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

Diagnostic accuracy of point-of-care cardiac ultrasound for acute coronary syndromes in patients presenting with chest pain to the emergency department: a single-center prospective study

BACKGROUND AND IMPORTANCE

The diagnostic accuracy of focused cardiac ultrasound (FoCUS) performed in patients presenting to the emergency department (ED) with chest pain is currently unknown.

OBJECTIVE

The objective of this study was to assess the diagnostic accuracy of regional wall motion abnormalities detected with FoCUS for non-ST-elevation acute coronary syndrome (NSTE-ACS) diagnosis.

DESIGN

A Single-center prospective observational study conducted in 2022 in the ED of the University Hospital Careggi, Italy.

SETTING AND PARTICIPANTS

Adult patients presenting to the ED with acute nontraumatic chest pain were enrolled, irrespective of the presence of previous regional wall motion abnormalities. Patients with ST-segment elevation myocardial infarctions and patients with hemodynamic instability were excluded. FoCUS was performed at presentation by a trained ED physician.

OUTCOME MEASURES AND ANALYSIS

The final diagnosis of NSTE-ACS vs. alternative diagnosis was adjudicated by an ED physician blinded to FoCUS results after a 30-day follow-up. To assess if regional wall motion abnormalities were an independent predictor of NSTE-ACS, a multivariable logistic regression model was built. Diagnostic performance measures were calculated. A sensitivity analysis considering only type-1 NSTEMIs (i.e. plaque rupture/thrombosis) was conducted.

MAIN RESULTS

Among 686 patients, NSTE-ACS was adjudicated in 106 (15.5%) patients, 67 of which were NSTEMIs. A total of 87 (12.7%) patients had regional wall motion abnormalities detected by FoCUS, which were an independent predictor of NSTE-ACS in the multivariable logistic regression analysis. Regional wall motion abnormalities had a sensitivity of 42.5% (33.0-51.9), a specificity of 92.8% (90.6-94.9), a negative predictive value of 89.8% (87.4-92.2), and a positive predictive value of 51.7% (41.2-62.2), for NSTE-ACS. Results were consistent in the sensitivity analysis.

CONCLUSIONS

In ED patients with chest pain and no ST elevation, the detection of regional wall motion abnormalities was a predictor of NSTE-ACS. Despite a high specificity, which indicated a possible role of FoCUS in the rule-in of NSTE-ACS, sensitivity was too low to allow a safe rule-out using FoCUS results alone.

From Atherosclerotic Plaque to Myocardial Infarction-The Leading Cause of Coronary Artery Occlusion

Cardiovascular disease (CVD) constitutes the most common cause of death worldwide. In Europe alone, approximately 4 million people die annually due to CVD. The leading component of CVD leading to mortality is myocardial infarction (MI). MI is classified into several types. Type 1 is associated with atherosclerosis, type 2 results from inadequate oxygen supply to cardiomyocytes, type 3 is defined as sudden cardiac death, while types 4 and 5 are associated with procedures such as percutaneous coronary intervention and coronary artery bypass grafting, respectively. Of particular note is type 1, which is also the most frequently occurring form of MI. Factors predisposing to its occurrence include, among others, high levels of low-density lipoprotein cholesterol (LDL-C) in the blood, cigarette smoking, chronic kidney disease (CKD), diabetes mellitus (DM), hypertension, and familial hypercholesterolaemia (FH). The primary objective of this review is to elucidate the issues with regard to type 1 MI. Our paper delves into, amidst other aspects, its pathogenesis, risk assessment, diagnosis, pharmacotherapy, and interventional treatment options in both acute and long-term conditions.

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.

Copeptin for the differentiation of type 1 versus type 2 myocardial infarction or myocardial injury

BACKGROUND

The rapid and reliable differentiation of myocardial infarction (MI) due to atherothrombosis (T1MI) from MI due to supply-demand mismatch (T2MI) or acute myocardial injury is of major clinical relevance due to very different treatments, but still a major unmet clinical need. This study aimed to investigate whether copeptin, a stress hormone produced in the hypothalamus, helps to differentiate between T1MI versus T2MI or injury.

