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.

Perioperative copeptin: predictive value and risk stratification in patients undergoing major noncardiac surgery-a prospective observational cohort study

PURPOSE

Biomarkers can aid in perioperative risk stratification. While preoperative copeptin has been associated with adverse events, intraoperative information is lacking and this association may rather reflect a baseline risk. Knowledge about correlations between postoperative copeptin measurements and clinically relevant outcomes is scarce. We examined the association of perioperative copeptin concentrations with postoperative all-cause mortality and/or major adverse cardiac and cerebrovascular events (MACCE) at 12 months and 30 days as well as with perioperative myocardial injury (PMI).

METHODS

We conducted a prospective observational cohort study of adults undergoing noncardiac surgery with intermediate to high surgical risk in Basel, Switzerland, and Düsseldorf, Germany from February 2016 to December 2020. We measured copeptin and cardiac troponin before surgery, immediately after surgery (0 hr) and once between the second and fourth postoperative day (POD 2-4).

RESULTS

A primary outcome event of a composite of all-cause mortality and/or MACCE at 12 months occurred in 48/502 patients (9.6%). Elevated preoperative copeptin (> 14 pmol·L-1), immediate postoperative copeptin (> 90 pmol·L-1), and copeptin on POD 2-4 (> 14 pmol·L-1) were associated with lower one-year MACCE-free and/or mortality-free survival (hazard ratio [HR], 2.89; 95% confidence interval [CI], 1.62 to 5.2; HR, 2.07; 95% CI, 1.17 to 3.66; and HR, 2.47; 95% CI, 1.36 to 4.46, respectively). Multivariable analysis continued to show an association for preoperative and postoperative copeptin on POD 2-4. Furthermore, elevated copeptin on POD 2-4 showed an association with 30-day MACCE-free survival (HR, 2.15; 95% CI, 1.18 to 3.91). A total of 64 of 489 patients showed PMI (13.1%). Elevated preoperative copeptin was not associated with PMI, while immediate postoperative copeptin was modestly associated with PMI.

CONCLUSION

The results of the present prospective observational cohort study suggest that perioperative copeptin concentrations can help identify patients at risk for all-cause mortality and/or MACCE. Other identified risk factors were revised cardiac risk index, body mass index, surgical risk, and preoperative hemoglobin.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02687776); first submitted 9 February 2016.

Single Troponin Measurement to Rule Out Myocardial Infarction: JACC Review Topic of the Week

The term "single-sample rule-out" refers to the ability of very low concentrations of high-sensitivity cardiac troponin (hs-cTn) on presentation to exclude acute myocardial infarction with high clinical sensitivity and negative predictive value. Observational and randomized studies have confirmed this ability. Some guidelines endorse use of a concentration of hs-cTn at the assay's limit of detection, while other studies have validated the use of higher concentrations, allowing this approach to identify a greater proportion of patients at low risk. In most studies, at least 30% of patients can be triaged with this approach. The concentration of hs-cTn varies according to the assay used and sometimes how regulations permit reporting. It is clear that patients need to be at least 2 hours from the onset of symptoms being evaluated. Caution is warranted, particularly with older patients, women, and patients with underlying cardiac comorbidities.

Accurate Classification and Prediction of Acute Myocardial Infarction through an ARMD Procedure

The risk stratification of acute myocardial infarction (AMI) patients is of prime importance for clinical management and prognosis assessment. Thus, we propose an ensemble machine learning analysis procedure named ADASYN-RFECV-MDA-DNN (ARMD) to address sample-unbalanced problems and enable stratification and prediction of AMI outcomes. The ARMD analysis procedure was applied to the NMR data of sera from 534 AMI-related subjects in four categories with an extremely imbalanced sample proportion. Firstly, the adaptive synthetic sampling (ADASYN) algorithm was used to address the issue of the original sample imbalance. Secondly, the recursive feature elimination with cross-validation (RFECV) processing and random forest mean decrease accuracy (RF-MDA) algorithm was performed to identify the differential metabolites corresponding to each AMI outcome. Finally, the deep neural network (DNN) was employed to classify and predict AMI events, and its performance was evaluated by comparing the four traditional machine learning methods. Compared with the other four machine learning models, DNN presented consistent superiority in almost all of the model parameters including precision, f1-score, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and classification accuracy, highlighting the potential of deep learning in classification and stratification of clinical diseases. The ARMD analysis procedure was a practical analysis tool for supervised classification and regression modeling of clinical diseases.

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.

Copeptin plus troponin in the rapid rule out of acute myocardial infarction and prognostic value on post-myocardial infarction outcomes: a systematic review and diagnostic accuracy study

BACKGROUND

A critical and unmet therapeutic need is the prompt and reliable exclusion of acute myocardial infarction (AMI), which would allow for prompt discharge from the emergency department. High-sensitivity troponin (HS-TnT) combined with copeptin has been proposed to expedite the diagnostic exclusion of AMI in addition to its predictive usefulness in the intermediate and long-term outcomes of AMI. The European Society of Cardiology recommends the Global Registry of Acute Coronary Events (GRACE) as a prognostic score to manage acute coronary syndrome (ACS) without ST segment elevation. The purpose of this study was to compare the diagnostic accuracy of HS-TnT combined with copeptin in ruling out AMI compared to HS-TnT alone. By combining a low GRACE score (108) with negative HS-TnT (14 ng/L) and copeptin (14 pmol/L), non-ST and ACS were reliably ruled out, including non-ST segment elevation MI and unstable angina.

