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

External validation of the myocardial-ischaemic-injury-index machine learning algorithm for the early diagnosis of myocardial infarction: a multicentre cohort study

BACKGROUND

The myocardial-ischaemic-injury-index (MI3) is a novel machine learning algorithm for the early diagnosis of type 1 non-ST-segment elevation myocardial infarction (NSTEMI). The performance of MI3, both when using early serial blood draws (eg, at 1 h or 2 h) and in direct comparison with guideline-recommended algorithms, remains unknown. Our aim was to externally validate MI3 and compare its performance with that of the European Society of Cardiology (ESC) 0/1h-algorithm.

METHODS

In this secondary analysis of a multicentre international diagnostic cohort study, adult patients (age >18 years) presenting to the emergency department with symptoms suggestive of myocardial infarction were prospectively enrolled from April 21, 2006, to Feb 27, 2019 in 12 centres from five European countries (Switzerland, Spain, Italy, Poland, and Czech Republic). Patients were excluded if they presented with ST-segment-elevation myocardial infarction, did not have at least two serial high-sensitivity cardiac troponin I (hs-cTnI) measurements, or if the final diagnosis remained unclear. The final diagnosis was centrally adjudicated by two independent cardiologists using all available medical records, including serial hs-cTnI measurements and cardiac imaging. The primary outcome was type 1 NSTEMI. The performance of MI3 was directly compared with that of the ESC 0/1h-algorithm.

FINDINGS

Among 6487 patients, (median age 61·0 years [IQR 49·0-73·0]; 2122 [33%] female and 4365 [67%] male), 882 (13·6%) patients had type 1 NSTEMI. The median time difference between the first and second hs-cTnI measurement was 60·0 mins (IQR 57·0-70·0). MI3 performance was very good, with an area under the receiver-operating-characteristic curve of 0·961 (95% CI 0·957 to 0·965) and a good overall calibration (intercept -0·09 [-0·2 to 0·02]; slope 1·02 [0·97 to 1·08]). The originally defined MI3 score of less than 1·6 identified 4186 (64·5%) patients as low probability of having a type 1 NSTEMI (sensitivity 99·1% [95% CI 98·2 to 99·5]; negative predictive value [NPV] 99·8% [95% CI 99·6 to 99·9]) and an MI3 score of 49·7 or more identified 915 (14·1%) patients as high probability of having a type 1 NSTEMI (specificity 95·0% [94·3 to 95·5]; positive predictive value [PPV] 69·1% [66·0-72·0]). The sensitivity and NPV of the ESC 0/1h-algorithm were higher than that of MI3 (difference for sensitivity 0·88% [0·19 to 1·60], p=0·0082; difference for NPV 0·18% [0·05 to 0·32], p=0·016), and the rule-out efficacy was higher for MI3 (11% difference, p<0·0001). Specificity and PPV for MI3 were superior (difference for specificity 3·80% [3·24 to 4·36], p<0·0001; difference for PPV 7·84% [5·86 to 9·97], p<0·0001), and the rule-in efficacy was higher for the ESC 0/1h-algorithm (5·4% difference, p<0·0001).

INTERPRETATION

MI3 performs very well in diagnosing type 1 NSTEMI, demonstrating comparability to the ESC 0/1h-algorithm in an emergency department setting when using early serial blood draws.

FUNDING

Swiss National Science Foundation, Swiss Heart Foundation, the EU, the University Hospital Basel, the University of Basel, Abbott, Beckman Coulter, Roche, Idorsia, Ortho Clinical Diagnostics, Quidel, Siemens, and Singulex.

E, Jones J, Li J. Evaluation of Age and Sex Differences in Contemporary versus High-Sensitivity Troponin I Measurement in Hospitalized Patients