METHODS

In a retrospective analysis, 1271 unselected consecutive patients presenting with symptoms suggestive of MI to the emergency department were evaluated. Patients diagnosed with ST-elevation MI were excluded. All patients with elevated cardiac troponin I (cTnI) concentration possibly indicating MI were classified into T1MI, T2MI, or acute myocardial injury using detailed clinical assessment and coronary imaging. Copeptin plasma concentration was measured in a blinded fashion. A multicenter diagnostic study with central adjudication of the final diagnosis served as external validation cohort (n = 1390).

RESULTS

Among 1161 patients, 154 patients had increased cTnI concentration. Of these, 78 patients (51%) were classified as T1MI and 76 (49%) as T2MI or myocardial injury. Patients with T2MI or myocardial injury had significantly higher copeptin plasma concentration between patients versus T1MI (21,4 pmol/l versus 8,1 pmol/l, p = 0,001). A multivariable regression analysis revealed that higher concentrations of copeptin and C-reactive protein, higher heart rate at presentation and lower frequency of smoking remained significantly associated with T2MI and myocardial injury. Findings were largely confirmed in the external validation cohort.

CONCLUSION

In patients without ST-segment elevation, copeptin concentration was higher in T2MI and myocardial Injury versus T1MI and may help in their differential diagnosis.

Machine Learning for Myocardial Infarction Compared With Guideline-Recommended Diagnostic Pathways

BACKGROUND

Collaboration for the Diagnosis and Evaluation of Acute Coronary Syndrome (CoDE-ACS) is a validated clinical decision support tool that uses machine learning with or without serial cardiac troponin measurements at a flexible time point to calculate the probability of myocardial infarction (MI). How CoDE-ACS performs at different time points for serial measurement and compares with guideline-recommended diagnostic pathways that rely on fixed thresholds and time points is uncertain.

METHODS

Patients with possible MI without ST-segment-elevation were enrolled at 12 sites in 5 countries and underwent serial high-sensitivity cardiac troponin I concentration measurement at 0, 1, and 2 hours. Diagnostic performance of the CoDE-ACS model at each time point was determined for index type 1 MI and the effectiveness of previously validated low- and high-probability scores compared with guideline-recommended European Society of Cardiology (ESC) 0/1-hour, ESC 0/2-hour, and High-STEACS (High-Sensitivity Troponin in the Evaluation of Patients With Suspected Acute Coronary Syndrome) pathways.

RESULTS

In total, 4105 patients (mean age, 61 years [interquartile range, 50-74]; 32% women) were included, among whom 575 (14%) had type 1 MI. At presentation, CoDE-ACS identified 56% of patients as low probability, with a negative predictive value and sensitivity of 99.7% (95% CI, 99.5%-99.9%) and 99.0% (98.6%-99.2%), ruling out more patients than the ESC 0-hour and High-STEACS (25% and 35%) pathways. Incorporating a second cardiac troponin measurement, CoDE-ACS identified 65% or 68% of patients as low probability at 1 or 2 hours, for an identical negative predictive value of 99.7% (99.5%-99.9%); 19% or 18% as high probability, with a positive predictive value of 64.9% (63.5%-66.4%) and 68.8% (67.3%-70.1%); and 16% or 14% as intermediate probability. In comparison, after serial measurements, the ESC 0/1-hour, ESC 0/2-hour, and High-STEACS pathways identified 49%, 53%, and 71% of patients as low risk, with a negative predictive value of 100% (99.9%-100%), 100% (99.9%-100%), and 99.7% (99.5%-99.8%); and 20%, 19%, or 29% as high risk, with a positive predictive value of 61.5% (60.0%-63.0%), 65.8% (64.3%-67.2%), and 48.3% (46.8%-49.8%), resulting in 31%, 28%, or 0%, who require further observation in the emergency department, respectively.

CONCLUSIONS

CoDE-ACS performs consistently irrespective of the timing of serial cardiac troponin measurement, identifying more patients as low probability with comparable performance to guideline-recommended pathways for MI. Whether care guided by probabilities can improve the early diagnosis of MI requires prospective evaluation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00470587.

