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Background: This prospective, two-centre study derived and validated predictive algorithms for the Siemens Atellica IM high-sensitivity cardiac troponin I (hs-cTnI) assay in the emergency department (ED)., Methods: Algorithms for predicting 30-day myocardial infarction type 1 and 2 (MI) and death or non-ST-elevation myocardial infarction (NSTEMI, type 1 and 2) at index admission were developed from a derivation cohort of 1896 patients and validated using a synthetic dataset with nearly 1 million patient cases. Performance was compared to the European Society of Cardiology algorithms for hs-cTnT (Roche Diagnostics) and hs-cTnI (Abbott Diagnostics)., Results: An admission hs-cTnI concentration < 5 ng/L had a negative predictive value (NPV) and sensitivity for 30-day MI or death of 99.5 - 99.7 and 98.1- 98.8%, respectively, in the derivation cohort and validation dataset. The NPV and sensitivity was ≥99.7% and ≥98.8% for ruling out index NSTEMI. A 0-1-hour algorithm with baseline hs-cTnI concentration < 10 ng/L and Δ change < 3 ng/L had NPV of ≥99.5% and sensitivity ≥97.3% for predicting 30-day MI or death, and a ≥99.5% sensitivity and NPV for index NSTEMI. Rule-in algorithms of either 0-hour hs-cTnI ≥ 120 ng/L or 0-1 h Δ change ≥ 12 ng/L had positive predictive value (PPV) ≥ 73% and specificity >96% for 30-day MI or death and index NSTEMI. The results were comparable to established hs-cTn algorithms., Conclusions: This study presents Siemens Atellica hs-cTnI algorithms for diagnosis and risk-prediction in the ED with performance comparable to established hs-cTnT (Roche) and hs-cTnI (Abbott) algorithms., (© The Author(s) 2025. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Biomarkers are used for long-term risk prediction of cardiovascular (CV) events in patients presenting with suspected acute coronary syndromes., Objectives: This study investigated whether there are sex differences in the long-term prognostic value of biomarkers in patients presenting with suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS)., Methods: High-sensitivity cardiac troponin (hs-cTn), hs-cTnI, N-terminal pro-B-type natriuretic peptide (NT-proBNP), growth differentiation factor (GDF)-15, and C-reactive protein (CRP) concentrations were measured in 1,476 patients admitted with suspected NSTE-ACS. Patients were followed up for a median of 1,547 (IQR: 873-1,842) days until a primary composite endpoint of all-cause mortality, incident myocardial infarction, or heart failure hospitalization. A secondary endpoint of CV death was also registered., Results: For the primary endpoint, a log2 increase of hs-cTn and hs-cTnI concentration was associated with a higher adjusted hazard ratio in women (hs-cTn: 1.3, 95% CI: 1.2-1.5; hs-cTnI: 1.2, 95% CI: 1.1-1.2) than in men (hs-cTn: 1.1, 95% CI: 1.0-1.2; hs-cTnI: 1.0, 95% CI: 1.0-1.1); P value for interaction with sex: 0.009 (hs-cTn) and 0.005 (hs-cTnI). A similar interaction was shown for NT-proBNP (P for interaction: 0.043). GDF-15 and CRP were independent predictors of the primary endpoint, but the interaction by sex was nonsignificant., Conclusions: In contrast to CRP and GDF-15, increasing concentrations of hs-cTn, hs-cTnI, and NT-proBNP are associated with higher risk of death and CV events in female than in male patients presenting with suspected NSTE-ACS. Sex-adjustment of hs-cTn and NT-proBNP