RESULTS

The present research included nine studies with a total of 13,232 participants. The negative predictive value (NPV) for copeptin and HS-TnT was found to be slightly higher in combination (62-99%) than for HS-TnT alone (60-99%). The sensitivity of copeptin ranged from 0% to 100%, with a pooled sensitivity of 0.79 (CI 95% 0.76, 0.82). The specificity of copeptin ranged from 13% to 100%, with a pooled specificity of 0.89 (CI 95% 0.85, 0.91), a pooled positive likelihood ratio (PLR) of 9.86 (CI 95% 4.42, 22.02), and a pooled negative likelihood ratio (NLR) of 0.08. (95% CI 0.01, 0.44).

CONCLUSIONS

The use of combined negative copeptin and highly sensitive troponin testing in low-to-intermediate risk patients with suspected acute coronary syndrome resulted in a quick discharge with a safe and rapid rule out of non-ST + ACS.

Improving the ACS Triage-Using High Sensitivity TroponinI and Copeptin for Early 'Rule-Out' of AMI

Rule-out of acute myocardial infarction (AMI) in patients presenting with acute chest pain at the emergency department (ED) is a major challenge across the globe. Patients presenting very early with chest pain may provide a diagnostic challenge even when using a cardiac necrosis specific biomarker, high sensitivity troponin (hs-Tn) as they are elevated at 3-6 h after the symptom onset. Copeptin is a marker of acute hemodynamic stress which is released within few minutes of the occurrence of MI and is elevated immediately at the presentation of patients with AMI. This indicates a complementary pathophysiology and kinetics of these two biomarkers. Hence, we evaluated whether or not a protocol with combined testing of copeptin and hs-TnI at admission in patients presenting with chest pain within 6 h in low to intermediate risk and suspected ACS leads to an earlier diagnosis of AMI and thereby, aids to prevent a higher proportion of major adverse cardiac events than the current standard protocol followed in ED. A total of 148 patients as per the inclusion criterion were recruited for the study. The dual biomarker copeptin and hs-TnI allows a rule-out of AMI at presentation with a sensitivity of 100% and NPV of 99.8%. Hence, the use of dual biomarker in conjunction with clinical assessment may obviate the need for a prolonged stay in the ED and retesting hs-TnI after 2 h (for delta check) in more than two-thirds of the patients. The inclusion of these tests could have an impact on the economic burden of the ED without jeopardizing the outcome for the patient.

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.

Feasibility of prehospital identification of non-ST-elevation myocardial infarction by ECG, troponin and echocardiography

Background

Prehospital identification and selection of treatment strategy in patients with suspected non-ST-elevation myocardial infarction (NSTEMI) is challenging. The aim of this study was to evaluate the feasibility and diagnostic accuracy of prehospital ECG, troponin T (TnT) and transthoracic echocardiography (TTE) acquired by paramedics in early identification of NSTEMI.

Methods

Consecutive patients requesting an ambulance from Sorlandet Hospital, Norway due to chest pain between November 2017 and January 2020 were screened for inclusion in the study. One ambulance was equipped with ECG recorder, point-of-care TnT test and TTE scanner, and six paramedics were given necessary training. ECG, TnT result and TTE images were acquired prehospitally and transferred to an in-hospital cardiologist. NSTEMI was suspected in patients with ischaemic ECG changes, elevated TnT or myocardial regional wall motion abnormalities (RWMA) at TTE.

Results

A total of 253 patients were included in the study. ECG was interpretable by cardiologists in 243 (96%), TnT in 238 (94%) and TTE images in 240 (95%) patients. NSTEMI was the discharge diagnosis in 22 (9%) of these patients. Four (18%) patients with NSTEMI had ischaemic ECG changes, elevated TnT and RWMA at TTE. Eight (36%) patients with NSTEMI had positive findings at two of the diagnostic methods, six (27%) patients had positive findings at one, and four (18%) patients had no positive findings in any of the diagnostic methods. In three patients (14%) with NSTEMI, RWMA was the only positive test. The negative and positive predictive values for RWMA were 42% and 96%, respectively.

Conclusions

Prehospital acquisition of ECG, TnT and interpretable TTE images by paramedics were feasible in most patients with chest pain. Based on these examinations, it was possible to identify the majority of cases with NSTEMI prehospitally and admit the patients directly to a hospital with facilities for percutaneous coronary intervention (PCI) for further treatment.

Trial registration number

NCT04223986.

Improvement of outcome prediction of hospitalized patients with COVID-19 by a dual marker strategy using high-sensitive cardiac troponin I and copeptin

Background

COVID-19 has been associated with a high prevalence of myocardial injury and increased cardiovascular morbidity. Copeptin, a marker of vasopressin release, has been previously established as a risk marker in both infectious and cardiovascular disease.

Methods

This prospective, observational study of patients with laboratory-confirmed COVID-19 infection was conducted from June 6th to November 26th, 2020 in a tertiary care hospital. Copeptin and high-sensitive cardiac troponin I (hs-cTnI) levels on admission were collected and tested for their association with the primary composite endpoint of ICU admission or 28-day mortality.

Results

A total of 213 eligible patients with COVID-19 were included of whom 55 (25.8%) reached the primary endpoint. Median levels of copeptin and hs-cTnI at admission were significantly higher in patients with an adverse outcome (Copeptin 29.6 pmol/L, [IQR, 16.2–77.8] vs 17.2 pmol/L [IQR, 7.4–41.0] and hs-cTnI 22.8 ng/L [IQR, 11.5–97.5] vs 10.2 ng/L [5.5–23.1], P < 0.001 respectively). ROC analysis demonstrated an optimal cut-off of 19.3 pmol/L for copeptin and 16.8 ng/L for hs-cTnI and an increase of either biomarker was significantly associated with the primary endpoint. The combination of raised hs-cTnI and copeptin yielded a superior prognostic value to individual measurement of biomarkers and was a strong prognostic marker upon multivariable logistic regression analysis (OR 4.274 [95% CI, 1.995–9.154], P < 0.001). Addition of copeptin and hs-cTnI to established risk models improved C-statistics and net reclassification indices.

