cause mortality when used in validated multivariable regression models. In novel multivariable regression models including medication, age, left ventricular ejection fraction, and discharge creatinine, cMyC remained an independent predictor of death and had no interactions with medical therapies at discharge.

CONCLUSION

Cardiac myosin-binding protein C may aid physicians in the rapid triage of patients with suspected AHF.

Diagnostic and Prognostic Biomarkers for Myocardial Infarction

The incidence of myocardial infarction (MI) increases every year worldwide. Better diagnostic and prognostic biomarkers for clinical applications are the consistent pursuit of MI research. In addition to electrocardiogram, echocardiography, coronary angiography, etc., circulating biomarkers are essential for the diagnosis, prognosis, and treatment effect monitoring of MI patients. In this review, we assessed both strength and weakness of MI circulating biomarkers including: (1) originated from damaged myocardial tissues including current golden standard cardiac troponin, (2) released from non-myocardial tissues due to MI-induced systems reactions, and (3) preexisted in blood circulation before the occurrence of MI event. We also summarized newly reported MI biomarkers. We proposed that the biomarkers preexisting in blood circulation before MI incidents should be emphasized in research and development for MI prevention in near future.

Cardiac troponins: are there any differences between T and I?

The most recent international guidelines recommend the measurement of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) using high-sensitivity methods (hs-cTn) for the detection of myocardial injury and the differential diagnosis of acute coronary syndromes. Myocardial injury is a prerequisite for the diagnosis of acute myocardial infarction, but also a distinct entity. The 2018 Fourth Universal Definition of Myocardial Infarction states that myocardial injury is detected when at least one value above the 99th percentile upper reference limit is measured in a patient with high-sensitivity methods for cTnI or cTnT. Not infrequently, increased hs-cTnT levels are reported in patients with congenital or chronic neuromuscular diseases, while the hs-cTnI values are often in the normal range. Furthermore, some discrepancies between the results of laboratory tests for the two troponins are occasionally found in individuals apparently free of cardiac diseases, and also in patients with cardiac diseases. In this review article, authors discuss the biochemical, pathophysiological and analytical mechanisms which may cause discrepancies between hs-cTnI and hs-cTnT test results.

Cardiac troponin I in SARS-CoV-2-patients: The additional prognostic value of serial monitoring

BACKGROUND

Major cardiac complications have been described in SARS-CoV-2 patients. The study of cardiac troponin' kinetic release is the recommended approach to differentiate acute from chronic injury, in order to clinically manage different cardiac diseases.

AIM

To investigate whether serial measurements of high sensitivity troponin I (hs-cTnI) might provide additional information in SARS-CoV-2 patients's clinical management.

METHODS

113 consecutive patients suffering from microbiology proven SARS-CoV2-infection have been studied. Hs-cTnI has been measured in lithium-heparin plasma samples using STAT High Sensitive Troponin I (Architect _i2000, Abbott Diagnostics), being 99th percentiles 16 and 34 ng/L for females and males respectively.

RESULTS

In 69 out of 113 patients hs-cTnI has been measured, showing in 31 (45%) values higher than 99th percentiles in at least one occasion. In 50 patients (72%) a kinetic evaluation (at least 2 measurements during 24 h) has been carried out. Patients were subdivided into five groups: 1 (n = 44) and 2 (n = 19) no measurement of hs-cTnI or no monitoring respectively; 3 (n = 15) no significant variations during monitoring; 4 (n = 8) and 5 (n = 27) significant variations with values persistently below or sometimes higher than 99th percentiles, respectively. Group 5 patients had a longer hospital stay (median 37 days, p = 0.0001), a more aggressive disease (6 out of 27, 22%, died), more often need admission to ICU (n = 25, 92.6%, p < 0.0001), and show one or more peak values, sometime preceded by severe hypoxia.

CONCLUSIONS

In SARS-CoV-2 patients, hs-cTnI serial monitoring may provide additional data to stratify risk, establish prognosis and gaining epidemiological insight on cardiac involvement in this pandemic disease.

Clinical relevance of biological variation of cardiac troponins

The high-sensitivity immunoassays for cardiac troponin I (hs-cTnI) and cardiac troponin T (hs-cTnT) are recommended by all the most recent international guidelines as gold standard laboratory methods for the detection of myocardial injury and diagnosis of acute myocardial infarction (AMI). In this review article, the Authors aimed at discussing the relevant biochemical, physiological, and clinical issues related to biological variability of cTnI and cTnT. Cardiac troponins, measured with hs-cTn methods, show a better clinical profile than the other cardio-specific biomarkers (such as the natriuretic peptides, BNP and NT-proBNP). In particular, the hs-cTn methods are characterized by a low intra-individual index of variation (<0.6) and reduced analytical imprecision (about 5% CV) at the clinical cut-off value (i.e., the 99th percentile URL value). Moreover, recent studies have reported that differences between two hs-cTn measured values (RCV) >30% can be considered statistically significant. These favourable biological characteristics and analytical performance of hs-cTn methods significantly improved the accuracy in the diagnostic process of acute coronary syndromes (ACS) in patients admitted to emergence department. In addition, several studies have demonstrated the clinical usefulness of cardiovascular risk evaluation with hs-cTn methods in some groups of patients with clinical conditions at high cardiovascular risk (such as systemic hypertension, severe obesity, diabetes mellitus, renal insufficiency, and chronic obstructive pulmonary disease). However, screening programs in the general population with hs-cTn methods for cardiovascular risk stratification require further investigation to define the optimal target populations, timing of measurement, and preventive interventions.