may increase the accuracy of long-term CV prognostication in women and men., Competing Interests: Funding Support and Author Disclosures This study was financed by a grant from the Western Norway Regional Health Authority (grant number: 912265). Dr G.M.S. Myrmel has had a part time research grant from Trond Mohn Foundation and currently is receiving a Ph.D. grant from the Western Norway Regional Health Authority (grant number: F-12589). The reagent costs for GDF-15 were covered by Roche Diagnostics. The sponsor had no influence on the analyzing or interpretation of the data, nor on the writing of the manuscript. Dr Aakre has served on the advisory board of Roche Diagnostics, Siemens Healthineers, and SpinChip; consultant honoraria from CardiNor; lecturing honorarium from Siemens Healthineers, Roche Diagnostics, Mindray, and Snibe Diagnostics; and research grants from Siemens Healthineers and Roche Diagnostics. She is an Associate Editor of Clinical Biochemistry and Chair of the IFCC Committee of Clinical Application of Cardiac Bio-markers. Dr Omland has received speaker and/or consultancy honoraria from Abbott Diagnostics, Bayer, CardiNor, Roche Diagnostics, and Siemens Healthineers and has received research support from Abbott Diagnostics, Novartis, Roche Diagnostics, via Akershus University Hospital. Dr Skadberg has received lecture fees from Abbott Diagnostics. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: There are limited data regarding the utility of follow-up cardiac troponin (cTn) measurements after admission for acute chest pain and how long-term stability of myocardial injury and prognostic value differ when using cardiac troponin T (cTnT) or I (cTnI)., Methods: We measured high-sensitivity (hs)-cTnT (Roche Diagnostics) and hs-cTnI (Siemens Healthineers) during hospitalization for acute chest pain and after 3 months. Acute myocardial injury was defined as concentrations > sex-specific upper reference limit (URL) during hospitalization and ≤URL at 3-months. Chronic myocardial injury (CMI) was defined as concentrations > URL at both time points. Patients were followed from the 3-month sampling point for a median of 1586 (IQR 1161-1786) days for a primary composite endpoint of all-cause mortality, myocardial infarction (MI), revascularization, and heart failure, and a secondary endpoint of all-cause mortality., Results: Among 754 patients, 33.8% (hs-cTnT) and 19.2% (hs-cTnI) had myocardial injury during hospitalization. The rate of CMI was 5 times higher by hs-cTnT (20%) assay than hs-cTnI (4%), while acute myocardial injury was equally common; 14% (hs-cTnT) and 15% (hs-cTnI), respectively (6% and 5% when excluding index non-ST-elevation MI (NSTEMI). For hs-cTnT, peak index concentration, 3-month concentration and classification of CMI predicted the primary endpoint; hazard ratios (HRs) 1.38 (95% CI 1.20-1.58), 2.34 (1.70-3.20), and 2.31 (1.30-4.12), respectively. For hs-cTnI, peak index concentration predicted the primary endpoint; HR 1.14 (1.03-1.25). This association was nonsignificant after excluding index NSTEMI., Conclusions: Acute myocardial injury is equally frequent, whereas CMI is more prevalent using hs-cTnT assay than hs-cTnI. Measuring hs-cTnT 3 months after an acute chest pain episode could assist in further long-term risk assessment. ClinicalTrials.gov Registration Number: NCT02620202., (© Association for Diagnostics & Laboratory Medicine 2024.)