Type of evidence supporting ACC/AHA and ESC clinical practice guidelines for acute coronary syndrome

AIM

The aim of clinical practice guidelines for ST elevation myocardial infarction (STEMI) and non-ST elevation acute coronary syndrome (NSTE-ACS) is to assist healthcare professionals in clinical decision-making. We evaluated the type of studies supporting these guidelines and their recommendations.

METHODS

All references and recommendations in the 2013 and 2014 ACC/AHA and 2017 and 2020 (ESC clinical guidelines for STEMI and NSTE-ACS were reviewed. References were classified into meta-analyses, randomised, non-randomised, and other types (e.g., position papers, reviews). Recommendations were classified according to class and their level of evidence (LOE).

RESULTS

We retrieved 2128 non-duplicated references: 8.4% were meta-analyses, 26.2% randomised studies, 44.7% non-randomised studies, and 20.7% 'other' papers. Meta-analyses were based on randomised data in 78% of cases and used individual-patient data in 20.2%. Compared to non-randomised studies, randomised studies were more frequently multicentre (85.5% vs. 65.5%) and international (58.2% vs. 28.5%). The type of studies supporting recommendations varied as per the LOE of the recommendation. For LOE-A recommendations, the breakdown of supporting recommendations was: 18.5% meta-analyses, 56.6% randomised studies, 16.6% non-randomised studies and 8.3% 'other' papers; for LOE-B this breakdown was 9%, 39.8%, 38.2%, and 12.9%; and for LOE-C; 4.6%, 19.3%, 30.3%, and 45.9%.

CONCLUSIONS

The references supporting the ACC/AHA and ESC guidelines on STEMI and NSTE-ACS consisted of non-randomised studies in ~ 45% of cases, with less than a third of the references consisting of meta-analyses and randomised studies. The type of studies supporting guideline recommendations varied widely by the LOE of the recommendation.

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.

High-Sensitivity Cardiac Troponin Assays: Ready for Prime Time!

Rapid and accurate triage of patients presenting with chest pain to an emergency department (ED) is critical to prevent ED overcrowding and unnecessary resource use in individuals at low risk of acute myocardial infarction (AMI) and to efficiently and effectively guide patients at high risk to definite therapy. The use of biomarkers for rule-out or rule-in of suspected AMI has evolved substantially over the last several decades. Previously well-established biomarkers have been replaced by cardiac troponin (cTn). High-sensitivity cTn (hs-cTn) assays represent the newest generation of cTn assays and offer tremendous advantages, including improved sensitivity and precision. Still, implementation of these assays in the United States lags behind several other areas of the world. Within this educational review, we discuss the evolution of biomarker testing for detection of myocardial injury, address the specifics of hs-cTn assays and their recommended use within triage algorithms, and highlight potential challenges in their use. Ultimately, we focus on implementation strategies for hs-cTn assays, as they are now clearly ready for prime time.

Establishing optimal cutoff values for high-sensitivity cardiac troponin algorithms in risk stratification of acute myocardial infarction

Acute myocardial infarction (AMI) is a leading cause of mortality globally, highlighting the need for timely and accurate diagnostic strategies. Cardiac troponin has been the biomarker of choice for detecting myocardial injury. A dynamic change in concentrations supports the diagnosis of AMI in the setting of evidence of acute myocardial ischemia. The new generation of high-sensitivity cardiac troponin (hs-cTn) assays has significantly improved analytical sensitivity but at the expense of decreased clinical specificity. As a result, sophisticated algorithms are required to differentiate AMI from non-AMI patients. Establishing optimal hs-cTn cutoffs for these algorithms to rule out and rule in AMI has been the subject of intensive investigations. These efforts have evolved from examining the utility of the hs-cTn 99th percentile upper reference limit, comparing the percentage versus absolute delta thresholds, and evaluating the performance of an early European Society of Cardiology-recommended 3 h algorithm, to the development of accelerated 1 h and 2 h algorithms that combine the admission hs-cTn concentrations and absolute delta cutoffs to rule out and rule in AMI. Specific cutoffs for individual confounding factors such as sex, age, and renal insufficiency have also been investigated. At the same time, concerns such as whether the small delta thresholds exceed the analytical and biological variations of hs-cTn assays and whether the algorithms developed in European study populations fit all other patient cohorts have been raised. In addition, the accelerated algorithms leave a substantial number of patients in a non-diagnostic observation zone. How to properly diagnose patients falling in this zone and those presenting with elevated baseline hs-cTn concentrations due to the presence of confounding factors or comorbidities remain open questions. Here we discuss the developments described above, focusing on criteria and underlying considerations for establishing optimal cutoffs. In-depth analyses are provided on the influence of biological variation, analytical imprecision, local AMI rate, and the timing of presentation on the performance metrics of the accelerated hs-cTn algorithms. Developing diagnostic strategies for patients who remain in the observation zone and those presenting with confounding factors are also reviewed.

