Predictors of high sensitivity cardiac troponin T in chronic kidney disease patients: a cross-sectional study in the chronic renal insufficiency cohort (CRIC)

Urine high-sensitive troponin I in children cannot offer an applicable alternative to serum

Introduction

In children, congenital heart defects represent the primary cause of increased serum troponin I. The elimination process of cardiac troponin I from the bloodstream and the factors influencing this process remain unknown. The objective of this study was to explore the role of troponin I as an indicator of cardiac damage in children both in serum and urine, a concept previously investigated in adults.

Methods

Our prospective study involved 70 children under 24 months of age. The first group underwent ventricular septal defect repair, while the second group involved children who had undergone partial cavopulmonary anastomosis. For these groups, urine and serum troponin I were assessed on four occasions. The third group, consisting of healthy children, underwent a single measurement of urine troponin I.

Results

Serum troponin I values exhibited an expected elevation in the early postoperative period, followed by a return to lower levels. Significantly higher concentrations of serum troponin I were observed in the first group of children (p < 0.05). A positive correlation was found between troponin I in the first three measurements and cardiopulmonary bypass and aortic cross-clamping time. There was no discernible increase in urine troponin I directly related to myocardial damage; troponin I couldn't be detected in most urine samples.

Discussion

The inability to detect troponin I in urine remains unexplained. Potential explanatory factors may include the isoelectric point of troponin I, elevated urinary concentrations of salts and urea, variations in urine acidity (different pH levels), and a relatively low protein concentration in urine.

Additional Benefits of Serum Oncostatin M Levels Compared to Cardiac Troponin in Non-ST Elevation Myocardial Infarction

Background

The use of high-sensitivity troponin levels increases the sensitivity of the diagnosis of non-ST elevation myocardial infarction (NSTEMI). However, the inclusion of other factors in the differential diagnosis, apart from atherothrombosis causing myocardial injury, decreases the specificity of high-sensitivity troponin. In this study, we compared the efficacy of high-sensitivity troponin with serum oncostatin M in NSTEMI cases with elevated urea and creatinine.

Methods

This study was performed with a prospective cross-sectional sample. Ninety participants with coronary angiography performed due to a preliminary diagnosis of NSTEMI were included. High-sensitivity troponin I, creatine kinase-MB, lactate dehydrogenase, serum transaminase and oncostatin M levels were quantitatively measured for the first 4-8 hours from the onset of symptoms. All participants had coronary angiography performed within the first 12 hours after attending the emergency service. Based on coronary angiography data, patients with significant coronary stenosis or occlusion detected during coronary angiography were defined as group A, and patients with no occlusion in the coronary artery and who did not require an additional interventional procedure were defined as group B. The SYNTAX 2 score was used to determine the severity of coronary artery disease.

Results

Patients in both groups A and B had similar age, sex distribution and comorbidities. Group A had higher serum urea, creatinine, oncostatin M and high-sensitivity troponin I values than group B. With 585 pg/ml as the cut-off value, serum oncostatin M had a sensitivity of 88.6% and specificity of 85% for the diagnosis of NSTEMI. Logistic regression multivariate analysis showed that serum oncostatin M and high-sensitivity troponin I values had diagnostic efficacy for NSTEMI. Serum oncostatin M was found to be more effective than high-sensitivity troponin I in patients with elevated urea and creatinine.

Conclusions

Serum oncostatin M had similar sensitivity and specificity for NSTEMI diagnosis as high-sensitivity troponin I. Serum OSM can especially be considered as a complementary diagnostic biomarker for NSTEMI in patients with renal dysfunction.

Association between Myocardial Oxygen Supply and Demand and Myocardial Injury in Patients with End-Stage Kidney Disease

AIM

In patients with end-stage kidney disease (ESKD), it is unclear whether an imbalance between myocardial oxygen supply and demand leads to myocardial injury (MI). This study clarifies the association between the balance of the rate pressure product (RPP), consisting of the systolic blood pressure multiplied by the pulse rate (PR), a marker for myocardial oxygen demand, and hemoglobin (Hb), a marker for oxygen supply, with MI.

METHODS

A total of 283 consecutive unselected patients for hemodialysis were enrolled in this retrospective, cross-sectional study, and were divided into four groups according to Hb levels (high or low) and RPP. Potential imbalances between myocardial oxygen supply and demand were defined as patients with simultaneous high RPP and low Hb levels. The odds ratio (OR) for MI, defined as cardiac troponin T (cTnT) of ≥ 0.15 ng/mL was investigated using logistic regression analysis between the four patient groups.

RESULTS

The mean age was 68.7 years, 71.3% were men, and 52.6% had diabetes. The mean Hb level was 9.0 g/dL, and 20.5% of patients were latently diagnosed with MI. The median RPP and cTnT level was 12,144 and 0.083 ng/mL, respectively. When exposed to simultaneous high RPP with low Hb, OR significantly increased compared with that of the well-balanced group (RPP ＜12,500 and Hb ≥ 9.0 g/dL; OR 3.63, p＜0.05). Similar results were obtained in multivariate analysis after adjusting for confounding variables. These associations were enhanced or weakened when the Hb cut-off level became lower (Hb=8 g/dL) or higher (Hb=10 g/dL).

CONCLUSIONS

As the myocardial oxygen supply and demand balance in patients with ESKD is potentially associated with MI, appropriate management for blood pressure, PR, and anemia may prevent MI.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Exploring the relation between Interleukin-6 and high-sensitive cardiac troponin T in asymptomatic hemodialysis patient: A cross-sectional study

BACKGROUND

High-sensitive cardiac troponin T (h-cTnT), which serves as a marker for myocardial damage, has also been linked to adverse outcomes in asymptomatic hemodialysis patients. This study aims to explore the correlation between interleukin-6 (IL-6) and h-cTnT in asymptomatic hemodialysis patients to unravel the relationship between inflammation and cardiovascular risk.

METHODS

A cross-sectional study involving 81 patients was conducted from November 2022 to March 2023 at An-Najah National University Hospital in Palestine. We gathered clinical data, including comorbidities, and obtained blood samples for measuring IL-6 and h-cTnT levels. We performed statistical analyses, including correlation tests and linear regression, to assess the associations between these variables.

RESULTS

The study revealed a notable increase in both h-cTnT and IL-6 levels, and a significant correlation between the two (rho = 0.463, P<0.001) in asymptomatic hemodialysis patients. Likewise, h-cTnT levels displayed positive correlations with age (rho = 0.519, P<0.001) and negative correlations with albumin (rho = -0.297, p = 0.007) and transferrin saturation (rho = -0.227, P = 0.042). IL-6 levels exhibited correlations with age (rho = 0.422, P<0.001), albumin (rho = -0.389, P<0.001), iron (rho = -0.382, P<0.001), and transferrin saturation (rho = -0.362, P = 0.001). Notably, higher h-cTnT levels were associated with diabetes, hypertension, a history of coronary artery disease, cerebrovascular accidents, older age, and male gender.

CONCLUSION

This study underscores the significant association between the inflammatory marker IL-6 and h-cTnT in asymptomatic hemodialysis patients, suggesting that inflammation may play an essential role in the elevation of h-cTnT levels. This association may have implications for predicting cardiovascular events and guiding interventions to reduce cardiovascular disease morbidity and mortality in hemodialysis patients.

Association of high-sensitivity cardiac troponin T with all-cause and cardiovascular mortality in older adults with low lean mass: A 14.6-year longitudinal study

BACKGROUND

Current evidence on the association between high-sensitivity cardiac troponin T (hs-cTnT) levels and mortality in elderly sarcopenic patients is limited. This study aimed to investigate the association of serum hs-cTnT concentrations with all-cause and cardiovascular mortality in older adults with low lean mass (LLM) and without baseline cardiovascular disease.

METHODS

This prospective cohort study included 369 older adults (representing 3.2 million people) from the National Health and Nutrition Examination Survey 1999-2004. Individuals were linked to national death records until 31 December 2019. The weighted Kaplan-Meier analysis, Cox proportional hazards models, restricted cubic spline models, stratified analysis, interaction analysis, and sensitivity analysis were performed to examine the association between hs-cTnT levels and mortality in older adults with LLM.

RESULTS

During 4697 person-years of follow-up (median duration, 14.6 years), 228 (65.6%) deaths were documented, including 56 (15.8%) deaths from cardiovascular disease. Individuals with a hs-cTnT level of ≥14 ng/L had 2.1- and 4.4-fold higher risks of all-cause and cardiovascular mortality, respectively. Compared with the lowest quartile, the fourth quartile of hs-cTnT levels was significantly associated with 3.1- and 6.4-fold higher risks of all-cause and cardiovascular mortality, respectively. Each one standard deviation increase in natural log-transformed hs-cTnT levels significantly and linearly increased the risks of all-cause and cardiovascular mortality by 39% and 61%, respectively. Stratified and sensitivity analyses confirmed the robustness of the association.

CONCLUSIONS

In this nationally representative cohort of US older adults with LLM, higher serum hs-cTnT concentrations were significantly associated with increased risks of all-cause and cardiovascular mortality.