Objective: Growth differentiation factor-15 (GDF-15) is a predictor of death and cardiovascular events when measured during index hospitalisation in patients with acute chest pain. This study investigated the prognostic utility of measuring GDF-15 3 months after an admission with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS)., Methods: GDF-15 was measured at baseline and 3 months after admission in 758 patients admitted with suspected NSTE-ACS. Patients were followed for a median of 1540 (IQR: 1087-1776) days after the 3-month visit. The primary endpoint was all-cause mortality, while the secondary composite endpoint included all-cause mortality, incident myocardial infarction and heart failure hospitalisation during follow-up., Results: In patients with GDF-15 ≥1200 pg/mL (n=248), 18% died and 25% met the composite endpoint. In patients with GDF-15 <1200 pg/mL (n=510), 1.7% died and 4% met the composite endpoint. The GDF-15 concentration (log2 transformed) at 3 months was significantly associated with all-cause mortality (adjusted HR: 2.2, 95% CI: 1.4 to 3.3, p<0.001) and the composite endpoint (adjusted HR: 1.9, 95% CI: 1.4 to 2.7, p<0.001), independently of traditional risk factors and baseline troponin T. A 10% change in GDF-15 concentration from baseline to the 3-month visit was associated with increased risk of all-cause mortality (HR: 1.06, 95% CI: 1.01 to 1.13, p=0.031), adjusting for baseline GDF-15 concentrations., Conclusions: High GDF-15 concentrations 3 months after admission for suspected NSTE-ACS are associated with long-term mortality and cardiovascular events, independent of traditional risk factors and troponin T. A change in GDF-15 concentration can provide prognostic information., Competing Interests: Competing interests: KMA has served on advisory board for Roche Diagnostics and SpinChip, consultant honoraria from CardiNor, lecturing honorarium from Siemens Healthineers and Snibe Diagnostics, and research grants from Siemens Healthineers and Roche Diagnostics. She is the Associate Editor of Clinical Biochemistry and Chair of the IFCC Committee of Clinical Application of Cardiac Bio-markers. TO has received speaker and/or consultancy honoraria from Abbott Diagnostics, Bayer, CardiNor, Roche Diagnostics and Siemens Healthineers, and has received research support from Abbott Diagnostics, Novartis, Roche Diagnostics, via Akershus University Hospital. ØS has received lecture fees from Abbott Diagnostics. GMSM, O-TS, HLT, JL, ROB, VVSB, ØRM and KV have no disclosures., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Patients presenting with symptoms suggestive of acute coronary syndrome (ACS) contribute to a high workload and overcrowding in the Emergency Department (ED). Accelerated diagnostic protocols for non-ST-elevation myocardial infarction have proved challenging to implement. One obstacle is the turnaround time for analyzing high-sensitivity cardiac troponin (hs-cTn). In the WESTCOR-POC study (Clinical Trials number NCT05354804) we aim to evaluate safety and efficiency of a 0/1 h hs-cTn algorithm utilizing a hs-cTnI point of care (POC) instrument in comparison to central laboratory hs-cTnT measurements., Design: This is a prospective single-center randomized clinical trial aiming to include 1500 patients admitted to the ED with symptoms suggestive of ACS. Patients will receive standard investigations following the European Society of Cardiology 0/1h protocols for centralized hs-cTnT measurements or the intervention using a 0/1h POC hs-cTnI algorithm. Primary end-points are 1) Safety; death, myocardial infarction or acute revascularization within 30 days 2) Efficiency; length of stay in the ED, 3) Cost- effectiveness; total episode cost, 4) Patient satisfaction, 5) Patient symptom burden and 6) Patients quality of life. Secondary outcomes are 12-months death, myocardial infarction or acute revascularization, percentage discharged after 3 and 6 h, total length of hospital stay and all costs related to hospital contact within 12 months., Conclusion: Results from this study may facilitate implementation of POC hs-cTn testing assays and accelerated diagnostic protocols in EDs, and may serve as a valuable resource for guiding future investigations for the use of POC high sensitivity troponin assays in outpatient clinics and prehospital settings.

Objectives: Chronic myocardial injury (CMI) is defined as stable concentrations of cardiac troponin T or I (cTnT or cTnI) above the assay-specific 99th percentile upper reference limit (URL) and signals poor outcome. The clinical implications of diagnosing CMI are unclear. We aimed to assess prevalence and association of CMI with long-term prognosis using three different high-sensitivity cTn (hs-cTn) assays., Methods: A total of 1,292 hospitalized patients without acute myocardial injury had cTn concentrations quantified by hs-cTn assays by Roche Diagnostics, Abbott Diagnostics and Siemens Healthineers. The median follow-up time was 4.1 years. The prevalence of CMI and hazard ratios for mortality and cardiovascular (CV) events were calculated based on the URL provided by the manufacturers and compared to the prognostic accuracy when lower percentiles of cTn (97.5, 95 or 90), limit of detection or the estimated bioequivalent concentrations between assays were used as cutoff values., Results: There was no major difference in prognostic accuracy between cTnT and cTnI analyzed as continuous variables. The correlation between cTnT and cTnI was high (r=0.724-0.785), but the cTnT assay diagnosed 3.9-4.5 times more patients with having CMI based on the sex-specific URLs (TnT, n=207; TnI Abbott, n=46, TnI Siemens, n=53) and had higher clinical sensitivity and AUC at the URL., Conclusions: The prevalence of CMI is highly assay-dependent. cTnT and cTnI have similar prognostic accuracy for mortality or CV events when measured as continuous variables. However, a CMI diagnosis according to cTnT has higher prognostic accuracy compared to a CMI diagnosis according to cTnI., (© 2023 the author(s), published by De Gruyter, Berlin/Boston.)