Background: With the transition from the contemporary (cTnI) to high-sensitivity troponin assay (hs-cTnI), concerns have arisen regarding the diagnostic differences between these two assays due to analytical distinctions. This study aims to evaluate the age and sex differences between these two assays, as well as the differences resulting from using two different 99th percentile values of the high-sensitivity troponin assay. Method: A retrospective observational study was conducted at an academic medical center, encompassing a total of 449 lithium heparin plasma samples included in the dataset. Both contemporary and high-sensitivity troponin were simultaneously measured using Siemens ADVIA Centaur analyzers. Two sets of sex-specific 99th percentile URLs from the Siemens study (cutoff-1) and Universal Sample Bank data (cutoff-2) were used for the data analysis. Results: The use of cutoff-1 or cutoff-2 had a negligible impact on troponin classification. Troponin elevation significantly increased in individuals > 50 years old for males and >40 years old for females, with both troponin assays. A receiver operating characteristic analysis did not find significant differences between the two assays. The Kaplan-Meier curves showed no differences in survival in cTnI according to the non-sex-specific 99th URL or hs-cTnI (cutoff-2) but showed a slight difference in survival in hs-cTnI (cutoff-1). Conclusions: Overall, there were no significant differences in age and sex in the diagnostic performance between the contemporary and high-sensitivity troponin assays. Selection criteria for the establishment of the 99th percentile URL should be standardized to avoid the misinterpretation of the troponin results.

External validation of the 0/1h-algorithm and derivation of a 0/2h-algorithm using a new point-of-care Hs-cTnI assay

BACKGROUND

The high-sensitivity cardiac troponin (hs-cTn) I point-of-care (POC) hs-cTnI-PATHFAST assay has recently become clinically available.

METHODS

We aimed to externally validate the hs-cTnI-PATHFAST 0/1h-algorithm recently developed for the early diagnosis of non-ST-segment-elevation myocardial infarction (NSTEMI) and derive and validate a 0/2-algorithm in patients presenting to the emergency department with acute chest discomfort included in a multicenter diagnostic study. Two independent cardiologists centrally adjudicated the final diagnoses using all the clinical and study-specific information available including serial measurements of hs-cTnI-Architect.

RESULTS

Among 1,532 patients (median age 60 years, 33% [n = 501] women), NSTEMI was the final diagnosis in 13%. External validation of the hs-cTnI-PATHFAST 0/1h-algorithm showed very high negative predictive value (NPV; 100% [95%CI, 99.5%-100%]) and sensitivity 100% (95%CI, 98.2%-100%) for rule-out of NSTEMI. Positive predictive value (PPV) and specificity for rule-in of NSTEMI were high (74.9% [95%CI, 68.3%-80.5%] and 96.4% [95%CI, 95.2%-97.3%], respectively). Among 1,207 patients (median age 61 years, 32% [n = 391] women) available for the derivation (n = 848) and validation (n = 359) of the hs-cTnI-PATHFAST 0/2h-algorithm, a 0h-concentration <3 ng/L or a 0h-concentration <4 ng/L with a 2h-delta <4ng/L ruled-out NSTEMI in 52% of patients with a NPV of 100% (95%CI, 98-100) and sensitivity of 100% (95%CI, 92.9%-100%) in the validation cohort. A 0h-concentration ≥90ng/L or a 2h-delta ≥ 55ng/L ruled-in 38 patients (11%): PPV 81.6% (95%CI, 66.6-90.8), specificity 97.7% (95%CI, 95.4-98.9%).

CONCLUSIONS

The POC hs-cTnI-PATHFAST assay allows rapid and effective rule-out and rule-in of NSTEMI using both a 0/1h- and a 0/2h-algorithm with high NPV/sensitivity for rule-out and high PPV/specificity for rule-in.

CLINICAL TRIAL REGISTRATION

NCT00470587.

Derivation and external validation of machine-learning models for risk stratification in chest pain with normal troponin

AIMS

Risk stratification of patients with chest pain and a high-sensitivity cardiac troponin T (hs-cTnT) concentration

METHODS AND RESULTS

Four machine-learning-based models and one logistic regression (LR) model were trained on 4075 patients (single-centre Spanish cohort) and externally validated on 3609 patients (international prospective Advantageous Predictors of Acute Coronary syndromes Evaluation cohort). Models were compared with GRACE and HEART scores and a single undetectable hs-cTnT-based strategy (u-cTn; hs-cTnT < 5 ng/L and time from symptoms onset >180 min). Probability thresholds for safe discharge were derived in the derivation cohort. The endpoint occurred in 105 (2.6%) patients in the training set and 98 (2.7%) in the external validation set. Gradient boosting full (GBf) showed the best discrimination (area under the curve = 0.808). Calibration was good for the reduced neural network and LR models. Gradient boosting full identified the highest proportion of patients for safe discharge (36.7 vs. 23.4 vs. 27.2%; GBf vs. LR vs. u-cTn, respectively) with similar safety (missed endpoint per 1000 patients: 2.2 vs. 3.5 vs. 3.1, respectively). All derived models were superior to the HEART and GRACE scores (P < 0.001).

