High-sensitivity cardiac troponin assays: From improved analytical performance to enhanced risk stratification

The relative merits of using a high-sensitivity cardiac Troponin T assay compared to a nonhigh-sensitivity troponin T assay after noncardiac surgery

INTRODUCTION

Troponin elevation after noncardiac surgery is associated with an elevated risk of 30-day mortality. Little is known about relative merit of using a high-sensitivity Troponin T (hsTnT), the fifth-generation assay, vs the nonhigh sensitivity Troponin T (non-hsTnT), the fourth-generation assay, in the noncardiac surgery setting. We aimed to identify whether hsTnT can identify additional patients at risk that would have gone undetected with non-hsTnT measurement.

METHODS

The VISION Study included 40,004 noncardiac surgery patients with postoperative troponin measurements. Among them, 1,806 patients had both fourth-generation non-hsTnT and fifth-generation hsTnT concomitant measurements (4,451 paired results). We compared the absolute concentrations, the timing, and the impact of different thresholds on predicting 30-day major cardiovascular complications (composite of death, nonfatal cardiac arrest, coronary revascularization, and congestive heart failure).

RESULTS

Based on the manufacturers' threshold of 14 ng/L, 580 (32.1%) patients had postoperative hsTnT concentrations greater than the threshold, while their non-hsTnT concentrations were below the manufacturer's threshold. These 580 patients had higher risk of major cardiovascular events (OR 2.33; CI 95% 1.04-5.23; P = .049) than patients with hsTnT concentrations below the manufacturer threshold. Among patients with myocardial injury after noncardiac surgery, only 50% would be detected by the fourth-generation non-hsTnT assay at 6 to 12 hours postoperative as compared to 85% with the fifth-generation hsTnT assay (P-value < .001).

CONCLUSIONS

Within the first 3 postoperative days, fifth-generation hsTnT identified at least 1 in 3 patients with troponin elevation that would have gone undetected by fourth-generation non-hsTnT using published thresholds in this setting. Furthermore, fifth-generation hsTnT identified patients with an elevation earlier than fourth-generation non-hsTnT, indicating potential to improve postoperative risk stratification.

Circulating long noncoding RNA PDE4DIPP6: A novel biomarker for improving the clinical management of non-ST-segment elevation myocardial infarction

BACKGROUND

Long noncoding RNAs (lncRNAs) have emerged as promising diagnostic biomarkers. Here, we investigated the cardiac-expressed and plasma-detectable lncRNA PDE4DIPP6 as a biomarker for non-ST-segment elevation myocardial infarction (NSTEMI), specifically assessing its potential to enhance the diagnostic efficacy of high-sensitivity cardiac troponin (hs-cTnT).

METHODS AND RESULTS

The study enrolled individuals presenting with suspected acute coronary syndrome (ACS). LncRNA quantification was performed in plasma samples using RT-qPCR. The discriminatory performance was assessed by calculating the Area Under the Curve (AUC). Reclassification metrics, including the Integrated Discrimination Improvement (IDI) and Net Reclassification Improvement (NRI) indexes, were utilized to evaluate enhancements in diagnostic accuracy. Among the 252 patients with suspected ACS, 50.8 % were diagnosed with ACS, and 13.9 % with NSTEMI. Initially, the association of lncRNA PDE4DIPP6 with ACS was investigated. Elevated levels of this lncRNA were observed in ACS patients compared to non-ACS subjects. No association was found between lncRNA PDE4DIPP6 levels and potential confounding factors, nor was a significant correlation with hs-cTnT levels (rho = 0.071). The inclusion of lncRNA PDE4DIPP6 on top of hs-cTnT significantly improved the discrimination and classification of ACS patients, as reflected by an enhanced AUC of 0.734, an IDI of 0.066 and NRI of 0.471. Subsequently, the lncRNA PDE4DIPP6 was evaluated as biomarker of NSTEMI. Elevated levels of the lncRNA were observed in NSTEMI patients compared to patients without NSTEMI. Consistent with previous findings, the addition of lncRNA PDE4DIPP6 to hs-cTnT improved the discrimination and classification of patients, increasing the AUC from 0.859 to 0.944, with an IDI of 0.237 and NRI of 0.658.

CONCLUSION

LncRNA PDE4DIPP6 offers additional diagnostic insights beyond hs-cTnT, suggesting its potential to improve the clinical management of patients with NSTEMI.

Troponin T Assessment Allows for Identification of Mutation Carriers among Young Relatives of Patients with LMNA-Related Dilated Cardiomyopathy

Background:LMNA-related dilated cardiomyopathy (LMNA-DCM) caused by mutations in the lamin A/C gene (LMNA) is one of the most common forms of hereditary DCM. Due to the high risk of mutation transmission to offspring and the high incidence of ventricular arrhythmia and sudden death even before the onset of heart failure symptoms, it is very important to identify LMNA-mutation carriers. However, many relatives of LMNA-DCM patients do not report to specialized centers for clinical or genetic screening. Therefore, an easily available tool to identify at-risk subjects is needed. Methods: We compared two cohorts of young, asymptomatic relatives of DCM patients who reported for screening: 29 LMNA mutation carriers and 43 individuals from the control group. Receiver operating characteristic (ROC) curves for potential indicators of mutation carriership status were analyzed. Results: PR interval, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and high-sensitivity cardiac troponin T (hscTnT) serum levels were higher in the LMNA mutation carrier cohort. Neither group differed significantly with regard to creatinine concentration or left ventricular ejection fraction. The best mutation carriership discriminator was hscTnT level with an optimal cut-off value at 5.5 ng/L, for which sensitivity and specificity were 86% and 93%, respectively. The median hscTnT level was 11.0 ng/L in LMNA mutation carriers vs. <3.0 ng/L in the control group, p < 0.001. Conclusions: Wherever access to genetic testing is limited, LMNA mutation carriership status can be assessed reliably using the hscTnT assay. Among young symptomless relatives of LMNA-DCM patients, a hscTnT level >5.5 ng/L strongly suggests mutation carriers.

