0/1-Hour Triage Algorithm for Myocardial Infarction in Patients With Renal Dysfunction

Troponin Cut-Offs for Acute Myocardial Infarction in Patients with Impaired Renal Function—A Systematic Review and Meta-Analysis

Identifying acute myocardial infarction in patients with renal disease is notoriously difficult, due to atypical presentation and chronically elevated troponin. The aim of this study was to identify a specific troponin T/troponin I cut-off value for diagnosis of acute myocardial infarction in patients with renal impairment via meta-analysis. Two investigators screened 2590 publications from MEDLINE, Embase, PubMed, Web of Science, and the Cochrane library. Only studies that investigated alternative cut-offs according to renal impairment were included. Fifteen articles fulfilled the inclusion criteria. Six studies were combined for meta-analysis. The manufacturer’s upper reference level for troponin T is 14 ng/L. Based on the meta-analyses, cut-off values for troponin in patients with renal impairment with myocardial infarction was 42 ng/L for troponin I and 48 ng/L for troponin T. For patients on dialysis the troponin T cut-off is even higher at 239 ng/L. A troponin I cut-off value for dialysis patients could not be established due to lack of data. The 15 studies analyzed showed considerable diversity in study design, study population, and the definition of myocardial infarction. Further studies are needed to define a reliable troponin cut-off value for patients with kidney disease, especially in dialysis patients, and to allow necessary subanalysis.

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

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

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.

Distribution and specificity of high-sensitivity cardiac troponin T in older adults without acute cardiac conditions: cross-sectional results from the population-based AugUR study

OBJECTIVE

European guidelines recommended a uniform upper reference limit of high-sensitivity cardiac troponin T (hsTnT) to rule out non-ST segment elevation myocardial infarction. Our study aimed to provide a hsTnT reference distribution and to assess the specificity of the 14 ng/L cut-off value in the mobile population ≥70 years of age.

DESIGN

A cross-sectional analysis was performed in the German AugUR study (Altersbezogene Untersuchungen zur Gesundheit der University of Regensburg).

SETTING

Study population was the mobile population aged 70+ years living in the city and county of Regensburg, Germany.

PARTICIPANTS

A random sample was derived from the local population registries of residence. Of the 5644 individuals invited, 1133 participated (response ratio=20.1%). All participants came to the study centre and were mentally and physically mobile to conduct the protocol (face-to-face interview, blood draw and standardised transthoracic echocardiography). None of the participants was in an acute state of myocardial infarction.

RESULTS

Among the 1129 individuals with hsTnT measurements (overall median=10.0 ng/L(25th, 75th percentile)=(7.0, 15.0 ng/L)), hsTnT was higher among the older individuals and higher among men (men 70-74 years median=9.6 ng/L (7.2, 13.1 ng/L); men 90-95 years median=21.2 ng/L (14.6, 26.0 ng/L); women 70-74 years median=6.3 ng/L (4.7, 8.7 ng/L); and women 90-95 years median=18.0 ng/L (11.0, 21.0 ng/L)). In participants with impaired kidney function (eGFR_crea <60 mL/min/1.73 m²), hsTnT was elevated (median=13.6 ng/L (9.4, 20.6 ng/L)).Specificity of recommended upper reference limit, 14 ng/L, is 68%. Most false positives were among men aged >79 years (specificity=34%). In a healthy subgroup (n=96, none of the following: overt heart disease, impaired renal function, blood pressure >160/100 mm Hg, left ventricular hypertrophy and diastolic/systolic dysfunction), specificity was 90%.

CONCLUSION

In the elderly population without acute myocardial infarction, hsTnT further increases with age showing different levels for men and women. The specificity of the 14 ng/L cut-off is considerably lower than 99%, even in healthy subjects.

High-Sensitivity Cardiac Troponin T in Patients with Severe Chronic Kidney Disease and Suspected Acute Coronary Syndrome

(1) Background: Patients with severe chronic kidney disease (CKD G4-G5) often have chronically elevated high-sensitivity cardiac troponin T (hs-cTnT) values above the 99th percentile of the upper reference limit. In these patients, optimal cutoff levels for diagnosing non-ST-elevation acute coronary syndrome (NSTE-ACS) requiring revascularization remain undefined. (2) Methods: Of 11,912 patients undergoing coronary angiography from 2012 to 2017 for suspected NSTE-ACS, 325 (3%) had severe CKD. Of these, 290 with available serial hs-cTnT measurements were included, and 300 matched patients with normal renal function were selected as a control cohort. (3) Results: In the CKD cohort, 222 patients (76%) had NSTE-ACS with indication for coronary revascularization. Diagnostic performance was high at presentation and similar to that of the control population (AUC, 95% CI: 0.81, 0.75-0.87 versus 0.85, 0.80-0.89, p = 0.68), and the ROC-derived cutoff value was 4 times higher compared to the conventional 99th percentile. Combining the ROC-derived cutoff levels for hs-cTnT at presentation and absolute 3 h changes, sensitivity increased to 98%, and PPV and NPV improved up to 93% and 86%, respectively. (4) Conclusions: In patients with severe CKD and suspected ACS, the diagnostic accuracy of hs-cTnT for the diagnosis of NSTE-ACS requiring revascularization is improved by using higher assay-specific cutoff levels combined with early absolute changes.

Cardiac troponin and defining myocardial infarction

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

External validation of a high-sensitive troponin I algorithm for rapid evaluation of acute myocardial infarction in a Danish cohort

AIMS

An accelerated diagnostic algorithm for ruling-in or ruling-out myocardial infarction (MI) after 1 hour (1 h) has recently been derived and internally validated for the Siemens ADVIA Centaur TNIH assay. We aimed to validate the diagnostic performance of the TNIH 0 h/1 h algorithm ad modum Boeddinghaus in a Danish cohort.

METHODS AND RESULTS

Patients with chest pain suggestive of MI were prospectively enrolled. High-sensitive troponin I (TNIH) was measured at admission (0 h) and after 30 minutes (30 m), 1 h, and 3 hours (3 h). We externally validated the TNIH 0 h/1 h algorithm ad modum Boeddinghaus in Danish patients. Moreover, we applied the algorithm using the second TNIH measurement at 30 m instead of 1 h. We enrolled 1003 patients: median (Q1-Q3) age 64 (52-74) years, 42% female, and 23% with previous MI. Myocardial infarction was the final diagnosis in 9% of patients. Median (Q1-Q3) times from admission to 30 m and 1 h blood draw were 35 min (30-37 min) and 67 min (62-75 min), respectively. Using the 0 h and 1 h results, 468 (47%) patients were assigned to rule-out, 104 (10%) to rule-in, and 431 (43%) to the observational zone. This resulted in a negative predictive value of 100% (95% confidence interval: 99.2-100%), sensitivity of 100% (95.9-100%), positive predictive value of 79.8 (70.8-87.0%), and specificity of 97.7% (96.5-98.6%). The diagnostic performance after 30 m was similar.

CONCLUSIONS

The TNIH 0 h/1 h algorithm ad modum Boeddinghaus performed excellently for rule-out of MI in a Danish cohort. The Boeddinghaus algorithm also performed excellently after only 30 m.