CONCLUSION

Machine-learning and LR prediction models were superior to the HEART, GRACE, and u-cTn for risk stratification of patients with chest pain and a baseline hs-cTnT

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587, https://clinicaltrials.gov/ct2/show/NCT00470587.

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Key Words

• Machine learning
• Myocardial infarction
• Prediction
• Troponin

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MESH Headings

• Humans
• Troponin
• Prospective Studies
• Biomarkers
• Troponin T
• Chest Pain/diagnosis
• Chest Pain/etiology
• Risk Assessment

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Grants

• Swiss National Science Foundation

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Affiliation(s)

Agustín Fernández-Cisnal Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Pedro Lopez-Ayala Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Ernesto Valero Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Luca Koechlin Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Arturo Catarralá Clinical Biochemistry Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), València 46010, Spain
Jasper Boeddinghaus Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
José Noceda Emergency Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), València 46010, Spain
Thomas Nestelberger Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Òscar Miró Emergency Department, Hospital Clinic, Barcelona, Catalonia, Spain
Núñez Julio Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Christian Mueller Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Juan Sanchis Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain

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Accelerated -Rule-Out of acute Myocardial Infarction using prehospital copeptin and in-hospital troponin: The AROMI study

AIMS

The present acute myocardial infarction (AMI) rule-out strategies are challenged by the late temporal release of cardiac troponin. Copeptin is a non-specific biomarker of endogenous stress and rises early in AMI, covering the early period where troponin is still normal. An accelerated dual-marker rule-out strategy combining prehospital copeptin and in-hospital high-sensitivity troponin T could reduce length of hospital stay and thus the burden on the health care systems worldwide. The AROMI trial aimed to evaluate if the accelerated dual-marker rule-out strategy could safely reduce length of stay in patients discharged after early rule-out of AMI.

METHODS AND RESULTS

Patients with suspected AMI transported to hospital by ambulance were randomized 1:1 to either accelerated rule-out using copeptin measured in a prehospital blood sample and high-sensitivity troponin T measured at arrival to hospital or to standard rule-out using a 0 h/3 h rule-out strategy. The AROMI study included 4351 patients with suspected AMI. The accelerated dual-marker rule-out strategy reduced mean length of stay by 0.9 h (95% confidence interval 0.7-1.1 h) in patients discharged after rule-out of AMI and was non-inferior regarding 30-day major adverse cardiac events when compared to standard rule-out (absolute risk difference -0.4%, 95% confidence interval -2.5 to 1.7; P-value for non-inferiority = 0.013).

CONCLUSION

Accelerated dual marker rule-out of AMI, using a combination of prehospital copeptin and first in-hospital high-sensitivity troponin T, reduces length of hospital stay without increasing the rate of 30-day major adverse cardiac events as compared to using a 0 h/3 h rule-out strategy.

Combining glucose and high-sensitivity cardiac troponin in the early diagnosis of acute myocardial infarction

Glucose is a universally available inexpensive biomarker, which is increased as part of the physiological stress response to acute myocardial infarction (AMI) and may therefore help in its early diagnosis. To test this hypothesis, glucose, high-sensitivity cardiac troponin (hs-cTn) T, and hs-cTnI were measured in consecutive patients presenting with acute chest discomfort to the emergency department (ED) and enrolled in a large international diagnostic study (NCT00470587). Two independent cardiologists centrally adjudicated the final diagnosis using all clinical data, including serial hs-cTnT measurements, cardiac imaging and clinical follow-up. The primary diagnostic endpoint was index non-ST-segment elevation MI (NSTEMI). Prognostic endpoints were all-cause death, and cardiovascular (CV) death or future AMI, all within 730-days. Among 5639 eligible patients, NSTEMI was the adjudicated final diagnosis in 1051 (18.6%) patients. Diagnostic accuracy quantified using the area under the receiver-operating characteristics curve (AUC) for the combination of glucose with hs-cTnT and glucose with hs-cTnI was very high, but not higher versus that of hs-cTn alone (glucose/hs-cTnT 0.930 [95% CI 0.922-0.937] versus hs-cTnT 0.929 [95% CI 0.922-0.937]; glucose/hs-cTnI 0.944 [95% CI 0.937-0.951] versus hs-cTnI 0.944 [95% CI 0.937-0.951]). In early-presenters, a dual-marker strategy (glucose < 7 mmol/L and hs-cTnT < 5/hs-cTnI < 4 ng/L) provided very high and comparable sensitivity to slightly lower hs-cTn concentrations (cTnT/I < 4/3 ng/L) alone, and possibly even higher efficacy. Glucose was an independent predictor of 730-days endpoints. Our results showed that a dual marker strategy of glucose and hs-cTn did not increase the diagnostic accuracy when used continuously. However, a cutoff approach combining glucose and hs-cTn may provide diagnostic utility for patients presenting ≤ 3 h after onset of symptoms, also providing important prognostic information.

Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers

The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.

Rapid identification of sepsis in the emergency department

Objectives

Recent research has helped define the complex pathways in sepsis, affording new opportunities for advancing diagnostics tests. Given significant advances in the field, a group of academic investigators from emergency medicine, intensive care, pathology, and pharmacology assembled to develop consensus around key gaps and potential future use for emerging rapid host response diagnostics assays in the emergency department (ED) setting.

Methods

A modified Delphi study was conducted that included 26 panelists (expert consensus panel) from multiple specialties. A smaller steering committee first defined a list of Delphi statements related to the need for and future potential use of a hypothetical sepsis diagnostic test in the ED. Likert scoring was used to assess panelists agreement or disagreement with statements. Two successive rounds of surveys were conducted and consensus for statements was operationally defined as achieving agreement or disagreement of 75% or greater.

Results

Significant gaps were identified related to current tools for assessing risk of sepsis in the ED. Strong consensus indicated the need for a test providing an indication of the severity of dysregulated host immune response, which would be helpful even if it did not identify the specific pathogen. Although there was a relatively high degree of uncertainty regarding which patients would most benefit from the test, the panel agreed that an ideal host response sepsis test should aim to be integrated into ED triage and thus should produce results in less than 30 minutes. The panel also agreed that such a test would be most valuable for improving sepsis outcomes and reducing rates of unnecessary antibiotic use.

Conclusion

The expert consensus panel expressed strong consensus regarding gaps in sepsis diagnostics in the ED and the potential for new rapid host response tests to help fill these gaps. These finding provide a baseline framework for assessing key attributes of evolving host response diagnostic tests for sepsis in the ED.

Methods for analyzing positive cardiac troponin assay interference

OBJECTIVES

The cardiac damage biomarkers cardiac troponin T (cTnT) and troponin I (cTnI) are used to identify patients with myocardial infarction (MI). To make the correct clinical decisions it is important to identify false positive results due to troponin assay interference. Often interferences are caused by high-molecular weight immunocomplexes called macrotroponin that may result in false troponin elevations because of delayed troponin clearance, or heterophilic antibodies that crosslink troponin assay antibodies and generate troponin-independent signals.

DESIGN & METHODS

We describe and compare four methods for cTnI assay interference analysis using a protein G spin column method, gel filtration chromatography and two versions of a sucrose gradient ultracentrifugation for cTnI assay interference analysis on five patients with confirmed cTnI interference and one MI patient without cTnI interference from our troponin interference referral center.

RESULTS

The protein G spin column method had a high between run variability but was still able to identify all five patients with cTnI interference. The sucrose gradient ultracentrifugation methods and the gel filtration method had simlar performancec and correctly identified the immunocomplexes that caused the cTnI interference.

CONCLUSIONS

Our experience is that these methods are sufficient to safely confirm or exclude positive cTnI assay interference.

Diagnostic discrimination of a novel high-sensitivity cardiac troponin I assay and derivation/validation of an assay-specific 0/1h-algorithm

BACKGROUND

We aimed to assess the diagnostic utility of the Dimension EXL LOCI High-Sensitivity Troponin I (hs-cTnI-EXL) assay.

METHODS

This multicenter study included patients with chest discomfort presenting to the emergency department. Diagnoses were centrally and independently adjudicated by two cardiologists using all available clinical information. Adjudication was performed twice including serial measurements of high-sensitivity cardiac troponin (hs-cTn) I-Architect (primary analysis) and serial measurements of hs-cTnT-Elecsys (secondary analysis) in addition to the clinically used (hs)-cTn. The primary objective was to assess and compare the discriminatory performance of hs-cTnI-EXL, hs-cTnI-Architect and hs-cTnT-Elecsys for acute myocardial infarction (MI). Furthermore, we derived and validated a hs-cTnI-EXL-specific 0/1h-algorithm.