Conclusion

The combination of raised copeptin and hs-cTnI upon admission is an independent predictor of ICU admission or 28-day mortality in hospitalized patients with COVID-19.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01970-4.

Hochsensitive kardiale Troponine zur Diagnose des akuten Koronarsyndroms ohne ST-Hebung

Die Diagnose des akuten Koronarsyndroms basiert im Wesentlichen auf 3 Säulen: der klinischen Präsentation, dem 12-Kanal-Elektrokardiogramm und der seriellen Messung von Biomarkern zur Quantifizierung einer Myokardschädigung. Durch die Entwicklung von hochsensitiven kardialen Troponin-Assays (hs-cTn) mit verbesserter analytischer Sensitivität konnte die Zeit nach Eintreten einer Myokardschädigung bis zu deren Nachweis durch im Blut zirkulierendes Troponin relevant verkürzt werden. Somit können einerseits Myokardinfarkte frühzeitig erkannt werden und es erlaubt andererseits auch die Detektion kleinerer Infarkte, die bisher unentdeckt blieben. Aufgrund der hohen Sensitivität kann bei Patienten mit sehr niedrigen hs-cTn-Konzentrationen frühzeitig ein akuter Myokardinfarkt ausgeschlossen werden bzw. nach anderen Differenzialdiagnosen gesucht werden. Patienten mit deutlich erhöhten hs-cTn-Konzentrationen können rascher identifiziert werden und einer unmittelbaren invasiven Abklärung und Aufnahme auf eine Überwachungsstation zugeführt werden. Die im August 2020 neu publizierten europäischen Richtlinien für die Diagnose von akuten Myokardinfarkten ohne ST-Hebung empfehlen die Anwendung von diagnostischen Algorithmen basierend auf seriellen hs-cTn-Messungen nach 1 oder 2 (3) Stunden für eine sichere und schnelle Diagnosestellung. Diese Arbeit soll einen Überblick über die aktuellen Richtlinienempfehlungen im Hinblick auf die Anwendung von hs-cTn in der Früherkennung des akuten Koronarsyndroms geben.

The significance of transaminase ratio (AST/ALT) in acute myocardial infarction

Introduction

Fernando De Ritis described the significance of the transaminase (AST/ALT) ratio in 1957, and since then it has been commonly used to screen liver diseases. The liver is sensitive to hemodynamic changes because it receives approximately one-quarter of total cardiac output. We aimed to investigate the AST/ALT ratio changes in patients with acute myocardial infarction without any history of liver diseases in the Chinese Han population.

Material and methods

We analyzed a total of 120 patients with acute myocardial infarction admitted to the cardiology department of Zhongnan Hospital of Wuhan University between January 2019 and June 2019. AST/ALT ratio of the first blood test was calculated for all patients.

Results

The mean De Ritis ratio (AST/ALT) was higher in patients with ST-segment elevation myocardial infarction (STEMI) (3.2261 ±2.41379) than in non-ST-segment elevation myocardial infarction (NSTEMI) (2.2089 ±1.63177) patients. The difference was statistically significant (p = 0.002).

Conclusions

AST/ALT ≥ 2.0 has a strong association with total coronary occlusion. We might rely on this test to predict coronary occlusion without age difference.

Troponin least significant change (z-score) is associated with poor clinical outcomes in patients presenting to the emergency department

BACKGROUND

A rise and/or fall in high sensitivity cardiac troponin (hs-Tn) is critical in defining acute myocardial injury and therefore the diagnosis of acute myocardial infarction. A significant rise in hs-Tn is not well defined in current guidelines. Calculation of a z-score for two consecutive hs-Tn measurements is a method-independent measure of dynamic troponin elevation. However, the association of hs-Tn z-score with outcomes for unselected emergency department admissions is unknown. Moreover, the association of non-dynamic troponin elevations, as defined by a normal z-score, with clinical outcomes remains to be assessed.

METHODS

We retrospectively calculated z-scores for patients presenting to emergency department over 18 months who had serial troponin measurements with at least one result >99th percentile using the Abbott hs-TnI assay. We assessed the association of z-score with discharge diagnosis, cardiac interventions, inpatient mortality, length of stay and readmission rates.

RESULTS

There were 2062 presentations for 1830 patients where a z-score was calculated. Z-score was elevated in 1080 presentations. Dynamic troponin elevation (z-score ≥ 2) was associated with acute myocardial infarction (OR = 9.1, P < 0.01), admission to an inpatient unit (95 vs. 88%, P < 0.01), increased inpatient length of stay (97 vs. 65 days, P < 0.01), inpatient coronary intervention (21 vs. 6%, P < 0.01) and mortality (4.4 vs. 2.4%, P < 0.05) compared with myocardial injury with a static troponin elevation.

CONCLUSIONS

Z-score is an assay-independent tool to alert clinicians of significant, dynamic troponin elevation and acute myocardial injury. It is associated with poorer clinical outcomes.

Cardiac troponins: are there any differences between T and I?