TRIAL REGISTRATION NUMBER

NCT03634384.

TRIAL REGISTRY NAME AND URL

Rapid Use of High-Sensitive Cardiac Troponin I for Ruling-in and Ruling-out Acute Myocardial Infarction (RACING-MI), https://clinicaltrials.gov/ct2/show/NCT03634384.

Cardiac Troponin Thresholds and Kinetics to Differentiate Myocardial Injury and Myocardial Infarction

BACKGROUND

Although the 99th percentile is the recommended diagnostic threshold for myocardial infarction, some guidelines also advocate the use of higher troponin thresholds to rule in myocardial infarction at presentation. It is unclear whether the magnitude or change in troponin concentration can differentiate causes of myocardial injury and infarction in practice.

METHODS

In a secondary analysis of a multicenter randomized controlled trial, we identified 46 092 consecutive patients presenting with suspected acute coronary syndrome without ST-segment-elevation myocardial infarction. High-sensitivity cardiac troponin I concentrations at presentation and on serial testing were compared between patients with myocardial injury and infarction. The positive predictive value and specificity were determined at the sex-specific 99th percentile upper reference limit and rule-in thresholds of 64 ng/L and 5-fold of the upper reference limit for a diagnosis of type 1 myocardial infarction.

RESULTS

Troponin was above the 99th percentile in 8188 patients (18%). The diagnosis was type 1 or type 2 myocardial infarction in 50% and 14% and acute or chronic myocardial injury in 20% and 16%, respectively. Troponin concentrations were similar at presentation in type 1 (median [25th-75th percentile] 91 [30-493] ng/L) and type 2 (50 [22-147] ng/L) myocardial infarction and in acute (50 [26-134] ng/L) and chronic (51 [31-130] ng/L) myocardial injury. The 99th percentile and rule-in thresholds of 64 ng/L and 5-fold upper reference limit gave a positive predictive value of 57% (95% CI, 56%-58%), 59% (58%-61%), and 62% (60%-64%) and a specificity of 96% (96%-96%), 96% (96%-96%), and 98% (97%-98%), respectively. The absolute, relative, and rate of change in troponin concentration were highest in patients with type 1 myocardial infarction (P<0.001 for all). Discrimination improved when troponin concentration and change in troponin were combined compared with troponin concentration at presentation alone (area under the curve, 0.661 [0.642-0.680] versus 0.613 [0.594-0.633]).

CONCLUSIONS

Although we observed important differences in the kinetics, cardiac troponin concentrations at presentation are insufficient to distinguish type 1 myocardial infarction from other causes of myocardial injury or infarction in practice and should not guide management decisions in isolation. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01852123.

The association of anaemia and high-sensitivity cardiac troponin and its effect on diagnosing myocardial infarction

AIMS

Anaemia is common in patients with acute myocardial infarction (MI). We investigated the association of high-sensitivity cardiac troponin (hs-cTn) and haemoglobin (Hb) and the influence of anaemia on the performance of diagnostic protocols for suspected MI.

METHODS AND RESULTS

Patients with suspected MI were consecutively enrolled at a tertiary centre. Final diagnoses were independently adjudicated by two cardiologists. Performance measures of hs-cTn-based algorithms were compared for anaemic and non-anaemic patients (Hb <12 g/dL in women and <13 g/dL in men). The influence of anaemia on survival (median follow-up 1.7 years) was investigated using multivariable cox-regression analysis and the association of Hb and hs-cTn by multivariable linear regression analysis. Overall, 2223 patients were included, of whom 415 (18.7%) had anaemia. In anaemic patients, the incidence of MI was similar; however, chronic myocardial injury was significantly more prevalent (20.1% vs. 48.2%). The negative predictive value to rule-out MI was similar for both algorithms and all assays in patients with anaemia, although the positive predictive value to rule-in MI was partly reduced for the 0/3-h algorithm. Fewer anaemic patients were triaged after 1 h. Anaemia was an independent predictor of death. Adjusted for patient characteristics, Hb was significantly associated with hs-cTn. By providing a point-based tool, the Hb-associated hs-cTn concentration and thus chronic myocardial injury may be predicted.

CONCLUSION 

Anaemia partly affects the rule-in, but not the rule-out of MI in hs-cTn-based diagnostic protocols. Hs-cTn concentrations and thus chronic myocardial injury may be predicted by clinical variables and Hb.

TRIAL REGISTRATION

clinicaltrials.gov (NCT02355457 and NCT03227159).

Clinical implications of isolated troponinemia following immune checkpoint inhibitor therapy

Cardiovascular adverse events induced by immune checkpoint inhibitors (ICIs) have gained significant interest over the past decade due to their impact on short- and long-term outcomes. They were initially thought to be rare, but the increasing use of ICIs in the treatment of both advanced and early stages of various malignancies has resulted in a substantial increase in their incidence. Different guidelines have proposed screening measures for ICI-induced myocarditis by incorporating troponin measurements at baseline and during the first few weeks of treatment. However, no specific guidelines have been developed yet regarding the interpretation of an asymptomatic rise in troponins. This state-of-the art review aims to provide an overview of the clinical relevance of elevated troponins during checkpoint inhibition and recommendations on how to manage elevated troponin levels during ICI therapy.

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.

Early Rule-Out Strategies in the Emergency Department Utilizing High-Sensitivity Cardiac Troponin Assays

BACKGROUND

Over the past decade, intense collaboration between academic investigators and the diagnostic industry have allowed the integration of high-sensitivity cardiac troponin (hs-cTn) assays into clinical practice worldwide. The hs-cTn assays, with their increased diagnostic accuracy for acute myocardial infarction (AMI), have facilitated the maturation of early rule-out strategies. The first iteration was complex and required the combination of a biomarker panel, the electrocardiogram, and a clinical risk score and allowed the safe rule-out of AMI in only 10% of patients with acute chest pain. In contrast, the latest iterations, including the European Society of Cardiology (ESC) 0/1-h algorithm, are simple. They are based on hs-cTn concentrations only and allow the safe rule-out or rule-in of AMI in up to 75% of patients.

CONTENT

The purposes of this minireview are (a) to describe the best validated hs-cTn-based strategies for early rule-out of AMI, (b) to discuss the advantages and limitations of the different strategies, (c) to identify patient subgroups requiring particular attention, (d) to recognize challenges for widespread clinical implementation, and (e) to provide guidance on strategies for their safe and effective clinical implementation.

SUMMARY

Physicians and institutions may choose among several well-validated rule-out algorithms. The ESC 0/1-h algorithm for hs-cTnT or hs-cTnI seems to be the most attractive option today. It best balances safety and efficacy, and it has been derived and validated for all currently available hs-cTnT/I assays, facilitating widespread clinical implementation.