Diagnostic value of high sensitivity cardiac troponin T (hs-cTnT) in dialysis patients with myocardial infarction

Background

As a sensitive diagnostic marker for myocardial infarction (MI) in people with normal renal function, elevated high sensitivity cardiac troponin T (hs-cTnT) was often found in chronic kidney disease (CKD) patients requiring dialysis. However, the accuracy of baseline hs-cTnT in the diagnosis of MI (including Type 1 MI (T1MI) and Type 2 MI (T2MI)) in dialysis patients is still controversial. The aim of this study was to retrospectively explore whether there were any clinical indices that could increase the predictive value of hs-cTnT on admission for MI occurrence in dialysis patients.

Methods

Here, 136 patients with uremia who underwent regular dialysis with coronary angiography in the First Affiliated Hospital of Nanjing Medical University from August 2017 to October 2021 were enrolled. According to the coronary angiography results and the presence of clinical symptoms, the patients were divided into: (1). AMI group (n = 69; angiography positive) and Control group (n = 67; angiography negative); (2). T1MI group (n = 69; angiography positive), T2MI group (n = 7; angiography negative & symptomatic), and Control group (n = 60; angiography negative & asymptomatic).

Results

Here, we found the mean hs-cTnT on admission in the Control group was much lower than that in the AMI group. Hs-cTnT alone had a mediocre predictive performance, with an AUROC of 0.7958 (95% CI: 0.7220, 0.8696). Moreover, the ROC curve of hs-cTnT combined with the Triglyceride (TG), Time of dialysis, and Albumin (Alb) showed a higher sensitivity area [0.9343 (95% CI: 0.8901, 0.9786)] than that of single hs-cTnT. Next, hs-cTnT combined with the TG, Time of dialysis, and Alb also presented a better performance in predicting T1MI [0.9150 (95% CI: 0.8678, 0.9621)] or T2MI (0.9167 [0.9167 (95% CI: 0.8427, 0.9906)] occurrences. Last, these combined variables could better distinguish patient between T1MI and T2MI group than hs-cTnT alone.

Conclusions

On admission, a combination of hs-cTnT, TG, Time of dialysis, and Alb presented a higher sensitivity than hs-cTnT alone in predicting MI occurrence in dialysis patients, suggesting a better diagnostic approach for future clinical applications.

Outcomes of European Society of Cardiology 0/1-h algorithm with high-sensitivity cardiac troponin T among patients with coronary artery disease

OBJECTIVE

The European Society of Cardiology (ESC) 0/1-h Algorithm with high-sensitivity cardiac troponin T (hs-cTnT) has shown promising results in risk stratification and management of patients with coronary artery disease (CAD). However, its outcomes and clinical implications in the context of developing countries remain understudied.

METHODS

This cohort study aimed to evaluate the outcomes and clinical significance of the ESC 0/1-h Algorithm in a developing country setting. A total of 3534 patients with CAD were enrolled, with 1125 in the Rule-Out group and 2409 in the Rule-In group. Baseline characteristics, performance metrics, primary and secondary outcomes, and predictors of Rule-In and Rule-Out groups were assessed.

RESULTS

The study enrolled 3534 patients with CAD, with 1125 in the Rule-Out group and 2409 in the Rule-In group. The 0/1-h Algorithm with hs-cTnT demonstrated improved performance compared to Troponin T at Presentation. It exhibited higher sensitivity, specificity, negative predictive value, positive predictive value, and area under the curve (AUC) for risk stratification in patients with CAD. Significant differences were observed in baseline characteristics between the Rule-Out and Rule-In groups, including age, gender, and comorbidities. The Rule-In group had a higher incidence of adverse cardiac events and underwent more invasive procedures compared to the Rule-Out group. Age, gender, hypertension, diabetes, and smoking were identified as significant predictors of Rule-In and Rule-Out. These findings highlight the clinical significance of implementing the 0/1-h Algorithm in the management of patients with CAD in a developing country setting.

CONCLUSION

The algorithm's performance, along with its ability to identify high-risk patients and predict outcomes, highlights its potential to enhance patient care and outcomes in resource-limited settings.

High-sensitivity Troponin I Predicts Major Cardiovascular Events after Non-Cardiac Surgery: A Vascular Events in Non-Cardiac Surgery Patients Cohort Evaluation (VISION) Substudy

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS), based on measurement of troponin T, is associated with perioperative major adverse cardiovascular events (MACE). We therefore determined the high-sensitivity troponin I (hsTnI) thresholds associated with 30 day MACE after non-cardiac surgery.

METHODS

We performed a nested biobank cohort study of 4553 patients from the Vascular Events in Non-Cardiac Surgery Patients Cohort Evaluation (VISION) Study. We measured hsTnI (ADVIA Centaur® hsTnI assay) on postoperative days 1 to 3 in patients ≥45 years undergoing non-cardiac surgery. An iterative Cox proportional hazard model determined peak postoperative hsTnI thresholds independently associated with MACE (i.e., death, myocardial infarction occurring on postoperative day 4 or after, non-fatal cardiac arrest, or congestive heart failure) within 30 days after surgery.

