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.

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.

Sex-specific inequalities in the use of drug-coated balloons for small coronary artery disease: a report from the BASKET-SMALL 2 trial.

BACKGROUND AND OBJECTIVES: Recent data have established non-inferiority of drug-coated balloons (DCB) compared to drug-eluting stents (DES) for treatment of small-vessel coronary artery disease. Since coronary vessels in women might have anatomical and pathophysiological particularities, the safety of the DCB strategy among women compared to men needs to be assessed in more detail. METHODS: In BASKET-SMALL 2, patients with de novo lesions in coronary vessels < 3 mm and an indication for percutaneous coronary intervention were randomly allocated (1:1) to DCB vs. DES after successful lesion preparation. The primary objective of the randomized trial was to establish non-inferiority of DCB vs. DES regarding major adverse cardiac events (MACE; i.e., cardiac death, non-fatal myocardial infarction, and target vessel revascularization) after 12 months. The aim of the current sub-analysis is to evaluate whether the DCB strategy is equally safe among women and men after 12 and 36 months. RESULTS: Among 758 randomized patients, 382 were assigned to DCB (23% women) and 376 to DES (30% women). In general, women were older, had more often diabetes mellitus and renal insufficiency, and presented more often with an acute coronary syndrome, whereas men were more often smokers, had multivessel disease and a previous history of acute myocardial infarction, and received a treatment with a statin. After 3 years, the primary clinical end point was not significantly different between groups (13% women vs. 16% men, HR 0.82; 95% CI 0.52-1.30; p = 0.40). There was no interaction between sex and coronary intervention strategy regarding MACE at 36 months (10% women vs. 16% men in DCB, 16% women vs. 15% men in DES; pinteraction = 0.31). CONCLUSION: In small native coronary artery disease, there was no statistically significant effect of sex on the difference between DCB and DES regarding MACE up to 36 months. CLINICAL TRIAL REGISTRATION: URL: http://www. CLINICALTRIALS: gov . Unique identifier: NCT01574534. CAD coronary artery disease, MACE major adverse cardiovascular events, HR Hazard ratio, DCB drug-coated balloon, DES drug-eluting stent.

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.

[Management of acute coronary syndrome without ST-segment elevation]. / Management des akuten Koronarsyndroms ohne ST-Strecken-Hebung.

The collective term acute coronary syndrome (ACS) encompasses ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation ACS (NSTE-ACS). The latter comprises unstable angina pectoris and non-ST-segment elevation myocardial infarction (NSTEMI). The diagnosis of STEMI necessitates an immediate referral to cardiac catheterization. The diagnostics and management of NSTE-ACS are more challenging. The current guidelines of the European Society of Cardiology (ESC) for treatment of NSTE-ACS were published in 2020 and deal with the topics of diagnostics, risk stratification, antithrombotic treatment, invasive or non-invasive coronary diagnostics and long-term treatment. The focus of the guidelines is on the application of high-sensitivity cardiac troponin assay(hs-cTn) combined with verified diagnostic algorithms to enable a rapid triage decision (rule-in as possible NSTEMI or rule-out as NSTEMI excluded) in the emergency room or the chest pain unit.

A 0/1h-algorithm using cardiac myosin-binding protein C for early diagnosis of myocardial infarction.