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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Chest Pain in Cancer Patients: Prevalence of Myocardial Infarction and Performance of High-Sensitivity Cardiac Troponins

Background

Little is known about patients with cancer presenting with acute chest discomfort to the emergency department (ED).

Objectives

The aim of this study was to assess the prevalence of acute myocardial infarction (AMI), outcomes, and the diagnostic utility of recommended diagnostic tools in this population.

Methods

Patients presenting with chest pain to the ED were prospectively enrolled in an international multicenter diagnostic study with central adjudication. Cancer status was assessed prospectively and additional cancer details retrospectively. Findings were externally validated in an independent multicenter cohort.

Results

Among 8,267 patients, 711 (8.6%) had cancer. Patients with cancer had a higher burden of cardiovascular risk factors and pre-existing cardiac disease. Total length of stay in the ED (5.2 hours vs 4.3 hours) and hospitalization rate (49.8% vs 34.3%) were both increased in patients with cancer (P < 0.001 for both). Among 8,093 patients eligible for the AMI analyses, those with cancer more often had final diagnoses of AMI (184 of 686 with cancer [26.8%] vs 1,561 of 7,407 without cancer [21.1%]; P < 0.001). In patients with cancer, high-sensitivity cardiac troponin T (hs-cTnT) but not high sensitivity cardiac troponin I (hs-cTnI) concentration had lower diagnostic accuracy for non-ST-segment elevation myocardial infarction (for hs-cTnT, area under the curve: 0.89 [95% CI: 0.86-0.92] vs 0.94 [95% CI: 0.93-0.94] [P < 0.001]; for hs-cTnI, area under the curve: 0.93 [95% CI: 0.91-0.95] vs 0.95 [95% CI: 0.94-0.95] [P = 0.10]). In patients with cancer, the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms maintained very high safety but had lower efficacy, with twice the number of patients remaining in the observe zone. Similar findings were obtained in the external validation cohort.

Conclusions

Patients with cancer have a substantially higher prevalence of AMI as the cause of chest pain. Length of ED stay and hospitalization rates are increased. The diagnostic performance of hs-cTnT and the efficacy of both the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms is reduced. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study; NCT00470587).

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.

High-Sensitivity Cardiac Troponin for Risk Assessment in Patients With Chronic Coronary Artery Disease

BACKGROUND

Cardiac troponin is used for risk stratification of patients with acute coronary syndromes; however, the role of testing in other settings remains unclear.

OBJECTIVES

The aim of this study was to evaluate whether cardiac troponin testing could enhance risk stratification in patients with chronic coronary artery disease independent of disease severity and conventional risk measures.

METHODS

In a prospective cohort of consecutive patients with symptoms suggestive of stable angina attending for outpatient coronary angiography, high-sensitivity cardiac troponin I was measured before angiography, and clinicians were blinded to the results. The primary outcome was myocardial infarction or cardiovascular death during follow-up.