The cardiovascular-dialysis nexus: the transition to dialysis is a treacherous time for the heart

Chronic kidney disease (CKD) patients require dialysis to manage the progressive complications of uraemia. Yet, many physicians and patients do not recognize that dialysis initiation, although often necessary, subjects patients to substantial risk for cardiovascular (CV) death. While most recognize CV mortality risk approximately doubles with CKD the new data presented here show that this risk spikes to >20 times higher than the US population average at the initiation of chronic renal replacement therapy, and this elevated CV risk continues through the first 4 months of dialysis. Moreover, this peak reflects how dialysis itself changes the pathophysiology of CV disease and transforms its presentation, progression, and prognosis. This article reviews how dialysis initiation modifies the interpretation of circulating biomarkers, alters the accuracy of CV imaging, and worsens prognosis. We advocate a multidisciplinary approach and outline the issues practitioners should consider to optimize CV care for this unique and vulnerable population during a perilous passage.

Cardiovascular biomarkers in patients with COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has increased awareness that severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2) may have profound effects on the cardiovascular system. COVID-19 often affects patients with pre-existing cardiac disease, and may trigger acute respiratory distress syndrome (ARDS), venous thromboembolism (VTE), acute myocardial infarction (AMI), and acute heart failure (AHF). However, as COVID-19 is primarily a respiratory infectious disease, there remain substantial uncertainty and controversy whether and how cardiovascular biomarkers should be used in patients with suspected COVID-19. To help clinicians understand the possible value as well as the most appropriate interpretation of cardiovascular biomarkers in COVID-19, it is important to highlight that recent findings regarding the prognostic role of cardiovascular biomarkers in patients hospitalized with COVID-19 are similar to those obtained in studies for pneumonia and ARDS in general. Cardiovascular biomarkers reflecting pathophysiological processes involved in COVID-19/pneumonia and its complications have a role evaluating disease severity, cardiac involvement, and risk of death in COVID-19 as well as in pneumonias caused by other pathogens. First, cardiomyocyte injury, as quantified by cardiac troponin concentrations, and haemodynamic cardiac stress, as quantified by natriuretic peptide concentrations, may occur in COVID-19 as in other pneumonias. The level of those biomarkers correlates with disease severity and mortality. Interpretation of cardiac troponin and natriuretic peptide concentrations as quantitative variables may aid in risk stratification in COVID-19/pneumonia and also will ensure that these biomarkers maintain high diagnostic accuracy for AMI and AHF. Second, activated coagulation as quantified by D-dimers seems more prominent in COVID-19 as in other pneumonias. Due to the central role of endothelitis and VTE in COVID-19, serial measurements of D-dimers may help physicians in the selection of patients for VTE imaging and the intensification of the level of anticoagulation from prophylactic to slightly higher or even therapeutic doses.

High-sensitivity troponin assays for early rule-out of acute myocardial infarction in people with acute chest pain: a systematic review and economic evaluation

BACKGROUND

Early diagnosis of acute myocardial infarction is important, but only 20% of emergency admissions for chest pain will actually have an acute myocardial infarction. High-sensitivity cardiac troponin assays may allow rapid rule out of myocardial infarction and avoid unnecessary hospital admissions.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of high-sensitivity cardiac troponin assays for the management of adults presenting with acute chest pain, in particular for the early rule-out of acute myocardial infarction.

METHODS

Sixteen databases were searched up to September 2019. Review methods followed published guidelines. Studies were assessed for quality using appropriate risk-of-bias tools. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies; otherwise, random-effects logistic regression was used. The health economic analysis considered the long-term costs and quality-adjusted life-years associated with different troponin testing methods. The de novo model consisted of a decision tree and a state-transition cohort model. A lifetime time horizon (of 60 years) was used.

RESULTS

Thirty-seven studies (123 publications) were included in the review. The high-sensitivity cardiac troponin test strategies evaluated are defined by the combination of four factors (i.e. assay, number and timing of tests, and threshold concentration), resulting in a large number of possible combinations. Clinical opinion indicated a minimum clinically acceptable sensitivity of 97%. When considering single test strategies, only those using a threshold at or near to the limit of detection for the assay, in a sample taken at presentation, met the minimum clinically acceptable sensitivity criterion. The majority of the multiple test strategies that met this criterion comprised an initial rule-out step, based on high-sensitivity cardiac troponin levels in a sample taken on presentation and a minimum symptom duration, and a second stage for patients not meeting the initial rule-out criteria, based on presentation levels of high-sensitivity cardiac troponin and absolute change after 1, 2 or 3 hours. Two large cluster randomised controlled trials found that implementation of an early rule-out pathway for myocardial infarction reduced length of stay and rate of hospital admission without increasing cardiac events. In the base-case analysis, standard troponin testing was both the most effective and the most costly. Other testing strategies with a sensitivity of 100% (subject to uncertainty) were almost equally effective, resulting in the same life-year and quality-adjusted life-year gain at up to four decimal places. Comparisons based on the next best alternative showed that for willingness-to-pay values below £8455 per quality-adjusted life-year, the Access High Sensitivity Troponin I (Beckman Coulter, Brea, CA, USA) [(symptoms > 3 hours AND < 4 ng/l at 0 hours) OR (< 5 ng/l AND Δ < 5 ng/l at 0 to 2 hours)] would be cost-effective. For thresholds between £8455 and £20,190 per quality-adjusted life-year, the Elecsys® Troponin-T high sensitive (Roche, Basel, Switzerland) (< 12 ng/l at 0 hours AND Δ < 3 ng/l at 0 to 1 hours) would be cost-effective. For a threshold > £20,190 per quality-adjusted life-year, the Dimension Vista® High-Sensitivity Troponin I (Siemens Healthcare, Erlangen, Germany) (< 5 ng/l at 0 hours AND Δ < 2 ng/l at 0 to 1 hours) would be cost-effective.

CONCLUSIONS

High-sensitivity cardiac troponin testing may be cost-effective compared with standard troponin testing.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154716.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 33. See the NIHR Journals Library website for further project information.

Clinical History and Detectable Troponin Concentrations below the 99th Percentile for Risk Stratification of Patients with Chest Pain and First Normal Troponin

Decision-making is challenging in patients with chest pain and normal high-sensitivity cardiac troponin T (hs-cTnT; <99th percentile; <14 ng/L) at hospital arrival. Most of these patients might be discharged early. We investigated clinical data and hs-cTnT concentrations for risk stratification. This is a retrospective study including 4476 consecutive patients presenting to the emergency department with chest pain and first normal hs-cTnT. The primary endpoint was one-year death or acute myocardial infarction, and the secondary endpoint added urgent revascularization. The number of primary and secondary endpoints was 173 (3.9%) and 252 (5.6%). Mean hs-cTnT concentrations were 6.9 ± 2.5 ng/L. Undetectable (<5 ng/L) hs-cTnT (n = 1847, 41%) had optimal negative predictive value (99.1%) but suboptimal sensitivity (90.2%) and discrimination accuracy (AUC = 0.664) for the primary endpoint. Multivariable analysis was used to identify the predictive clinical variables. The clinical model showed good discrimination accuracy (AUC = 0.810). The addition of undetectable hs-cTnT (≥ or <5 ng/L; HR, hazard ratio = 3.80; 95% CI, confidence interval 2.27–6.35; p = 0.00001) outperformed the clinical model alone (AUC = 0.836, p = 0.002 compared to the clinical model). Measurable hs-cTnT concentrations (between detection limit and 99th percentile; per 0.1 ng/L, HR = 1.13; CI 1.06–1.20; p = 0.0001) provided further predictive information (AUC = 0.844; p = 0.05 compared to the clinical plus undetectable hs-cTnT model). The results were reproducible for the secondary endpoint and 30-day events. Clinical assessment, undetectable hs-cTnT and measurable hs-cTnT concentrations must be considered for decision-making after a single negative hs-cTnT result in patients presenting to the emergency department with acute chest pain.