RESULTS

Adjudicated MI was the diagnosis in 204/1454 (14%) patients. The area under the receiver operating characteristics curve for hs-cTnI-EXL was 0.94 (95%CI, 0.93-0.96), and comparable to hs-cTnI-Architect (0.95; 95%CI, 0.93-0.96) and hs-cTnT-Elecsys (0.93; 95%CI, 0.91-0.95). In the derivation cohort (n = 813), optimal criteria for rule-out of MI were <9ng/L at presentation (if chest pain onset >3h) or <9ng/L and 0h-1h-change <5ng/L, and for rule-in ≥160ng/L at presentation or 0h-1h-change ≥100ng/L. In the validation cohort (n = 345), these cut-offs ruled-out 56% of patients (negative predictive value 99.5% (95%CI, 97.1-99.9), sensitivity 97.8% (95%CI, 88.7-99.6)), and ruled-in 9% (positive predictive value 83.3% (95%CI, 66.4-92.7), specificity 98.3% (95%CI, 96.1-99.3)). Secondary analyses using adjudication based on hs-cTnT measurements confirmed the findings.

CONCLUSIONS

The overall performance of the hs-cTnI-EXL was comparable to best-validated hs-cTnT/I assays and an assay-specific 0/1h-algorithm safely rules out and accurately rules in acute MI.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587.

Electroanalytical point-of-care detection of gold standard and emerging cardiac biomarkers for stratification and monitoring in intensive care medicine - a review

Determination of specific cardiac biomarkers (CBs) during the diagnosis and management of adverse cardiovascular events such as acute myocardial infarction (AMI) has become commonplace in emergency department (ED), cardiology and many other ward settings. Cardiac troponins (cTnT and cTnI) and natriuretic peptides (BNP and NT-pro-BNP) are the preferred biomarkers in clinical practice for the diagnostic workup of AMI, acute coronary syndrome (ACS) and other types of myocardial ischaemia and heart failure (HF), while the roles and possible clinical applications of several other potential biomarkers continue to be evaluated and are the subject of several comprehensive reviews. The requirement for rapid, repeated testing of a small number of CBs in ED and cardiology patients has led to the development of point-of-care (PoC) technology to circumvent the need for remote and lengthy testing procedures in the hospital pathology laboratories. Electroanalytical sensing platforms have the potential to meet these requirements. This review aims firstly to reflect on the potential benefits of rapid CB testing in critically ill patients, a very distinct cohort of patients with deranged baseline levels of CBs. We summarise their source and clinical relevance and are the first to report the required analytical ranges for such technology to be of value in this patient cohort. Secondly, we review the current electrochemical approaches, including its sub-variants such as photoelectrochemical and electrochemiluminescence, for the determination  of important CBs highlighting the various strategies used, namely the use of micro- and nanomaterials, to maximise the sensitivities and selectivities of such approaches. Finally, we consider the challenges that must be overcome to allow for the commercialisation of this technology and transition into intensive care medicine.

Additive value of bioclinical risk scores to high sensitivity troponins-only strategy in acute coronary syndrome

BACKGROUND

Discharging patients home as quickly as possible, or gaining the ability to eliminate a serious event is a goal requested by clinicians in the emergency department (ED). For this, risk scores, taking into account co-morbidities, have been established. The aim of our study consists to evaluate in patients with chest pain admitted in ED the risk stratification obtained with clinico-biological risk scores (CCS, GRACE score, TIMI score and HEART score) using Ortho hs-cTnI assay (Ortho Clinical Diagnostics, Illkirch, France) on the Vitros 3600® instrument or Roche hs-cTnT assay on the Cobas8000/e801® module (Roche diagnostics, Meylan, France), with comparison to hs-cTn-only strategy. Prognostic performances were evaluated according to AMI with or without STEMI, and deaths during hospitalization.