Background: Acute chest pain is associated with an increased risk of death and cardiovascular events even when acute myocardial infarction (AMI) has been excluded. Growth differentiation factor-15 (GDF-15) is a strong prognostic marker in patients with acute chest pain and AMI, but the prognostic value in patients without AMI is uncertain. This study sought to investigate the ability of GDF-15 to predict long-term prognosis in patients presenting with acute chest pain without AMI., Methods: In total, 1320 patients admitted with acute chest pain without AMI were followed for a median of 1523 days (range: 4 to 2208 days). The primary end point was all-cause mortality. Secondary end points included cardiovascular (CV) death, future AMI, heart failure hospitalization, and new-onset atrial fibrillation (AF)., Results: Higher concentrations of GDF-15 were associated with increased risk of death from all causes (median concentration in non-survivors vs survivors: 2124 pg/mL vs 852 pg/mL, P < 0.001), and all secondary end points. By multivariable Cox regression, GDF-15 concentration ≥4th quartile (compared to <4th quartile) remained an independent predictor of all-cause death (adjusted hazard ratio (HR): 2.75; 95% CI, 1.69-4.45, P < 0.001), CV death (adjusted HR: 3.74; 95% CI, 1.31-10.63, P = 0.013), and heart failure hospitalization (adjusted HR: 2.60; 95% CI, 1.11-6.06, P = 0.027). Adding GDF-15 to a model consisting of established risk factors and high-sensitivity cardiac troponin T (hs-cTnT) led to a significant increase in C-statistics for prediction of all-cause mortality., Conclusions: Higher concentrations of GDF-15 were associated with increased risk of mortality from all causes and risk of future CV events., (© American Association for Clinical Chemistry 2023.)

Objective: To describe the magnitude and predictors of symptom burden (SB) and quality of life (QoL) 3 months after hospital admission for acute chest pain., Design: Prospective observational study., Setting: Single centre, outpatient follow-up., Participants: 1506 patients., Outcomes: Scores reported for general health (RAND-12), angina-related health (Seattle Angina Questionnaire 7 (SAQ-7)) and dyspnoea (Rose Dyspnea Scale) 3 months after hospital admission for chest pain., Methods: A total of 1506 patients received questionnaires assessing general health (RAND-12), angina-related health (SAQ-7) and dyspnoea (Rose Dyspnea Scale) 3 months after discharge. Univariable and multivariable regression models identified predictors of SB and QoL scores. A mediator analysis identified factors mediating the effect of an unstable angina pectoris (UAP) diagnosis., Results: 774 (52%) responded. Discharge diagnoses were non-ST elevation myocardial infarction (NSTEMI) (14.2%), UAP (17.1%), non-coronary cardiac disease (6.6%), non-cardiac disease (6.3%) and non-cardiac chest pain (NCCP) (55.6%). NSTEMI had the most favourable, and UAP patients the least favourable SAQ-7 scores (median SAQ7-summary; 88 vs 75, p<0.001). NCCP patients reported persisting chest pain in 50% and dyspnoea in 33% of cases. After adjusting for confounders, revascularisation predicted better QoL scores, while UAP, current smoking and hypertension predicted worse outcome. NSTEMI and UAP patients who were revascularised reported higher scores (p<0.05) in SAQ-7-QL, SAQ7-PL, SAQ7-summary (NSTEMI) and all SAQ-7 domains (UAP). Revascularisation altered the unstandardised beta value (>±10%) of an UAP diagnosis for all SAQ-7 and RAND-12 outcomes., Conclusions: Patients with NSTEMI reported the most favourable outcome 3 months after hospitalisation for chest pain. Patients with other diseases, in particular UAP patients, reported lower scores. Revascularised NSTEMI and UAP patients reported higher QoL scores compared with patients receiving conservative treatment. Revascularisation mediated all outcomes in UAP patients., Trial Registration Number: NCT02620202., Competing Interests: Competing interests: KMA has served on one advisory