The most recent international guidelines recommend the measurement of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) using high-sensitivity methods (hs-cTn) for the detection of myocardial injury and the differential diagnosis of acute coronary syndromes. Myocardial injury is a prerequisite for the diagnosis of acute myocardial infarction, but also a distinct entity. The 2018 Fourth Universal Definition of Myocardial Infarction states that myocardial injury is detected when at least one value above the 99th percentile upper reference limit is measured in a patient with high-sensitivity methods for cTnI or cTnT. Not infrequently, increased hs-cTnT levels are reported in patients with congenital or chronic neuromuscular diseases, while the hs-cTnI values are often in the normal range. Furthermore, some discrepancies between the results of laboratory tests for the two troponins are occasionally found in individuals apparently free of cardiac diseases, and also in patients with cardiac diseases. In this review article, authors discuss the biochemical, pathophysiological and analytical mechanisms which may cause discrepancies between hs-cTnI and hs-cTnT test results.

A Possible Mechanism behind Faster Clearance and Higher Peak Concentrations of Cardiac Troponin I Compared with Troponin T in Acute Myocardial Infarction

BACKGROUND

Although cardiac troponin I (cTnI) and troponin T (cTnT) form a complex in the human myocardium and bind to thin filaments in the sarcomere, cTnI often reaches higher concentrations and returns to normal concentrations faster than cTnT in patients with acute myocardial infarction (MI).

METHODS

We compared the overall clearance of cTnT and cTnI in rats and in patients with heart failure and examined the release of cTnT and cTnI from damaged human cardiac tissue in vitro.

RESULTS

Ground rat heart tissue was injected into the quadriceps muscle in rats to simulate myocardial damage with a defined onset. cTnT and cTnI peaked at the same time after injection. cTnI returned to baseline concentrations after 54 h, compared with 168 h for cTnT. There was no difference in the rate of clearance of solubilized cTnT or cTnI after intravenous or intramuscular injection. Renal clearance of cTnT and cTnI was similar in 7 heart failure patients. cTnI was degraded and released faster and reached higher concentrations than cTnT when human cardiac tissue was incubated in 37°C plasma.

CONCLUSION

Once cTnI and cTnT are released to the circulation, there seems to be no difference in clearance. However, cTnI is degraded and released faster than cTnT from necrotic cardiac tissue. Faster degradation and release may be the main reason why cTnI reaches higher peak concentrations and returns to normal concentrations faster in patients with MI.

Application of the fourth universal definition of myocardial infarction in clinical practice

Purpose: The Fourth Universal Definition of Myocardial Infarction (MI) has highlighted the different pathophysiological mechanisms that may lead to ischaemic and non-ischaemic myocardial injury and has emphasised that the diagnosis of myocardial infarction requires the presence of acute myocardial ischaemia in the setting of acute myocardial injury. This case based review intends to illustrate basic principles on how to apply this new, revised definition in clinical practice.Methods and Results: The distinction between different types of MIs (type 1 or type 2) and the delineation of MI from acute non-ischaemic myocardial injury may be challenging in individual patients, which is illustrated by presenting and discussing real-life routine cases.Conclusions: Type 1 MI is a consequence of coronary plaque rupture or erosion with intracoronary thrombus formation that is usually apparent on coronary angiography. Plausible triggering mechanisms causing myocardial oxygen supply/demand mismatch must be identified for the diagnosis of type 2 MI and its treatment should focus initially on management of the underlying disease attributable to acute myocardial ischaemia.

Early kinetics of cardiac troponin in suspected acute myocardial infarction

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. Registered at ClinicalTrials.gov (Identifier: NCT00470587).

Diagnostic and prognostic value of ST-segment deviation scores in suspected acute myocardial infarction

BACKGROUND

Recent advances in digital electrocardiography technology allow evaluating ST-segment deviations in all 12 leads as quantitative variables and calculating summed ST-segment deviation scores. The diagnostic and prognostic utility of summed ST-segment deviation scores is largely unknown.

METHODS

We aimed to explore the diagnostic and prognostic utility of the conventional and the modified ST-segment deviation score (Better Analysis of ST-segment Elevations and Depressions in a 12- Lead-ECG-Score (BASEL-Score): sum of elevations in the augmented voltage right - lead (aVR) plus absolute, unsigned ST-segment depressions in the remaining leads) in patients presenting with suspected non-ST-segment elevation myocardial infarction. The diagnostic endpoint was non-ST-segment elevation myocardial infarction, adjudicated by two independent cardiologists. Prognostic endpoint was mortality during two-year follow up.

RESULTS

Among 1330 patients, non-ST-segment elevation myocardial infarction was present in 200 (15%) patients. Diagnostic accuracy for non-ST-segment elevation myocardial infarction as quantified by the area under the receiver-operating-characteristics curve was significantly higher for the BASEL-Score (0.73; 95% confidence interval 0.69-0.77) as compared to the conventional ST-segment deviation score (0.53; 95% confidence interval 0.49-0.57, p<0.001). The BASEL-Score provided additional independent diagnostic value to dichotomous electrocardiogram variables (ST-segment depression, T-inversion, both p<0.001) and to high-sensitivity cardiac troponin (p<0.001) as well as clinical judgment at 90 min (p<0.001). Similarly, only the BASEL-Score proved to be an independent predictor of two year mortality.

CONCLUSIONS

The modified ST-segment deviation score BASEL-Score focusing on ST-segment elevation in aVR and ST-segment depressions in the remaining leads provides incremental diagnostic and prognostic information.

Rapid rule out for suspected myocardial infarction: is the algorithm appropriate for all?