Advancements in biomarkers for cardiovascular disease: diagnosis, prognosis, and therapy

Biomarkers are essential tools in the practice of cardiology. They assist with diagnosis, prognosis, and guiding therapy in many different cardiovascular diseases. Numerous biomarkers have become strongly associated with different cardiovascular conditions, such as troponin with acute coronary syndrome and natriuretic peptides with heart failure. Even though these biomarkers have been in practice for almost two decades, their uses continue to expand beyond their original roles. Additionally, many new biomarkers have been discovered with increasing utility in cardiovascular disease, including soluble suppression of tumorigenicity 2, galectin 3, and biomarkers of fibrosis, metabolism, and inflammation. How these old and new biomarkers are being expanded into clinical practice is constantly in evolution. This review will highlight some of the recent major advancements in the rapidly evolving field of biomarkers.

Evaluation of the 0 h/1 h high-sensitivity cardiac troponin T algorithm in diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) in Han population

OBJECTIVES

A rapid 0 h/1 h algorithm using high-sensitivity cardiac troponin T (hs-cTnT) for rule-out and rule-in of non-ST-segment elevation myocardial infarction (NSTEMI) is recommended by the European Society of Cardiology. We aim to prospectively evaluate the diagnostic performance of the algorithm in Chinese Han patients with suspected NSTEMI.

METHODS

In this prospective diagnostic cohort study, 577 patients presenting to the emergency department with suspected NSTEMI and recent (<12 h) onset of symptoms were enrolled. The levels of serum hs-cTnT were measured on admission, 1 h later and 4-14 h later. All patients underwent the initial clinical assessment and were triaged into three groups (rule-out, rule-in and observe) according to the 0 h/1 h algorithm. The major cardiovascular events (MACE) were evaluated at the 7-day and 30-day follow-ups.

RESULTS

Among 577 enrolled patients, NSTEMI was the final diagnosis for 106 (18.4%) patients. Based on the hs-cTnT 0 h/1 h algorithm, 148 patients (25.6%) were classified as rule-out, 278 patients (48.2%) as rule-in and 151 patients (26.2%) were assigned to the observe group. The rule-out approach resulted in a sensitivity of 100% and negative predictive value of 100%. The rule-in approach resulted in a specificity of 62.9% [95% CI (58.5-67.2%)] and positive predictive value of 37.1% [95%CI (31.3-42.8%)]. No MACE was observed in the rule-out group within 30-day follow-up.

CONCLUSIONS

The hs-cTnT 0 h/1 h algorithm is a safe tool for early rule-out of NSTEMI, while probably not an effective strategy for accurate rule-in of NSTEMI in Chinese Han population.

The role of cardiac testing with the 0/1-hour high-sensitivity cardiac troponin algorithm evaluating for acute myocardial infarction

BACKGROUND

The role of cardiac testing in the 3 zones (rule-out, observation, and rule-in) of the 0/1-hour algorithm to evaluate for acute myocardial infarction (AMI) has not been well studied. This study evaluated the 0/1-hour algorithm with a high-sensitivity cardiac troponin (hs-cTnI) assay and investigated cardiac testing in the 3 zones.

METHODS

Patients (n = 552) at a single urban center were enrolled if they were evaluated for AMI. Blood samples were obtained at presentation, 1 hour, and 3 hours for hs-cTnI. Follow-up at 30 to 45 days for death/AMI was done. The results of echocardiograms, stress testing, and coronary angiography were recorded.

RESULTS

In total, 45 (8.2%) had AMI (27 Type 1 and 18 Type 2) during the index hospitalization while at follow-up death/AMI occurred in 11 (2.0%) of patients. The rule-out algorithm had a negative predictive value for AMI of 99.6% while the rule-in zone had a positive predictive value of 56.6%. The MACE rate at follow-up was 0.4% for those in the rule-out group. There were 6/95 (6.3%) abnormal stress tests in the rule-out zone and 4 of these were false positives.

CONCLUSIONS

The 0/1-hour algorithm had high diagnostic sensitivity and negative predictive value for AMI, and adverse events were very low in patients in the rule-out zone. Noninvasive testing in rule-out zone patients had low diagnostic yield.

A Test in Context: Interpretation of High-Sensitivity Cardiac Troponin Assays in Different Clinical Settings

High-sensitivity cardiac troponin (hs-cTn) assays have the ability to detect minute troponin concentrations and resolve minor changes in biomarker concentrations. Clinically, this allows for the ability to rapidly identify or exclude acute myocardial injury in the setting of acute chest discomfort-thus providing more rapid evaluation for acute myocardial infarction-but the improvements in troponin assays also create avenues for other applications where troponin release from the cardiomyocyte might confer prognostic information. These situations include cardiovascular risk assessment across a wide range of clinical circumstances, including apparently-well individuals, those at risk for heart disease, and those with prevalent cardiovascular disorders. The optimal hs-cTn threshold for each circumstance varies by the assay used and by the population assessed. This review will provide context for how hs-cTn assays might be interpreted depending on the application sought, reviewing results from studies leveraging hs-cTn for applications beyond "acute myocardial infarction diagnostic evaluation."

High-sensitive cardiac troponin for the diagnosis of acute myocardial infarction in different chronic kidney disease stages

BACKGROUND

Chronic kidney disease (CKD) are associated with acute myocardial infarction (AMI). High-sensitive cardiac troponin (hs-cTn) has been evidenced to enhance the early diagnostic accuracy of AMI, but hs-cTn levels are often chronically elevated in CKD patients, which reduces their diagnostic utility. The aim of this study was to derive optimal cutoff-values of hs-cTn levels in patients with CKD and suspected AMI.

METHODS

In this retrospective paper, a total of 3295 patients with chest pain (2758 in AMI group and 537 in Non-AMI group) were recruited, of whom 23.1% were had an estimated glomerular filtration rate (eGFR) of < 60 mL min-1 (1.73 m2)-1. Hs-cTnI values were measured at presentation.

RESULTS

AMI was diagnosed in 83.7% of all patients. The optimal value of hs-TnI in diagnosing AMI was 1.15 ng mL-1, which were higher in males than females comparing different cutoff-values of subgroups divided by age, gender and renal function, and which increased monotonically with decreasing of eGFR because in patients with CKD without AMI, the correlation between hs-cTnI and renal function is low but significant (r2 = 0.067, P < 0.001).

CONCLUSIONS

Different optimal cutoff-values of hs-cTnI in the diagnosis of AMI in patients with CKD were helpful to the clinical diagnosis of AMI in various populations and were higher in males than females, but which was needed to be validated by multicenter randomized controlled clinical studies in the future.