Utility of Cardiac Troponins in Patients With Chronic Kidney Disease

Cardiovascular disease is a major cause of death worldwide especially in patients with chronic kidney disease (CKD). Troponin T and troponin I are cardiac biomarkers used not only to diagnose acute myocardial infarction (AMI) but also to prognosticate cardiovascular and all-cause mortality. The diagnosis of AMI in the CKD population is challenging because of their elevated troponins at baseline. The development of high-sensitivity cardiac troponins shortens the time needed to rule in and rule out AMI in patients with normal renal function. While the sensitivity of high-sensitivity cardiac troponins is preserved in the CKD population, the specificity of these tests is compromised. Hence, diagnosing AMI in CKD remains problematic even with the introduction of high-sensitivity assays. The prognostic significance of troponins did not differ whether it is detected with standard or high-sensitivity assays. The elevation of both troponin T and troponin I in CKD patients remains strongly correlated with adverse cardiovascular and all-cause mortality, and the prognosis becomes poorer with advanced CKD stages. Interestingly, the degree of troponin elevation appears to be predictive of the rate of renal decline via unclear mechanisms though activation of the renin-angiotensin and other hormonal/oxidative stress systems remain suspect. In this review, we present the latest evidence of the use of cardiac troponins in both the diagnosis of AMI and the prognosis of cardiovascular and all-cause mortality. We also suggest strategies to improve on the diagnostic capability of these troponins in the CKD/end-stage kidney disease population.

Cardiospecific Troponins as Laboratory Biomarkers of Myocardial Cell Injury in Hypertension: A Mini-Review

To date, it is well known that a significant number of diseases of cardiovascular genesis (coronary heart disease, myocardial infarction, cardiomyopathy, Takotsubo syndrome, heart failure, etc.) and extra-cardiac genesis (renal failure, chronic obstructive pulmonary disease, sepsis, diabetes mellitus, etc.) cause injury to contractile cells of the heart muscle (myocardial cells). The most sensitive and specific criteria for proving myocardial cell injury are cardiospecific troponins (CSTns) - CSTnI and CSTnT. According to the current clinical recommendations of the European, American, and Russian Cardiological Communities, CSTnI and CSTnT are the main biomarkers for early diagnosis of myocardial infarction. Hypertension is one of the most dangerous and common risk factors for the development of cardiovascular pathologies and is associated with a high risk of dangerous cardiovascular complications. Therefore, there is an urgent need to search for new biomarkers for the timely assessment of the prognosis of patients with hypertension. This mini-review aims to substantiate the possibilities of using the cardiomarkers (CSTnI and CSTnT) to assess the prognosis of patients suffering from hypertension and to discuss potential mechanisms that cause injury to myocardial cells and increase serum levels of CSTnI and CSTnT. This is a narrative mini-review, which was prepared using the following databases: Pubmed/Medline, PubMed Central, Embase, Scopus, and Web of Science. The following keywords were used in the literature search: "myocardial cells", "injury", "damage", and "hypertension" in combination with the terms "mechanisms of injury" "predictive significance", "cardiac troponins", or "cardiospecific troponins".

Optimizing the Clinical Use of High-Sensitivity Troponin Assays: A Review

Ischemic heart diseases (IHDs) remain a global health concern. Many IHD cases go undiagnosed due to challenges in the initial diagnostic process, particularly in cases of acute myocardial infarction (AMI). High-sensitivity cardiac troponin (hs-cTn) assays have revolutionized myocardial injury assessment, but variations in diagnostic cut-off values and population differences have raised challenges. This review addresses essential laboratory and clinical considerations for hs-cTn assays. Laboratory guidelines discuss the importance of establishing standardized 99th-percentile upper reference limits (URLs) considering factors such as age, sex, health status, and analytical precision. The reference population should exclude individuals with comorbidities like diabetes and renal disease, and rigorous selection is crucial. Some clinical guidelines emphasize the significance of sex-specific URL limits while others do not. They highlight the use of serial troponin assays for AMI diagnosis. In addition, timely reporting of accurate hs-cTn results is essential for effective clinical use. This review aims to provide a clearer understanding among laboratory professionals and clinicians on how to optimize the use of hs-cTn assays in clinical settings in order to ensure accurate AMI diagnosis and thus improve patient care and outcomes.

Diagnosis of cardiovascular disease in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

Myocardial injury before noncardiac surgery

Non-cardiac surgical procedures present a significant circulatory stress and can potentially trigger cardiovascular events, such as myocardial infarction and heart failure. Myocardial injury before non-cardiac surgery is associated with an increased risk of mortality and major cardiovascular complications during perioperative period, as well as up to 5 years after non-cardiac surgery. While the definition of preoperative myocardial injury is not yet clear, it is generally understood as myocardial injury resulting from various causes of troponin elevation without acute coronary syndrome prior to surgery. Detecting preoperative myocardial injury through routine troponin monitoring is crucial for reducing perioperative risk, but it is also challenging. The aim of this review is to discuss the definition of preoperative myocardial injury, its pathophysiology, implications on clinical practice and decision-making for patients with elevated troponin levels before non-cardiac surgery.

Case report: The presence of third-degree atrioventricular block caused by pulmonary embolism masquerading as acute ST-segment elevation myocardial infarction

Background

Pulmonary embolism (PE) typically presents with chest pain, tachypnea, hemoptysis, syncope, and increased markers of myocardial injury. On an electrocardiogram (ECG), sinus tachycardia, right bundle branch block (RBBB), S1Q3T3 pattern, and/or precordial T-wave inversion may be observed. Despite being one of the common causes of chest pain, a third-degree atrioventricular block (III° AVB) is rare in cases of PE, which can lead to difficulties in diagnosis or even overlooking this condition.

Case summary

In this case report, we present a patient who was transferred to our hospital with suspected acute myocardial infarction (AMI). The patient's ECG showed ST-segment elevation in the inferior wall and a III° AVB, combined with significantly increased markers of myocardial injury. Interestingly, the patient also had a history of cerebral hemorrhage (ICH) for 7 days prior to being transferred to our hospital. After undergoing a systematic examination and evaluation, the final diagnosis for the patient was PE.

Conclusions

In addition to considering common symptoms, it is important not to overlook rare symptoms when diagnosing a disease. This case serves as an example of how the misdiagnosis rate for PE can be reduced by conducting a comprehensive clinical evaluation and paying attention to all clinical clues and examination results.

[Effect of co-morbid chronic kidney disease on the accuracy of cardiac troponin levels for diagnosis of acute myocardial infarction]

OBJECTIVE

To evaluate the accuracy of cardiac troponin (cTn) levels in the diagnosis of acute myocardial infarction (AMI) in patients with chronic kidney disease (CKD) and explore a potential strategy for improving the diagnostic accuracy.

METHODS

We retrospectively analyzed the data from patients with high-risk chest pain admitted in Zhujiang Hospital from January, 2018 to December, 2020, including 126 patients with and 272 patients without CKD, and 122 patients diagnosed to have AMI and 276 patients without AMI. The baseline clinical data of the patients and blood test results within 12 h after admission were collected.

RESULTS

In patients without AMI, cTnT level was significantly higher in those with co-morbid CKD than in those without CKD (P < 0.001), and showed a moderate negative correlation with eGFR (rs=- 0.501, P < 0.001), while cTnI level did not differ significantly between the two groups (P=0.72). In patients with CKD, the optimal cutoff level was 0.177 μg/L for cTnT and 0.415 ng/mL for cTnI for diagnosis of AMI, for which cTnI had a higher specificity than cTnT. The diagnostic model combining both cTnT and cTnI levels [P=eY/(1+ eY), Y=6.928 (cTnT)-0.5 (cTnI)-1.491] had a higher AUC value than cTn level alone.

CONCLUSION

In CKD patients, the cutoff level of cTn is increased for diagnosing AMI, and cTnI has a higher diagnostic specificity than cTnT. The combination of cTnT and cTnI levels may further improve diagnostic efficacy for AMI.

Diagnostic Role and Methods of Detection of Cardiac Troponins: An Opinion from Historical and Current Points of View

The laboratory methods for the determination of cardiac troponins (cTnI, cTnT) used nowadays are extremely diverse, which has a significant impact on our understanding of the biology and diagnostic the value of cTnI and cTnT as biomarkers. The main classification of methods for the determination of cTnI and cTnT is based on the sensitivity of the immunoassay. Low- and moderately sensitive detection methods are known to be relatively less sensitive, which leads to a relatively late confirmation of cardiomyocyte death. Due to the new highly sensitive methods used to determine cTnI and cTnT, designated as a highly or ultrasensitive immunoassays (hs-TnT and hs-TnT), we received new, revised data about the biology of cardiac troponin molecules. In particular, it became clear that they can be considered products of normal myocardium metabolism since hs-TnT and hs-TnT are detected in almost all healthy patients. It also turned out that hs-TnT and hs-TnT differ by gender (in men, troponin concentration in the blood is higher than in women), age (in elderly patients, the levels of troponins are higher than in young ones) and circadian cycles (morning concentrations of troponins are higher than in the evening). A large variety of methods for determining cTnI and cTnT, differing in their diagnostic capabilities, creates the need for tests to perform an unbiased assessment of the analytical characteristics of each method. This review focuses on the most pressing issues related to the discussion of the biological characteristics of cardiac troponin and the analytical characteristics of troponin immunoassays from a historical and contemporary point of view.