Aims

Patients presenting to the emergency department (ED) with cardiac chest pain and high-sensitive troponin I (HsTnI) less than 5 ng/L have very good prognosis and low risk for major adverse cardiovascular events. The 2015 European Society of Cardiology (ESC) guidelines for non-ST-elevation myocardial infarction (MI)/acute coronary syndrome (ACS) suggests that patients with normal high-sensitive troponin, which are free of chest pain and have a global registry of acute coronary events (GRACE) score less than 140 are eligible for discharge from the hospital for outpatient workup. Our hypothesis suggests that not all patients with GRACE score under 140 should be discharged for ambulatory tests even with undetectable HsTnI as recommended in the guidelines.

Methods and results

Population-based retrospective cohort study in a large tertiary care centre. The study population included all patients discharged from the hospital between 1 February 2016 and 28 February 2019 following rule out of MI. During the study period, a total of 13 800 patients were discharged from the hospital after rule out of MI. Among them, 9236 (67%) had HsTnI below 5 ng/L. A total of 7705 patients (83%) met the criteria for low (n = 7162) or moderate (n = 543) GRACE risk score. Moderate-risk patients had significantly more adverse events than low-risk patients (4.6% vs. 2.1%, P &lt; 0.001). They are in higher risk of death (0.5% vs. 0.1%, P = 0.042), revascularization (3.9% vs. 1.8%, P = 0.0047), and readmission due to ACS (1.1% vs. 0.4%, P = 0.031).

Conclusion

Patients presenting to the ED with chest pain and HsTnI less than 5 ng/L and GRACE score under 140 have 2–4% adverse event in 60 days. The differences between the groups suggest using rapid rule out algorithms for only low-risk patients with GRACE score under 73.

Diagnosis and risk stratification of chest pain patients in the emergency department: focus on acute coronary syndromes. A position paper of the Acute Cardiovascular Care Association

This paper provides an update on the European Society of Cardiology task force report on the management of chest pain. Its main purpose is to provide an update on the decision algorithms and diagnostic pathways to be used in the emergency department for the assessment and triage of patients with chest pain symptoms suggestive of acute coronary syndromes.

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

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

Clinical Use of a New High-Sensitivity Cardiac Troponin I Assay in Patients with Suspected Myocardial Infarction

BACKGROUND

We aimed to validate the clinical performance of the high-sensitivity cardiac troponin I [VITROS^® Immunodiagnostic Products hs Troponin I (hs-cTnI-VITROS)] assay.

METHODS

We enrolled patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction (AMI). Final diagnoses were centrally adjudicated by 2 independent cardiologists considering all clinical information, including cardiac imaging: first, using serial hs-cTnT-Elecsys (primary analysis) and, second, using hs-cTnI-Architect (secondary analysis) measurements in addition to the clinically used (hs)-cTn. hs-cTnI-VITROS was measured at presentation and at 1 h in a blinded fashion. The primary objective was direct comparison of diagnostic accuracy as quantified by the area under the ROC curve (AUC) of hs-cTnI-VITROS vs hs-cTnT-Elecsys and hs-cTnI-Architect, and in a subgroup also hs-cTnI-Centaur and hs-cTnI-Access. Secondary objectives included the derivation and validation of an hs-cTnI-VITROS-0/1-h algorithm.

RESULTS

AMI was the adjudicated final diagnosis in 158 of 1231 (13%) patients. At presentation, the AUC for hs-cTnI-VITROS was 0.95 (95% CI, 0.93-0.96); for hs-cTnT-Elecsys, 0.94 (95% CI, 0.92-0.95); and for hs-cTnI-Architect, 0.92 (95% CI, 0.90-0.94). AUCs for hs-cTnI-Centaur and hs-cTnI-Access were 0.95 (95% CI, 0.94-0.97). Applying the derived hs-cTnI-VITROS-0/1-h algorithm (derivation cohort n = 519) to the validation cohort (n = 520), 53% of patients were ruled out [sensitivity, 100% (95% CI, 94.1-100)] and 14% of patients were ruled in [specificity, 95.6% (95% CI, 93.4-97.2)]. Patients ruled out by the 0/1-h algorithm had a survival rate of 99.8% at 30 days. Findings were confirmed in the secondary analyses using the adjudication including serial measurements of hs-cTnI-Architect.

CONCLUSIONS

The hs-cTnI-VITROS assay has at least comparable diagnostic accuracy with the currently best validated hs-cTnT and hs-cTnI assays.

CLINICALTRIALSGOV IDENTIFIER

NCT00470587.

Combining High-Sensitivity Cardiac Troponin I and Cardiac Troponin T in the Early Diagnosis of Acute Myocardial Infarction

BACKGROUND

Combining 2 signals of cardiomyocyte injury, cardiac troponin I (cTnI) and T (cTnT), might overcome some individual pathophysiological and analytical limitations and thereby increase diagnostic accuracy for acute myocardial infarction with a single blood draw. We aimed to evaluate the diagnostic performance of combinations of high-sensitivity (hs) cTnI and hs-cTnT for the early diagnosis of acute myocardial infarction.

METHODS

The diagnostic performance of combining hs-cTnI (Architect, Abbott) and hs-cTnT (Elecsys, Roche) concentrations (sum, product, ratio, and a combination algorithm) obtained at the time of presentation was evaluated in a large multicenter diagnostic study of patients with suspected acute myocardial infarction. The optimal rule-out and rule-in thresholds were externally validated in a second large multicenter diagnostic study. The proportion of patients eligible for early rule-out was compared with the European Society of Cardiology 0/1 and 0/3 hour algorithms.