Diagnostic Performance of High-Sensitivity Cardiac Troponin T Strategies and Clinical Variables in a Multisite US Cohort

BACKGROUND

European data support the use of low high-sensitivity troponin (hs-cTn) measurements or a 0/1-hour (0/1-h) algorithm for myocardial infarction to exclude major adverse cardiac events (MACEs) among patients in the emergency department with possible acute coronary syndrome. However, modest US data exist to validate these strategies. This study evaluated the diagnostic performance of an initial hs-cTnT measure below the limit of quantification (LOQ: 6 ng/L), a 0/1-h algorithm, and their combination with history, ECG, age, risk factors, and initial troponin (HEART) scores for excluding MACE in a multisite US cohort.

METHODS

A prospective cohort study was conducted at 8 US sites, enrolling adult patients in the emergency department with symptoms suggestive of acute coronary syndrome and without ST-elevation on ECG. Baseline and 1-hour blood samples were collected, and hs-cTnT (Roche; Basel, Switzerland) was measured. Treating providers blinded to hs-cTnT results prospectively calculated HEART scores. MACE (cardiac death, myocardial infarction, and coronary revascularization) at 30 days was adjudicated. The proportion of patients with initial hs-cTnT measures below the LOQ and risk according to a 0/1-h algorithm was determined. The negative predictive value (NPV) was calculated for both strategies when used alone or with a HEART score.

RESULTS

Among 1462 participants with initial hs-cTnT measures, 46.4% (678 of 1462) were women and 37.1% (542 of 1462) were Black with an age of 57.6±12.9 (mean±SD) years. MACEs at 30 days occurred in 14.4% (210 of 1462) of participants. Initial hs-cTnT measures below the LOQ occurred in 32.8% (479 of 1462), yielding an NPV of 98.3% (95% CI, 96.7-99.3) for 30-day MACEs. A low-risk HEART score with an initial hs-cTnT below the LOQ occurred in 20.1% (294 of 1462), yielding an NPV of 99.0% (95% CI, 97.0-99.8) for 30-day MACEs. A 0/1-h algorithm was complete in 1430 patients, ruling out 57.8% (826 of 1430) with an NPV of 97.2% (95% CI, 95.9-98.2) for 30-day MACEs. Adding a low HEART score to the 0/1-h algorithm ruled out 30.8% (441 of 1430) with an NPV of 98.4% (95% CI, 96.8-99.4) for 30-day MACEs.

CONCLUSIONS

In a prospective multisite US cohort, an initial hs-cTnT below the LOQ combined with a low-risk HEART score has a 99% NPV for 30-day MACEs. The 0/1-h hs-cTnT algorithm did not achieve an NPV >99% for 30-day MACEs when used alone or with a HEART score. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02984436.

A Practical Approach for the Use of High-Sensitivity Cardiac Troponin Assays in the Evaluation of Patients With Chest Pain

Chest pain is a common clinical presentation, especially in the emergency department. Both rapid identification of patients with myocardial infarction as well as those with noncardiac chest pain is important in order to start therapy in the former and avoid unnecessary investigations and delay in discharge in the latter. Beside electrocardiogram, cardiac biomarkers are a key element in decision making. Conventional creatinine kinase and troponin assays are not sensitive enough and have to be repeated at least 6 to 12 hours after initial evaluation. New high-sensitivity cardiac troponin (hs-cTn) tests are currently available and if used appropriately can substantially improve management. Because of their high sensitivity and accuracy, these tests allow measurement of very low serum troponin levels, such as those present in healthy individuals and can detect small changes in troponin concentration within a short time frame. These tests are thus, very useful for the early diagnosis of myocardial infarction but can also be elevated in several other conditions that result in myocardial injury. A good understanding of the analytical characteristics of these assays is of uppermost importance for their appropriate use in clinical practice.

Biomarker-Guided Risk Assessment for Acute Kidney Injury: Time for Clinical Implementation?

Acute kidney injury (AKI) is a common and serious complication in hospitalized patients, which continues to pose a clinical challenge for treating physicians. The most recent Kidney Disease Improving Global Outcomes practice guidelines for AKI have restated the importance of earliest possible detection of AKI and adjusting treatment accordingly. Since the emergence of initial studies examining the use of neutrophil gelatinase-associated lipocalin (NGAL) and cycle arrest biomarkers, tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein (IGFBP7), for early diagnosis of AKI, a vast number of studies have investigated the accuracy and additional clinical benefits of these biomarkers. As proposed by the Acute Dialysis Quality Initiative, new AKI diagnostic criteria should equally utilize glomerular function and tubular injury markers for AKI diagnosis. In addition to refining our capabilities in kidney risk prediction with kidney injury biomarkers, structural disorder phenotypes referred to as "preclinical-" and "subclinical AKI" have been described and are increasingly recognized. Additionally, positive biomarker test findings were found to provide prognostic information regardless of an acute decline in renal function (positive serum creatinine criteria). We summarize and discuss the recent findings focusing on two of the most promising and clinically available kidney injury biomarkers, NGAL and cell cycle arrest markers, in the context of AKI phenotypes. Finally, we draw conclusions regarding the clinical implications for kidney risk prediction.

High-sensitivity troponins in dialysis patients: variation and prognostic value

Background

Dialysis patients have a high prevalence of cardiovascular mortality but also elevated cardiac troponins (cTns) even without signs of cardiac ischaemia. The study aims to assess variation and prognostic value of high-sensitivity cTnI and cTnT in prevalent dialysis patients.

Methods

In 198 prevalent haemodialysis (HD) and 78 peritoneal dialysis (PD) patients, 4-monthly serum troponin I and T measurements were obtained. Reference change values (RCVs) were used for variability assessment and competing-risk regression models for survival analyses; maximal follow-up was 50 months.

Results

HD and PD patients had similar troponin levels [median (interquartile range) troponin I: 25 ng/L (14–43) versus 21 ng/L (11–37), troponin T: 70 ng/L (44–129) versus 67 ng/L (43–123)]. Of troponin I and T levels, 42% versus 98% were above the decision level of myocardial infarction. RCVs were +68/−41% (troponin I) and +29/−23% (troponin T). Increased variability of troponins related to higher age, male sex, protein-energy wasting and congestive heart failure, but not ischaemic heart disease or dialysis form. Elevated troponin T, but not troponin I, predicted death after adjusting for confounders.

Conclusions

A large proportion of prevalent dialysis patients without current established or ongoing cardiac events have elevated levels of high-sensitivity cTns. Mortality risk was doubled in patients with persistently high troponin T levels. The large intraindividual variation of cTns suggests that serial measurements and reference change levels may be used to improve diagnostic utility. However, evidence-based recommendations require more data from large studies of dialysis patients with cardiac events.