METHODS

Patients admitted to the ED presenting chest pain or symptoms suggesting of acute coronary syndrome (ACS) were included. Hs-cTnT was performed on a Roche hs-cTnT assay on the Cobas8000/e801® module using a fifth-generation assay and was used for the clinical diagnosis. In addition, hs-cTnI was tested using Ortho hs-cTnI assay on the Vitros 3600® analyzer. Retrospectively, we collected the variables needed for each score in clinical records. Our endpoint were occurrence of AMI in patients with chest pain after presentation to the ED and all cause death during the hospitalization.

RESULTS

We enrolled 160 patients with suspected ACS. The adjudicated diagnosis was AMI in 37 patients (with 9 STEMI and 28 NSTEMI), cardiac pathologies in 57 patients and other causes in 66 patients. The majority of patients were classified at high risk for each risk scores (from 42% to 68%) whatever the considered hs-cTn assay, except for TIMI score. Cohen's kappa agreements with GRACE, TIMI and HEART scores were excellent between Roche hs-cTnT vs Ortho hs-cTnI. The AUC of the HEART score was highest for both hs-cTn to predict AMI, NSTEMI or death, with no statistical difference according to the hs-cTn (p = NS) assay used. NRI analysis confirmed the interest of HEART score which improved individual risk prediction for AMI (or NSTEMI) and death.

CONCLUSION

In view of our results, the decision aids using only biological variables (hs-cTn-only strategy and CCS) would seem more effective for rule-out AMI whereas bioclinical risk scores could better identify patients at low and high risk for mortality. In consequence, risk scores taking in account comorbidities, appear necessary to determine the outcome and thus to adapt the therapeutic options. It is interesting to note that the HEART score could be useful for the rule out AMI but also for the risk prediction as confirmed by the NRI.

Novel Criteria for the Observe-Zone of the ESC 0/1h-hs-cTnT Algorithm

Background: The non-ST elevation myocardial infarction (NSTEMI) guidelines of the European Society of Cardiology (ESC) recommend a 3h cardiac troponin determination in patients triaged to the observe-zone of the ESC 0/1h-algorithm; however, no specific cut-off for further triage is endorsed. Recently, a specific cut-off for 0/3h high-sensitivity cardiac troponin T (hs-cTnT) change (7ng/L) was proposed warranting external validation. Methods: Patients presenting with acute chest discomfort to the emergency department were prospectively enrolled into an international multicenter diagnostic study. Final diagnoses were centrally adjudicated by two independent cardiologists applying the 4th universal definition of MI, based on complete cardiac work-up, cardiac imaging and serial hs-cTnT. Hs-cTnT concentrations were measured at presentation, after 1h and 3h. The objective was to externally validate the proposed cut-off, and if necessary, derive and internally as well as externally validate novel 0/3h-criteria for the observe-zone of the ESC 0/1h-hs-cTnT-algorithm in an independent multicenter cohort. Results: Among 2076 eligible patients, application of the ESC 0/1h-hs-cTnT-algorithm triaged 1512 patients (72.8%) to either rule-out or rule-in of NSTEMI, remaining 564 patients (27.2%) in the observe-zone (adjudicated NSTEMI prevalence 120/564 patients, 21.3%). The suggested 0/3h-hs-cTnT-change of <7ng/L triaged 517 patients (91.7%) towards rule-out, resulting in a sensitivity of 33.3% (95%CI 25.5-42.2), missing 80 patients with NSTEMI, and ≥7ng/L triaged 47 patients towards rule-in (8.3%), resulting in a specificity of 98.4% (95%CI 96.8-99.2). Novel derived 0/3h-criteria for the observe-zone patients ruled-out NSTEMI with a 3h hs-cTnT concentration <15 ng/L and a 0/3h-hs-cTnT absolute change <4 ng/L, triaging 138 patients (25%) towards rule-out, resulting in a sensitivity of 99.2% (95%CI 96.0-99.9), missing 1 patient with NSTEMI. A 0/3h-hs-cTnT absolute change ≥6 ng/L triaged 63 patients (11.2%) towards rule-in, resulting in a specificity of 98% (95%CI 96.2-98.9) Thereby, the novel 0/3h-criteria reduced the number of patients in the observe zone by 36%, and the number of T1MI by 50%. Findings were confirmed in both internal and external validation. Conclusions: A combination of a 3h hs-cTnT concentration (<15 ng/L) and a 0/3h absolute change (<4 ng/L) is necessary to safely rule-out NSTEMI in patients remaining in the observe-zone of the ESC 0/1h-hs-cTnT-algorithm. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT00470587.