RESULTS

Combining hs-cTnI and hs-cTnT concentrations did not consistently increase overall diagnostic accuracy as compared with the individual isoforms. However, the combination improved the proportion of patients meeting criteria for very early rule-out. With the European Society of Cardiology 2015 guideline recommended algorithms and cut-offs, the proportion meeting rule-out criteria after the baseline blood sampling was limited (6% to 24%) and assay dependent. Application of optimized cut-off values using the sum (9 ng/L) and product (18 ng²/L²) of hs-cTnI and hs-cTnT concentrations led to an increase in the proportion ruled-out after a single blood draw to 34% to 41% in the original (sum: negative predictive value [NPV] 100% [95% confidence interval (CI), 99.5% to 100%]; product: NPV 100% [95% CI, 99.5% to 100%]) and in the validation cohort (sum: NPV 99.6% [95% CI, 99.0-99.9%]; product: NPV 99.4% [95% CI, 98.8-99.8%]). The use of a combination algorithm (hs-cTnI <4 ng/L and hs-cTnT <9 ng/L) showed comparable results for rule-out (40% to 43% ruled out; NPV original cohort 99.9% [95% CI, 99.2-100%]; NPV validation cohort 99.5% [95% CI, 98.9-99.8%]) and rule-in (positive predictive value [PPV] original cohort 74.4% [95% Cl, 69.6-78.8%]; PPV validation cohort 84.0% [95% Cl, 79.7-87.6%]).

CONCLUSIONS

New strategies combining hs-cTnI and hs-cTnT concentrations may significantly increase the number of patients eligible for very early and safe rule-out, but do not seem helpful for the rule-in of acute myocardial infarction.

CLINICAL TRIAL REGISTRATION

URL (APACE): https://www.clinicaltrial.gov . Unique identifier: NCT00470587. URL (ADAPT): www.anzctr.org.au . Unique identifier: ACTRN12611001069943.

High-Sensitivity Cardiac Troponin I Assay for Early Diagnosis of Acute Myocardial Infarction

BACKGROUND

The aim of this study was to validate the clinical performance of the Beckman Access high-sensitivity cardiac troponin I (hs-cTnI) assay.

METHODS

We enrolled patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction (AMI). Final diagnoses were centrally adjudicated by 2 independent cardiologists with all clinical information including cardiac imaging twice: first, using serial hs-cTnT (Elecsys, primary analysis), and second, using hs-cTnI (Architect, secondary analysis) measurements in addition to the clinically used hs-cTn. hs-cTnI Access was measured at presentation and at 1 h. The primary objective was a direct comparison of diagnostic accuracy as quantified by the area under the ROC curve (AUC) of hs-cTnI Access vs the hs-cTnT Elecsys and hs-cTnI Architect assays. Secondary objectives included the derivation and validation of an hs-cTnI Access-specific 0/1-h algorithm.

RESULTS

AMI was the adjudicated final diagnosis in 243 of 1579 (15.4%) patients. The AUC at presentation for hs-cTnI Access was 0.95 (95% CI, 0.94–0.96), higher than hs-cTnI Architect [0.92 (95% CI, 0.91–0.94; P &lt; 0.001)] and comparable to hs-cTnT Elecsys [0.94 (95% CI, 0.93–0.95; P = 0.12)]. Applying the derived hs-cTnI Access 0/1-h algorithm (derivation cohort n = 686) to the validation cohort (n = 680), 60% of patients were ruled out [sensitivity, 98.9% (95% CI, 94.3–99.8)], and 15% of patients were ruled in [specificity, 95.9% (95% CI, 94.0–97.2)]. Patients ruled out by the 0/1-h algorithm had a survival rate of 100% at 30 days. Findings were confirmed in the secondary analyses by the adjudication including serial measurements of Architect hs-cTnI.

CONCLUSIONS

Diagnostic accuracy and clinical utility of the Beckman hs-cTnI Access assay are very high and at least comparable to Roche hs-cTnT and Abbott hs-cTnI assays. ClinicalTrials.gov Identifier: NCT00470587.

Peri-operative copeptin concentrations and their association with myocardial injury after vascular surgery: A prospective observational cohort study

BACKGROUND

Copeptin levels in conjunction with cardiac troponin may be used to rule out early myocardial infarction in patients presenting with chest pain. Raised pre-operative copeptin has been shown to be associated with postoperative cardiac events. However, very little is known about the peri-operative time course of copeptin or the feasibility of very early postoperative copeptin measurement to diagnose or rule-out myocardial injury.

OBJECTIVES

In this preparatory analysis for a larger trial, we sought to examine the time course of peri-operative copeptin and identify the time at which concentrations returned to pre-operative levels. Second, in an explorative analysis, we sought to examine the association of copeptin in general and at various time points with myocardial injury occurring within the first 48 h.

DESIGN

Preparatory analysis of a prospective, observational cohort study.

SETTING

Single university centre from February to July 2016.

PATIENTS

A total of 30 consecutive adults undergoing vascular surgery.

INTERVENTION

Serial peri-operative copeptin measurements.

MAIN OUTCOME MEASURE

We measured copeptin concentrations before and immediately after surgery (0 h), then at 2, 4, 6 and 8 h after surgery and on the first and second postoperative day. Postoperative concentrations were compared with pre-operative levels with a Wilcoxon signed-rank test. Second, we explored an association between postoperative copeptin concentrations and myocardial injury by the second postoperative day. Myocardial injury was defined as a 5 ng l increase between pre-operative and postoperative high-sensitivity cardiac troponin T with an absolute peak of at least 20 ng l.

