High-sensitivity cardiac troponin I and T methods for the early detection of myocardial injury in patients on chemotherapy

Review of Literature and Recommended Procedures for Management of Unusual Cases of False Positive Troponin Tests

Heterophile antibodies are immunoglobulins produced by the immune system in response to exposure to animal and bacterial antigens, blood transfusions, autoimmune disorders, hematologic malignancies, dialysis, and pregnancy. Recently, these antibodies have garnered significant attention due to their impact on the accuracy of laboratory test results. Heterophile antibodies can bind not only to specific antigens but also to those from different species, including the antibodies used in laboratory tests. This cross-reactivity with foreign proteins is the basis for their interference in immunological assays, such as those measuring cardiospecific troponins (cTn). This manuscript reviews the literature on cases of heterophile antibody interference in troponin testing and proposes an algorithm for identifying such interference when clinical discrepancies arise. Recognizing and addressing heterophile antibody interference is crucial, particularly for tests like those for troponins, which are key biomarkers in the diagnosis and management of emergency and intensive care patients. The literature emphasizes the need for accurate procedures to distinguish true cardiac damage from false positives, thereby preventing unnecessary additional tests and hospitalizations.

Proposed framework regarding management of patients with breast cancer and anti-cancer treatment-related elevation in cardiac troponin

Cardiac biomarkers are a vital component within the first edition of the European Society of Cardiology guidelines in Cardio-Oncology. Specifically, they are mentioned in the definition of mild asymptomatic cancer therapy-related cardiac dysfunction, where left ventricular systolic function is ≥50 % with two outcomes; either a new decrease in global longitudinal strain >15 % from baseline and/or a new rise in cardiac biomarkers above the defined 99th percentile cut off values. Cardiac troponin is one such biomarker. Many of the treatments for breast cancer have published data on cardiac dysfunction and/or cardiovascular toxicity, and such may lead to an elevation in cardiac troponin. However, there is conflicting and incomplete data regarding how to approach an elevated cardiac troponin during anti-cancer treatment, which has confounded patient care in the clinical trial setting. We propose a novel framework to guide physicians in treatment-related elevation of cardiac troponin in the breast cancer population. Secondly, the additive role which the recommendation that cardiac troponin carries within mild asymptomatic definitions of CTRCD is the subject of great debate. We suggest a reflection on the role of biomarkers, specifically in reference to cardiac troponin.

Troponin Test, Not Only a Number: An Unusual Case of False Positive

Heterophile antibodies, which can arise from infections, autoimmune disorders, or exposure to animal antigens, can interfere with immunoassays. These antibodies can cross-react with the test reagents used in troponin assays, causing a false elevation in troponin levels. The paper describes a case of a 37-year-old male drug abuser admitted to the emergency room with chest pain. A series of troponin measurements performed using different assays gave discrepant results. Only thanks to the use of Scantibodies HBT tubes, which remove heterophile antibodies, was it possible to make a correct diagnosis of troponin negativity. In conclusion, a correct laboratory/clinical approach to the identification of heterophile antibody interference is essential for accurate troponin testing in order to avoid false positive results. Implementing neutralizing tests can significantly improve the reliability of these diagnostic assays, ensuring better patient outcome.

High-Sensitivity Cardiac Troponins in Patients With Chest Pain and Treatment With Oral Antineoplastic Agents Associated With Cardiovascular Toxicity

BACKGROUND

Knowledge is limited on the clinical implications of high-sensitivity cardiac troponin (hs-cTn) measurements in patients treated with oral antineoplastic agents associated with cardiovascular side effects. This study investigated the diagnostic performance of hs-cTnT for myocardial infarction.

METHODS

Among all visits to 7 different emergency departments (EDs) from December 9, 2010 to August 31, 2017, we included visits by patients presenting with chest pain who had ≥1 hs-cTnT measured. Patients treated with oral antineoplastic agents associated with cardiovascular toxicity were identified. Logistic regression models were used to estimate the performance of hs-cTnT for diagnosing myocardial infarction.