RESULTS

MACE occurred in 89/4545 (2.0%) patients. Peak hsTnI values of <75 ng/L, 75 ng/L to <1000 ng/L, and ≥1000 ng/L were associated with 1.2% (95% CI, 0.9-1.6), 7.1% (95% CI, 4.8-10.5), and 25.9% (95% CI, 16.3-38.4) MACE, respectively. Compared to peak hsTnI <75 ng/L, values 75 ng/L to <1000 ng/L and ≥1000 ng/L were associated with adjusted hazard ratios (aHR) of 4.53 (95% CI, 2.75-7.48) and 16.17 (95% CI, 8.70-30.07), respectively. MACE was observed in 9% of patients with peak hsTnI ≥75 ng/L vs 1% in patients with peak hsTnI <75 ng/L (aHR 5.76; 95% CI, 3.64-9.11). A peak hsTnI ≥75 ng/L was associated with MACE in the presence (aHR 9.35; 95% CI, 5.28-16.55) or absence (aHR 3.99; 95% CI, 2.19-7.25) of ischemic features of myocardial injury.

CONCLUSION

A peak postoperative hsTnI ≥75 ng/L was associated with >5-fold increase in the risk of 30 days MACE compared to levels <75 ng/L. This threshold could be used for MINS diagnosis when the ADVIA Centaur hsTnI assay is used. Clinicaltrials.gov Registration Number: NCT00512109.

Development and validation of a nomogram for predicting significant coronary artery stenosis in suspected non-ST-segment elevation acute coronary artery syndrome with low-to-intermediate risk stratification

Background

Patients with non-ST-segment coronary artery syndrome (NSTE-ACS) have significant heterogeneity in their coronary arteries. A better assessment of significant coronary artery stenosis (SCAS) in low-to-intermediate risk NSTE-ACS patients would help identify who might benefit from invasive coronary angiography (ICA). Our study aimed to develop a multivariable-based model for pretesting SCAS in suspected NSTE-ACS with low-to-intermediate risk.

Methods

This prediction nomogram was constructed retrospectively in 469 suspected NSTE-ACS patients with low-to-intermediate risk. Patients were divided into a development group (n = 331, patients admitted to hospital before 1 May 2021) and a temporal validation group (n = 138, patients admitted to hospital since 1 May 2021). The outcome was existing SCAS, including left main artery stenosis ≥50% or any subepicardial coronary artery stenosis ≥70%, all confirmed by invasive coronary angiography. Pretest predictors were selected using Least Absolute Shrinkage and Selection Operator (LASSO) and stepwise logistic regression.

Results

Derivation analyses from the development group (n = 331, admitted before 1 May 2021) generated the 7 strongest predictors out of 25 candidate variables comprising smoker, diabetes, heart rate, cardiac troponin T, N-terminal pro-B-type natriuretic peptide, high-density lipoprotein cholesterol, and left atrial diameter. This nomogram model showed excellent discrimination ability with an area under the receiver operating characteristic curve (AUC) of 0.83 in the development set and 0.79 in the validation dataset. Good calibration was generally displayed, although it slightly overestimated patients' SCAS risk in the validation group. Decision curve analysis demonstrated the clinical benefit of this model, indicating its value in clinical practice. Furthermore, an optimal cut-off of prediction probability was assigned as 0.61 according to the Youden index.

Conclusion

A prediction nomogram consisting of seven readily available clinical parameters was established to pretest the probability of SCAS in suspected NSTE-ACS patients with low-to-intermediate risk, which may serve as a cost-effective risk stratification tool and thus assist in initial decision making.

Point-of-care heart failure platform: where are we now and where are we going to?

INTRODUCTION

Heart failure (HF) remains a leading cause of cardiovascular (CV) mortality in patients with CV disease. The point-of-care (POC) HF platform seems to be an ideal non-invasive workflow-adapted system for personally adjusted management of patients with HF.

AREAS COVERED

In the present manuscript, we reviewed the literature covering some relevant studies regarding the role of point-of care heart failure platform in the risk stratification, earlier diagnosis and prognostically beneficial treatment of patients with different phenotypes of HF.

EXPERT OPINION

POC HF platform including personal consultation, optimization of the comorbidity treatment, step-by-step HF diagnostic algorithm, single biomarker measurements, has also partially been provided in the current guidelines. Although there are several obstacles to implement POC in routine practice, such as education level, aging, affordability of health care, even partial implementation of POC can also improve clinical outcomes. POC seems to be an evolving model, more research studies are required to clearly see whether it helps to make better decisions with diagnosis and care of HF, as well helps to achieve better clinical outcomes.In summary, the POC HF platform is considered to be a more effective tool than conventional algorithm of HF management.

High-Sensitivity Troponin: A Review on Characteristics, Assessment, and Clinical Implications

The use of high-sensitivity cardiac troponin (hs-cTn) assays has become part of the daily practice in most of the laboratories worldwide in the initial evaluation of the typical chest pain. Due to their early surge, the use of hs-cTn may reduce the time needed to recognise myocardial infarctions (MI), which is vital for the patients presenting in the emergency departments for chest pain. The latest European Society of Cardiology Guidelines did not only recognise their central role in the diagnosis algorithm but also recommended their use for rapid rule-in/rule-out of MI. High-sensitivity cardiac troponins are also powerful prognostic markers for long-term events and mortality, not only in a wide spectrum of other cardiovascular diseases (CVD) but also in several non-CVD pathologies. Moreover, these biomarkers became a powerful tool in special populations, such as paediatric patients and, most recently, COVID-19 patients. Although highly investigated, the assessment and interpretation of the hs-cTn changes are still challenging in the patients with basal elevation such as CKD or critically ill patients. Moreover, there are still various analytical characteristics not completely understood, such as circadian or sex variability, with major clinical implications. In this context, the present review focuses on summarizing the most recent research in the current use of hs-cTn, with a main consideration for its role in the diagnosis of MI but also its prognostic value. We have also carefully selected the most important studies regarding the challenges faced by clinicians from different specialties in the correct interpretation of this biomarker. Moreover, future perspectives have been proposed and analysed, as more research and cross-disciplinary collaboration are necessary to improve their performance.

Cardiac Troponin I and Risk of Stroke: A Mendelian Randomization Study

Purpose

Methods

Results

Conclusion

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.