Comparison of pre- and postoperative myocardial injuries on mortality after non-cardiac surgery: a retrospective analysis using an inverse probability weighting adjustment

Although both pre- and postoperative myocardial injuries are strongly associated with an increased postoperative mortality, no study has directly compared the effects of pre- and postoperative myocardial injuries on 30-day mortality after non-cardiac surgery. Therefore, we evaluated and compared the effects of pre- and postoperative myocardial injury on 30-day mortality after non-cardiac surgery. From January 2010 to December 2016, patients undergoing non-cardiac surgery were stratified into either the normal (n = 3182), preoperative myocardial injury (n = 694), or postoperative myocardial injury (n = 756) groups according to the peak cardiac troponin value. Myocardial injury was defined as a sole elevation of cardiac troponin value above the 99th percentile upper reference limit without ischemic symptom using the 4th universal definition of myocardial infarction. Patients in the preoperative myocardial injury group were further divided into the attenuated (n = 177) or persistent myocardial injury group (n = 517) according to the normalization of cardiac troponin level in postoperative period. As the primary outcome, postoperative 30-day mortalities were compared among the groups using the weighted Cox proportional-hazards regression models with the inverse probability weighting. Compared with the normal group, postoperative 30-day mortality was increased significantly both in the pre- and postoperative myocardial injury groups (1.4% vs. 10.7%; hazard ratio [HR] 3.12; 95% confidence interval [CI] 1.62-6.01; p = 0.001 and 1.4% vs. 7.4%; HR 4.49; 95% CI 2.34-8.60; p < 0.001, respectively), however, there was no difference between the pre- and postoperative myocardial injury groups (HR, 1.44; 95% CI 0.79-2.64; p = 0.45). In addition, the attenuated myocardial injury group showed a significantly lower postoperative 30-day mortality than the persistent myocardial injury group (5.6% vs. 12.4%; HR 2.23; 95% CI 1.17-4.44; p = 0.02). In patients undergoing non-cardiac surgery, preoperative myocardial injury also increased postoperative 30-day mortality to a similar degree of postoperative myocardial injury. Further studies on the importance of preoperative myocardial injury are needed.Clinical trial number and registry URL: KCT0004348 ( www.cris.nih.go.kr ).

Mildly Elevated Cardiac Troponin below the 99th-Percentile Upper Reference Limit after Noncardiac Surgery

BACKGROUND AND OBJECTIVES

In patients with perioperative cardiac troponin (cTn) I below the 99th-percentile upper range of limit (URL), mortality according to cTn I level has not been fully evaluated. This study evaluated the association between postoperative cTn I level above the lowest limit of detection but within the 99th-percentile URL and 30-day mortality after noncardiac surgery.

METHODS

Patients with cTn I values below the 99th-percentile URL during the perioperative period were divided into a no-elevation group with cTn I at the lowest limit of detection (6 ng/L) and a minor elevation group with cTn I elevation below the 99th percentile URL (6 ng/L < cTn I < 40 ng/L). The primary outcome was 30-day mortality.

RESULTS

Of the 5,312 study participants, 2,582 (48.6%) were included in the no-elevation group and 2,730 (51.4%) were included in the minor elevation group. After propensity score-matching, the minor elevation group showed significantly increased 30-day mortality (0.5% vs. 2.3%; hazard ratio, 4.30; 95% confidence interval, 2.23-8.29; p<0.001). The estimated cutoff value of cTn I to predict 30-day mortality was 6 ng/L with the area under the receiver operating characteristic curve 0.657.

CONCLUSIONS

A mild elevation of cTn I within the 99th-percentile URL after noncardiac surgery was significantly associated with increased 30-day mortality as compared with the lowest limit of detection.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0004244.

Volatile versus total intravenous anesthesia for 30-day mortality following non-cardiac surgery in patients with preoperative myocardial injury

We evaluated whether volatile anesthetics can improve the postoperative outcomes of non-cardiac surgery in patients with preoperative myocardial injury defined by the cardiac troponin elevation. From January 2010 to June 2018, 1254 adult patients with preoperative myocardial injury underwent non-cardiac surgery under general anesthesia and were enrolled in this study. Patients were stratified into following two groups according to anesthetic agents; 115 (9.2%) patients whose anesthesia was induced and maintained with continuous infusion of propofol and remifentanil (TIVA group) and 1139 (90.8%) patients whose anesthesia was maintainted with volatile anesthetics (VOLATILE group). The primary outcome was 30-day mortality. To diminish the remifentanil effect, a further analysis was conducted after excluding the patients who received only volatile anesthetics without remifentanil infusion. In a propensity-score matched analysis, 30-day mortality was higher in the TIVA group than the VOLATILE group (17.0% vs. 9.1%; hazard ratio [HR] 2.60; 95% confidence interval [CI], 1.14-5.93; p = 0.02). In addition, the TIVA group showed higher 30-day mortality than the VOLATILE group, even after eliminating the effect of remifentanil infusion (15.8% vs. 8.3%; HR 4.62; 95% CI, 1.82-11.74; p = 0.001). In our study, the use of volatile anesthetics showed the significant survival improvement after non-cardiac surgery in patients with preoperative myocardial injury, which appears to be irrelevant to the remifentanil use. Further studies are needed to confirm this beneficial effect of volatile anesthetics. Clinical trial number and registry URL: KCT0004349 (www.cris.nih.go.kr).

Role of a cardio-renal multi-disciplinary team meeting in managing cardiovascular risk in patients on kidney transplant waitlists

BACKGROUND

Waitlisted kidney transplant patients suffer from excess cardiovascular events. The benefits of regular cardiac investigations, potentially harmful and expensive, are unknown. We investigate the effectiveness of a cardio-renal MDT in managing high cardiovascular risk waitlisted transplant patients to prevent events and enable transplantation.

METHODS

Clinical outcomes in waitlisted transplant candidates managed by our cardio-renal MDT protocol were compared against our standard protocol. Data compared include the transplantation, event, and death rates, cost of cardiac investigations and procedures, and graft, patient survival, and re-hospitalization rates in transplanted patients.

RESULTS

207 patients were studied (81 standard, 126 cardio-renal MDT). Over 2.7 years, the cardio-renal MDT protocol transplanted more patients than the standard group (35% vs 21%; P = .02). The managing cost per patient per year was higher in the standard group (£692 vs £610). This was driven by more echocardiograms and more tests per patient in the standard group (P < .01). There was no difference in adverse events or death. There was no difference in re-hospitalization, graft or patient survival rate in transplanted patients.

CONCLUSIONS

Our cardio-renal MDT was effective in managing high-risk kidney transplant candidates with greater rates of transplantation and low rates of events at a lower cost.

Impact of comorbidities on peak troponin levels and mortality in acute myocardial infarction

OBJECTIVES

To characterise peak cardiac troponin levels, in patients presenting with acute myocardial infarction (AMI), according to their comorbid condition and determine the influence of peak cardiac troponin (cTn) levels on mortality.

METHODS

We included patients with the first admission for AMI in the UK. We used linear regression to estimate the association between eight common comorbidities (diabetes mellitus, previous angina, peripheral arterial disease, previous myocardial infarction (MI), chronic kidney disease (CKD), cerebrovascular disease, chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD)) and peak cTn. Peak cTn levels were adjusted for age, sex, smoking status and comorbidities. Logistic regression and restricted cubic spline models were employed to investigate the association between peak cTn and 180-day mortality for each comorbidity.