board for Roche Diagnostics and received lecturing fees from Siemens Healthineers. TO has served on advisory boards for Abbott Diagnostics, Roche Diagnostics and Bayer and has received research support from Abbott Diagnostics, Novartis, Roche Diagnostics, Singulex and SomaLogic via Akershus University Hospital, and speaker’s or consulting honoraria from Roche Diagnostics, Siemens Healthineers and CardiNor. NS, TMN, O-TS, HLT, JL, ROB, ØS, VVSB, ØRM and KV have nothing to declare., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Evaluate the association between symptoms and risk of non-ST segment elevation myocardial infarction (NSTEMI) in patients admitted to an emergency department with suspected acute coronary syndrome based on sex and age., Design: Post hoc analysis of a prospective observational study conducted between September 2015 and May 2019., Setting: University hospital in Norway., Participants: 1506 participants >18 years of age (39.6% women and 31.0% 70 years of age or older)., Findings: The OR for NSTEMI was 9.4 if pain radiated to both arms, 3.0 if exertional chest pain was present during the last week and 2.9 if pain occurred during activity. Men had significantly lower OR compared with women if pain was dependent of position, respiration or palpation (OR 0.17 vs 0.53, p value for interaction 0.047). Patients <70 years had higher predictive value than older patients if they reported exertional chest pain the last week (OR 4.08 vs 1.81, 95%, p value for interaction 0.025) and lower if pain radiated to the left arm (OR 0.73 vs 1.67, p value for interaction 0.045)., Conclusions: Chest pain with radiation to both arms, exertional chest pain during the last week and pain during activity had the strongest predictive value for NSTEMI. The differences in symptom presentation and risk of NSTEMI between sex and age groups were small., Trial Registration Number: WESTCOR study ClinicalTrials.gov (NCT02620202)., Competing Interests: Competing interests: KMA has served on one advisory board for Roche Diagnostics and received lecturing fees from Siemens Healthineers. TO has received nonfinancial support to institution from Novartis, Abbott Diagnostics, Roche Diagnostics and Somalogic, received consulting fees from Roche Diagnostics, Abbott Diagnostics and CardiNor, received speaker’s honoraria from Siemens Healthineers, Roche Diagnostics and Abbott Diagnostics, is a member of IFCC Committee on Cardiovascular Biomarkers and has stocks in CardiNor. ØS has received lecture fees from Abbott Diagnostics., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: This study tested the hypothesis that combining stress-induced biomarkers (copeptin or glucose) with high-sensitivity cardiac troponin (hs-cTn) increases diagnostic accuracy for non-ST-elevation myocardial infarction (NSTEMI) in patients presenting to the emergency department., Methods and Results: The ability to rule-out NSTEMI for combinations of baseline hs-cTnT or hs-cTnI with copeptin or glucose was compared with the European Society of Cardiology (ESC) hs-cTnT/I-only rule-out algorithms in two independent (one Norwegian and one international multicentre) diagnostic studies. Among 959 patients (median age 64 years, 60.5% male) with suspected NSTEMI in the Norwegian cohort, 13% had NSTEMI. Adding copeptin or glucose to hs-cTnT/I as a continuous variable did not improve discrimination as quantified by the area under the curve {e.g. hs-cTnT/copeptin 0.91 [95% confidence interval (CI) 0.89-0.93] vs. hs-cTnT alone 0.91 (95% CI 0.89-0.93); hs-cTnI/copeptin 0.85 (95% CI 0.82-0.87) vs. hs-cTnI alone 0.93 (95% CI 0.91-0.95)}, nor did adding copeptin <9 mmol/L or glucose <5.6 mmol/L increase the sensitivity of the rule-out provided by hs-cTnT <5 ng/L or hs-cTnI <4 ng/L in patients presenting more than 3 h after chest pain onset (target population in the ESC-0 h-algorithm). The combination decreased rule-out efficacy significantly (both P < 0.01). These findings were confirmed among 1272 patients (median age 62 years, 69.3% male) with suspected NSTEMI in the international validation cohort, of which 20.7% had NSTEMI. A trend towards increased sensitivity for the hs-cTnT/I/copeptin combinations (97-100% vs. 91-97% for the ESC-0 h-rule-out cut-offs) was observed in the Norwegian cohort., Conclusion: Adding copeptin or glucose to hs-cTnT/I did not increase diagnostic performance when compared with current ESC guideline hs-cTnT/I-only 0 h-algorithms., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The European Society of Cardiology (ESC) rule-out algorithms use cutoffs optimized for exclusion of non-ST elevation myocardial infarction (NSTEMI). We investigated these and several novel algorithms for the rule-out of non-ST elevation acute coronary syndrome (NSTE-ACS) including less urgent coronary ischemia., Method: A total of 1504 unselected patients with suspected NSTE-ACS were included and divided into a derivation cohort (n = 988) and validation cohort (n = 516). The primary endpoint was the diagnostic performance to rule-out NSTEMI and unstable angina pectoris during index hospitalization. The secondary endpoint was combined MI, all-cause mortality (within 30 days) and urgent (24 h) revascularization. The ESC algorithms for high-sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) were compared to different novel low-baseline (limit of detection), low-delta (based on the assay analytical and biological variation), and 0-1-h and 0-3-h algorithms., Results: The prevalence of NSTE-ACS was 24.8%, 60.0% had noncardiac chest pain, and 15.2% other diseases. The 0-1/0-3-h algorithms had superior clinical sensitivity for the primary endpoint compared to the ESC algorithm (validation cohort); hs-cTnT: 95% vs 63%, and hs-cTnI: 87% vs 64%, respectively. Regarding the secondary endpoint, the algorithms had similar clinical sensitivity (100% vs 94%-96%) but lower clinical specificity (41%-19%) compared to the ESC algorithms (77%-74%). The rule-out rates decreased by a factor of 2-4., Conclusion: Low concentration/low-delta troponin algorithms improve the clinical sensitivity for a combined endpoint of NSTEMI and unstable angina pectoris, with the cost of a substantial reduction in total rule-out rate. There was no clear benefit compared to ESC for diagnosing high-risk events., (© American Association for Clinical Chemistry 2021.)

Aims: Troponin-based algorithms are made to identify myocardial infarctions (MIs) but adding either standard acute coronary syndrome (ACS) risk criteria or a clinical risk score may identify more patients eligible for early discharge and patients in need of urgent revascularization., Methods and Results: Post-hoc analysis of the WESTCOR study including 932 patients (mean 63 years, 61% male) with suspected NSTE-ACS. Serum samples were collected at 0, 3, and 8-12 h and high-sensitivity cTnT (Roche Diagnostics) and cTnI (Abbott Diagnostics) were analysed. The primary endpoint was MI, all-cause mortality, and unplanned revascularizations within 30 days. Secondary endpoint was non-ST-elevation myocardial infarction (NSTEMI) during index hospitalization. Two combinations were compared: troponin-based algorithms (ESC 0/3 h and the High-STEACS algorithm) and either ACS risk criteria recommended in the ESC guidelines, or one of eleven clinical risk scores, HEART, mHEART, CARE, GRACE, T-MACS, sT-MACS, TIMI, EDACS, sEDACS, Goldman, and Geleijnse-Sanchis. The prevalence of primary events was 21%. Patients ruled out for NSTEMI and regarded low risk of ACS according to ESC guidelines had 3.8-4.9% risk of an event, primarily unplanned revascularizations. Using HEART score instead of ACS risk criteria reduced the number of events to 2.2-2.7%, with maintained efficacy. The secondary endpoint was met by 13%. The troponin-based algorithms without evaluation of ACS risk missed three-index NSTEMIs with a negative predictive value (NPV) of 99.5% and 99.6%., Conclusion: Combining ESC 0/3 h or the High-STEACS algorithm with standardized