Serial high-sensitivity cardiac troponin testing for the diagnosis of myocardial infarction: a scoping review

OBJECTIVES

We aimed to assess the diversity and practices of existing studies on several assays and algorithms for serial measurements of high-sensitivity cardiac troponin (hs-cTn) for risk stratification and the diagnosis of myocardial infarction (MI) and 30-day outcomes in patients suspected of having non-ST-segment elevation MI (NSTEMI).

METHODS

We searched multiple databases including MEDLINE, EMBASE, Science Citation Index, the Cochrane Database of Systematic Reviews and the CENTRAL databases for studies published between January 2006 and November 2021. Studies that assessed the diagnostic accuracy of serial hs-cTn testing in patients suspected of having NSTEMI in the emergency department (ED) were eligible. Data were analysed using the scoping review method.

RESULTS

We included 86 publications, mainly from research centres in Europe, North America and Australasia. Two hs-cTn assays, manufactured by Abbott (43/86) and Roche (53/86), dominated the evaluations. The studies most commonly measured the concentrations of hs-cTn at two time points, at presentation and a few hours thereafter, to assess the two-strata or three-strata algorithm for diagnosing or ruling out MI. Although data from 83 studies (97%) were prospectively collected, 0%-90% of the eligible patients were excluded from the analysis due to missing blood samples or the lack of a final diagnosis in 53 studies (62%) that reported relevant data. Only 19 studies (22%) reported on head-to-head comparisons of alternative assays.

CONCLUSION

Evidence on the accuracy of serial hs-cTn testing was largely derived from selected research institutions and relied on two specific assays. The proportions of the eligible patients excluded from the study raise concerns about directly applying the study findings to clinical practice in frontline EDs.

PROSPERO REGISTRATION NUMBER

CRD42018106379.

Applications of cardiac biomarkers in chronic kidney disease

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death in individuals with chronic kidney disease (CKD). The mechanisms connecting CKD and cardiovascular disease are complex, and serum biomarkers can help improve our understanding. Nt-proBNP and troponin have documented success as biomarkers to diagnose and provide mechanistic insights in non-CKD populations. The purpose of this review is to summarize evidence suggesting efficacy and potential for clinical application of Nt-proBNP and troponin in individuals with CKD.

RECENT FINDINGS

Our understanding of how Nt-proBNP and Troponin should be interpreted in those with CKD is evolving. Although both biomarkers are in part cleared by the kidney, elevated levels predominantly reflect cardiovascular disease. Both Nt-proBNP and troponin are associated with risk for future cardiovascular events in CKD. Determining CKD-specific cutoffs and using biomarkers to guide therapy remains under active investigation.

SUMMARY

Of the many serum biomarkers under investigation, Nt-proBNP and troponin best meet the criteria for effective biomarkers in CKD. Assays are widely available and proven to be accurate in CKD populations. Nt-proBNP and troponin deserve special focus in ongoing research of cardiovascular risk reduction in CKD, especially to identify patients at the highest risk, suggest targetable mechanisms and assess treatment efficacy.

Hypertension as One of the Main Non-Myocardial Infarction-Related Causes of Increased Cardiospecific Troponins: From Mechanisms to Significance in Current Medical Practice

It is well known that many pathological conditions of both cardiovascular diseases (CVDs) (coronary heart disease, myocardial infarction, arrhythmias, myocarditis, cardiomyopathy, etc.) and non-cardiac (sepsis, anemia, kidney diseases, diabetes mellitus, etc.) origin in the course of their development cause injury to contractile cardiac muscle cells - myocardial cells (MCs). One of the most sensitive and specific criteria for detecting MC injury are cardiospecific troponins (CTs), which are regulatory protein molecules that are released into the blood serum from MC upon their death or injury. Current methods for determining CTs are called high-sensitive ones, and their main advantage is a very low minimum detectable concentration (limit of detection) (average 1 - 10 ng/L or less), which allows early detection of minor MC injury at the earliest stages of CVDs, and therefore they can change the understanding of disease development mechanisms and open up new diagnostic possibilities. One of the most common and dangerous early diseases of the cardiovascular system is hypertension (HT). The novelty of this article lies in the discussion of a new diagnostic direction - predicting the risk of developing CVDs and their dangerous complications in patients with HT by determining the concentration of CTs. In addition, pathophysiological mechanisms underlying MC injury and the release of CTs into the bloodstream and the elimination of CTs into the urine are proposed. This information will contribute to additional fundamental and clinical research to verify the new diagnostic possibility of using CTs in clinical practice (for the management of patients with HT).

Heart-Type Fatty Acid Binding Protein, Cardiovascular Outcomes, and Death: Findings From the German CKD Cohort Study

RATIONALE & OBJECTIVE

Heart-type fatty acid binding protein (H-FABP) is a biomarker that has been shown to provide long-term prognostic information in patients with coronary artery disease independently of high-sensitivity troponin T (hs-TNT). We examined the independent associations of H-FABP with cardiovascular outcomes in patients with chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

4,951 patients enrolled in the German Chronic Kidney Disease (GCKD) study with an estimated glomerular filtration rate of 30-60 mL/min/1.73 m² or overt proteinuria (urinary albumin-creatinine ratio > 300 mg/g or equivalent).

EXPOSURE

Serum levels of H-FABP and hs-TNT were measured at study entry.

OUTCOME

Noncardiovascular (non-CV) death, CV death, combined major adverse CV events (MACE), and hospitalization for congestive heart failure (CHF).

ANALYTICAL APPROACH

Hazard ratios (HRs) for associations of H-FABP and hs-TNT with outcomes were estimated using Cox regression analyses adjusted for established risk factors.

RESULTS

During a maximum follow-up of 6.5 years, 579 non-CV deaths, 190 CV deaths, 522 MACE, and 381 CHF hospitalizations were observed. In Cox regression analyses adjusted for established risk factors, H-FABP was associated with all 4 outcomes, albeit with lower HRs than those found for hs-TNT. After further adjustment for hs-TNT levels, H-FABP was found to be associated with non-CV death (HR, 1.57 [95% CI, 1.14-2.18]) and MACE (HR, 1.40 [95% CI, 1.02-1.92]) but with neither CV death (HR, 1.64 [95% CI, 0.90-2.99]) nor CHF hospitalizations (HR, 1.02 [95% CI, 0.70-1.49]).

LIMITATIONS

Single-point measurements of H-FABP and hs-TNT. Uncertain generalizability to non-European populations.

CONCLUSIONS

In this large cohort of patients with CKD, H-FABP was associated with non-CV death and MACE, even after adjustment for hs-TNT. Whether measurement of H-FABP improves cardiovascular disease risk prediction in these patients warrants further studies.

Update on Disease-Specific Biomarkers in Transthyretin Cardiac Amyloidosis

PURPOSE OF REVIEW

Transthyretin cardiac amyloidosis (ATTR-CM) is an infiltrative cardiomyopathy and an increasingly recognized cause of morbidity and mortality. There remains substantial delay between initial symptoms and diagnosis. With the recent emergence of various targeted therapies proven to reduce morbidity and mortality, there is an imperative to diagnose subclinical disease. Biomarkers may be well-suited for this role.

RECENT FINDINGS

Conventional markers of heart failure, such as natriuretic peptides and cardiac troponins, and estimated glomerular filtration rate are associated with risk in ATTR-CM. Circulating transthyretin (TTR) levels parallel TTR kinetic stability, correlate with disease severity, and may serve as indirect markers of ATTR-CM disease activity and response to targeted treatment. There is also growing evidence for the correlation of TTR to retinol-binding protein 4, a biomarker which independently associates with this disease. The rate-limiting step for ATTR pathogenesis is dissociation of the TTR homotetramer, which may be quantified using subunit exchange to allow for early risk assessment, prognostication, and assessment of treatment response. The protein species that result from the dissociation and misfolding of TTR are known as nonnative transthyretin (NNTTR). NNTTR is quantifiable via peptide probes and is a specific biomarker whose reduction is positively correlated with improvement in neuropathic ATTR amyloidosis. Neurofilament light chain (NfL) is released into the blood after axonal damage and correlates with neuropathic ATTR amyloidosis, but its clinical use in ATTR-CM is uncertain. Conventional markers of heart failure, transthyretin, retinol-binding protein 4, transthyretin kinetic stability, nonnative transthyretin, peptide probes, and neurofilament light chain have potential as biomarkers to enable early, subclinical diagnosis in patients with transthyretin cardiac amyloidosis.