RESULTS

Immediate postoperative copeptin concentrations (median [interquartile range]) increased nearly eight-fold from pre-operative values (8.5 [3.6 to 13.8] to 64.75 pmol l [29.6 to 258.7]; P < 0.001). Copeptin concentrations remained elevated until returning to baseline on the second postoperative day. Postoperative copeptin was significantly higher in patients experiencing myocardial injury than in those who did not (P = 0.02). The earliest most promising single time point for diagnosis may be immediately after surgery (0 h). The receiver-operating characteristics curve for immediate postoperative copeptin and myocardial injury by the second postoperative day was 0.743 (95% confidence interval 0.560 to 0.926).

CONCLUSION

Copeptin concentrations are greatly increased after vascular surgery and remain so until the 2nd postoperative day. Postoperative copeptin concentrations appear to be higher in patients who go on to exhibit myocardial injury. Immediate postoperative copeptin concentrations show promise for eliminating or identifying those at risk of myocardial injury.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02687776, Mauermann/Lurati Buse.

Predicting Acute Myocardial Infarction with a Single Blood Draw

BACKGROUND

We desired to determine cardiac troponin (cTn) concentrations necessary to achieve a positive predictive value (PPV) of ≥75% for acute myocardial infarction (AMI) to justify immediate admission of patients to a monitored unit and, in general, early coronary angiography.

METHODS

In a prospective multicenter diagnostic study enrolling patients presenting to the emergency department with symptoms suggestive of AMI, final diagnoses were adjudicated by 2 independent cardiologists based on clinical information including cardiac imaging. cTn concentrations were measured using 5 different sensitive and high-sensitivity cTn (hs-cTn) assays in a blinded fashion at presentation and serially thereafter. The diagnostic end point was PPV for rule-in of AMI of initial cTn concentrations alone and in combination with early changes.

RESULTS

Among 3828 patients, 616 (16%) had an AMI. At presentation, 7% to 14% of patients had cTnT/I concentrations associated with a PPV of ≥75%. Adding absolute or relative changes did not significantly further increase the PPV. PPVs increased from 46.5% (95% CI, 43.6–49.4) for hs-cTnT at presentation &gt;14 ng/L to 78.9% (95% CI, 74.7–82.5) for &gt;52 ng/L (P &lt; 0.001), whereas PPVs in higher hs-cTnT strata remained largely unchanged [e.g., 82.4% (95% CI, 77.5–86.7) for &gt;80 ng/L vs 83.9% (95% CI, 76.0–90.1) for &gt;200 ng/L (P = 0.72)]. The addition of early changes in hs-cTnT further increased the PPV up to 60 ng/L, but not for higher concentrations.

CONCLUSIONS

Serial sampling does not seem necessary for predicting AMI and concurrent decision-making in about 10% of patients, as it only marginally increases the PPV for AMI and not in a statistically or clinically significant way.

ClinicalTrials.gov Identifier

NCT00470587.

Comparison of fourteen rule-out strategies for acute myocardial infarction

BACKGROUND

The clinical availability of high-sensitivity cardiac troponin (hs-cTn) has enabled the development of several innovative strategies for the rapid rule-out of acute myocardial infarction (AMI). Due to the lack of direct comparisons, selection of the best strategy for clinical practice is challenging.

METHODS

In a prospective international multicenter diagnostic study enrolling 3696 patients presenting with suspected AMI to the emergency department, we compared the safety and efficacy of 14 different hs-cTn-based strategies: hs-cTn concentrations below the limit of detection (LoD), dual-marker combining hs-cTn with copeptin, ESC 0 h/1 h-algorithm, 0 h/2 h-algorithm, 2 h-ADP-algorithm, NICE-algorithm, and ESC 0 h/3 h-algorithm, each using either hs-cTnT or hs-cTnI. The final diagnosis of AMI was adjudicated by two independent cardiologists using all available clinical information including cardiac imaging and serial hs-cTn concentrations.

RESULTS

AMI was the final diagnosis in 16% of patients. Using hs-cTnT, safety quantified by the negative predictive value (NPV) and sensitivity was very high (99.8-100% and 99.5-100%) and comparable for all strategies, except the dual-marker approach (NPV 98.7%, sensitivity 96.7%). Similarly, using hs-cTnI, safety quantified by the NPV and sensitivity was very high (99.7-100% and 98.9-100%) and comparable for all strategies, except the dual-marker approach (NPV 96.9%, sensitivity 90.4%) and the NICE-algorithm (NPV 99.1%, sensitivity 94.7%). Efficacy, quantified by the percentage of patients eligible for rule-out, differed markedly, and was lowest for LoD-algorithm (15.7-26.8%).

CONCLUSION

All rapid rule-out algorithms, except the dual-marker strategy and the NICE-algorithm using hs-cTnI, favorably combine safety and efficacy, and can be considered for routine clinical practice.

CLINICAL TRIAL REGISTRATION

NCT00470587, http://clinicaltrials.gov/show/NCT00470587.

Cardiac Troponin - diagnostic problems and impact on cardiovascular disease

The definition of a high-sensitivity cardiac Troponin (cTn) assay describes the ability to quantify a cardiac biomarker level in at least 50% of healthy individuals. This advance in analytic sensitivity has come with a perceived loss of specificity in the most classic application - chest pain triage and the diagnosis of acute myocardial infarction (AMI). As cardiac Troponin can no longer be used as a dichotomous test, the medical field is increasingly moving towards a more granular interpretation. However, rapid rule-out/rule-in algorithms for AMI still rely on concrete thresholds for efficient triage, irrespective of the patient's comorbidities. Owing to a slightly elevated cTn value, evermore patients appear to fall into an indeterminate risk zone of diagnostic uncertainty. The reasons are manifold, spanning biological variation, analytical issues, increased plasma membrane permeability and the potential cytosolic release of cTn. This review provides a contemporary overview of the literature concerning the use of cardiac Troponin in chronic and acute cardiovascular care. Key messages High-sensitivity cardiac Troponin assays have transformed the assessment of cardiovascular disease. Rapid rule-out algorithms for chest pain triage have become increasingly complicated, but enable safe rule-out. Cardiac Troponin tracks mid- to long-term risk in patients with hyperlipidaemia, heart failure and renal dysfunction.