RESULTS

We identified 214,165 visits, of which 2695 (1.3%) occurred in patients with oral antineoplastic treatment associated with cardiovascular toxicity. Treatment was associated with a higher myocardial infarction incidence (8.2% vs 5.7%), but the overall diagnostic accuracy for a myocardial infarction was lower in patients with versus without treatment, paralleled by a lower specificity and PPV with the 0 h hs-cTnT rule-in cut-off of 52 ng/L (92.6% [95% CI: 91.6-93.6] vs 96.8% [95% CI: 96.8-96.9], and 42.8 [95% CI: 37.4-48.2] vs 49.5 [95% CI: 48.6-50.4], respectively). The majority (72%) of patients with treatment were assigned to an intermediate risk group, in whom the risk of myocardial infarction was reduced by 29% (OR 0.71, 95% CI: 0.57-0.89).

CONCLUSIONS

Diagnostic accuracy of hs-cTnT for myocardial infarction is reduced among patients on treatment with oral antineoplastic agents associated with cardiovascular toxicity. Most patients would be assigned to an intermediate risk group, in whom only 4% will have a final myocardial infarction diagnosis.

Circulating Cardiovascular Biomarkers in Cancer Therapeutics-Related Cardiotoxicity: Review of Critical Challenges, Solutions, and Future Directions

Cardiotoxicity is a growing concern in the oncology population. Transthoracic echocardiography and multigated acquisition scans have been used for surveillance but are relatively insensitive and resource intensive. Innovative imaging techniques are constrained by cost and availability. More sensitive, cost-effective cardiotoxicity surveillance strategies are needed. Circulating cardiovascular biomarkers could provide a sensitive, low-cost solution. Biomarkers such as troponins, natriuretic peptides (NPs), novel upstream signals of oxidative stress, inflammation, and fibrosis as well as panomic technologies have shown substantial promise, and guidelines recommend baseline measurement of troponins and NPs in all patients receiving potential cardiotoxins. Nonetheless, supporting evidence has been hampered by several limitations. Previous reviews have provided valuable perspectives on biomarkers in cancer populations, but important analytic aspects remain to be examined in depth. This review provides comprehensive assessment of critical challenges and solutions in this field, with focus on analytical issues relating to biomarker measurement and interpretation. Examination of evidence pertaining to common and serious forms of cardiotoxicity reveals that improved study designs incorporating larger, more diverse populations, registry-based approaches, and refinement of current definitions are key. Further efforts to harmonize biomarker methodologies including centralized biobanking and analyses, novel decision limits, and head-to-head comparisons are needed. Multimarker algorithms incorporating machine learning may allow rapid, personalized risk assessment. These improvements will not only augment the predictive value of circulating biomarkers in cardiotoxicity but may elucidate both direct and indirect relationships between cardiovascular disease and cancer, allowing biomarkers a greater role in the development and success of novel anticancer therapies.

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.

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.

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.

N-Terminal Pro Brain Natriuretic Peptide, sST2, and Galectin-3 Levels in Breast Cancer Survivors

NT-proBNP, soluble ST2 (sST2), and galectin-3 are biomarkers of cardiac dysfunction that have been proposed as identifiers of patients experiencing asymptomatic cardiac dysfunction after anthracycline-based chemotherapy. This study aimed to compare the proportion of breast cancer (BC) survivors with elevated serum levels of these three putative biomarkers by prior receipt of anthracycline (yes vs. no). Five-hundred-eighty survivors of BC who had received anthracycline-based chemotherapy were matched by age and time between diagnosis and serum storage to 580 who had not. Cardiac biomarker levels were analyzed using immunoassays. Analyses were carried out using linear and logistic regression models. Anthracycline recipients had higher values of NT-proBNP than non-recipients (mean 116.0 ng/L vs. 97.0 ng/L, respectively; p < 0.001). Values for ST2 and galectin-3 did not significantly differ by receipt of anthracycline. After further adjustment for age at breast cancer diagnosis, ethnicity, and receipt of trastuzumab, associations between receipt of anthracycline and higher NT-proBNP persisted (p < 0.001), showing that NT-proBNP may be a biomarker of cardiovascular toxicity after receipt of anthracycline-based chemotherapy. Further research to assess the clinical utility of NT-proBNP testing after receipt of anthracycline is recommended. sST2 and galectin-3 do not appear to differentiate between anthracycline recipients and non-recipients amongst breast cancer survivors.

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.

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.