Cardiac Troponins as Biomarkers of Cardiac Myocytes Damage in Case of Arterial Hypertension: From Pathological Mechanisms to Predictive Significance

Background. Many pathological conditions of both cardiovascular and non-cardiac origin in the course of their development cause damage to contractile cardiac muscle cells—cardiac myocytes (CMCs). One of the most sensitive and specific criteria for detecting CMCs are cardiac troponins (CTs), which are regulatory protein molecules that are released into the blood serum from CMCs upon their death or damage. New (high-sensitive) methods for detecting CTs allow the detection of minor CMCs damages at the earliest stages of cardiovascular diseases and can therefore change the understanding of disease development mechanisms and open up new diagnostic possibilities. One of the most common and dangerous early diseases of the cardiovascular system is arterial hypertension. The purpose of this paper is to summarize the pathophysiological mechanisms underlying CMCs damage and CTs release into the bloodstream in the case of arterial hypertension and to state the clinical significance of increased CTs levels in patients with arterial hypertension. Materials and methods. This is a descriptive review, which was prepared using the following databases: Embase, Pubmed/Medline and Web of Science. The following key words were used in the literature search: “myocardial injury” and “arterial hypertension” in combination with the terms “cardiac troponins” and “mechanisms of increase”. Conclusions. According to a literature analysis, CMCs damage and CTs release in the case of arterial hypertension occur according to the following pathophysiological mechanisms: myocardial hypertrophy, CMCs apoptosis, damage to the CMC cell membrane and increase in its permeability for CTs molecules, as well as changes in the glomerular filtration rate. Most often, increased CTs serum levels in case of arterial hypertension indicate an unfavorable prognosis. Data on the CTs predictive significance in case of arterial hypertension open the prospects for the use of these biomarkers in the choice of patient management plans.

Association of Serum Osteoprotegerin Level With Myocardial Injury and Cardiovascular Calcification in Chronic Kidney Disease Patients

Background

Chronic kidney disease has emerged as a significant independent risk factor for cardiovascular disease. Cardiovascular calcification is an active process involving a complex interaction of inducers and inhibitors. High sensitivity cardiac troponin T assay detects troponin T with higher sensitivity and precision at an earlier point of time than the conventional assays, and is associated with poor outcomes. Serum osteoprotegerin is classed as an inhibitory factor for cardiovascular calcification. It is involved in the pathological processes of vascular damage and linked to the excess cardiovascular morbidity. The aim of the present study was to evaluate the extent of cardiovascular calcification and serum high sensitivity cardiac troponin T level, and their association with serum osteoprotegerin level in patients with chronic kidney disease stages 3-5.

Methods

90 chronic kidney disease patients were enrolled in this study, and they were divided into two groups: group (1) included 45 non-dialysis-dependent chronic kidney disease patients (stages 3-5) and group (2) included 45 chronic hemodialysis patients. Each group further subdivided according to the presence of cardiovascular calcification into subgroup A and B. Vascular calcifications were assessed by lateral lumbar, pelvis and hands X-ray radiographs. Valvular calcification was assessed by echocardiography. Serum cardiac troponin T was measured by high sensitivity assay and serum osteoprotegerin was measured by ELISA.

Results

Cardiovascular calcification distribution was 22.2% in group (1) and 33.3% in group (2). Serum osteoprotegerin and troponin T in calcification groups (1A and 2A) were significantly higher than non-calcification groups (1B and 2B; P < 0.001). Osteoprotegerin correlated positively with high sensitivity cardiac troponin T (rs = 0.72, P < 0.001). cardiovascular calcification correlated positively with osteoprotegerin, troponin T, and phosphorus. osteoprotegerin and phosphorus were significant independent predictors of cardiovascular calcification at cut-off values ≥4.6 ng/L and ≥6.95 mg/dl, respectively (P < 0.001). Serum phosphorus and creatinine were independent predictors of osteoprotegerin (P < 0.001 and 0.048, respectively).

Conclusion

Osteoprotegerin is strongly associated with cardiovascular calcification and high sensitivity cardiac troponin T. In addition, there is a positive association between calcification and troponin T. This suggests a role for osteoprotegerin in the pathogenesis and risk stratification of cardiovascular calcification and myocardial injury in chronic kidney disease patients with a potential role as a therapeutic target.

Metabolic Pathway of Cardiospecific Troponins: From Fundamental Aspects to Diagnostic Role (Comprehensive Review)

Many molecules of the human body perform key regulatory functions and are widely used as targets for the development of therapeutic drugs or as specific diagnostic markers. These molecules undergo a significant metabolic pathway, during which they are influenced by a number of factors (biological characteristics, hormones, enzymes, etc.) that can affect molecular metabolism and, as a consequence, the serum concentration or activity of these molecules. Among the most important molecules in the field of cardiology are the molecules of cardiospecific troponins (Tns), which regulate the processes of myocardial contraction/relaxation and are used as markers for the early diagnosis of ischemic necrosis of cardiomyocytes (CMC) in myocardial infarction (MI). The diagnostic value and diagnostic capabilities of cardiospecific Tns have changed significantly after the advent of new (highly sensitive (HS)) detection methods. Thus, early diagnostic algorithms of MI were approved for clinical practice, thanks to which the possibility of rapid diagnosis and determination of optimal tactics for managing patients with MI was opened. Relatively recently, promising directions have also been opened for the use of cardiospecific Tns as prognostic markers both at the early stages of the development of cardiovascular diseases (CVD) (arterial hypertension (AH), heart failure (HF), coronary heart disease (CHD), etc.), and in non-ischemic extra-cardiac pathologies that can negatively affect CMC (for example, sepsis, chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), etc.). Recent studies have also shown that cardiospecific Tns are present not only in blood serum, but also in other biological fluids (urine, oral fluid, pericardial fluid, amniotic fluid). Thus, cardiospecific Tns have additional diagnostic capabilities. However, the fundamental aspects of the metabolic pathway of cardiospecific Tns are definitively unknown, in particular, specific mechanisms of release of Tns from CMC in non-ischemic extra-cardiac pathologies, mechanisms of circulation and elimination of Tns from the human body, mechanisms of transport of Tns to other biological fluids and factors that may affect these processes have not been established. In this comprehensive manuscript, all stages of the metabolic pathway are consistently and in detail considered, starting from release from CMC and ending with excretion (removal) from the human body. In addition, the possible diagnostic role of individual stages and mechanisms, influencing factors is analyzed and directions for further research in this area are noted.

The Importance of Cardiac Troponin Metabolism in the Laboratory Diagnosis of Myocardial Infarction (Comprehensive Review)

The study of the metabolism of endogenous molecules is not only of great fundamental significance but also of high practical importance, since many molecules serve as drug targets and/or biomarkers for laboratory diagnostics of diseases. Thus, cardiac troponin molecules have long been used as the main biomarkers for confirmation of diagnosis of myocardial infarction, and with the introduction of high-sensitivity test methods, many of our ideas about metabolism of these cardiac markers have changed significantly. In clinical practice, there are opening new promising diagnostic capabilities of cardiac troponins, the understanding and justification of which are closely connected with the fundamental principles of the metabolism of these molecules. Our current knowledge about the metabolism of cardiac troponins is insufficient and extremely disconnected from various literary sources. Thus, many researchers do not sufficiently understand the potential importance of cardiac troponin metabolism in the laboratory diagnosis of myocardial infarction. The purpose of this comprehensive review is to systematize information about the metabolism of cardiac troponins and during the discussion to focus on the potential impact of cTns metabolism on the laboratory diagnosis of myocardial infarction. The format of this comprehensive review includes a sequential consideration and analysis of the stages of the metabolic pathway, starting from possible release mechanisms and ending with elimination mechanisms. This will allow doctors and researchers to understand the significant importance of cTns metabolism and its impact on the laboratory diagnosis of myocardial infarction.

High sensitivity cardiac troponin, a cardiac marker predicting death in patients with kidney disease: a dose-response Meta-analysis of cohort studies

BACKGROUND

Patients with kidney disease are at increased risk of adverse mortality events. Numerous studies have demonstrated the positive association of high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) with all-cause and cardiovascular (CV) mortality in patients with kidney disease; however, the dose-response meta-analysis have not been reported. We therefore performed this study to evaluate the dose-response associations of hs-cTn with risk of all-cause and CV mortality to improve risk stratification.

METHODS

We searched three databases (PubMed, Embase, and Web of Science) to identify relevant prospective cohort studies published up to January 12, 2021. Random-effects models were used to summarize relative risks (RRs) and 95% confidence intervals (CIs) of all-cause and CV mortality. Restricted cubic splines were used to fit the dose-response associations.

RESULTS

For each 10 ng/L increase in hs-cTnT and hs-cTnI, the risk increased by 14% (RR = 1.14, 95% CI, 1.10-1.18) and 19% (RR = 1.19, 95% CI, 1.09-1.31) for all-cause mortality, 25% (RR = 1.25, 95% CI, 1.13-1.38) and 19% (RR = 1.19, 95% CI, 1.10-1.29) for CV mortality. A linear trend was found between hs-cTnT and all-cause mortality, whereas a non-linear trend was found in hs-cTnI. Additionally, both hs-cTnT and hs-cTnI were shown to have linear trends with CV mortality.