Clinical Validation of a Novel High-Sensitivity Cardiac Troponin I Assay for Early Diagnosis of Acute Myocardial Infarction

BACKGROUND

Clinical performance of the novel high-sensitivity cardiac troponin I (Siemens-hs-cTnI-Centaur) assay is unknown. We aimed to clinically validate the Siemens-hs-cTnI-Centaur assay and develop 0/1-h and 0/2-h algorithms.

METHODS

We enrolled patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction (AMI). Final diagnoses were centrally adjudicated by 2 independent cardiologists including all clinical information twice: first, using serial hs-cTnT (Roche-Elecsys, primary analysis); second, using hs-cTnI (Abbott-Architect, secondary analysis) measurements in addition to the clinically applied (hs)-cTn. Siemens-hs-cTnI-Centaur was measured at presentation, 1 h, and 2 h. The primary objective was a direct comparison of diagnostic accuracy, quantified by the area under the ROC curve (AUC), of Siemens-hs-cTnI-Centaur vs the 2 established hs-cTn assays (Roche-hs-cTnT-Elecsys, Abbott-hs-cTnI-Architect). Secondary objectives included the development of Siemens-hs-cTnI-Centaur-specific 0/1-h and 0/2-h algorithms.

RESULTS

AMI was the final diagnosis in 318 of 1755 (18%) patients (using Roche-hs-cTnT-Elecsys for adjudication). The AUC at presentation for Siemens-hs-cTnI-Centaur was 0.94 (95% CI, 0.92–0.96) and comparable with 0.95 (95% CI, 0.93–0.97) for Roche-hs-cTnT-Elecsys and 0.93 (95% CI, 0.90–0.96) for Abbott-hs-cTnI-Architect. Applying the derived Siemens-hs-cTnI-Centaur 0/1-h algorithm to the validation cohort, 46% of patients were ruled out (sensitivity, 99.1%; 95% CI, 95.3–100), and 18% of patients were ruled in (specificity, 94.1%; 95% CI, 91.8–95.9). The Siemens-hs-cTnI-Centaur 0/2-h algorithm ruled out 55% of patients (sensitivity, 100%; 95% CI, 94.1–100), and ruled in 18% of patients (specificity, 96.0%; 95% CI, 93.1–97.9). Findings were confirmed in the secondary analyses using serial measurements of Abbott-hs-cTnI-Architect for adjudication.

CONCLUSIONS

Diagnostic accuracy and clinical utility of the novel Siemens-hs-cTnI-Centaur assay are high and comparable with the established hs-cTn assays. ClinicalTrials.gov Identifier: NCT00470587

Sensitive Troponin I and Stress Testing in the Emergency Department for the Early Management of Chest Pain Using 2-Hour Protocol

BACKGROUND

Despite improvements in identifying high-risk patients with non-ST segment ACS (acute coronary syndrome), low risk patients presenting with atypical chest pain and non-diagnostic Electrocardiogram (ECG) continued to undergo unnecessary admissions and testing. Since 1992, our chest pain protocol included using 4-hour serial biomarkers from ED admission in combination with stress testing to evaluate these patients. Our study aimed at determining whether a new accelerated diagnostic protocol using sensitive cardiac troponin I (cTnI) 2 hours after admission to the ED followed by stress testing is safe and effective in emergency settings, allowing for appropriate triage, earlier discharge and reducing costs.

METHODS

We conducted a single center randomized trial at Presence St. Francis Hospital Chest pain center in Evanston, Illinois enrolling sixty-four consecutive patients with atypical chest pain and non-diagnostic ECG, participants were randomized to accelerated 2 hrs protocol or our pre-existing 4-hrs protocol. Sixty patients completed the protocol and were randomized to either a 2-hour (29 patients) or 4-hour protocol using both I-STAT and PATHFAST cTnI (31 Patients). Troponin I was evaluated at 0 and at 2 hours from ED presentation with and additional draw for patients in the 4-hour rule out-group. Patients with normal serial biomarkers were then evaluated with stress testing and qualified for earlier discharge if the stress test was negative, while those with a positive biomarker at any time were admitted. Thirty-six patients had exercise treadmill stress test and 24 patients had either nuclear or Echo stress test.

RESULTS

Fifty-three patients had a normal stress test and were discharged home. One patient in the 4-hour group with normal serial troponins developed ventricular tachycardia/fibrillation during the recovery period of a regular stress test. Six patients had a positive PATHFAST cTnI and a normal I-STAT cTnI at 2-hours. Two out of these six patients evaluated by coronary angiography. One patient had severe tortuous coronaries but no significant obstructive lesion and one had a severe CAD who needed Coronary artery bypass grafting (CABG). Three of the six patients had a normal stress test and one patient decided to leave without further testing. None of the patients with a normal stress test had a major cardiac event or adverse cardiac outcome at six-month follow up.

CONCLUSION

This study demonstrates that the 2 hours accelerated protocol using high sensitivity Troponin assay at 0 and 2 hours with comprehensive clinical evaluation and ECG followed by stress testing might be successful in identifying low-risk patient population who may benefit from early discharge from ED reducing associated costs and length of stay.