Troponin T Elevation After Percutaneous Left Atrial Appendage Occlusion

Background: Cardiac troponin T (cTNT) has been widely used in detecting cardiac damage. Elevated cTNT level has been reported to be associated with increased mortality in multiple cardiac conditions. It is not uncommon to observe an increased level of cTNT in patients after left atrial appendage occlusion (LAAO). The objective of the study is to study the incidence, significance, and factors associated with cTNT elevation after LAAO.

Methods: We prospectively included patients who underwent LAAO from January 2019 to July 2020 in Fudan Zhongshan Hospital. Patients were divided into those with elevated cTNT after procedure and those with normal postprocedure cTNT. All individuals were followed up for 1 year. The primary outcome is major adverse cardiovascular events, which include myocardial infarction, heart failure, cardiac death, and stroke. The second outcome is periprocedure complication, including chest pain, tachycardia, cardiac tamponade, change of electrocardiograph, and atrial thrombus.

Results: A total of 190 patients were enrolled. Of the patients, 85.3% had elevated cTNT after LAAO, while 14.7% of them did not. Exposure time, dosage of contrast, types of devices, shapes, and sizes of LAA could contribute to elevated postprocedure cTNT. We found that patients with a Watchman device were more likely to have elevated postprocedure cTNT than those with a Lambre device (89.2 vs. 76.7%, p = 0.029). LAAO shapes were associated with cTNT levels in patients with a Watchman device, while the diameter of the outer disc and LAA depth mattered for the Lambre device. There was no significant difference in the primary and second outcome between the two groups (p-value: 0.619, 0.674).

Conclusion: LAAO was found to be commonly accompanied with cTNT elevation, which might not to be related to the complications and adverse cardiac outcomes within 1 year of follow-up. Moreover, eGFR at baseline, exposure time, dosage of contrast, types of LAAO device, and LAA morphology could contribute to cTNT elevation.

microRNA-3646 serves as a diagnostic marker and mediates the inflammatory response induced by acute coronary syndrome

Acute coronary syndrome (ACS) is one of the main syndromes of coronary artery disease with high mortality. The identification of biomarkers associated with disease occurrence and progression could improve early detection and risk prediction. This study was aimed to reveal the clinical significance and function of miR-3646 in ACS.

The expression of miR-3646 was evaluated in ACS patients, healthy volunteers, and non-ACS patients and estimated the clinical significance of miR-3646. The ACS modeling rats were also established in this study to explore the potential mechanism underlying the function of miR-3646. miR-3646 was upregulated in ACS patients compared with healthy volunteers and non-ACS patients. The expression of miR-3646 was positively correlated with the severity and progression of ACS patients and could discriminate ACS patients from healthy volunteers and non-ACS patients. The knockdown of miR-3646 could reverse the inflammatory response induced by ACS.miR-3646 serves as a diagnostic biomarker for ACS. The knockdown of miR-3646 could alleviate ACS by reversing inflammatory response. These results provide a potential therapeutic target of ACS.

Comparison of Perioperative High-Sensitive Troponin T and Troponin I Assays in Cardiac Surgery

BACKGROUND

Troponin measurements are among the standard parameters for monitoring perioperative myocardial ischaemia after cardiosurgical procedures. As high-sensitive assays continue to replace older analytic parameters with lower sensitivity, this study aimed to compare perioperative profiles of a high-sensitive troponin T assay (hsTnT, Roche Diagnostics, Mannheim, Germany) with a troponin I assay (sTnI, Siemens Healthcare Diagnostics, Eschborn, Germany).

METHODS

A total of 287 consecutive patients undergoing a typical spectrum of cardiac procedures from August 2017 to March 2018 monitored with the hsTnT assay were compared with a propensity-matched collective analysed with the sTnI assay. For side-by side comparison, the peak troponin (Tmax) values were scaled to a z-score distribution before comparison.

RESULTS

Despite absolute postoperative hsTnT and sTnI values differing by an order of magnitude, parameters could be scaled to a common distribution with kernel density curves overlapping 92%. Both parameters showed equal behaviour in subgroup analyses regarding relevant perioperative factors, such as type of procedure, cross-clamping time, and type of cardioplegic solution. However, there were some differences regarding pre-existing renal impairment between both parameters. In both groups, renal failure patients with chronic kidney disease stages IV or V as well as patients on haemodialysis exhibited a marked Tmax increase of >100% compared with normal kidney function (hsTnT, +121%; 2,383.5 vs 1,078.8 ng/L; p=0.0006; and sTnI, +149%; 27.3 ng/mL vs 11.0 ng/mL; p=0.009). However, in patients with moderately impaired renal function, those in the hsTnT group, but not in the sTnI cohort, showed significantly increased Tmax values (CKD stages II or III, 1,233.5 ng/L [+14%] and 1,314.1 ng/L [+22%] vs 1,078.8 ng/L; p=0.01 and p=0.03). In these patients, the postoperative interval until Tmax was reached was also significantly increased (14.4 and 19.0 hrs vs 12.4 hrs for chronic kidney disease stages II and III; p=0.0038 and p<0.001), indicating a higher rate of accumulation in the hsTnT parameter.

CONCLUSION

In the context of cardiac surgery, this study found that both parameters behaved in a similar manner under most relevant circumstances. Despite significant difference in the absolute serum concentration, hsTnT and sTnI can be scaled to virtually identical distributions. However, renal impairment did affect both parameters differently with troponin T but not troponin I, showing evidence of accumulation in moderately impaired renal disease.