High-sensitivity methods for cardiac troponins: The mission is not over yet

The measurement of cardiac troponin (cTn) is recommended by all guidelines as the gold standard for the differential diagnosis of Acute Coronary Syndromes. The aim of this review is to discuss in details some key issues regarding both analytical and clinical characteristics of the high-sensitivity methods for cTn (hs-cTn), which are still considered controversial or unresolved. In particular, the major clinical concern regarding hs-cTn methods is the difficulty to differentiate the pathophysiological mechanism responsible for biomarker release from cardiomyocytes after reversible or irreversible injury, respectively. Indeed, recent experimental and clinical studies have demonstrated that different circulating forms of cTnI and cTnT can be respectively measured in plasma samples of patients with reversible or irreversible myocardial injury. Accordingly, a new generation of hs-Tn methods should be set up, based on immunometric immunoassays or chromatographic techniques, specific for circulating peptide forms more characteristics for reversible or irreversible myocardial injury. It is conceivable that this new generation of hs-cTn methods will complete the mission regarding the laboratory tests for specific cardiac biomarkers, started more than 20 years ago, which has already revolutionized the diagnosis, prognosis and management of patients with cardiac diseases.

Comparison of Two Commercially Available Immunoassays for the Measurement of Bovine Cardiac Troponin I in Cattle With Induced Myocardial Injury

Background: Multiple cardiac troponin I (cTnI) immunoassays are commercially available. Overall, assays have not been standardized, and inter-assay differences in the detection of the analyte cardiac troponin I can be clinically relevant.

Objective: To compare the diagnostic accuracy of the commercially available Abbott i-STAT®1 cTnI immunoassay (i-STAT) and the previously validated ADVIA Centaur TnI-Ultra immunoassay (Centaur) in cattle.

Hypothesis: There will be significant differences in bovine serum cTnI results measured by the Centaur and i-STAT methods.

Animals: Ten dairy cows with experimentally induced myocardial injury due to monensin administration. Thirty apparently healthy dairy cows with no history of monensin exposure served as controls.

Methods: Blood was collected at various time points after administration of a single dose of monensin (20 to 50 mg/kg) via orogastric tube. A total of 112 blood samples were collected. Cardiac TnI concentration was analyzed with the two methods and the association between methods analyzed via linear regression. Bland-Altman analysis to evaluate agreement between methods was performed on samples divided into groups (cTnI < 1.0 ng/mL and cTnI ≥ 1.0 ng/mL).

Results: Analyzer results were linearly correlated with each other (R² = 0.931). Samples with cTnI concentrations <1.0 ng/mL had a bias of −0.13 ± 0.20 ng/mL and samples with cTnI concentrations >1.0 ng/mL had a bias of −9.81 ± 13.26 ng/mL.

Conclusions and clinical importance: The results of this study reveal that cTnI concentrations determined with the i-STAT are systematically lower compared to the concentrations determined by the Centaur.

Cardiotoxic effects and myocardial injury: the search for a more precise definition of drug cardiotoxicity

Drug-induced cardiotoxicity is a major clinical problem; cardiotoxic drugs may induce both cardiac dysfunction and myocardial injury. Several recent studies reported that cardiac troponins measured with high-sensitivity methods (hs-cTn) can enable the early detection of myocardial injury related to chemotherapy or abuse of drugs that are potentially cardiotoxic. Several authors have some concerns about the standard definition of cardiotoxicity, in particular, regarding the early evaluation of chemotherapy cardiotoxicity in cancer patients. Several recent studies using the hs-cTn assay indicate that myocardial injury may precede by some months or years the diagnosis of heart failure (HF) based on the evaluation of left ventricular ejection fraction (LVEF). Accordingly, hs-cTn assay should considered to be a reliable laboratory test for the early detection of asymptomatic or subclinical cardiotoxic damage in patients undergoing cancer chemotherapy. In accordance with the Fourth Universal Definition of Myocardial Infarction and also taking into account the recent experimental and clinical evidences, the definition of drug-cardiotoxicity should be updated considering the early evaluation of myocardial injury by means of hs-cTn assay. It is conceivable that the combined use of hs-cTn assay and cardiac imaging techniques for the evaluation of cardiotoxicity will significantly increase both diagnostic sensitivity and specificity, and also better prevent chemotherapy-related left ventricular (LV) dysfunction and other adverse cardiac events. However, large randomized clinical trials are needed to evaluate the cost/benefit ratio of standardized protocols for the early detection of cardiotoxicity using hs-cTn assay in patients receiving chemotherapy for malignant diseases.