CONCLUSION

Our meta-analysis suggests that hs-cTn had high sensitivity in predicting mortality events. All dose-response trends were rising rather than falling, conferring that any increase in the levels of hs-cTn may possibly predict a death prognosis among CKD patients.

Novel Biomarkers Detected by Proteomics Predict Death and Cardiovascular Events in Hemodialysis Patients

End-stage kidney disease increases mortality and the risk of cardiovascular (CV) disease. It is crucial to explore novel biomarkers to predict CV disease in the complex setting of patients receiving hemodialysis (HD). This study investigated the association between 92 targeted proteins with all-cause death, CV death, and composite vascular events (CVEs) in HD patients. From December 2010 to March 2011, 331 HD patients were included and followed prospectively for 5 years. Serum was analyzed for 92 CV-related proteins using Proseek Multiplex Cardiovascular I panel, a high-sensitivity assay based on proximity extension assay (PEA) technology. The association between biomarkers and all-cause death, CV death, and CVEs was evaluated using Cox-regression analyses. Of the PEA-based proteins, we identified 20 proteins associated with risk of all-cause death, 7 proteins associated with risk of CV death, and 17 proteins associated with risk of CVEs, independent of established risk factors. Interleukin-8 (IL-8), T-cell immunoglobulin and mucin domain 1 (TIM-1), and C-C motif chemokine 20 (CCL20) were associated with increased risk of all-cause death, CV death, and CVE in multivariable-adjusted models. Stem cell factor (SCF) and Galanin peptides (GAL) were associated with both decreased risk of all-cause death and CV death. In conclusion, IL-8, TIM-1, and CCL20 predicted death and CV outcomes in HD patients. Novel findings were that SCF and GAL were associated with a lower risk of all-cause death and CV death. The SCF warrants further study with regard to its possible biological effect in HD patients.

Biology of Cardiac Troponins: Emphasis on Metabolism

Simple Summary

Cardiovascular diseases, including myocardial infarction, are among the most common diseases worldwide. Markers associated with the diagnosis of myocardial infarction have been in the spotlight for many years. The most commonly used markers of myocardial infarction are cardiac troponins. However, insufficient understanding of the biology and metabolism of cardiac troponins does not allow us to fully unlock the full diagnostic potential of these cardiomarkers. In this article, I summarized and discussed in detail the features of the metabolism of cardiac troponins. I conducted a comprehensive review of current literary sources and presented my point of view. The format of the manuscript includes a consistent description of the biology and stages of the metabolism of cardiac troponins, starting from the release and circulation, and ending with the features of elimination of cardiac troponins. The possible influence of the biology of cardiac troponins on the diagnostic value of cardiac troponins is analyzed. Based on the analysis of the literature, I found a close relationship between the diagnostic value of cardiac troponins and their biology/metabolism. Further research is needed to increase the diagnostic value of cardiac troponins, and to fully unlock their diagnostic potential.

Abstract

Understanding of the biology of endo- and exogenous molecules, in particular their metabolism, is not only of great theoretical importance, but also of high practical significance, since many molecules serve as drug targets or markers for the laboratory diagnostics of many human diseases. Thus, cardiac troponin (cTns) molecules have long been used as key markers for the confirmation of diagnosis of myocardial infarction (MI), and with the introduction of contemporary (high sensitivity) test methods, many of our concepts related to the biology of these cardiac markers have changed significantly. In current clinical practice, there are opening new promising diagnostic capabilities of cTns, the understanding and justification of which is closely connected with the theoretical principles of the metabolism of these molecules. However, today, the biology and metabolism of cTns have not been properly investigated; in particular, we do not know the precise mechanisms of release of these molecules from the myocardial cells (MCs) of healthy people and the mechanisms of circulation, and the elimination of cTns from the bloodstream. The main purpose of this manuscript is to systematize information about the biology of cTns, with an emphasis on the metabolism of cTns. The format of this paper, starting with the release of cTns in the blood and concluding with the metabolism/filtration of troponins, provides a comprehensive yet logically easy way for the readers to approach our current knowledge in the framework of understanding the basic mechanisms by which cTns are produced and processed. Conclusions. Based on the analysis of the current literature, the important role of biology and all stages of metabolism (release, circulation, removal) of cTns in laboratory diagnostics should be noted. It is necessary to continue studying the biology and metabolism of cTns, because this will improve the differential diagnosis of MI and i a new application of cTns immunoassays in current clinical practice.

Prospective Cardiovascular Surveillance of Immune Checkpoint Inhibitor-Based Combination Therapy in Patients With Advanced Renal Cell Cancer: Data From the Phase III JAVELIN Renal 101 Trial

PURPOSE

Both immune checkpoint inhibitors (ICIs) and vascular endothelial growth factor receptor (VEGFR) inhibitors are approved for advanced renal cell carcinoma treatment and can cause cardiovascular events (CVs); thus, combination therapy could lead to major adverse CV events (MACE). Cardiac serum biomarker assessment and imaging, including left ventricular ejection fraction (LVEF) monitoring, can be used to evaluate MACE.

METHODS

To our knowledge, the JAVELIN Renal 101 trial, assessing avelumab plus axitinib versus sunitinib in patients with advanced renal cell carcinoma, is the first randomized study of ICI plus VEGFR inhibitor treatment to include prospective serial cardiac monitoring of LVEF and serum cardiac biomarkers.

RESULTS

MACE (defined as grade ≥ 3 CV AEs) occurred in 31 patients (7.1%) in the combination arm and 17 patients (3.9%) in the sunitinib arm. Patients in the combination arm who had high baseline troponin T values were at higher risk of MACE versus patients with low values (MACE in 6/35 v 7/135, respectively; relative risk, 3.31; 95% CI, 1.19 to 9.22). This association was not observed in patients treated with sunitinib. Other CV baseline risk factors and serum cardiac biomarkers were not significantly predictive for MACE, although a trend toward an association with dyslipidemia was seen in the combination arm. No clinical value of on-treatment routine monitoring of LVEF in relation to MACE was observed. Although LVEF decline was significantly more frequent in the combination arm, most patients recovered, and decline was not associated with other significant cardiac events or symptoms.

CONCLUSION

Patients with high baseline troponin T levels receiving ICI and VEGFR combinations may need to be monitored more closely for MACE. Routine monitoring of LVEF in asymptomatic patients is not recommended.

Interpretation of Cardiac and Non-Cardiac Causes of Elevated Troponin T Levels in Non-Acute Coronary Syndrome Patients in the Emergency Department

The definition of myocardial infarction was updated in 2000 to include an elevation of cardiac troponin T or I (cTnT or xTnI) alongside clinical evidence of myocardial infarction. The redefinition was jointly done by the American College of Cardiology Committee and the European Society of Cardiology. Since then, cardiac troponin T and I have assumed the position as the primary biochemical markers for diagnosing myocardial infarction. The high sensitivity of cardiac troponin for myocardial necrosis influenced the decision to include cardiac troponins (cTn) in the diagnostic pathway. An elevated cTn level indicates the presence of myocardial injury. However, it does not give the underlying reason for the damage. Apart from acute myocardial infarction (AMI), a range of potential diseases feature troponin release, including heart failure, acute pulmonary embolism, end-stage renal disease, and myocarditis. However, regardless of the mechanism that triggers the release from cardiac myocytes, elevated cTnI and cTnT typically implies a poor prognosis. This review attempts to explain both the cardiac and non-cardiac causes of increased cTnT in emergency department patients.

Determinants and Outcomes Associated With Urinary Calcium Excretion in Chronic Kidney Disease

CONTEXT

Abnormalities in calcium metabolism are common in chronic kidney disease (CKD). Diminished urinary calcium excretion may promote vascular calcification and increased urinary calcium excretion may lead to nephrolithiasis and nephrocalcinosis, conditions associated with CKD.

OBJECTIVE

To study predictors of urinary calcium excretion and its association with adverse clinical outcomes in CKD.

DESIGN, SETTING AND PATIENTS

This study assessed 3768 nondialysis participants in the Chronic Renal Insufficiency Cohort study from April 2003 to September 2008. Participants were followed up to October 2018.

EXPOSURE

Clinically plausible predictors of urinary calcium excretion and 24-h urinary calcium excretion at baseline.

MAIN OUTCOME MEASURES

Urinary calcium excretion; incident end stage kidney disease (ESKD), CKD progression [50% estimated glomerular filtration rate (eGFR) decline or incident ESKD], all-cause mortality, and atherosclerotic cardiovascular disease events.

RESULTS

eGFR was positive correlated with 24-h urinary calcium excretion. The variables most strongly associated with 24-h urinary calcium excretion in males and females were 24-h urinary sodium (β = 0.19 and 0.28, respectively), serum parathyroid hormone (β = -0.22 and -0.20, respectively), loop diuretics (β = 0.36 and 0.26, respectively), thiazide diuretics (β = -0.49 and -0.53, respectively), and self-identified black race (β = -0.23 and -0.27, respectively). Lower urinary calcium excretion was associated with greater risks of adverse outcomes, but these associations were greatly attenuated or nullified after adjustment for baseline eGFR.