Laboratory-related issues in the measurement of cardiac troponins with highly sensitive assays

A number of assay-related issues can affect the performance of cardiac troponin (cTn) measurement in everyday practice. In this respect, it is vital that all information on cTn assays is known and that the performance characteristics of assays are objectively assessed and adequately described. The advent of the latest generation of more sensitive cTn assays has heralded a new wave of information about low concentrations of cTn in blood. These recent generation assays have improved analytical sensitivity and corresponding performance at low cTn concentrations when compared to their predecessors, providing a convincing goal for laboratory medicine in helping clinicians in the diagnosis of acute myocardial infarction. Crucial to the clinical utility of highly sensitive cTn assays is the laboratorians' role in closely scrutinizing proposed assays and defining their value in relation to available evidence. Analytical, as well as pre-analytical and post-analytical, aspects must be documented. In this review, we describe what laboratory professionals should know about their cTn assay performance characteristics and the pre-analytical prerequisites for robustness to ensure optimal post-analytical reporting.

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.

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

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

Mid-Term Survival and Risk Factors Associated With Myocardial Injury After Fenestrated and/or Branched Endovascular Aortic Aneurysm Repair

OBJECTIVE

Myocardial injury after non-cardiac surgery (MINS) is an independent predictor of post-operative mortality in non-cardiac surgery patients and may increase health costs. Few data are available for MINS in vascular surgery patients, in general, and those undergoing fenestrated/branched endovascular aortic repairs (F/BEVAR), in particular. The incidence of MINS after F/BEVAR, the associated risk factors, and prognosis have not been determined. The aim of the present study was to help fill these knowledge gaps.

METHODS

A single centre, retrospective study was carried out at a high volume F/BEVAR centre in a university hospital. Adult patients who underwent F/BEVAR between October 2010 and December 2018 were included. A high sensitivity troponin T (HsTnT) assay was performed daily in the first few post-operative days. MINS was defined as a HsTnT level ≥ 14 ng/L (MINS₁₄) or ≥ 20 ng/L (MINS₂₀). After assessment of the incidence of MINS, survival up to two years was estimated in a Kaplan-Meier analysis and the groups were compared according to MINS status. A secondary aim was to identify predictors of MINS.

RESULTS

Of the 387 included patients, 240 (62.0%) had MINS₁₄ and 166 (42.9%) had MINS₂₀. In multivariable Cox models, both conditions were significantly associated with poor two year survival (MINS14: adjusted hazard ratio [aHR] 2.15, 95% confidence interval [CI] 1.10 - 4.19; MINS₂₀: aHR 2.43, 95% CI 1.36 - 4.34). In a multivariable logistic regression, age, revised cardiac risk index, duration of surgery, pre-operative estimated glomerular filtration rate (eGFR), and haemoglobin level were independent predictors of MINS.

CONCLUSION

After F/BEVAR surgery, the incidence of MINS was particularly high, regardless of the definition considered (MINS₁₄ or MINS₂₀). MINS was significantly associated with poor two year survival. The modifiable predictors identified were duration of surgery, eGFR, and haemoglobin level.

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

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

Optimal cut-off value of elevated cardiac troponin concentrations for myocardial injury predicts clinical outcomes in adult patients with COVID-19: a dose-response analysis protocol for systematic review

INTRODUCTION

Acute myocardial injury in patients with COVID-19 infection has been recognised as one important complication associated with in-hospital mortality. The potential dose-response effect of cardiac troponin (cTn) concentrations on adverse clinical outcomes has not been systematically studied. Hence, we will conduct a comprehensive dose-response meta-analysis to quantitatively evaluate the relationship between elevated cTn concentrations and in-hospital adverse clinical outcomes in patients with COVID-19.

METHODS

We will search PubMed, EMBASE, Cochrane Library and ISI Knowledge via Web of Science databases, as well as preprint databases (medRxiv and bioRxiv), from inception to October 2021, to identify all retrospective and prospective cohorts and randomised controlled studies using related keywords. The primary outcome will be all-cause mortality during hospitalisation. The secondary outcome will be major adverse event (MAE). To conduct a dose-response meta-analysis of the potential linear or restricted cubic spline regression relationship between elevated cTn concentrations and all-cause mortality or MAE, studies with three or more categories of cTn concentrations will be included. Univariable or multivariable meta-regression and subgroup analyses will be conducted to compare elevated and non-elevated categories of cTn concentration. Sensitivity analyses will be used to assess the robustness of our results by removing each included study at one time to obtain and evaluate the remaining overall estimates of all-cause mortality or MAE.

ETHICS AND DISSEMINATION

In accordance with the Institutional Review Board/Independent Ethics Committee of Fuwai Hospital, ethical approval was waived for this systematic review protocol. This meta-analysis will be disseminated through a peer-reviewing process for journal publication and conference communication.

PROSPERO REGISTRATION NUMBER

CRD42020216059.

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

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

Prognostic value of cardiac troponin levels in patients presenting with supraventricular tachycardias

BACKGROUND

An association between paroxysmal supraventricular tachycardias (PSVT) and elevated cardiac troponin I (cTnI) has been reported in small studies, even in the absence of significant coronary artery or structural heart disease. We sought to explore the prognostic significance of elevated cTnI among patients presenting with PSVT.

METHODS

This is a retrospective single-center observational study conducted between January 2014 and Decemebr 2016. 165 patients (60% men, mean age 55 ± 17 year-old) with an acute episode of regular supraventricular tachyarrhythmia were admitted to the emergency department at Rambam Medical Center. 131 patients had at least one serum cTnI value measured. Of those, 57 had a positive result, defined as serum cTnI of more than 0.028 ng/dL.

RESULTS

Multivariate analysis showed that heart rate > 150 beats per minute (bpm) on admission (OR = 3.9; 95% CI 1.1.6-9.5; p < 0.003) and history of coronary artery disease (CAD) (OR = 3.4; 95% CI 1.2-10.1; p = 0.026) were the only independent predictors of cTnI elevation. After mean follow-up period of 23 ± 7 months, the combined primary outcome of death, coronary intervention (PCI) or myocardial infarction (MI) occurred in 7 patients (12.3%) out of 57 patients with positive cTnI and in zero patients with negative cTn (p = 0.002). Cox proportional hazard model showed that elevated cTnI on admission was an independent predictor of adverse outcomes only in patients with known coronary artery disease (CAD) (HR = 3.3, p = 0.05).