RESULTS

330 367 patients with ST elevation myocardial infarction and non-ST elevation myocardial infarction were identified. Adjusted peak cTn levels were significantly higher in patients with CKD (adjusted % difference in peak cTnT for CKD=42%, 95% CI 13.1 to 78.4) and significantly lower for patients with COPD, previous angina, previous MI and CHF when compared with patients without the respective comorbidities (reference group) (cTnI; COPD=-21.7%, 95% CI -29.1 to -13.4; previous angina=-24.2%, 95% CI -29.6 to -8.3; previous MI=-13.5%, 95% CI -20.6 to -5.9; CHF=-28%, 95% CI -37.2 to -17.6). Risk of 180-day mortality in most of the comorbidities did not change substantially after adjusting for peak cTn. In general, cTnI had a stronger association with mortality than cTnT.

CONCLUSIONS

In this nationwide analysis of patients presenting with AMI, comorbidities substantially influenced systemic concentrations of peak cTn. Comorbid illness is a significant predictor of mortality regardless of peak cTn levels and should be taken into consideration while interpreting cTn both as a diagnostic and prognostic biomarker.

Performance of Novel High-Sensitivity Cardiac Troponin I Assays for 0/1-Hour and 0/2- to 3-Hour Evaluations for Acute Myocardial Infarction: Results From the HIGH-US Study

STUDY OBJECTIVE

We determine the accuracy of high-sensitivity cardiac troponin I (hs-cTnI), European-derived, rapid, acute myocardial infarction, rule-out/rule-in algorithms applied to a US emergency department (ED) population.

METHODS

Adults presenting to the ED with suspected acute myocardial infarction were included. Plasma samples collected at baseline and between 40 and 90 minutes and 2 and 3 hours later were analyzed in core laboratories using the Siemens Healthineers hs-cTnI assays. Acute myocardial infarction diagnosis was independently adjudicated. The sensitivity, specificity, and negative and positive predictive values for rapid acute myocardial infarction rule-out/rule-in using European algorithms and 30-day outcomes are reported.

RESULTS

From 29 US medical centers, 2,113 subjects had complete data for the 0/1-hour algorithm analyses. With the Siemens Atellica Immunoassay hs-cTnI values, 1,065 patients (50.4%) were ruled out, with a negative predictive value of 99.7% and sensitivity of 98.7% (95% confidence interval 99.2% to 99.9% and 96.3% to 99.6%, respectively), whereas 265 patients (12.6%) were ruled in, having a positive predictive value of 69.4% and specificity of 95.7% (95% confidence interval 63.6% to 74.7% and 94.7% to 96.5%, respectively). The remaining 783 patients (37.1%) were classified as having continued evaluations, with an acute myocardial infarction incidence of 5.6% (95% confidence interval 4.2% to 7.5%). The overall 30-day risk of death or postdischarge acute myocardial infarction was very low in the ruled-out patients but was incrementally increased in the other groups (rule-out 0.2%; continued evaluations 2.1%; rule-in 4.8%). Equivalent results were observed in the 0/2- to 3-hour analyses and when both algorithms were applied to the hs-cTnI ADVIA Centaur measurements.

CONCLUSION

The European rapid rule-out/rule-in acute myocardial infarction algorithm hs-cTnI cut points can be harmonized with a demographically and risk-factor diverse US ED population.

Performance of the ESC 0/1-h and 0/3-h Algorithm for the Rapid Identification of Myocardial Infarction Without ST-Elevation in Patients With Diabetes

OBJECTIVE

Patients with diabetes mellitus (DM) have elevated levels of high-sensitivity cardiac troponin (hs-cTn). We investigated the diagnostic performance of the European Society of Cardiology (ESC) algorithms to rule out or rule in acute myocardial infarction (AMI) without ST-elevation in patients with DM.

RESEARCH DESIGN AND METHODS

We prospectively enrolled 3,681 patients with suspected AMI and stratified those by the presence of DM. The ESC 0/1-h and 0/3-h algorithms were used to calculate negative and positive predictive values (NPV, PPV). In addition, alternative cutoffs were calculated and externally validated in 2,895 patients.

RESULTS

In total, 563 patients (15.3%) had DM, and 137 (24.3%) of these had AMI. When the ESC 0/1-h algorithm was used, the NPV was comparable in patients with and without DM (absolute difference [AD] -1.50 [95% CI -5.95, 2.96]). In contrast, the ESC 0/3-h algorithm resulted in a significantly lower NPV in patients with DM (AD -2.27 [95% CI -4.47, -0.07]). The diagnostic performance for rule-in of AMI (PPV) was comparable in both groups: 0/1-h (AD 6.59 [95% CI -19.53, 6.35]) and 0/3-h (AD 1.03 [95% CI -7.63, 9.7]). Alternative cutoffs increased the PPV in both algorithms significantly, while improvements in NPV were only subtle.

CONCLUSIONS

Application of the ESC 0/1-h algorithm revealed comparable safety to rule out AMI comparing patients with and without DM, while this was not observed with the ESC 0/3-h algorithm. Although alternative cutoffs might be helpful, patients with DM remain a high-risk population in whom identification of AMI is challenging and who require careful clinical evaluation.

The Asia-Pacific Society of Cardiology (APSC) Expert Committee Consensus Recommendations for Assessment of Suspected Acute Coronary Syndrome Using High-Sensitivity Cardiac Troponin T in the Emergency Department

The Asia-Pacific Society of Cardiology (APSC) high-sensitivity troponin T (hs-TnT) consensus recommendations and rapid algorithm were developed to provide guidance for healthcare professionals in the Asia-Pacific region on assessing patients with suspected acute coronary syndrome (ACS) using a hs-TnT assay. Experts from Asia-Pacific convened in 2 meetings to develop evidence-based consensus recommendations and an algorithm for appropriate use of the hs-TnT assay. The Expert Committee defined a cardiac troponin assay as a high-sensitivity assay if the total imprecision is ≤10% at the 99th percentile of the upper reference limit and measurable concentrations below the 99th percentile are attainable with an assay at a concentration value above the assay's limit of detection for at least 50% of healthy individuals. Recommendations for single-measurement rule-out/rule-in cutoff values, as well as for serial measurements, were also developed. The Expert Committee also adopted similar hs-TnT cutoff values for men and women, recommended serial hs-TnT measurements for special populations, and provided guidance on the use of point-of-care troponin T devices in individuals suspected of ACS. These recommendations should be used in conjunction with all available clinical evidence when making the diagnosis of ACS.