CONCLUSION

Urinary calcium excretion is markedly lower in individuals with CKD compared to the general population. Determinants of urinary calcium excretion differed between sexes and levels of CKD. Associations between urinary calcium excretion and adverse clinical events were substantially confounded by eGFR.

Cardiac troponins: current information on the main analytical characteristics of determination methods and new diagnostic possibilities

The methods used to diagnose cardiovascular diseases are constantly being improved, leading to an expanded perception of the diagnostic value of biomarkers and their new diagnostic possibilities. One striking example are the main biomarkers used to diagnose acute myocardial infarction: cardiac troponins. The first methods for determining cardiac troponins (proposed 30 years ago) were characterized by extremely low sensitivity. Therefore, they could only detect large acute myocardial infarctions. These methods were also characterized by low specificity, expressed as a high probability of cross-reactivity with skeletal troponin isoforms, which generated false-positive results in the presence of skeletal myopathies and skeletal muscle lesions. With the introduction of high-sensitivity cardiac troponins into clinical practice, the possibility of early diagnosis and exclusion of acute myocardial infarction by assessing troponin concentrations in the first few hours (from admission to the first hour, second hour, or third hour) has become more specific. Our knowledge about cardiac troponins has changed over the years and promising new medical uses have emerged. This paper reviews current data on the diagnostic value of cardiac troponins, the main methods used for their determination, and their analytical characteristics from historical and modern insights.

Revisited Upper Reference Limits for Highly Sensitive Cardiac Troponin T in Relation to Age, Sex, and Renal Function

(1) Background: Highly sensitive cardiac troponin T (hs-cTnT) plays an essential role in the diagnosis of myocardial injury. The upper reference limit of the respective assay is generally applied, irrespective of age, renal function, or sex. We aimed to identify age-adjusted and sex-adjusted upper reference limits in relation to renal function in a large population-based cohort without cardiac diseases. (2) Methods: We included 5428 subjects of the population-based LIFE-Adult cohort, free of diagnosed cardiac diseases. Sex-adjusted and age-adjusted 99th percentiles for hs-cTnT in subjects with preserved renal function were obtained. (3) Results: The hs-cTnT values were higher in men of all age groups. In both sexes, an increasing age positively correlated with higher hs-cTnT values. Hs-cTnT weakly correlated with serum creatinine. The three-dimensional analysis of age, creatinine, and hs-cTnT showed no relevant additional effect of creatinine on hs-cTnT. In men aged above 60 and women above 70, the calculated 99th percentiles clearly exceeded the commonly applied thresholds. (4) Conclusion: Age and sex have a major impact on the serum concentration of hs-cTnT, while renal function does not. We propose to consider age-adjusted and sex-adjusted reference values.

[Mechanisms of increase and diagnostic role of highly sensitive troponins in arterial hypertension]

Improvement in immunochemical methods for the determination of key biomarkers of acute myocardial infarction has led not only to an improvement in the early diagnosis of acute myocardial infarction, but also to a change in many of our ideas about the biology and diagnostic role of cardiac troponins. Modern (highly and ultrasensitive) laboratory methods for the determination of cardiac troponin molecules in human biological fluids are highly sensitive, which makes it possible to detect even the smallest damage to cardiomyocytes that occur at the early stages of many pathologies of cardiac (coronary heart disease, arterial hypertension, etc.) and extracardiac etiology (renal failure, sepsis, chronic obstructive pulmonary disease and others), as well as under the influence of a number of physiological conditions, including the influence of physical exercises, psychoemotional stress, gender characteristics (higher levels of cardiac troponins in men, compared with women), age characteristics (an increase in the concentration of cardiac troponins with age) and circadian characterisics (prevalence of morning values of cardiac troponins concentration over evening ones). In this regard, the diagnostic capabilities of the use of highly sensitive cardiac troponins have been significantly expanded. One of the promising areas for the use of highly sensitive cardiac troponins includes the assessment of the risk of adverse cardiovascular events both in healthy patients and in patients with various risk factors for their development, one of which can be considered arterial hypertension. This article systematizes the results of clinical studies evaluating the diagnostic role of highly sensitive cardiac troponins in biological fluids (blood serum and urine) in hypertension and discusses in detail the mechanisms of increasing the levels of highly sensitive troponins in this pathological condition.

Elevation Mechanisms and Diagnostic Consideration of Cardiac Troponins under Conditions Not Associated with Myocardial Infarction. Part 2

This article proceeds with a discussion of the causes and mechanisms of an elevation in cardiac troponins in pathological conditions not associated with acute myocardial infarction. The second part of the article discusses the causes and mechanisms of cardiac troponins elevation in diabetes mellitus, arterial hypertension, hereditary cardiomyopathies, cardiac arrhythmias (atrial fibrillation, supraventricular tachycardia), acute aortic dissection, and diseases of the central nervous system (strokes, subarachnoidal hemorrhage). The final chapter of this article discusses in detail the false-positive causes and mechanisms of elevated cardiac troponins.

Cardiac Troponins Metabolism: From Biochemical Mechanisms to Clinical Practice (Literature Review)

The metabolic processes of endo- and exogenous compounds play an important role in diagnosing and treating patients since many metabolites are laboratory biomarkers and/or targets for therapeutic agents. Cardiac troponins are one of the most critical biomarkers to diagnose cardiovascular diseases, including acute myocardial infarction. The study of troponin metabolism is of great interest as it opens up new possibilities for optimizing laboratory diagnostics. This article discusses in detail the key stages of the cardiac troponins metabolism, in particular the mechanisms of release from a healthy myocardium, mechanisms of circulation in the bloodstream, possible mechanisms of troponin penetration into other biological fluids (oral fluid, cerebrospinal fluid, pericardial and amniotic fluids), mechanisms of elimination of cardiac troponins from the blood, and daily changes in the levels of troponins in the blood. Considering these aspects of cardiac troponin metabolism, attention is focused on the potential value for clinical practice.

The Main Causes and Mechanisms of Increase in Cardiac Troponin Concentrations Other Than Acute Myocardial Infarction (Part 1): Physical Exertion, Inflammatory Heart Disease, Pulmonary Embolism, Renal Failure, Sepsis

The causes and mechanisms of increased cardiac troponin T and I (cTnT and cTnI) concentrations are numerous and are not limited to acute myocardial infarction (AMI) (ischemic necrosis of cardiac myocytes). Any type of reversible or irreversible cardiomyocyte injury can result in elevated serum cTnT and cTnI levels. Researchers and practitioners involved in the diagnosis and treatment of cardiovascular disease, including AMI, should know the key causes and mechanisms of elevated serum cTnT and cTnI levels. This will allow to reduce or completely avoid diagnostic errors and help to choose the most correct tactics for further patient management. The purpose of this article is to discuss the main causes and mechanisms of increase in cardiac troponins concentrations in frequently occurring physiological (physical exertion, psycho-emotional stress) and pathological conditions (inflammatory heart disease, pulmonary embolism, chronic renal failure and sepsis (systemic inflammatory response)) not related to myocardial infarction.

Prospective Analysis of Role of hsTnT and NT-proBNP in Prediction of Neurogenic Stress Cardiomyopathy in Patients with Aneurysmal Subarachnoid Haemorrhage

Background

Neurogenic stress cardiomyopathy (NSC), also known as stress-induced cardiomyopathy (SIC), is a significant complication of aneurysmal subarachnoid hemorrhage and an important contributor to morbidity mortality.

Objective

This prospective observational study assessed whether the high sensitive troponin T (hsTnT) and N-terminal pro-B-type natriuretic peptide (NTproBNP) helps in the prediction of NSC after SAH.

Methods

The consecutive patients with aSAH without any cardiac history were included prospectively over 12 months. Neurological assessment for the grade of SAH (Hunt & Hess and WFNS grade), electrocardiogram, and echocardiography done at admission. The serial measurements of serum hsTnT and NTproBNP for consecutive 7 days done. The NSC is defined as transient hypokinesia of the ventricular wall on echocardiography.

Results

The study included 69 patients, and 7 (10.1%) were diagnosed with NSC. The NSC had a positive correlation with Hunt and Hess grade (P = 0.010), and the serum levels of hsTnT and NTproBNP were higher in patients with NSC in comparison to without NSC over all 7 days. The peak levels of hsTnT and NTproBNP were significantly higher in patients with cardiomyopathy (P = 0.000 and 0.032, respectively). The best cut-off level of peak hsTnT was 0.032 pg/dl to predict cardiomyopathy with sensitivity and specificity of 100% and 80%, respectively, and NTproBNP was 430.6 ng/dL with sensitivity and specificity of 86% and 73%, respectively.

Conclusion

The peak levels of hsTnT and NTproBNP with abnormal ECG and echocardiography at admission help identify NSC in the early phase of aSAH.