CONCLUSION

Elevated cTnI among patients presenting with PSVT appears to have prognostic significance only in patients with history of CAD. In this patient group elevated cTnI is associated with increased risk of adverse cardiac outcomes. We therefore believe serum cTnI should be measured selectively, such as in patients with symptoms of ischemic chest pain and a high pretest likelihood of having CAD.

Myocardial Infarction With Nonobstructive Coronary Arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is the current term used to describe patients who have a myocardial infarction but have normal, non-obstructed coronary arteries on a coronary angiogram. There is still much debate over the definition, diagnosis, management and treatment of MINOCA. However, MINOCA is not a benign condition; prompt recognition and diagnosis can lead to better management and treatment and thus improve patient outcomes. This review article will update the most recent definition of MINOCA, discuss epidemiology and etiology, and review the diagnostic workup and management options for patients presenting with signs and symptoms of MINOCA.

Association Between Renal Function and Troponin T Over Time in Stable Chronic Kidney Disease Patients

Background People with reduced glomerular filtration rate (GFR) often have elevated cardiac troponin T (cTnT) levels. It remains unclear how cTnT levels develop over time in those with chronic kidney disease (CKD). The aim of this study was to prospectively study the association between cTnT and GFR over time in older advanced-stage CKD patients not on dialysis. Methods and Results The EQUAL (European Quality Study) study is an observational prospective cohort study in stage 4 to 5 CKD patients aged ≥65 years not on dialysis (incident estimated GFR, <20 mL/min/1.73 m²). The EQUAL cohort used for the purpose of this study includes 171 patients followed in Sweden between April 2012 and December 2018. We used linear mixed models, adjusted for important groups of confounders, to investigate the effect of both measured GFR and estimated GFR on high-sensitivity cTnT (hs-cTnT) trajectory over 4 years. Almost all patients had at least 1 hs-cTnT measurement elevated above the 99th percentile of the general reference population (≤14 ng/L). On average, hs-cTnT increased by 16%/year (95% CI, 13-19; P<0.0001). Each 15 mL/min/1.73 m2 lower mean estimated GFR was associated with a 23% (95% CI, 14-31; P<0.0001) higher baseline hs-cTnT and 9% (95% CI, 5-13%; P<0.0001) steeper increase in hs-cTnT. The effect of estimated GFR on hs-cTnT trajectory was somewhat lower than a previous myocardial infarction (15%), but higher than presence of diabetes mellitus (4%) and male sex (5%). Conclusions In CKD patients, hs-cTnT increases over time as renal function decreases. Lower CKD stage (each 15 mL/min/1.73 m2 lower) is independently associated with a steeper hs-cTnT increase over time in the same range as other established cardiovascular risk factors.

Analytical validation of a highly sensitive point-of-care system for cardiac troponin I determination

Background

Highly sensitive cardiac troponin assays (hs-cTn) are not available as point-of-care (POC) measurements. As rapid testing cannot be achieved at the expense of clinical performance, there is an urgent need to develop and rigorously validate POC hs-cTn. Konica Minolta (KM) has recently developed a surface plasmon-field enhanced fluorescence spectroscopy-based POC hs-cTn I system.

Methods

We validated the analytical characteristics of the KM POC system according to the international guidelines.

Results

Limit of blank (LoB) and limit of detection (LoD) were 0.35 and 0.62 ng/L, respectively, hs-cTn I concentrations corresponding to a total CV of 20%, 10% and 5% were 1.5, 3.9 and 11.0 ng/L, respectively. Method comparison studies showed that KM calibration was successfully traced to higher-order references. Limit of quantitation (LoQ), i.e. the hs-cTn I concentration having a total error of measurement of ≤34%, was 10.0 ng/L. The upper reference limit (URL) for 600 healthy blood donors was calculated at 12.2 ng/L (90% confidence interval [CI]: 9.2–39.2), while sex-partitioned URLs were 20.6 (males) and 10.7 ng/L (females), respectively (p < 0.0001). KM assay measured hs-cTn I concentrations >LoD in 65.7% of all reference individuals, in 76.7% of males and in 54.7% of females, respectively.

Conclusions

The KM system joins the characteristics of POC systems to the analytical performance of hs-cTn.

Clinicopathological complexity in the application of the universal definition of myocardial infarction

A universal definition of myocardial infarction (UDMI) has been established, periodically updated, and refined over the past twenty years. The primary purpose of the UDMI is to bring uniformity and accuracy to clinical diagnosis. Herein, a review and analysis of the UDMI is presented with emphasis on clinicopathological correlation. Determination of the presence of myocardial injury is based on the detection of abnormal serum cardiac biomarkers, particularly cardiac troponin (cTn), and in the current fourth iteration of the UDMI, high sensitivity (hs)-cTn. Differentiation of myocardial infarction from other causes of myocardial injury requires the documentation of clinical evidence of myocardial ischemia. In this review, difficulties in applying the UDMI in actual practice are discussed, based on the experience and perspective of those of us who face these problems as part of our own practice of pathology. The complexity in application of the UDMI is highlighted by the presentation of five illustrative cases involving the differential diagnosis of myocardial injury and myocardial infarction due to atherothrombotic and nonatherothrombotic coronary artery disease. The cases include myocardial infarction due to severe coronary atherosclerosis, supply-demand mismatch, coronary artery dissection associated with an eosinophilic coronary periarteritis, and coronary thromboembolism, and a case with a differential diagnosis of myocarditis and myocardial infarction. These cases illustrate how pathological findings can contribute to more accurate application of the UDMI and how, when critically applied, the UDMI can be used to better characterize myocardial infarcts in clinical practice.