Early evaluation of myocardial injury by means of high-sensitivity methods for cardiac troponins after strenuous and prolonged exercise

All the latest international guidelines recommend that cardiac troponin (cTn) I and T should be considered the preferred biomarkers for diagnosis of acute myocardial infarction. However, only in the last 5 years, a progressive improvement in analytical performance of immunometric assays has allowed the measurement of circulating levels of cTnI and cTnT in the large part of apparently healthy adult subjects. The routine use of these high-sensitivity methods for cardiac troponin (hs-cTn) assay has in a short time demonstrated that cardiac troponin concentrations frequently increase after strenuous prolonged exercise in healthy athletes. This acute response of hs-cTn assay following exercise was at first considered to be physiological and without long-term adverse consequences. More recent studies have suggested that exercise-induced increases in hs-cTn values may not be always a physiological response to exercise, but, conversely, it should sometimes be considered as an early cardiovascular risk marker. The aim of this review is to provide an overview of acute and chronic effects of strenuous physical exercise on hs-cTn circulating levels and also to discuss the potential pathophysiological and clinical implications of biomarker responses.

Evidence on clinical relevance of cardiovascular risk evaluation in the general population using cardio-specific biomarkers

In recent years, the formulation of some immunoassays with high-sensitivity analytical performance allowed the accurate measurement of cardiac troponin I (cTnI) and T (cTnT) levels in reference subjects. Several studies have demonstrated the association between the risk of major cardiovascular events and cardiac troponin concentrations even for biomarker values within the reference intervals. High-sensitivity cTnI and cTnT methods (hs-cTn) enable to monitor myocardial renewal and remodelling, and to promptly identify patients at highest risk ofheart failure. An early and effective treatment of individuals at higher cardiovascular risk may revert the initial myocardial remodelling and slow down heart failure progression. Specific clinical trials should be carried out to demonstrate the efficacy and efficiency of the general population screening by means of cost-benefit analysis, in order to better identify individuals at higher risk for heart failure (HF) progression with hs-cTn methods.

The effects of a 50 km ultramarathon race on high sensitivity cardiac troponin I and NT-proBNP in highly trained athletes

BACKGROUND

High sensitivity cardiac troponins I (hs-cTnI) and T (hs-cTnT) and natriuretic peptides (BNP and NT-proBNP) are universally recognized as cardiac reference biomarkers in patients with acute coronary syndromes and heart failure respectively. However, while on one hand the high sensitivity methods of cardiac biomarkers have provided answers to fundamental pathophysiological and clinical questions in patients with heart disease, less information is available on their assessment in paraphysiological conditions, such as high intensity exercise in healthy athletes. The aim of this study was to evaluate hs-cTnI and NT-proBNP in highly trained runners after a 50 km ultramarathon.

METHODS

We have enrolled 20 highly trained male athletes who have run a 50 km ultramarathon. Blood samples were collected 2 hours before the start of the race (T0) and 20 minutes after the end of the race (T1). The blood concentrations of hs-cTnI and NT-proBNP measured before the race were within reference intervals in all runners.

RESULTS

Hs-cTnI significantly increased after the end of the race (median: 19 ng/L [IQR: 12.5-25.75] versus 6 ng/L [IQR: 4.25-8.0]; P<0.001), in three cases over the upper reference limit (URL) of 34 ng/L. NT-proBNP also significantly increased (median: 78 ng/L [IQR: 68.25-87.75] versus 22 ng/L [IQR: 18.25-26.75]; P<0.001). Three other athletes reached concentration over the URL (125 ng/L).

CONCLUSIONS

Our study showed a significant increase in hs-cTnI and NT-proBNP in highly trained athletes after a 50 km ultramarathon race, and 30% of runners had the values of cardiac biomarkers above URL. More studies with a larger number of athletes will be needed to better understand the effects of intense exercise on the heart of trained athletes.

Analytical performance of cardiac troponin assays - Current status and future needs

Concurrent with the introduction of cardiac troponin measurements into the diagnostic definition of myocardial infarction (MI), clinicians and laboratory professionals signaled a clear clinical need for improved analytical quality. This was an important precipitant for developing high-sensitivity cardiac troponin (hs-cTn) assays, currently used in rapid algorithms guiding investigations of patients presenting to the emergency department with possible MI. The hs-cTn assays were also important for the detection and monitoring of low-grade chronic myocardial injury, a condition that has been linked to increased long-term risk of cardiovascular morbidity and mortality. This review summarizes the general recommendations for defining analytical performance specifications while providing relevant clinical situations related to analytical performance. Importantly, outcome studies suggest analytical quality performance for hs-cTn is sufficient for early discharge of patients investigated for possible MI. However, bias due to change in calibrators or reagents may significantly affect the percentage of patients discharged. Biological variation data is suitable for defining performance specifications when hs-cTn measurements are used for diagnosing and monitoring chronic myocardial injury. Further improvement in analytical performance for hs-cTn testing may result in even faster decision making in the emergency setting; while also identifying those with chronic injury at risk for an adverse cardiac event.