Troponins, Acute Coronary Syndrome and Renal Disease: From Acute Kidney Injury Through End-stage Kidney Disease

The diagnosis of acute coronary syndromes (ACS) is heavily dependent on cardiac biomarker assays, particularly cardiac troponins. ACS, particularly non-ST segment elevation MI, are more common in patients with acute kidney injury, chronic kidney disease (CKD) and end-stage kidney disease (ESKD), are associated with worse outcomes than in patients without kidney disease and are often difficult to diagnose and treat. Hence, early accurate diagnosis of ACS in kidney disease patients is important using easily available tools, such as cardiac troponins. However, the diagnostic reliability of cardiac troponins has been suboptimal in patients with kidney disease due to possible decreased clearance of troponin with acute and chronic kidney impairment and low levels of troponin secretion due to concomitant cardiac muscle injury related to left ventricular hypertrophy, inflammation and fibrosis. This article reviews the metabolism and utility of cardiac biomarkers in patients with acute and chronic kidney diseases. Cardiac troponins are small peptides that accumulate in both acute and chronic kidney diseases due to impaired excretion. Hence, troponin concentrations rise and fall with acute kidney injury and its recovery, limiting their use in the diagnosis of ACS. Troponin concentrations are chronically elevated in CKD and ESKD, are associated with poor prognosis and decrease the sensitivity and specificity for diagnosis of ACS. Yet, the evidence indicates that the use of high-sensitivity troponins can confirm or exclude a diagnosis of ACS in the emergency room in a significant proportion of kidney disease patients; those patients in whom the results are equivocal may need longer in-hospital assessment.

Revisiting the Biological Variability of Cardiac Troponin: Implications for Clinical Practice

The diagnosis of acute myocardial injury requires a rise and/or fall of cardiac troponin (cTn) on serial testing, with at least one concentration above the 99th percentile value of a normal reference population according to the recently published Fourth Universal Definition of Myocardial Infarction.1 However, the magnitude of change in cTn that constitutes a significant rise and/or fall was again not specified in detail. High-sensitivity cardiac troponin (hs-cTn) assays can measure ten-fold lower concentrations of cTn with more precision than older assays, and can accurately quantify cTn in more than 50% of healthy individuals with a coefficient of variation of less than 10% at the 99th percentile. These hs-cTn assays are also able to detect the normal variations in cTn results that are due to biological variability. Understanding and quantifying the normal variations in cTn is important as this would allow significant changes to be better defined. Numerous studies have sought to investigate the biological variability of cTn over the last ten years. Such studies are usually conducted in healthy individuals, however individuals with chronic cardiac disease or chronic renal failure have also been examined. These studies have yielded varying results in regards to significant change values for cTn. In light of the recent redefinition for myocardial infarction, the purpose of this mini-review is to revisit the biological variability of cTn. In particular, we outline concepts for determining a significant change value, review the results of previous studies on the biological variation of cTn and discuss potential considerations for clinical practice.

Impact of statin use on high sensitive troponin T levels with moderate exercise

Background: High-sensitive cardiac troponin (hsTn) levels can be elevated due to non-pathological events such as strenuous exercise. However, the effect of statins on circulating hsTnT levels with moderate exercise is uncertain. Therefore, we evaluated the impact of statins on hsTnT level with moderate exercise. Methods: We enrolled a total of 56 patients: 26 statin users and 30 non-users. All patients were shown to have no coronary artery disease before participating in the study. Participants performed a fixed-protocol moderate level exercise. HsTnT levels were measured before and 4 h after the exercise. Participants were also grouped based on their hsTnT levels, as proposed in the recent European Society of Cardiology guideline (0-1 hour algorithm) for acute coronary syndromes without persistent ST-segment elevation. Results: Statin users showed a significant increase in serum hsTnT levels with moderate exercise (p = .004), whereas the control group showed a modest increase without statistical significance (p = .664). The percentage of patients whose hsTnT levels exceeded the rule-out limits for non-ST-segment myocardial infarction diagnosis (according to the 0-1 algorithm) after moderate exercise varied significantly between groups (p = .024). Conclusions: Statin therapy can cause a significant increase in hsTnT levels after moderate exercise. This increase can jeopardise the accuracy of clinical diagnoses based on the newly implemented algorithms. The awareness of these adverse effects of statins, mainly used by patients with high risk of coronary events, can prevent misdiagnosis or unnecessary hospitalisations.

Initial Concentrations of miR-1 MicroRNA Precursor and High-Sensitivity Troponin in the Diagnosis of Non-ST Myocardial Infarction among Patients with and Those without Chronic Kidney Disease

Background: The early diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) in patients with chronic kidney disease (CKD) remains a challenge. Methods: The study consecutively enrolled patients who had suffered from chest pain within 3 h whose electrocardiogram had no elevation in the ST segment. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2, and the diagnostic criteria for NSTEMI were defined according to the recommended guideline. Circulating microRNA-1 was collected and determined by quantitative real-time reverse transcription polymerase chain reaction. Results: A total of 456 patients with suspected NSTEMI were included. There were 115 patients in the CKD group, including 67 with NSTEMI, 20 with stable angina, 7 with unstable angina, 18 with heart failure, and 3 with other disorders. Compared with the NSTEMI group, the non-NSTEMI group just had significant differences in microRNA-1 and high-sensitivity cardiac troponin I (hs-cTnI) (both p < 0.05). The relative expression of microRNA-1 was significantly increased in the NSTEMI group as compared with that in the other disease groups (all p < 0.05). A receiver operating characteristic (ROC) curve analysis suggested that microRNA-1 and hs-cTnI had advantages in the early diagnosis of NSTEMI with CKD (AUC [area under the ROC curve] 0.879 and 0.812, respectively, both p < 0.05). Compared with that in the non-CKD group, the accuracy of microRNA-1 was almost as good in the CKD group (84.3 vs. 89.4%, p > 0.05). However, the diagnostic accuracy of hs-cTnI was significantly decreased (79.1 vs. 91.5%, p < 0.05), as was its specificity (75.0 vs. 95.5%, p < 0.05). There was no significant difference in the correlation between microRNA-1 and eGFR (p > 0.05), but a statistically significantly negative correlation between hs-cTnI and eGFR (p < 0.05). Conclusion: Circulating microRNA-1 is capable of early diagnosis of NSTEMI in patients with CKD suffering from chest pain.

Diagnosis and treatment of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis

This review represents different aspects of myocardial infarction in patient with end - stage renal disease on chronic hemodialysis. We discuss difficulties in diagnosis, optimal method of coronary revascularization, timing of hemodialysis session, medical therapy, as well as epidemiology and prognosis. There are no unambiguous answers to these problems because patients with end - stage renal disease were excluded from most of the studies.

Recommendations for Institutions Transitioning to High-Sensitivity Troponin Testing: JACC Scientific Expert Panel

High-sensitivity cardiac troponin (hs-cTn) I or T methods have been in use in certain regions for years but are now increasingly globally adopted, including in the United States. Accordingly, inevitable challenges are created for institutions transitioning from conventional cardiac troponin (cTn) assays. hs-cTn assays have higher analytic precision at lower concentrations, yielding greater clinical sensitivity for myocardial injury and allowing accurate recognition of small changes in troponin concentration (rise or fall) within a short time frame. Although much of the knowledge regarding troponin biology that was applicable with older troponin assays still holds true, considerable education regarding the differences between conventional cTn and hs-cTn is needed before medical systems convert to the newer methods. This includes a basic understanding of how hs-cTn testing differs from conventional cTn testing and how it is best deployed in different settings, such as the emergency department and inpatient services. This Expert Panel will review important concepts for institutional transition to hs-cTn methodology, providing recommendations useful for education before implementation.