[A review on the clinical application of high-sensitivity cardiac troponin T in neonatal diseases]

In recent years, high-sensitivity cardiac troponin T (hs-cTnT) has been recognized as an effective marker for myocardial injury in adults and can be used to diagnose acute myocardial injury and predict major adverse cardiovascular events. It is the gold standard for the diagnosis of acute myocardial infarction in adults. Neonates are a special group, and due to the changes of various physiological processes during the perinatal period, many laboratory markers used in adults may have a low clinical value in neonates. So far, for example, there is still no suitable cardiac serum biomarker that can reflect the true condition of neonatal myocardial injury. In recent years, new breakthroughs have been made in the application of hs-cTnT in the field of neonates. In order to fully understand the role of hs-cTnT in neonatal diseases, this article reviews the research advances in the biological and physiological features of hs-cTnT and its application in neonates.

Immediate versus delayed detection of Takotsubo syndrome after epileptic seizures

Takotsubo syndrome(TTS) is often preceded by emotional or physical stress. Epileptic seizures are described in >100 cases. It is unknown whether patients with immediate and delayed detection of seizure-induced TTS differ. We screened the literature and compared clinical and electrocardiographic (ECG) findings. In 48 cases with seizure-associated TTS, the time between seizure and TTS-detection was reported. Troponin levels were elevated in 37/40. ECG abnormalities were negative T-waves(40%), ST-elevations(33%) and ventricular fibrillation/flutter(10%). Immediate detection was reported in 23 patients, in the remaining 25 patients, TTS was detected 5-288 h postictally. Patients did not differ in gender, age or symptoms. Negative T-waves were more frequent in patients with delayed detection(64 vs. 13%, p = .0009), whereas ECG-abnormalities suggesting acute myocardial infarction tended to be more prevalent in patients with immediate detection. Due to lack of typical symptoms, seizure-induced TTS can be overlooked. Postictally, an ECG should be recorded and troponin levels measured. New T-wave inversions might indicate seizure-induced TTS.

High-sensitive cardiac troponin T: a biomarker of left-ventricular diastolic dysfunction in hemodialysis patients

OBJECTIVE

To identify the relationship between serum high-sensitive cardiac troponin T (hs-cTnT) and left ventricular diastolic dysfunction (LVDD) among maintenance hemodialysis patients and to further explore the value of hs-cTnT in evaluating and predicting LVDD in this special group of patients.

METHODS

In a cross-sectional study, 152 dialysis patients with end-stage renal disease (ESRD) underwent Hs-cTnT measurement using the high sensitivity assay. Echocardiography measurements were carried out according to the American Society of Echocardiography recommendations and E/E' > 15 or E' < 7 cm/s was defined as diastolic dysfunction. Demographic, biochemical, and echocardiographic values of left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), left atrial diameter, early/late peak velocities ratio (E/A), early peak diastolic annular velocity (E') and E/E' were compared across quartiles of hs-cTnT. The association of plasma hs-cTnT concentrations with echocardiographic parameters was analyzed by Spearman's correlation. The relationship between serum hs-cTnT and LVDD parameters of E/E' and E' was analyzed using multivariate regression analysis, and the value of hs-cTnT on assessing LVDD was evaluated by receiver-operating characteristic (ROC) curves.

RESULTS

The median value of hs-cTnT was 45 pg/ml (range 28-73). All patients had detectable hs-cTnT, while 88% had greater hs-cTnT than the 99th percentile of the general population (14 pg/ml). Serum hs-cTnT values showed a significantly positive correlation with E/E' (r = 0.739, p < 0.001) and LVMI (r = 0.608, p < 0.001), but showed a negative correlation with E' (r = - 0.554, p < 0.001). Serum hs-cTnT was not associated with LV systolic dysfunction. The associations of hs-cTnT with E/E' and E' persisted after multivariate adjustment for LVMI and comorbidities. In logistic multiple regression analysis, compared with the lowest quartile of hs-cTnT, the highest two quartiles were approximately 5 and 11 times more likely to have E/E' > 15 and 7 and 17 times more likely to have E' < 7 cm/s. The area under the ROC curve for hs-cTnT evaluating E/E' > 15 was 0.847 and evaluating E' < 7 cm/s was 0.799, which denoted a moderate accuracy.

CONCLUSIONS

Our studies suggest that serum hs-cTnT may serve as a biomarker of LVDD in hemodialysis patients.

Point-of-Care Diagnosis of Acute Myocardial Infarction in Central Vietnam: International Exchange, Needs Assessment, and Spatial Care Paths

OBJECTIVES

Objectives were to (a) advance point-of-care (POC) education, international exchange, and culture; (b) report needs assessment survey results from Thua Thien Hue Province, Central Vietnam; (c) determine diagnostic capabilities in regional health care districts of the small-world network of Hue University Medical Center; and (d) recommend Spatial Care Paths that accelerate the care of acute myocardial infarction (AMI) patients.

METHODS

We organized progressively focused, intensive, and interactive lectures, workshops, and investigative teamwork over a 2-year period. We surveyed hospital staff in person to determine the status of diagnostic testing at 15 hospitals in 7 districts. Questions focused on cardiac rapid response, prediabetes/diabetes, infectious diseases, and other serious challenges, including epidemic preparedness.

RESULTS

Educational exchange revealed a nationwide shortage of POC coordinators. Throughout the province, ambulances transfer patients primarily between hospitals, rarely picking up from homes. No helicopter rescue was available. Ambulance travel times from distant sites to referral hospitals were excessive, longer in costal and mountainous areas. Most hospitals (92.3%) used electrocardiogram and creatine phosphokinase-MB isoenzyme to diagnose AMI. Cardiac troponin I/T testing was performed only at large referral hospitals.