Elevation Mechanisms and Diagnostic Consideration of Cardiac Troponins under Conditions Not Associated with Myocardial Infarction. Part 1

Although cardiac troponins are considered the most specific biomarkers for the diagnosis of acute myocardial infarction (AMI), their diagnostic consideration goes far beyond the detection of this dangerous disease. The mechanisms of cardiac troponin elevation are extremely numerous and not limited to ischemic necrosis of cardiac myocytes. Practitioners should be well aware of the underlying pathological and physiological conditions that can lead to elevated serum levels of cardiac troponins to avoid differential diagnostic errors, which will be greatly increased if clinicians rely on laboratory data alone. This article presents a classification of the main causes of an elevation in cardiac troponins and discusses in detail the mechanisms of such elevation and the diagnostic consideration of cardiac troponins in some conditions not associated with AMI, such as physical exertion, inflammatory heart diseases (myocarditis and endocarditis), pulmonary embolism (PE), renal failure, and systemic inflammation (sepsis).

Clinical and Diagnostic Value of Highly Sensitive Cardiac Troponins in Arterial Hypertension

In modern laboratory diagnostics of cardiovascular diseases (CVD), there is a clear tendency toward an increase in the sensitivity of methods for determining key CVD biomarkers, among which highly sensitive cardiac troponins (hs-Tn) deserve special attention. The introduction of the latter into clinical practice made it possible not only to improve the early diagnosis of acute myocardial infarction but also to open up a number of additional valuable opportunities for the use of hs-Tn, including the assessment of the risk of developing CVD in a healthy population, detection and monitoring of early myocardial injuries in the early stages of CVD development (for example, with ischemic heart disease and arterial hypertension), with noncardiac pathologies (for example, sepsis, chronic obstructive pulmonary disease, chronic renal failure, stroke, cancer, etc), and diagnostics of CVD by using biological fluids that can be obtained by noninvasive methods. This article discusses in detail the diagnostic value of hs-Tn in serum and urine in cases of arterial hypertension. Also, the paper pays considerable attention to the consideration of the mechanisms underlying the increase in hs-Tn in serum and urine in cases of arterial hypertension.

High-Sensitive Cardiac Troponin T for Prediction of Cardiovascular Outcomes in Stable Maintenance Hemodialysis Patients: A 3-Year Prospective Study

BACKGROUND

Hemodialysis patients, who are often excluded from cardiovascular (CV) clinical trials, are associated with higher CV morbidity and mortality. The risk stratification scheme for these patients is lacking. Therefore, this investigation examined the independent CV prognostic value of high-sensitive cardiac troponin T (hs-cTnT) and added prognostic value over echocardiographic parameters and other clinical risk predictors in asymptomatic stable maintenance hemodialysis (MHD) patients.

METHODS

181 patients with end-stage renal disease undergoing MHD were eligible from the dialysis center of Tongren Hospital, Shanghai Jiao Tong University School of Medicine between October 2017 and September 2018. These patients were followed until September 2020 or until death. The median follow-up was 31 (IQR: 21-33) months. Outcome measures were all-cause mortality, first fatal or nonfatal CV events (CVEs), and 4-point composite major adverse CVEs (MACE). We performed multivariable Cox regression analysis using demographic, clinical, laboratory, and echocardiographic data to identify predictors of CV outcomes. We also evaluated the increased discriminative value associated with the addition of echocardiographic parameters and hs-cTnT using net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

During follow-up, 37 patients died, 84 patients suffered one or more CVEs, and 78 patients developed 4-point MACE. In univariable analyses, age, dialysis vintage, diastolic blood pressure, parathyroid hormone concentrations, hs-cTnT, B-type natriuretic peptide, left ventricular mass index (LVMI), and E/E' predicted all end points. hs-cTnT remained a strong predictor for each end point in multivariate analysis, whereas LVMI and E/E' did not. The addition of hs-cTnT on top of clinical and echocardiographic variables was associated with improvements in reclassification for CVEs (NRI = 44.6% [15.9-74.3%], IDI = 15.9% [5.7-31.0%], all p < 0.001), all-cause mortality (NRI = 35.5% [10.1-50.2%], p < 0.001, IDI = 4.4% [1.3-8.5%], p = 0.005), and 4-point MACE (NRI = 47.2% [16.1-64.9%], p < 0.001, IDI = 16.9% [5.5-37.3%], p = 0.005). Adding echocardiographic variables on top of clinical variables and hs-cTnT was not associated with significant improvements in NRI and IDI (all p > 0.05).

CONCLUSIONS

Our data suggest that hs-cTnT is a powerful independent predictor of CV outcome and all-cause mortality in stable MHD patients. The additional use of echocardiography for improvement of risk stratification is not supported by our results.

Association of Cardiac Troponin T Concentration on Admission with Prognosis in Critically Ill Patients without Myocardial Infarction: A Cohort Study

Purpose

To investigate the association of cardiac Troponin T (cTnT) with prognosis in critically ill patients without myocardial infarction.

Methods

Adult patients admitted to the intensive care units (ICUs) of the Beth Israel Deaconess Medical Center between 2008 and 2019 who were free of myocardial infarction with a length of ICU stay ≥24 hours and available cTnT records within 24 hours before and after ICU admission were included. The association between cTnT on ICU admission and hospital mortality was evaluated by multivariable logistic regression analysis. The discrimination capacity of cTnT on ICU admission for predicting hospital mortality was examined by receiver operating characteristic (ROC) analysis.

Results

A total of 2960 patients were included. Elevated cTnT (>0.01 ng/mL) was observed in 2730 (92.23%) patients with a higher hospital mortality compared to normal cTnT (11.21% versus 7.39%, P=0.075). There was no statistically significant association between elevated cTnT on ICU admission and hospital mortality (adjusted odds ratio 1.50, 95% confidence interval (CI) 0.88–2.57). Poor discrimination capacity was found for cTnT on ICU admission to predict hospital mortality (area under the ROC curve 0.48, 95% CI 0.44–0.53).

Conclusion

cTnT on ICU admission has limited prognostic value in critically ill patients without myocardial infarction.

Cardiac Troponins: Contemporary Biological Data and New Methods of Determination

Laboratory diagnosis plays one of the key roles in the diagnosis of many diseases, including cardiovascular diseases (CVD). The methods underlying the in vitro study of many CVD biomarkers, including cardiac troponins (cTnI and cTnT), are imperfect and are continually being improved to enhance their analytical performance, with sensitivity and specificity being the most important. Recently developed improved cTnI and cTnT detection methods, referred to as highly sensitive methods (hs-cTnI, hs-cTnT), have changed many of our ideas about the biology of cardiac troponins and opened up a number of additional diagnostic capabilities for practical healthcare. This article systematizes some relevant data on the biology of cardiac troponins as well as on methods for determining cTnI and cTnT with an analysis of the diagnostic value of their analytical characteristics (limit of blank, limit of detection, 99th percentile, coefficient of variation, and others). Data on extracardiac expression of cTnI and cTnT, mechanisms of formation and potential clinical significance of gender, age, and circadian characteristics of hs-cTnI and hs-cTnT content in serum are discussed. Considerable attention is paid to the discussion of new diagnostic capabilities of hs-cTnI, hs-cTnT, including consideration of promising possibilities for their study in biological fluids that can be obtained by non-invasive methods. Also, some possibilities of using hs-cTnI and hs-cTnT as prognostic laboratory biomarkers in healthy people (for example, to assess the risk of developing CVD) and in patients suffering from a number of pathological conditions that cause damage to cardiomyocytes are examined, and the potential mechanisms underlying the increase in hs-cTnI and hs-cTnT are discussed.

Myocardial Injury and the Risk of Stroke in Patients With Chronic Kidney Disease (From the Chronic Renal Insufficiency Cohort Study)

Patients with chronic kidney disease (CKD) are at increased risk for stroke. High-sensitivity troponin (hsTP), a marker of myocardial injury, has been associated with stroke risk in patients without CKD, but whether this applies to patients with CKD is not known. We assessed whether hsTP levels is associated with incident stroke in patients with mild-to-moderate CKD without a history of stroke enrolled in the Chronic Renal Insufficiency Cohort. Patients were followed for incident stroke, and the association with hsTP was assessed. A total of 3477 patients without prior stroke were included in this investigation. Over a median follow-up of 7.3 years, 101 (2.8%) patients had an incident stroke. Baseline hsTP was associated with a 9-year risk of stroke (quartile 1: 1.8%, quartile 2: 3.8%, quartile 3: 4.9%, quartile 4: 7.3%; P < .001). After adjusting for traditional stroke risk factors, patients in the fourth quartile (hazard ratio: 2.52, 95% CI: 1.10-5.76, P = .021) had higher risk of stroke when compared with the lowest quartile of hsTP. In conclusion, hsTP levels are associated with increased risk of incident stroke in patients with mild to moderate CKD, and this association remains significant despite the adjustment for traditional risk factors and CKD.

Elevated Cardiac Troponin Levels in Geriatric Patients Without ACS: Role of Comorbidities

Background

Elevated levels of cardiac troponin T as measured by a high-sensitivity test (hscTnT) are common in geriatric patients with a large spectrum of comorbidities but without acute coronary syndrome (ACS). However, the relative contribution of individual comorbidities has never been clearly addressed. This study aimed to determine the relationship between hscTnT elevation as a response variable and individual comorbidities, and to estimate the impact of individual comorbidities on hscTnT elevation in geriatric patients free of ACS.