clinical risk scores instead of ACS risk criteria halved the prevalence of rule-out patients in need of revascularization, with maintained efficacy., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background Cardiac troponin (cTn) permits early rule-out/rule-in of patients admitted with possible non-ST-segment-elevation myocardial infarction. In this study, we developed an admission and a 0/1 hour rule-out/rule-in algorithm for a troponin assay with measurable results in >99% of healthy individuals. We then compared its diagnostic and long-term prognostic properties with other protocols. Methods and Results Blood samples were collected at 0, 1, 3, and 8 to 12 hours from patients admitted with possible non-ST-segment-elevation myocardial infarction. cTnT (Roche Diagnostics), cTnI (Abbott) (Abbott Diagnostics), and cTnI (sgx) (Singulex Clarity System) were measured in 971 admission and 465 1-hour samples. An admission and a 0/1 hour rule-out/rule-in algorithm were developed for the cTnI (sgx) assay and its diagnostic properties were compared with cTnT ESC (European Society of Cardiology), cTnI (Abbott)ESC , and 2 earlier cTnI (sgx) algorithms. The prognostic composite end point was all-cause mortality and future nonfatal myocardial infarction during a median follow-up of 723 days. non-ST-segment-elevation myocardial infarction prevalence was 13%. The novel cTnI (sgx) algorithms showed similar performance regardless of time from symptom onset, and area under the curve was significantly better than comparators. The cTnI (sgx)0/1 hour algorithm classified 92% of patients to rule-in or rule-out compared with ≤78% of comparators. Patients allocated to rule-out by the prior published 0/1 hour algorithms had significantly fewer long-term events compared with the rule-in and observation groups. The novel cTnI (sgx)0/1 hour algorithm used a higher troponin baseline concentration for rule-out and did not allow for prognostication. Conclusions Increasingly sensitive troponin assays may improve identification of non-ST-segment-elevation myocardial infarction but could rule-out patients with subclinical chronic myocardial injury. Separate protocols for diagnosis and risk prediction seem appropriate.

Objectives. The main aim of the Aiming toWards Evidence baSed inTerpretation of Cardiac biOmarkers in patients pResenting with chest pain (WESTCOR-study) (Clinical Trials number NCT02620202) is to improve diagnostic pathways for patients presenting to the Emergency department (ED) with acute chest pain. Design. The WESTCOR-study is a two center, cross-sectional and prospective observational study recruiting unselected patients presenting to the ED with suspected non-ST elevation acute coronary syndrome (NSTE-ACS). Patient inclusion started September 2015 and we plan to include 2250 patients, finishing in 2019. The final diagnosis will be adjudicated by two independent cardiologists based on all available information including serial high sensitivity cardiac troponin measurements, coronary angiography, coronary CT angiography and echocardiography. The study includes one derivation cohort ( N  = 985) that will be used to develop rule out/rule in algorithms for NSTEMI and NSTE-ACS (if possible) using novel troponin assays, and to validate established NSTEMI algorithms, with and without clinical scoring systems. The study further includes one subcohort ( n  = 500) where all patients are examined with coronary CT angiography independent of biomarker status, aiming to assess the associations between biomarkers and the extent and severity of coronary atherosclerosis. Finally, an external validation cohort ( N  = 750) will be included at Stavanger University Hospital. Prospective studies will be based on the merged cohorts. Conclusion. The WESTCOR study will provide new diagnostic algorithms for early inclusion and exclusion of NSTE-ACS and insights in the associations between cardiovascular biomarkers, CT-angiographic findings and short and long-term clinical outcomes.