CONCLUSIONS

Central Vietnam must improve rapid diagnosis and treatment of AMI patients. Early upstream POC cardiac troponin testing on Spatial Care Paths will expedite transfers directly to hospitals capable of intervening, improving outcomes following coronary occlusion. Point-of-care coordinator certification and financial support will enhance standards of care cost-effectively. Training young physicians pivots on high-value evidence-based learning when POC cardiac troponin T/cardiac troponin I biomarkers are in place for rapid decision making, especially in emergency rooms.

Cardiac troponins: 25 years on the stage and still improving their clinical value

Twenty-five years ago, non-isotopic immunoassays for measuring the cardiac specific isoforms of troponin I (cTnI) and T (cTnT) were developed. Both biomarkers radically changed the diagnosis, prognosis, and therapy indication of acute coronary syndromes (ACS) and, particularly, of myocardial infarction (MI). However, cardiac troponins (cTn) rapidly demonstrated their usefulness in other cardiac and non-cardiac conditions, a part of the ischemic coronary diseases. Consequently, the number of patients to be tested for cTn and the number of tests requested to clinical laboratories sharply increased. Though the manufacturers continuously improved the analytical characteristics of the first cTn assays and produced different cTn assay "generations", the universal definition of myocardial infarction required less-than-available analytical imprecision at the cTn concentration used to assess MI (i.e. the 99th reference percentile). To address the clinical requirements, manufacturers developed the high-sensitivity cTn (hs-cTn) assays that allow to measure the 99th reference percentile with adequate precision, to detect cTn in many healthy subjects and, hence, to calculate the hs-cTn biological variation and especially to observe in very short time intervals serial differences in hs-cTn attributable to cardiac ischemia. Since the number of patients attending the emergency departments (ED) for a suspected ACS or MI is increasing, the improved properties of hs-cTn assays, allowing faster and safer patient assessment, will help to alleviate the sometimes overcrowded EDs. However, there are many biological, analytical, and clinical factors that can influence the true hs-cTn values of a patient. Clinicians and laboratory professionals should know about them for the best interpretation of the otherwise largely useful hs-cTn measurements. In conclusion, 25 years after their introduction for clinical use, "cTn are still on the stage and improving their clinical value".

Point-of-care testing (POCT) and evidence-based laboratory medicine (EBLM) - does it leverage any advantage in clinical decision making?

Point-of-care testing (POCT) is the analysis of patient specimens outside the clinical laboratory, near or at the site of patient care, usually performed by clinical staff without laboratory training, although it also encompasses patient self-monitoring. It is able to provide a rapid result near the patient and which can be acted upon immediately. The key driver is the concept that clinical decision making may be delayed when samples are sent to the clinical laboratory. Balanced against this are considerations of increased costs for purchase and maintenance of equipment, staff training, connectivity to the laboratory information system (LIS), quality control (QC) and external quality assurance (EQA) procedures, all required for accreditation under ISO 22870. The justification for POCT depends upon being able to demonstrate that a more timely result (shorter turnaround times (TATs)) is able to leverage a clinically important advantage in decision making compared with the central laboratory (CL). In the four decades since POCT was adapted for the self-monitoring of blood glucose levels by subjects with diabetes, numerous new POCT methodologies have become available, enabling the clinician to receive results and initiate treatment more rapidly. However, these instruments are often operated by staff not trained in laboratory medicine and hence are prone to errors in the analytical phase (as opposed to laboratory testing where the analytical phase has the least errors). In some environments, particularly remote rural settings, the CL may be at a considerable distance and timely availability of cardiac troponins and other analytes can triage referrals to the main centers, thus avoiding expensive unnecessary patient transportation costs. However, in the Emergency Department, availability of more rapid results with POCT does not always translate into shorter stays due to other barriers to implementation of care. In this review, we apply the principles of evidence-based laboratory medicine (EBLM) looking for high quality systematic reviews and meta-analyses, ideally underpinned by randomized controlled trials (RCTs), looking for evidence of whether POCT confers any advantage in clinical decision making in different scenarios.

Establishing reference intervals for galectin-3 concentrations in serum requires careful consideration of its biological determinants

BACKGROUND

Appropriately established reference intervals for laboratory biomarkers may help the interpretation of their results and facilitate clinical utilization.

OBJECTIVES

i) To determine reference intervals for serum galectin-3 measured using the Architect STAT immunoassay, and ii) to identify factors affecting galectin-3 concentrations.

METHODS

We recruited 533 questionnaire-identified apparently healthy individuals, in which laboratory biomarkers were used to detect asymptomatic myocardial injury and dysfunction, ongoing inflammation, hyperglycemia, dyslipidemia, and renal dysfunction. A final reference group of 180 subjects was selected.

RESULTS

2.5th and 97.5th percentiles of distribution of galectin-3 concentrations in the reference group (90% confidence interval) were 5.9 (5.0-6.8) and 18.1 (17.2-19.0) μg/L, respectively. Older age contributed to higher galectin-3 concentrations, but influenced derived reference intervals to a lesser extent. Other major determinants of galectin-3 concentrations observed in the questionnaire-screened population were not linked to galectin-3 in reference individuals. In aiming to decide if reference limits should be partitioned by age, we compared galectin-3 concentrations in subjects <40 (n=124) and ≥40years (n=56). Higher galectin-3 concentrations were found in older people (median, 12.4μg/L vs. 11.5μg/L, p=0.016). Accounting for manufacturer's declared imprecision at galectin-3 physiological concentrations of <10% (as CV) and the estimated URL for subjects ≥40 (18.8μg/L) and <40 (17.9μg/L), we recommend the adoption of a single URL for the overall adult population.

CONCLUSIONS

We established reference intervals for galectin-3 in which the effects of biological determinants were irrelevant. Although in healthy subjects age may affect galectin-3 release, this does not appear to necessitate age-related reference limits.