RESULTS

In 4,240 patients (age 66 years [IQR: 59-73 years], 33% female), coronary artery disease was identified in 3,888 (92%) who had 255 (6%) primary outcome events during a median follow-up of 2.4 years (IQR: 1.3-3.6 years). In patients with coronary artery disease, troponin concentrations were 2-fold higher in those with an event compared with those without (6.7 ng/L [IQR: 3.2-14.2 ng/L] vs 3.3 ng/L [IQR: 1.7-6.6 ng/L]; P < 0.001). Troponin concentrations were associated with the primary outcome after adjusting for cardiovascular risk factors and coronary artery disease severity (adjusted HR: 2.3; 95% CI: 1.7-3.0, log10 troponin; P < 0.001). A troponin concentration >10 ng/L identified patients with a 50% increase in the risk of myocardial infarction or cardiovascular death.

CONCLUSIONS

In patients with chronic coronary artery disease, cardiac troponin predicts risk of myocardial infarction or cardiovascular death independent of cardiovascular risk factors and disease severity. Further studies are required to evaluate whether routine testing could inform the selection of high-risk patients for treatment intensification. (Myocardial Injury in Patients Referred for Coronary Angiography [MICA]; ISRCTN15620297).

Rising and Falling High-Sensitivity Cardiac Troponin in Diagnostic Algorithms for Patients With Suspected Myocardial Infarction

Background High-sensitivity cardiac troponin (hs-cTn)-based diagnostic algorithms are recommended for the management of patients with suspected myocardial infarction (MI) without ST elevation. Although mirroring different phases of myocardial injury, falling and rising troponin patterns (FPs and RPs, respectively) are equally considered by most algorithms. We aimed to compare the performance of diagnostic protocols for RPs and FPs, separately. Methods and Results We pooled 2 prospective cohorts of patients with suspected MI and stratified patients to stable, FP, and RP during serial sampling separately for hs-cTnI and hs-cTnT and applied the European Society of Cardiology 0/1- and 0/3-hour algorithms comparing the positive predictive values to rule in MI. Overall, 3523 patients were included in the hs-cTnI study population. The positive predictive value for patients with an FP was significantly reduced compared with patients with an RP (0/1-hour: FP, 53.3% [95% CI, 45.0-61.4] versus RP, 76.9 [95% CI, 71.6-81.7]; 0/3-hour: FP, 56.9% [95% CI, 42.2-70.7] versus RP, 78.1% [95% CI, 74.0-81.8]). The proportion of patients in the observe zone was larger in the FP using 0/1-hour (31.3% versus 55.8%) and 0/3-hour (14.6% versus 38.6%) algorithms. Alternative cutoffs did not improve algorithm performances. Compared with stable hs-cTn, the risk for death or MI was highest in those with an FP (adjusted hazard ratio [HR], hs-cTnI 2.3 [95% CI, 1.7-3.2]; RP adjusted HR, hs-cTnI 1.8 [95% CI, 1.4-2.4]). Findings were similar for hs-cTnT tested in 3647 patients overall. Conclusions The positive predictive value to rule in MI by the European Society of Cardiology 0/1- and 0/3-hour algorithms is significantly lower in patients with FP than RP. These are at highest risk for incident death or MI. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02355457, NCT03227159.

Implementation of the ESC 0 h/1 h high-sensitivity troponin algorithm for decision-making in the emergency department

Diagnosis of non-ST-segment elevation acute coronary syndromes (NSTEACS) is based on 3 cornerstones: clinical presentation, 12-lead electrocardiogram, and cardiac troponin measurement. Advances in the development of high-sensitivity cardiac troponin (hs-cTn) assays have substantially improved the detection of cardiomyocyte injury in a shorter time period, and hs-cTn has consequently been established as the gold-standard biomarker for the assessment of patients with suspected NSTEACS. The implementation of these assays in clinical practice allows a faster "rule-out", especially among low-risk patients, as well as a safer and more rapid "rule-in", with its therapeutic consequences. Current guidelines for the diagnosis of NSTEACS recommend the use of hs-cTn applied in rapid diagnostic algorithms based on serial hs-cTn sampling within the first few hours. The current work provides an overview of the use of hs-cTn for the early detection of NSTEACS.

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

PROSPERO REGISTRATION NUMBER

CRD42018106379.