Methods

A nonexperimental, retrospective, matched, longitudinal cohort study was designed to evaluate the files of 7062 geriatric patients (aged ≥ 65 years) without ACS. The hscTnT levels of the patients have already been measured in all evaluated medical records. The dataset was split into 2 groups (0 and 1) based on the individual comorbidity (0 and 1) and hscTnT levels (≤ 14 ng/L = 0 and > 14 ng/L = 1).

Results

Our results show that although age was positively and significantly correlated with hscTnT (r = 0.17, P < 0.0001), the likelihood of experiencing elevated hscTnT levels in older individuals after having excluded ACS was related to the presence of comorbidities independently of their number (P < 0.0001). The regression coefficients (β) associated with renal insufficiency (0.71), cardiomyopathy (0.63), chronic obstructive pulmonary disease (0.30), diabetes (0.25), and anemia (0.22) indicated that there exists a significant association between these comorbidities and the elevated hscTnT levels (P < 0.001). The receiver operating characteristic curve for predictive modeling was estimated at 71% (P < 0.0001).

Conclusions

Elevated hscTnT levels were mostly associated with renal insufficiency, cardiac myopathies, chronic obstructive pulmonary disease, diabetes, and anemia in geriatric patients without ACS. Developing guidelines to accurately evaluate hscTnT elevation in geriatric patients with comorbidities, without ACS, is clinically essential.

High-sensitivity cardiac troponins: detection and central analytical characteristics

Recently, there have been some important changes in the laboratory diagnosis of patients with acute coronary syndrome, due to the introduction into routine practice of new high- and ultra-sensitive techniques for detection of myocardial damage biomarkers — cardiac troponins. Each method for cardiac troponins’ detection, among the existing wide variety of troponin immunoassays, has different analytical characteristics and allows the detection of different concentrations of troponins in the same patient. With an increasing number of companies developing high-sensitivity troponin immunoassays receiving regulatory approval, there is an urgent need for independent analytical and clinical evaluation of each method. This article discusses high- and ultrasensitive techniques for detection of cardiac troponins. The modern data on biochemical and metabolic characteristics of troponins, obtained using high- and ultra-sensitive techniques, are described: sex, age, circadian features and potential for detecting troponins in other biological fluids. Considerable attention is paid to the analytical characteristics of troponin immunoassays: limit of blank, limit of detection and limit of quantitation, coefficient of variation, as well as the 99th percentile and factors influencing it.

Treatment rationale for coronary heart disease in advanced CKD

Chronic kidney disease (CKD) is accompanied by coronary artery disease (CAD) in most patients. In this article we describe differences in the pathogenesis, diagnosis, and treatment of CAD compared with patients without kidney impairment. The histological phenotype as well as the clinical presentation of acute and chronic coronary syndromes differ from those of patients with normal kidney function. The risk of cardiovascular events including death is strikingly increased with higher stages of CKD. Traditional but even more nontraditional cardiovascular risk factors are contributing to this increase. Screening and diagnostic procedures show limited sensitivity and specificity. Lifestyle modification is important for reducing the progression of both CKD and CAD. A special emphasis should be placed on physical exercising. Equally important is a strict antihypertensive therapy due to the very high incidences of hypertension in CKD patients. Blockade of the renin-angiotensin-system is imperative providing that adverse effects can be managed. Target blood pressure should be at 130 mm Hg systolic. Antiglycemic treatment should be implemented with metformin and SGLT2-inhibitors as first-line therapy, and glomerular filtration rate thresholds must be respected for both drugs. The risk of hypoglycemia is increased with worsening kidney function. Statins are indicated for up to stage 5 CKD. When a revascularization procedure is indicated (percutaneous intervention or bypass grafting), higher rates or peri-interventional morbidity and mortality must be anticipated. Taken together, the available literature on patients with CKD and CAD is clearly restricted compared with that on CAD patients with preserved kidney function. Mechanisms of arteriosclerosis and atheromatosis in CKD deserve more attention in the future. One major innovation in the field is SGLT2-inhibitor treatment with its concordant advantages for kidney and cardiac protection.

Association of circulating cardiac biomarkers with electrocardiographic abnormalities in chronic kidney disease

BACKGROUND

Among patients with chronic kidney disease (CKD), the circulating cardiac biomarkers soluble ST2 (SST2), galectin-3, growth differentiation factor-15 (GDF-15), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin-T (hsTnT) possibly reflect pathophysiologic processes and are associated with clinical cardiovascular disease. Whether these biomarkers are associated with electrocardiographic findings is not known. The aim of this study was to test the association between serum cardiac biomarkers and the presence of electrocardiographic changes potentially indicative of subclinical myocardial disease in patients with CKD.

METHODS

We performed a cross-sectional analysis using 3048 participants from the Chronic Renal Insufficiency Cohort (CRIC) without atrial fibrillation, atrioventricular block, bundle branch block or a pacemaker at the baseline visit. Using logistic regression, we tested the association of each of the five cardiac biomarkers with baseline electrocardiogram (ECG) findings: PR interval >200 ms, QRS interval >100 ms and a prolonged QTc interval. Models were adjusted for demographic variables, measures of kidney function, prevalent cardiovascular disease and cardiovascular risk factors.

RESULTS

In adjusted models, hsTnT levels associated with prolonged PR {odds ratio [OR] 1.23 [95% confidence interval (CI) 1.08-1.40]}, QRS [OR 1.28 (95% CI 1.16-1.42)] and QTc [OR 1.94 (95% CI 1.50-2.51)] intervals. NT-proBNP levels were associated with prolonged QRS [OR 1.11 (95% CI 1.06-1.16)] and QTc [OR 1.82 (95% CI 1.58-2.10)] intervals. SST2, galectin-3 and GDF-15 were not significantly associated with any of the ECG parameters.

CONCLUSIONS

hsTnT and NT-proBNP were associated with ECG measures indicative of subclinical myocardial dysfunction. These results may support future research investigating the significance of myocardial ischemia and volume overload in the pathogenesis of dysfunctional myocardial conduction in CKD.

The impact of cardiac troponin in elderly patients in the absence of acute coronary syndrome: A systematic review

Comorbidities are common risk factors for rising cardiac troponin in non-acute coronary syndromes conditions. Furthermore, the risk for all-cause mortality appears to be correlated to the troponin levels. Consequently, measurement of cardiac troponin in hospital admission may contribute to predict the mortality risk in elderly patients. Among geriatric patients without acute coronary syndrome, with concomitant diseases, the correct interpretation of elevated cardiac troponin, particularly in emergency conditions poses a diagnostic dilemma. Although in several studies it is suggested that at the presence of comorbidity, there is an increase in cardiac troponin values, the elderly patients have not been included conclusively. In order to assess the diagnostic and prognostic role of cardiac troponin elevation in geriatric patients suffering from chronic diseases, a systematic review was performed. The study included the elderly patients free of acute coronary syndrome admitted to the hospital with concomitant disease, with a report of at least one cardiac troponin measurement. We found that elevated cardiac troponin is an independent prognostic factor, predicting all-cause morbidity and mortality burden in geriatric patients without acute coronary syndromes.

Quality of Life Is Associated with Cardiac Biomarkers, Echocardiographic Indices, and Mortality in CKD Stage 4-5 Patients Not on Dialysis

INTRODUCTION

Patients with CKD have an impaired health-related quality of life (QoL). Most studies have been conducted on dialysis patients, and less is known about QoL and its determinants in predialysis patients. We studied the association between QoL and comorbidities, cardiac biomarkers, echocardiography, and mortality in patients with CKD stage 4-5 not on dialysis.

METHODS

A total of 140 patients enrolled in the Chronic Arterial Disease, Quality of Life and Mortality in Chronic Kidney Injury (CADKID) study filled the Kidney Disease Quality of Life Short Form (KDQOL-SF) at the beginning of the study. Echocardiography and biochemical parameters were obtained at baseline. Patients were followed up for at least 2 years or until death.

RESULTS

The median age was 66 years, and 51 (36%) patients were female. The median estimated glomerular filtration rate was 13 mL/min per 1.73 m2. Obesity, diabetes, atrial fibrillation, and congestive heart failure were associated with lower QoL scores in multiple KDQOL-SF domains. Cardiac biomarkers, troponin T (p = 0.02), N-terminal pro-B-type natriuretic peptide (p = 0.006), and the echocardiographic parameter of cardiac systolic function left ventricular global longitudinal strain (p = 0.02) were significant predictors of lower physical component summary (PCS) score in multivariable regression models after controlling for age, BMI, and diabetes. A low PCS score predicted mortality in a multivariable Cox proportional hazards model [HR 0.96 (95% CI 0.92-0.99), p = 0.03]. QoL was not associated with kidney disease progression.

CONCLUSION

Impaired QoL in CKD stage 4-5 patients not on dialysis is associated with cardiac biomarker levels, echocardiographic indices, and mortality.