AIMS: Cardiac myosin-binding protein C (cMyC) demonstrated high diagnostic accuracy for the early detection of non-ST-elevation myocardial infarction (NSTEMI). Its dynamic release kinetics may enable a 0/1h-decision algorithm that is even more effective than the ESC hs-cTnT/I 0/1 h rule-in/rule-out algorithm. METHODS AND RESULTS: In a prospective international diagnostic study enrolling patients presenting with suspected NSTEMI to the emergency department, cMyC was measured at presentation and after 1 h in a blinded fashion. Modelled on the ESC hs-cTnT/I 0/1h-algorithms, we derived a 0/1h-cMyC-algorithm. Final diagnosis of NSTEMI was centrally adjudicated according to the 4th Universal Definition of Myocardial Infarction. Among 1495 patients, the prevalence of NSTEMI was 17%. The optimal derived 0/1h-algorithm ruled-out NSTEMI with cMyC 0 h concentration below 10 ng/L (irrespective of chest pain onset) or 0 h cMyC concentrations below 18 ng/L and 0/1 h increase <4 ng/L. Rule-in occurred with 0 h cMyC concentrations of at least 140 ng/L or 0/1 h increase ≥15 ng/L. In the validation cohort (n = 663), the 0/1h-cMyC-algorithm classified 347 patients (52.3%) as 'rule-out', 122 (18.4%) as 'rule-in', and 194 (29.3%) as 'observe'. Negative predictive value for NSTEMI was 99.6% [95% confidence interval (CI) 98.9-100%]; positive predictive value 71.1% (95% CI 63.1-79%). Direct comparison with the ESC hs-cTnT/I 0/1h-algorithms demonstrated comparable safety and even higher triage efficacy using the 0h-sample alone (48.1% vs. 21.2% for ESC hs-cTnT-0/1 h and 29.9% for ESC hs-cTnI-0/1 h; P < 0.001). CONCLUSION: The cMyC 0/1h-algorithm provided excellent safety and identified a greater proportion of patients suitable for direct rule-out or rule-in based on a single measurement than the ESC 0/1h-algorithm using hs-cTnT/I. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT00470587.

Incidence, clinical presentation, management, and outcome of acute pericarditis and myopericarditis.

AIMS: Little is known about the epidemiology, clinical presentation, management, and outcome of acute pericarditis and myopericarditis. METHODS AND RESULTS: The final diagnoses of acute pericarditis, myopericarditis, and non-ST-segment elevation myocardial infarction (NSTEMI) of patients presenting to seven emergency departments in Switzerland with acute chest pain were centrally adjudicated by two independent cardiologists using all information including serial measurements of high-sensitivity cardiac troponin T. The overall incidence of pericarditis and myopericarditis was estimated relative to the established incidence of NSTEMI. Current management and long-term outcome of both conditions were also assessed. Among 2533 chest pain patients, the incidence of pericarditis, myopericarditis, and NSTEMI were 1.9% (n = 48), 1.1% (n = 29), and 21.6% (n = 548), respectively. Accordingly, the estimated incidence of pericarditis and myopericarditis in Switzerland was 10.1 [95% confidence interval (95% CI) 9.3-10.9] and 6.1 (95% CI 5.6-6.7) cases per 100 000 population per year, respectively, vs. 115.0 (95% CI 112.3-117.6) cases per 100 000 population per year for NSTEMI. Pericarditis (85% male, median age 46 years) and myopericarditis (62% male, median age 56 years) had male predominance, and commonly (50% and 97%, respectively) resulted in hospitalization. No patient with pericarditis or myopericarditis died or had life-threatening arrhythmias within 30 days [incidence 0% (95% CI 0.0-4.8%)]. Compared with NSTEMI, the 2-year all-cause mortality adjusted hazard ratio of pericarditis and myopericarditis was 0.40 (95% CI 0.05-2.96), being 0.59 (95% CI 0.40-0.88) for non-cardiac causes of chest pain. CONCLUSION: Pericarditis and myopericarditis are substantially less common than NSTEMI and have an excellent short- and long-term outcome. CLINICAL TRIAL REGISTRATION: ClinicalTrial.gov, number NCT00470587, https://clinicaltrials.gov/ct2/show/NCT00470587.

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

BACKGROUND: The non-ST-segment-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 cutoff for further triage is endorsed. Recently, a specific cutoff for 0/3h high-sensitivity cardiac troponin T (hs-cTnT) change (7 ng/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 2 independent cardiologists applying the fourth universal definition of myocardial infarction, on the basis of complete cardiac workup, cardiac imaging, and serial hs-cTnT. Hs-cTnT concentrations were measured at presentation, after 1 hour, and after 3 hours. The objective was to externally validate the proposed cutoff, 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 NSTEMI, leaving 564 patients (27.2%) in the observe-zone (adjudicated NSTEMI prevalence, 120/564 patients, 21.3%). The suggested 0/3h-hs-cTnT-change of <7 ng/L triaged 517 patients (91.7%) toward rule-out, resulting in a sensitivity of 33.3% (95% CI, 25.5-42.2), missing 80 patients with NSTEMI, and ≥7 ng/L triaged 47 patients toward 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%) toward 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%) toward 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%s and the number of type 1 myocardial infarction 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. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT00470587.

Cinética temprana de troponina en pacientes con sospecha de infarto agudo de miocardio / Early kinetics of cardiac troponin in suspected acute myocardial infarction

Introducción y objetivos: La cinética de liberación de troponinas cardiacas ultrasensibles (Tnc-us) T e I en pacientes con sospecha de infarto agudo de miocardio (IAM) se desconoce completamente a día de hoy. Nuestro objetivo fue evaluar si la liberación de Tnc-us T/I en las fases iniciales del IAM sigue un patrón linear. Métodos: Estudio multicéntrico prospectivo diagnóstico donde se evaluó la liberación aguda de Tnc-us T/I durante la primera y segunda hora tras la presentación en servicios de urgencias utilizando 3 ensayos diferentes de Tnc-us T/I en pacientes con sospecha de IAM. El objetivo principal del estudio fue la correlación entre los cambios de valores de Tnc-us durante la presentación y 1h con respecto a los cambios durante la presentación y 2h en pacientes con IAM y diferentes subgrupos pre-especificados. El diagnóstico final fue adjudicado por 2 cardiólogos independientes, basándose en los valores seriados de Tnc-us T de las muestras del estudio y los valores adicionales de Tnc-us utilizados localmente. Resultados: Entre los 2.437 pacientes con todas las muestras disponibles de Tnc-usT, el IAM fue el diagnóstico final en 376 pacientes (15%). Para Tnc-usT el coeficiente de correlación entre los cambios 0/1h y 0/2h fue 0,931 (IC95%, 0,916-0,944), p <0,001. Resultados similares se obtuvieron con Tnc-usI (Architect) con coeficiente de correlación de 0,969 y con Tnc-usI (Centaur) con coefficiente de correlación de 0,934 (p <0,001 para los dos). Los resultados fueron consistentes entre los IAM tipo 1 y 2 y entre el subgrupo de pacientes con una presentación temprana tras el inicio del dolor torácico. Conclusiones: Pacientes que presentan en la fase temprana de IAM muestran una linearidad en la liberación de Tnc-usT y Tnc-usI. Esta linearidad ofrece la base fisiopatológica para usar con seguridad los algoritmos 0/1h anticipando los cambios que se producirán durante 0/2h y 0/3h. (AU)

Introduction and objectives: Release kinetics of high-sensitivity cardiac troponin (hs-cTn) T and I in patients with acute myocardial infarction (AMI) are incompletely understood. We aimed to assess whether hs-cTnT/I release in early AMI is near linear. Methods: In a prospective diagnostic multicenter study the acute release of hs-cTnT and hs-cTnI within 1 and 2hours from presentation to the emergency department was quantified using 3 hs-cTnT/I assays in patients with suspected AMI. The primary endpoint was correlation between hs-cTn changes from presentation to 1 hour vs changes from presentation to 2hours, among all AMI patients and different prespecified subgroups. The final diagnosis was adjudicated by 2 independent cardiologists, based on serial hs-cTnT from the serial study blood samples and additional locally measured hs-cTn values. Results: Among 2437 patients with complete hs-cTnT data, AMI was the adjudicated diagnosis in 376 patients (15%). For hs-cTnT, the correlation coefficient between 0- to 1-hour change and 0- to 2 hour change was 0.931 (95%CI, 0.916-0.944), P <.001. Similar findings were obtained with hs-cTnI (Architect) with correlation coefficients between 0- to 1-hour change and 0- to 2 hour change of 0.969 and hs-cTnI (Centaur) of 0.934 (P <.001 for both). Findings were consistent among type 1 and type 2 AMI and in the subgroup of patients presenting very early after chest pain onset. Conclusions: Patients presenting with early AMI showed a near linear release of hs-cTnT and hs-cTnI. This near linearity provides the pathophysiological basis for rapid diagnostic algorithms using 0- to 1-hour changes as surrogates for 0- to 2 hour or 0- to 3 hour changes. (AU)

External Validation and Extension of a Clinical Score for the Discrimination of Type 2 Myocardial Infarction.

BACKGROUND: The early non-invasive discrimination of Type 2 versus Type 1 Myocardial Infarction (T2MI, T1MI) is a major unmet clinical need. We aimed to externally validate a recently derived clinical score (Neumann) combing female sex, no radiating chest pain, and high-sensitivity cardiac troponin I (hs-cTnI) concentration ≤40.8 ng/L. METHODS: Patients presenting with acute chest discomfort to the emergency department were prospectively enrolled into an international multicenter diagnostic study. The final diagnoses of T2MI and T1MI were centrally adjudicated by two independent cardiologists using all information including cardiac imaging and serial measurements of hs-cTnT/I according to the fourth universal definition of MI. Model performance for T2MI diagnosis was assessed by formal tests and graphical means of discrimination and calibration. RESULTS: Among 6684 enrolled patients, MI was the adjudicated final diagnosis in 1079 (19%) patients, of which 242 (22%) had T2MI. External validation of the Neumann Score showed a moderate discrimination (C-statistic 0.67 (95%CI 0.64-0.71)). Model calibration showed underestimation of the predicted probabilities of having T2MI for low point scores. Model extension by adding the binary variable heart rate >120/min significantly improved model performance (C-statistic 0.73 (95% CI 0.70-0.76, p < 0.001) and had good calibration. Patients with the highest score values of 3 (Neumann Score, 9.9%) and 5 (Extended Neumann Score, 3.3%) had a 53% and 91% predicted probability of T2MI, respectively. CONCLUSION: The Neumann Score provided moderate discrimination and suboptimal calibration. Extending the Neumann Score by adding heart rate >120/min improved the model's performance.

Clinical presentation of patients with prior coronary artery bypass grafting and suspected acute myocardial infarction.

AIMS: Diagnosis of acute myocardial infarction (AMI) can be challenging in patients with prior coronary artery bypass grafting (CABG). METHODS AND RESULTS: Final diagnoses were adjudicated by two independent cardiologists using the universal definition of AMI among patients presenting to the emergency department (ED) with suspected AMI. Diagnostic accuracy of 34 chest pain characteristics (CPCs) and four electrocardiogram (ECG) signatures stratified according to the presence or absence of prior CABG were prospectively quantified. Among 4015 patients (no prior CABG: n = 3686; prior CABG: n = 329), prevalence of AMI and unstable angina were higher in patients with prior CABG (35% vs. 18%; 26% vs. 8%; both P < 0.001). Three CPCs (9%) and two electrocardiographic findings (50%) showed a different diagnostic performance (interaction P < 0.05) with loss of diagnostic value in patients with prior CABG. The diagnostic accuracy as quantified by the area under the curve (AUC) of the integrated clinical judgement was moderate to good in patients with prior CABG, and significantly lower compared to patients without prior CABG [AUC 0.80 (95% confidence interval (CI) 0.75-0.84) vs. AUC 0.87 (95% CI 0.86-0.89); P = 0.004]. Time to discharge from the ED was significantly longer in patients with prior CABG [359 (215-525) min vs. 300 (192-435) min; P < 0.001]. Key findings were confirmed in a large independent external validation cohort (n = 13 653). CONCLUSIONS: Patients with prior CABG presenting with suspected AMI have a high prevalence of AMI and unstable angina and lower diagnostic accuracy of CPCs and the ECG, possibly justifying liberal use of early coronary angiography in these vulnerable patients. CLINICALTRIALS.GOV REGISTRY: Number NCT00470587.